- Kinetic regularities of the chemical vapor deposition of nickel layers from bis-(ethylcyclopentadienyl)nickel
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Physicochemical regularities of the nickel layers chemical vapor deposition from bis-(ethylcyclopentadienyl)nickel were studied. Dependences of the growth rate of nickel layers on the deposition temperature, gas-fl ow linear rate, partial pressures of reagents, and substrate roughness, and also dependences of the thickness of a grown layer on time and on the position of a substrate on a susceptor were obtained.
- Protopopova,Alexandrov
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- Transformation of the metal networks under the influence of insertion elements: Transformation of nickel under the influence of nitrogen
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A detailed study has been undertaken on the transformation of nickel lattices under the influence of nitrogen as an insertion impurity. For this study, thin polycrystalline and monocrystalline layers of evaporated nickel have been heated in an atmosphere of ammonia. This nitriding process has been followed kinetically by electron diffraction. Using these techniques, it has been shown that the insertion of nitrogen atoms takes place in successive steps. First, a considerable expansion of the initial f.c.c. lattice of nickel (from α=3,52 to α=3,72 A) is observed with the formation of Ni4N. Then, if the nitriding is continued, this f.c.c. lattice of expanded nickel (Ni4N) is transformed into a hexagonal lattice of Ni3N. The exact structure of these nitrides has been determined and a mechanism of the transformation from the expanded, cubic nickel lattice (Ni4N) to the hexagonal nickel lattice (Ni3N) has been proposed. This mechanism consists, in part, of a series of microslips on the (111) plane and in the [112] direction of nickel atoms, similar to those produced in the martensitic transformation of cobalt, which transforms the stacking order of the {111} planes of the f.c.c. lattice into the stacking order of the {0001} planes of the hexagonal lattice. In addition, the diffusion of nitrogen results in another stacking transformation from the cubic {110} planes into the {1210} planes of the hexagonal variety.
- Terao, Nobuzo,Berghezan, Aurel
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- Magnetic properties of nanometric nickel particles
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We have prepared nickel metal fine particles with mean diameters as low as 4 nanometers and we have studied their magnetic properties. A superparamagnetic behaviour is found for the smallest particles even at helium temperature.
- Broto,Ousset,Rakoto,Askenazy,Dufor,Brieu,Mauret
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- Effect of processing conditions on the structure and collective magnetic properties of flowerlike nickel nanostructures
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To acquiring more insights into the relationship between the morphology and magnetic properties of magnetic nanocrystallites, uniform flowerlike Ni nanostructures with different branch lengths were fabricated via a simple solvothermal reduction route based on a series of comparative experiments. The formation mechanism of the Ni flowers was proposed. Moreover, the magnetic properties of the products were evaluated. Results indicate that the morphology of the Ni particles strongly depends on reaction temperature, and the branch length of the flowerlike Ni particles strongly depends on the initial concentration of Ni2+ ions. The flowerlike Ni particles with a longer branch length show higher coercivity value, which may be attributed to the peculiar microstructure. We believe the present research may provide an ideal example for the synthesis of assembled magnetic nanostructures with controllable morphology and magnetic properties.
- Gong, Chunhong,Tian, Juntao,Zhang, Jingwei,Zhang, Xuefeng,Yu, Laigui,Zhang, Zhijun
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- Via filling by electrodeposition superconformal silver and copper and conformal nickel
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Superconformal deposition of silver in vias was studied. The observed experimental fill behavior is compared with predictions from a model based on the curvature-enhanced accelerator coverage mechanism of superconformal deposition. Superconformal copper deposition and conformal nickel deposition results are also modeled. The previously published model predicts via filling behavior using the dependence of deposition rate kinetics on the coverage of adsorbed catalyst. The requisite kinetic parameters are obtained from independent current-voltage and current-time transient studies conducted on planar substrates.
- Josell,Baker,Witt,Wheeler,Moffat
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- Supercapacitor electrodes with high-energy and power densities prepared from monolithic NiO/Ni nanocomposites
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Impressive energy storage and delivery: A simple, cost-effective, and potentially scalable technique is described for fabricating support- and additive-free NiO/Ni nanocomposite electrodes (see picture) for electrochemical supercapacitors. Maximum performances of energy storage and delivery were simultaneously achieved by developing a slow-charging and fast-discharging procedure. Copyright
- Lu, Qi,Lattanzi, Michael W.,Chen, Yunpeng,Kou, Xiaoming,Li, Wanfeng,Fan, Xin,Unruh, Karl M.,Chen, Jingguang G.,Xiao, John Q.
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- Relation between plating overpotential and porosity of thin nickel electrolytic coatings
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The relation between plating overpotential and porosity of thin nickel electrolytic coatings (0.2 μm) was investigated. The porosity of nickel coatings was shown to be dependent on coating structure, which is determined by the plating over-potential. A lower porosity can be achieved by using a relatively high plating overpotential resulting in the deposition of nickel coatings with fine grains. A relation between the through-coating porosity of thin nickel coatings and the activation overpotential was identified. At plating current densities approaching the limiting current density, the porosity tends to increase due to a mass transport effect on the coating thickness distribution along the substrate surface.
- Fan,Celis,Roos
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- Effect of nickel precursors on the performance of Ni/AlMCM-41 catalysts for n-dodecane hydroconversion
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The bifunctional Ni/AlMCM-41 catalysts with 2.0 wt.% nickel loading were prepared by means of the wetness impregnation technique using three nickel precursors: nickel nitrate, alkaline tetraamine nickel nitrate and nickel citrate. The texture, crystal pha
- Fang, Kegong,Ren, Jie,Sun, Yuhan
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- Pulse reverse plating of Ni-Co alloys: Deposition kinetics of Watts, sulfamate and chloride electrolytes
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Fundamental electrochemical properties of electrolyte systems are the prerequisite for the development of a successful pulse deposition process. Three different electrolyte systems for the galvanic deposition of nickel cobalt alloys (chloride, Watts and sulfamate type) were investigated in order to reveal underlying deposition mechanisms and rate determining factors. The electrochemical experiments were supported by X-ray fluorescence analyses of the alloy composition in dependence on the current density and the type of bath. A special focus was set on the investigation of the passive (oxide) layer formation by the anodic pulses. The choice of electrolyte system strongly influences the reaction mechanism and thus the alloy deposition. Also the cobalt content within the deposited layer varied strongly in dependence on the electrolyte system used. While sulfamate and Watts baths show an ability for passive layer formation, the chloride bath exhibits a lower proneness to passivation, accompanied by pit formation.
- Hansal, Wolfgang E.G.,Tury, Barbara,Halmdienst, Martina,Varsányi, Magda Lakatos,Kautek, Wolfgang
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- Fabrication and magnetic properties of nickel dodecahedra
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Here we report a one-pot route for the synthesis of nickel dodecahedra with 52.3 ± 0.1 emu g-1 of saturation magnetization. The procedure is very simple, and only three chemicals (NiCl2·6H 2O, isopropanol and polyvinylpyrrolidone) are used throughout the entire synthetic process. During the reaction, it is believed that the application of isopropanol and the amount of polyvinylpyrrolidone play an essential role in forming the dodecahedral morphology of the final product. Furthermore, a formation process of twinning and the influence of reaction kinetic factors were proposed to explain the formation of nickel dodecahedra.
- Zhao, Lijun,Zhao, Lei,Zhang, Guangshu
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- Spark plasma sintering and hot isostatic pressing of nickel nanopowders elaborated by a modified polyol process and their microstructure, magnetic and mechanical characterization
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The microstructure, magnetic and mechanical properties of spark plasma sintered (SPS) and hot isostatic pressed (HIP) nickel nanopowders are investigated. The microstructure study shows that the increase in the particle size was more limited when consolidation was performed by the SPS than by the HIP process. The grain size is in the range 0.17-0.2 μm in the case of the SPS consolidated sample while it is in the range 0.4-0.62 μm in the case of the HIPed sample. The ratio of the yield stress in the HIP and SPS consolidated samples to the yield stress in the bulk nickel sample is greater than two and three times, respectively. Vickers microhardness measurements give the same ratios. A ferromagnetic behaviour was deduced from the magnetic characterizations of the as-prepared nickel powder as well as the consolidated samples.
- Bousnina,Dakhlaoui Omrani,Schoenstein,Madec,Haddadi,Smiri,Jouini
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- One-step synthesis of carbon nanotubes with Ni nanoparticles as a catalyst by the microwave-assisted polyol method
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Carbon nanotubes (CNTs) were firstly synthesized by the microwave-assisted polyol method and magnetic Ni nanoparticles were employed as a catalyst in the process. The structures, morphologies and magnetic properties of the as-synthesized samples were investigated by using X-ray diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM), respectively. Our results indicated that CNTs can be synthesized after the observation of a small electric spark with Ni particles used as a catalyst. TEM showed that the length of the hollow carbon nanotubes was of the order of micron. VSM demonstrated that Ni/CNTs composite was ferromagnetic characteristic with hysteretic behavior at room temperature.
- Liu, Xian-Song,Hu, Feng,Zhu, De-Ru,Jia, Dao-Ning,Wang, Peng-Peng,Ruan, Zheng,Cheng, Chun-Hao
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- Preparation and pattern recognition of metallic Ni ultrafine powders by electroless plating
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Using hydrazine hydrate as reductant, metallic Ni ultrafine powders were prepared from NiSO4 aqueous solution by electroless plating method. The factors including concentration of NiSO4, bathing temperature, ratio of hydrazine hydrat
- Zhang,Zhang,Wu,Wang,Jia,Jia
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- Cyclic voltammetry study of the NiP electrodeposition
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Cyclic voltammetry was used to investigate the deposition mechanism of NiP amorphous alloys. Whatever the cathodic potential for the deposition, the anodic going scan presents two well-formed anodic peaks preceded by a small current plateau. The two peaks are related to two alloys of different phosphorus content, and therefore in two different structural states. The formation of the first peak is controlled by a very slow kinetic process.
- Crousier, J.,Hanane, Z.,Crousier, J-P.
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- A novel chemical reduction route towards the synthesis of crystalline nickel nanoflowers from a mixed source
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A novel chemical reduction route was designed for the synthesis of nickel nanocrystals with distinct flowery shapes by using a mixture of two complexes of Ni(N2H4)32+ and Ni(dmg)2 (nickel dimethylglyoximate) as the nickel source. Formation of these flowers, comprising spherical centers and swordlike petals, was related to the varying stability and structural properties of the two precursors as well as the reaction conditions. Investigations of the time-dependent shape-evolution process indicated that spherical particles were formed first as flower centers, and then swordlike petals grew radially from the particle surfaces. A rational mechanism of formation was proposed on the basis of a range of contrasting experiments. Compared with bulk nickel, these nanoflowers exhibited an enhanced coercivity (Ms); and a decreased saturation magnetization (M s); this fact is attributed to their peculiar morphology. Wiley-VCH Verlag GmbH & Co. KGaA, 2005.
- Ni, Xiaomin,Zhao, Qingbiao,Zheng, Huagui,Song, Jimei,Zhang, Dongen,Zhang, Xiaojun
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- Comparison of the magnetic properties of metastable hexagonal close-packed Ni nanoparticles with those of the stable face-centered cubic Ni nanoparticles
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We report the first magnetic study of pure and metastable hexagonal close-packed (hep) Ni nanoparticles (sample 1). We also produced stable face-centered cubic (fcc) Ni nanoparticles, as mixtures with the hcp Ni nanoparticles (samples 2 and 3). We compared the magnetic properties of the hcp Ni nanoparticles with those of the fcc Ni nanoparticles by observing the evolution of magnetic properties from those of the hcp Ni nanoparticles to those of the fcc Ni nanoparticles as the number of fcc Ni nanoparticles increased from sample 1 to sample 3. The blocking temperature (TB) of the hcp Ni nanoparticles is ～12 K for particle diameters ranging between 8.5 and 18 nm, whereas those of the fcc Ni nanoparticles are 250 and 270 K for average particle diameters of 18 and 26 nm, respectively. The hcp Ni nanoparticles seem to be antiferromagnetic for T B and paramagnetic for T > TB. This is very different from the fcc Ni nanoparticles, which are ferromagnetic for T B and superparamagnetic for T > T B. This unusual magnetic state of the metastable hcp Ni nanoparticles is likely related to their increased bond distance (2.665 A), compared to that (2.499 A) of the stable fcc Ni nanoparticles.
- Jeon, Yoon Tae,Moon, Je Yong,Lee, Gang Ho,Park, Jeunghee,Chang, Yongmin
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- Flower-like hierarchical nickel microstructures: Facile synthesis, growth mechanism, and their magnetic properties
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Flower-like hierarchical nickel microstructures were prepared by a facile chemical reduction method requiring 4 h at temperature of 85°C without any template or external magnetic field. Nickel (II) sulfate hexahydrate was used as nickel source and hydrazine hydrate acted as the reducing agent. XRD study confirmed the highly crystalline with face-centered cubic (fcc) phase. SEM images revealed that the individual flower-like microstructures have an average diameter of 1-2 μm and are composed of sword-like nanopetals growing radially from the core of the spherical particles. HRTEM image and SAED pattern of the single petal show that the lattice spacing is 0.203 nm corresponding to the (1 1 1) plane of fcc nickel and the growth orientation is along [0 1 1] direction. A rational formation process of nickel micro-flowers was proposed. Magnetic hysteresis measurements revealed that the hierarchical nickel microstructures possess ferromagnetic behavior with an enhanced coercivity value of about 203.3 Oe.
- Chen, Huiyu,Xu, Chunju,Chen, Chuang,Zhao, Guizhe,Liu, Yaqing
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- Enhanced electrochemical performance of nanoplate nickel cobaltite (NiCo2O4) supercapacitor applications
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Well-ordered, unique interconnected nanostructured binary metal oxides with lightweight, free-standing, and highly flexible nickel foam substrate electrodes have attracted tremendous research attention for high performance supercapacitor applications owing to the combination of the improved electrical conductivity and highly efficient electron and ion transport channels. In this study, a unique interconnected nanoplate-like nickel cobaltite (NiCo2O4) nanostructure was synthesized on highly conductive nickel foam and its use as a binder-free material in energy storage applications was assessed. The nanoplate-like NiCo2O4 nanostructure electrode was prepared by a simple chemical bath deposition method under optimized conditions. The NiCo2O4 electrode delivered an outstanding specific capacitance of 2791 F g?1 at a current density of 5 A g?1 in a KOH electrolyte in a three-electrode system as well as outstanding cycling stability with 99.1% retention after 3000 cycles at a current density of 7 A g?1. The as-synthesized NiCo2O4 electrode had a maximum energy density of 63.8 W h kg?1 and exhibited an outstanding high power density of approximately 654 W h kg?1. This paper reports a simple and cost-effective process for the synthesis of flexible high performance devices that may inspire new ideas for energy storage applications.
- Yedluri, Anil Kumar,Kim, Hee-Je
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- Effect of boron on the microstructure and physical properties of chemically vapour deposited nickel films
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The solid solution addition of boron greatly enhances the strength and hardness of chemically vapor deposited (CVD) nickel while dramatically changing the microstructures. The solid solubility of boron in nickel is limited, and single-phase alloys containing in excess of 0.3 at% B are supersaturated with respect to the formation of one or more intermetallic boride phases. Single-phase Ni-B alloys containing 0 to 13.0 at% B were produced by CVD on polycrystalline copper substrates at 155°C in an atmospheric pressure process. The microstructure, mechanical and physical properties were characterized for the alloys both as-deposited and after various thermal treatments by using optical microscopy, transmission electron microscopy, X-ray diffraction and micro-indentation hardness testing with a diamond pyramid indentor. The grain size of the alloys was found to decrease sharply with rising boron content. Coneomitantly, the defect density of the material rose significantly, the microhardness increased and the ductility decreased. With annealing at a temperature of 300°C or greater, precipitation of the Ni3B intermetallic phase, recovery and grain growth occurred.
- Campbell, A. N.,Mullendore, A. W.,Hills, C. R.,Vandersande, J. B.
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- Magnetic field effects in electrochemical reactions
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The influence of an external magnetic field B on the electrochemical behaviour of the systems Cu2+/Cu, Ni2+/Ni, and [IrCl 6]2-/[IrCl6]3- has been studied. In the case of Cu depositions in an electrochemical cell with a large ratio of the electrode area and the cell volume the increase of the limiting current density with B can be explained with the interplay of natural convection and the Lorentz force acting on the resulting flow profile (magneto hydrodynamic or MHD effect). Ni depositions also show an MHD effect as well as a tendency to form more fine grained material in the presence of a magnetic field. The results on the homogeneous redox system [IrCl6]2-/[IrCl 6]3- at 50μm diameter micro electrodes are in qualitative agreement with recently proposed relationships to describe the influence of a B field on the limiting current density.
- Bund,Koehler,Kuehnlein,Plieth
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- Influence of the nature of organic ligands on the character of thermal decomposition products of CoII and NiII pivalate complexes with amino derivatives of pyridine
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The thermal stability and the solid-state thermal decomposition of the known mononuclear cobalt(II) and nickel(II) complexes [H2N(C 5H3N)N(H)C(Me)=NH]M(OOCBut)2, [(NH2)2C6H2Me2] 3M(OOCBut)2 and the new compounds L 2M(OOCBut)2 (L = = (2-NH2)C 5H3N, (2-NH2)(6-Me)C5H 3N), and [(2,6-NH2)2C5H 3N]2Ni(OOCBut)2 were studied by differential scanning calorimetry and thermogravimetric analysis. Efficient methods were developed for the synthesis of these complexes. The mononuclear complexes are thermally quite stable. The thermal stability of the complexes depends on the nature of the ligand and decreases in the series (2,6-NH 2)2C5H3N > H2N(C 5H3N)NHC(Me)=NH > (NH2)2C 6H2Me2 > (2-NH2)C 5H3N > (2-NH2)(6-Me)C5H 3N. The nickel(II) complexes are thermally more stable than the related cobalt(II) complexes. The thermolysis (500 °C) of Co and Ni pivalates is a destructive process. The phase composition of the decomposition products is determined by the nature of metal and coordinated ligands.
- Fomina,Dobrokhotova, Zh. V.,Aleksandrov,Bogomyakov,Novotortsev,Eremenko
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- Electrocodeposition of nickel nanocomposites using an impinging jet electrode
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The electrocodeposition of nickel alumina nanocomposites was investigated using an impinging jet electrode. The effects of jet flow rate, particle loading, and current density on the particle incorporation were studied. The amount of codeposited particles was determined using both electrogravimetric measurements and energy dispersive X-ray analysis. A maximum particle incorporation of about 5 wt % was found for a flow rate of 2.5 L min-1 and a current density of 10 A dm-2. The microstructure of the coatings was investigated via X-ray diffraction. As a result of increasing current density and particle incorporation, a loss of (100) texture and a relative enhancement of the (111), (220), and (311) reflections appeared. The microhardness of the nickel films increased significantly with the inclusion of alumina nanoparticles.
- Thiemig, Denny,Bund, Andreas,Talbot, Jan B.
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- Properties of electrodeposited nanocrystalline Ni-B alloy films
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The influence of the boron content on the various properties of nanocrystalline Ni-B alloy produced by electrodeposition was investigated. The considerable reduction in grain size was observed with increasing boron content. The internal stress was tensile
- Lee,Chang,Kwon
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- Magnetophoresis behaviour at low gradient magnetic field and size control of nickel single core nanobeads
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Magnetic separation of organic compounds, proteins, nucleic acids and other biomolecules, and cells from complex reaction mixtures is becoming the most suitable solution for large production in bioindustrial purification and extraction processes. Optimal magnetic properties can be achieved by the use of metals. However, they are extremely sensitive to oxidation and degradation under atmospheric conditions. In this work Ni nanoparticles are synthesised by conventional solution reduction process with the addition of a non-ionic surfactant as a surface agent. The nanoparticles were surfacted in citric acid and then coated with silica to form single core Ni nanobeads. A magnetophoresis study at different magnetic field gradients and at the different steps of synthesis route was performed using Horizontal Low Gradient Magnetic Field (HLGMF) systems. The reversible aggregation times are reduced to a few seconds, allowing a very fast separation process.
- Benelmekki,Montras,Martins,Coutinho,Martinez, Ll.M.
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- Synthesis and magneto-transport properties of single PEDOT/Ni and PEDOT/Ni30Fe70 core/shell nanowires
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Single polyethylenedioxythiophene (PEDOT) nanowires bridging pairs of electrodes were utilized as positive templates to create PEDOT/Ni and PEDOT/Ni30Fe70 core/shell nanowires by electrodepositing ferromagnetic material (i.e., Ni and
- Hangarter, Carlos M.,Rheem, Youngwoo,Stahovich, Thomas,Myung, Nosang V.
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- Low-temperature solvothermal approach to the synthesis of La 4Ni3O8 by topotactic oxygen deintercalation
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A chimie douce solvothermal reduction method is proposed for topotactic oxygen deintercalation of complex metal oxides. Four different reduction techniques were employed to qualitatively identify the relative reduction activity of each including reduction with H2 and NaH, solution-based reduction using metal hydrides at ambient pressure, and reduction under solvothermal conditions. The reduction of the Ruddlesden-Popper nickelate La4Ni3O10 was used as a test case to prove the validity of the method. The completely reduced phase La4Ni 3O8 was produced via the solvothermal technique at 150 °C-a lower temperature than by other more conventional solid state oxygen deintercalation methods.
- Blakely, Colin K.,Bruno, Shaun R.,Poltavets, Viktor V.
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- Aqueous solutions of colloidal nickel: Radiation-chemical preparation, absorption spectra, and properties
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Radiation-chemical reduction of Ni2+ ions in aqueous solutions of Ni(ClO4)2 containing sodium formate or isopropyl alcohol was studied, γ-Irradiation of deaerated solutions in the presence of polyethyleneimine, polyacrylate, or polyvinyl sulfate gives stable metal sols containing spherical particles 2-4 nm in diameter. The optical absorption spectra of nickel nanoparticles exhibit a band with a maximum at 215±5 nm (ε215 = 4.7 · 103 L mol-1 cm-1) and a shoulder at 350 nm. A mechanism for the radiation-chemical reduction of Ni2+ ions by hydrated electrons and organic radicals (CO2- radical anions in the case of HCOONa and Me2COH radicals in the case of Pr1OH). The redox potentials of the Ni2+/Ni0 and Ni+/Ni0 pairs (Ni0 is a nickel atom) are approximately -2.2 and -1.7 V, respectively. The nanoparticles are readily oxidized by O2, H2O2, and other oxidants. The reactions of these species with silver ions yield relatively stable nanoaggregates containing both nickel and silver in addition to silver nanoparticles.
- Ershov
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- Cooligomerization of Diene-1,3 catalyzed by Ni(0). Influence of the nature of organoaluminate reducing agent
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This paper presents the results of a study of the co-oligomerization of butadiene with diene functionality and gives evidence of the role of the nature of the organoaluminate.
- Brun,Tenaglia
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- Amperometric detection of hydrogen peroxide at nano-nickel oxide/thionine and celestine blue nanocomposite-modified glassy carbon electrodes
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A simple procedure was developed to prepare a glassy carbon (GC) electrode modified with nickel oxide (NiOx) nanoparticles and water-soluble dyes. By immersing the GC/NiOx modified electrode into thionine (TH) or celestine blue (CB) solutions for a short
- Noorbakhsh, Abdollah,Salimi, Abdollah
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- Studies of phase composition of Zn-Ni alloy obtained in acetate-chloride electrolyte by using XRD and potentiodynamic stripping
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The phase composition of Zn-Ni alloy electrodeposited in acetate-chloride electrolyte has been studied as a function of ZnCl2 concentration and cathodic current density (ic) by the potentiodynamic stripping and XRD methods. It appeared to be dependent only on the Zn/Ni ratio in the alloy, irrespective of whether the result was attained by varying the cathodic current density or by changing the [Zn2+]/[Ni2+] ratio in electrolyte. A Zn-Ni alloy dissolving in the potential range of ia, peak D can be obtained by the method of cyclic voltammetry. This phase is a compact black coating. It has been determined by potentiodynamic stripping that pure Ni oxidizes only in the range of positive potentials, while Zn-Ni alloy containing some quantity of Zn oxidizes in the range of negative potentials. It was determined that the preciser data of potentiodynamic stripping were obtained in electrolyte containing Cl- ions. Zn-Ni alloy can be chromated only in the case when the η-phase makes up a sufficiently large portion of Zn-Ni alloy.
- Petrauskas,Grincevi?iene,?e?uniene,Ju?kenas
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- SURFACE STATE,CATALYTIC ACTIVITY AND SELECTIVITY OF NICKEL CATALYSTS IN HYDROGENATION REACTIONS
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The X-ray photoelectron spectroscopic study of Raney and Urushibara nickel catalysts activatede under various conditions was undertaken to chyrycterize the surface state of the catalysts including thecatalists' structure.Raney nickel catalysts contain both oxidized and metallic aluminium in the activated phase.As for Urushibara nickel catalystsdigested with acetic acid or sodium hydroxide, metallic and oxidized zinc were observed in the catalysts surface.Based on the X.p.s. peak intensities for the catalysts, the structure of Urushibara nickel catalysts was found to be that of a supported catalysts, whereas Raney nickel catalysts showed X.p.s. features consistent with those expected for skeletal nickel catalysts.
- Yasuaki Okamoto,Yuriko Nitta,Toshinobu Imanaka,Shiichiro Teranishi
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- Electrodeposition and properties of composite coatings based on nickel
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Composite electrochemical platings based on nickel and containing graphite bisulfate as a dispersed phase were obtained. Their electrodeposition and tribological characteristics were studied and compared with those of electrolytic nickel deposits free from a disperse phase.
- Tseluikin,Vasilenko
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- Ammonia-assisted fabrication of flowery nanostructures of metallic nickel assembled from hexagonal platelets
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A simple one-pot solution method was reported for the synthesis of metallic nickel nanostructures assembled from hexagonal nanoplatelets. The process involved the reduction of nickelous salt with hydrazine in ammonia solution, and the reaction proceeded w
- Ni, Xiaomin,Zheng, Huagui,Yang, Qing,Tang, Kaibin,Liao, Guangxuan
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- Synthesis of nickel nanoparticles and carbon encapsulated nickel nanoparticles supported on carbon nanotubes
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Nickel nanoparticles were prepared and uniformly supported on multi-walled carbon nanotubes (MWCNTs) by reduction route with CNTs as a reducing agent at 600 °C. As-prepared nickel nanoparticles were single crystalline with a face-center-cubic phase and a size distribution ranging from 10 to 50 nm, and they were characterized by transmission electron microscopy (TEM), high-resolution TEM and X-ray diffraction (XRD). These nickel nanoparticles would be coated with graphene layers, when they were exposed to acetylene at 600 °C. The coercivity values of nickel nanoparticles were superior to that of bulk nickel at room temperature.
- Cheng, Jipeng,Zhang, Xiaobin,Ye, Ying
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- Fabrication of Ni-coated Al2O3 powders by the heterogeneous precipitation method
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Ni-coated Al2O3 powders were prepared by the heterogeneous precipitation method using Al2O3, Ni(NO3)2·6H2O and NH4HCO3 as the starting materials. The amorphous NiCO3·2Ni(OH)2·2H2O was uniformly coated on the surface of Al2O3 particles with the thickness of 20 nm. The amorphous coating layer was crystallized to NiO with the size of about 15 nm at 500°C for 2 hours in air, meantime, the dispersant was eliminated. NiO was completely reduced to Ni at 700°C for 4 hours in hydrogen atmosphere. Ni with the size of about 20 nm in the coating layer was spherical and weakly agglomerated. The continuous coating layer became discontinuous during heating treatment.
- Li, Guo-Jun,Huang, Xiao-Xian,Guo, Jing-Kun
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- Size-dependent orientation growth of large-area ordered Ni nanowire arrays
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Large-area ordered Ni nanowire arrays with different diameters have been fabricated by the direct current electrodeposition into the holes of porous anodic alumina membrane. The crystal structure and micrograph of nanowire arrays are characterized by X-ra
- Wang, Xue Wei,Fei, Guang Tao,Xu, Xi Jin,Jin, Zhen,Zhang, Li De
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- Electrooxidation of methanol on NiMn alloy modified graphite electrode
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Nickel and nickel-manganese alloy modified graphite electrodes (G/Ni and G/NiMn) prepared by galvanostatic deposition were examined for their redox process and electrocatalytic activities towards the oxidation of methanol in alkaline solutions. The methods of cyclic voltammetery (CV), chronoamperometry (CA) and impedance spectroscopy (EIS) were employed. In CV studies, in the presence of methanol NiMn alloy modified electrode shows a significantly higher response for methanol oxidation. The peak current of the oxidation of nickel hydroxide increase is followed by a decrease in the corresponding cathodic current in presence of methanol. The anodic peak currents show linear dependency upon the square root of scan rate. This behavior is the characteristic of a diffusion controlled process. Under the CA regime the reaction followed a Cottrellian behavior and the diffusion coefficient of methanol was found to be 4 × 10-6 cm2 s-1. A mechanism based on the electro-chemical generation of Ni3+ active sites and their subsequent consumptions by methanol have been discussed and the corresponding rate law under the control of charge transfer has been developed and kinetic parameters have been derived. The charge transfer resistance accessible both theoretically and through the EIS have been used as criteria for derivation of the rate constant.
- Danaee,Jafarian,Mirzapoor,Gobal,Mahjani
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- STRUCTURE AND CRYSTALLIZATION OF NICKEL-PHOSPHORUS ALLOYS PREPARED BY HIGH-RATE ELECTRODEPOSITION.
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Thin film nickel-phosphorus alloys are electrodeposited at a high rate using a specialized rapid electrolyte flow system. Current densities up to 2. 33 A/cm**2, which are difficult to maintain in conventional plating processes, can be used to produce satisfactory films. The deposits are characterized by x-ray diffraction and differential scanning calorimetry. Phosphorus content decreases with increasing current density and is virtually independent of the electrolyte flow rate above 5. 7 m/s, where the system is operating in the turbulent regime. Deposit structure depends strongly on the phosphorus content; it is amorphous or highly microcrystalline at greater than 14 atom percent (a/o) and crystalline at less than 14 a/o.
- Ng,Snyder,LaSala,Clemens,Fuerst
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- Polar symmetry and intercalation of new multilayered hybrid molybdates: [M2(pzc)2(H2O)x][Mo 5O16] (M = Co, Ni)
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The layered molybdate [M2(pzc)2(H2O) x][Mo5O16] (I: M = Ni, x = 5.0; II: M = Co, x = 4.0; pzc = pyrazinecarboxylate) hybrid solids were synthesized via hydrothermal reactions at 160-165°C. The structures were determined by single-crystal X-ray diffraction data for I (Cc, Z = 4; a = 33.217(4) A, b = 5.6416(8) A, c = 13.982(2) A, β = 99.407(8)°, and V = 2585.0(6) A3) and powder X-ray diffraction data for II (C2/c, Z = 4; a = 35.42(6) A, b = 5.697(9) A, c = 14.28(2) A, β = 114.95(4)°, and V = 2614(12) A3). The polar structure of I contains new [Ni2(pzc)2(H2O)5] 2+ double layers that form an asymmetric pattern of hydrogen bonds and covalent bonds to stair-stepped [Mo5O16]2- sheets, inducing a net dipole moment in the latter. In II, however, the [Co 2(pzc)2(H2O)4]2+ double layers have one less coordinated water and subsequently exhibit a symmetric pattern of covalent and hydrogen bonding to the [Mo5O 16]2- sheets, leading to a centrosymmetric structure. Thermogravimetric analyses and powder X-ray diffraction data reveal that I can be dehydrated and rehydrated with from 0 to 6.5 water molecules per formula unit, which is coupled with a corresponding contraction/expansion of the interlayer distances. Also, the dehydrated form of I can be intercalated by ～4.3 H2S molecules per formula unit, but the intercalation by pyridine or methanol is limited to less than one molecule per formula unit.
- Yan, Bangbo,Maggard, Paul A.
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- The hydrolysis behaviour of Mg2Ni and Mg2NiH4 in water or a 6 M KOH solution and its application to Ni nanoparticles synthesis
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Both Mg2Ni and Mg2NiH4 undergo hydrolysis in water and in a 6 M KOH alkaline solution. Mg2Ni spontaneously reacts with water to form Mg(OH)2, Ni and hydrogen. Mg2NiH4 first disso
- Wang, Huabin,Han, Lihong,Hu, Henry,Northwood, Derek O.
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- Alkalization of the near-cathode layer in electrodeposition of nickel from a chloride electrode
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Dependences of the pH at which hydrate formation begins and the pH of the near-cathode layer on the electrolysis modes (temperature, cathode current density, pH in the electrolyte bulk) and the dependence of the pH of the near-cathode layer on the distance from the cathode surface in a low-concentration chloride nickelplating electrolyte were studied. Pleiades Publishing, Ltd., 2010.
- Balakai,Arzumanova,Balakai
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- Formation of Ni chains induced by self-generated magnetic field
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Ultrafine chain-like Ni assemblies with a length of about 5 μm were successfully prepared by the reduction of Ni salts with hydrazine hydrate under normal pressure in the absence of any inorganic or organic templates. The resulting Ni chains were characte
- Gong, Chunhong,Tian, Juntao,Zhao, Tao,Wu, Zhishen,Zhang, Zhijun
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- Hydrangea-like NiCo-based Bimetal-organic Frameworks, and their Pros and Cons as Supercapacitor Electrode Materials in Aqueous Electrolytes
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Hydrangea-like NiCo-based bimetal-organic frameworks (NiCo-MOF) are synthesized in DMF-EtOH solution via a solvothermal method, using 4,4′-biphenyldicarboxylic acid as a ligand. NiCo-MOF having a highest capacity of 1056.6 F·g–1 at 0.5 A·g–1 and 457.7 F·g–1 even at 10 A·g–1 is achieved at a Ni/Co/BPDC molar ratio of 1:1:1, a temperature of 170 °C and a reaction time of 12 hours. It exhibits secondary 3D microsphere structures assembled by primary 2D nanosheet structures, good crystalline structure and good thermal stability below 350 °C in air. All the electrochemical data show that NiCo-MOF has the pros and cons as supercapacitor electrode materials in aqueous electrolytes. On the one hand, NiCo-MOF has a high capacity even at a high current density, low internal resistance, charge-transfer resistance and ion diffusion impendence, owing to the ordered coordination structure, 2D nanosheet structure and 3D assembled microsphere structure of NiCo-MOF. On the other hand, the cycling stability and rate capability are not ideal enough due to the hydrolysis of coordination bonds in aqueous electrolytes, especially, in alkaline solution. The good dispersion and high electrochemical activity of metal ions bring a high capacity for NiCo-MOF, but they result in the poor stability of NiCo-MOF. In the future work, finding a suitable organic electrolyte is an effective way to enhance the cycling stability of NiCo-MOF as well as deriving more stable skeleton materials from NiCo-MOF.
- Li, Qiaoqin,Wang, Xiaoqin,Yang, Nana,He, Fan,Yang, Yufei,Wu, Bohua,Chu, Jia,Zhou, Anning,Xiong, Shanxin
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- Electric double-layer capacitance of meso/macroporous activated carbon fibers prepared by the blending method: I. Nickel-loaded activated carbon fibers in propylene carbonate solution containing LiClO4 salt
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Meso/macroporous activated carbon fibers (ACFs), containing mesopores and macropores in addition to micropores, were prepared from carbonization and steam-activation of the phenolic resin fibers blended with a small amount (0.1 wt %) of an organic nickel complex. Conventional (microporous) ACF as reference sample, mainly composed of micropores, was also prepared from pure phenolic resin fibers without any agent. The electric double-layer capacitance of these ACFs was measured in propylene carbonate containing 1.0 mol dm-3 LiClO4 (1.0 M LiClO4/PC). The correlation between the capacitance and the BET (Brunauer-Emmett-Teller) specific surface area of the microporous ACFs showed the nonlinearity due to strong ion-sieving of micropores. The double-layer capacitance of the meso/macroporous ACFs was higher than the microporous ACF, because the ion-sieving effect of micropores was relaxed by the presence of meso/macropores. The relaxation by the meso/macropores was enhanced for the cation adsorption or the high current density measurement. These results confirm that the presence of many meso/macropores promotes the formation of an effective double layer or fast transfer of ions in the microporous structure.
- Shiraishi, Soshi,Kurihara, Hideyuki,Shi, Lan,Nakayama, Takuya,Oya, Asao
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- Magnetic nanochains of metal formed by assembly of small nanoparticles
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Ni nanochains are synthesized with diameters of 150-250 nm and lengths of 0.5-2 μm by assembly of small nanoparticles, which exhibit a magnetic coercivity over two orders of magnitude larger than that of bulk Ni.
- Liu, Chen-Min,Guo, Lin,Wang, Rong-Ming,Deng, Yuan,Xu, Hui-Bin,Yang, Shihe
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- Ni nanoparticles decorated titania nanotube arrays as efficient nonenzymatic glucose sensor
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A novel nonenzymatic glucose sensor was developed based on the Ni nanoparticles-loaded TiO2 nanotube arrays (Ni-NPs/TiO 2NTs). The Ni-NPs/TiO2NTs nanocomposites were prepared first by anodization of Ti foil, followed by pulsed electrodeposition method (PED) and characterized by SEM, XRD and XPS respectively. The results showed that spherical Ni nanoparticles were well dispersed and embedded in the TiO 2NTs. The electrochemical measurements presented that the activated Ni-NPs with a diameter of 40 nm displayed high electrocatalytic activity for the oxidation of glucose and a good sensitivity of 700.2 μA mM-1 cm-2 at applied potential 0.6 V, with detection limit of 2 μM (S/N = 3), and good linear range (from 0.004 to 4.8 mM). Such high sensitivity was attributed to the large surface area of the highly dispersed nanoparticles for electrocatalytic reaction and the fast electron transfer in the TiO 2NTs electrode. The good analytical performance, low cost and simple preparation method make this novel electrode material promising for the development of effective glucose nonenzymatic glucose sensor.
- Yu, Shujuan,Peng, Xiao,Cao, Guozhong,Zhou, Ming,Qiao, Lei,Yao, Jianyu,He, Huichao
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- Theoretical and Experimental Evaluation of the Reduction Potential of Straight-Chain Alcohols for the Designed Synthesis of Bimetallic Nanostructures
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Recently, the development of bimetallic nanoparticles with functional properties has been attempted extensively but with limited control over their morphological and structural properties. The reason was the inability to control the kinetics of the reduction reaction in most liquid-phase syntheses. However, the alcohol reduction technique has demonstrated the possibility of controlling the reduction reaction and facilitating the incorporation of other phenomena such as diffusion, etching, and galvanic replacement during nanostructure synthesis. In this study, the reduction potential of straight-chain alcohols has been investigated using molecular orbital calculations and experimentally verified by reducing transition metals. The alcohols with a longer chain exhibited higher reduction potential, and 1-octanol was found to be the strongest among alcohols considered. Furthermore, the experimental evaluation carried out via the synthesis of metallic Cu, Ni, and Co particles was consistent with the theoretical predictions. The reaction mechanism of metallic particle formation was also studied in detail in the Ni-1-octanol system, and the metal ions were confirmed to be reduced via the formation of nickel alkoxide. The results of this investigation were successfully implemented to synthesize Cu-Ni bimetallic nanostructures (core-shell, wire, and tube) via the incorporation of diffusion and etching besides the reduction reaction. These results suggest that the designed synthesis of a wide range of bimetallic nanostructures with more refined control has become possible.
- Ishijima, Masanao,Matsumoto, Takatoshi,Cuya Huaman, Jhon L.,Shinoda, Kozo,Uchikoshi, Masahito,Matsuo, Kohei,Suzuki, Kazumasa,Miyamura, Hiroshi,Balachandran, Jeyadevan
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p. 9432 - 9441
(2021/05/06)
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- Autoclave Synthesis of Finely Divided Nickel Powders
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Abstract: The reduction of divalent nickel with hydrazine hydrate from alkaline ammonia solutions at elevated temperatures was studied. A procedure to synthesize finely divided nickel powders was proposed. The morphology of the objects obtained under various synthesis conditions was investigated by scanning electron microscopy; it was shown that both needle-like and spherical particles can form. The specific surface area of the synthesized metallic nickel powders was determined by low-temperature nitrogen adsorption to be within the range 5–20 m2/g, depending on the synthesis conditions (the concentration of the initial salt in the solution, the pH, and the temperature). X-ray powder diffraction analysis showed that all the powders are mixtures of two phases: nickel (to 99%) and nickel hydroxide. X-ray photoelectron spectroscopy demonstrated that a particle of the powders consists of a nickel(0) core coated with several atomic layers of nickel hydroxide.
- Belousov, O. V.,Belousova, N. V.,Borisov, R. V.,Romanchenko, A. S.,Zeer, G. M.
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p. 1463 - 1468
(2021/11/24)
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- Morphology-control and template-free fabrication of bimetallic Cu–Ni alloy rods for ethanol electro-oxidation in alkaline media
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The design of highly efficient and stable non-noble transition metal-based electrocatalysts for the ethanol oxidation reaction (EOR) is imperative for the development of the direct ethanol fuel cells (DEFCs). In this work, we report a simple template-free method for preparing a type of rod-like Cu–Ni alloy particle with the unique porous structure and evaluate it as the electrocatalyst for the EOR in alkaline media. The pH, which was adjusted by the addition of NH3·H2O during the liquid-phase coprecipitation process, was found to be a key factor to shape Cu–Ni alloy precursor into a quasi-one-dimensional morphology. After annealing at a reducing atmosphere (H2/Ar = 5/95, v/v), well-alloyed Cu–Ni rods with the predefined molar ratio (Cu/Ni) of 1:1, a specific surface area of 6.84 m2 g?1, and the average pore size of 30.97 nm were obtained. Cyclic voltammetry (CV) and chronoamperometry (CA) test results show that the prepared Cu–Ni alloy catalyst demonstrated an anodic current peak of 86.10 mA cm?2 in the presence of 0.2 M ethanol and a 95% retention of current density after 2000 s, indicating its good electrochemical performance in terms of catalytical activity and long-term stability. This bottom-up synthesis strategy would enrich the fabrication methodologies and open up a promising avenue for preparing multiple Ni-based EOR electrocatalysts with the easy-controllable morphologies and porous structure at the industrial scale.
- Miao, Zelin,Xu, Changfan,Xu, Ziwei,Zhan, Jing
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- Self-assembled Ni/NiO impregnated polyaniline nanoarchitectures: A robust bifunctional catalyst for nitrophenol reduction and epinephrine detection
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It is extremely significant to address an urgency toward the development of low-cost and efficient catalysts. Herein, for the first time, we synthesize a novel self-assembled Ni/NiO@PANI by a combustible crystallization followed polymerization method, constructed by impregnation of Ni/NiO in sulfonic acid-doped polyaniline, which can be used as a bifunctional catalyst for electrochemical sensing of epinephrine (EP) and reduction of nitro- to amino-phenol (4-NP to 4-AP). Due to the unique nanoarchitecture, ferromagnetic feature of Ni, anti-corrosion feature of PANI, and synergy between the system (metal/metaloxide@carbon) leads superior performance: it can rapidly reduce the 4-NP pollutant to environmentally friendly 4-AP within 8 min, and easy magnetic recycling; Also, it can be used as a sensor for EP neurotransmitters with a sensitivity, detection, and quantification limit of 0.117 nAμM?1, 87.2, and 290.71 μM, respectively. This work provides a strategy to design low-cost and superior catalysts applied in catalysis and electrochemical sensor.
- Ramadoss, Manigandan,Chen, Yuanfu,Ranganathan, Suresh,Giribabu, Krishnan,Thangavelu, Dhanasekaran,Annamalai, Padmanaban,Vengidusamy, Narayanan
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- Synthesis, physical and electrochemical properties of CoMn2O4: application to photocatalytic Ni2+ reduction
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Nickel is a hazardous metal with a harmful effect on the health and environment. In this work, the photocatalytic reduction of Ni2+ was examined onto the hetero-system CoMn2O4/TiO2 under visible light irradiation. The spinel CoMn2O4 is prepared by co-precipitation and characterized in detail to correlate its structural, textural, morphological, compositional, optical and photoelectrochemical features. The effects of pH, catalyst dose and Ni2+ concentration were optimized. The Ni2+ reduction increased with decreasing both the catalyst dose and pH. The highest performance was obtained at pH 7.4, a catalyst dose of 1?g/L and Ni2+ concentration of 10?mg L?1 with a removal abatement of 88% after 180?min irradiation. The data were suitably fitted by the pseudo-first-order kinetic reaction with an apparent constant of 0.027?min?1. Besides, the durability and the stability of the hetero-system CoMn2O4/TiO2 were evaluated by four consecutive catalytic cycles.
- Kaci,Nasrallah,Kebir,Guernanou,Soukeur,Trari
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p. 1693 - 1712
(2021/01/20)
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- Facile synthesis of triple Ni-Mo-W alloys and their catalytic properties in chemical vapor deposition of chlorinated hydrocarbons
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The utilization of chlorine-containing organic wastes remains an actual problem. In the present research, sponge-like porous Ni-Mo-W alloys were prepared and used as catalysts for the catalytic chemical vapor deposition of 1,2-dichloroethane. The synthesis of the alloys was performed via a facile approach of high-temperature reductive thermolysis of the preliminarily prepared multicomponent precursors. The formation of alloys of exact composition was proven by precise X-ray diffraction analysis. The catalytic activity of the alloys in the decomposition of 1,2-dichloroethane was studied in a flow-through reactor at 600 °C for 2 h. The simultaneous presence of Mo and W in the composition of the Ni-based alloys was shown to have a synergetic effect on the process efficiency. The diameter of these fibers was found to be comparable with the size of metal particles formed as a result of initial alloys self-disintegration under the action of the aggressive reaction medium.
- Shubin, Yury V.,Bauman, Yury I.,Plyusnin, Pavel E.,Mishakov, Ilya V.,Tarasenko, Maria S.,Mel'gunov, Maxim S.,Stoyanovskii, Vladimir O.,Vedyagin, Aleksey A.
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- Synthesis, spectral characterization, density functional theory studies, and biological screening of some transition metal complexes of a novel hydrazide–hydrazone ligand of isonicotinic acid
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Novel Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Hg(II) complexes (1–7) of hydrazide–hydrazone ligand (H2L) derived from the condensation of isonicotinic acid hydrazide with (Z)-N′-(2-nitrobenzylidene)-3-oxobutanehydrazide have been prepared. The ligand and its chelates were characterized based on elemental analysis, spectral, thermal analysis, molar conductance, and magnetic moment measurements. Besides, density functional theory (DFT) computations have been conducted to study structures and energetics of the ligand and its complexes. The IR spectra showed that the ligand was chelated with the metal ion in a monobasic tridentate manner using ONO donors in all complexes except Zn(II) complex (5) where the ligand binds with Zn(II) ion as a dibasic tridentate utilizing ONO donors. The magnetic moment and electronic spectral data revealed octahedral and square pyramidal geometries for complexes (1, 7) and (2, 4, 5), respectively, whereas a square planar geometry was suggested for 3. DFT studies show that the Cd(II) center reveals interesting structural deviations from regular octahedral geometry in the resulting hexa-coordinated complex [Cd(H2L)2].2H2O (6) assumes a trigonal prismatic (TP) structure for this complex. The antibacterial and antifungal activities of the ligand and its complexes have been investigated with different bacterial and fungal strains. The data revealed that Hg(II) complex (7) demonstrated a very good antibacterial and antifungal activity than others. Highlights: A new hydrazide–hydrazone ligand of isonicotinic acid was synthesized. Seven mononuclear Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Hg(II) complexes of the new ligand were prepared and characterized by different tools. DFT studies have been carried out to study the structure of the ligand and its complexes. Antimicrobial activities of the ligand and its complexes were studied against a variety of bacterial and fungal strains by using disk diffusion method and results were compared with standard drugs.
- El-Nahas, Ahmed M.,Kashar, Tahani I.,Tolan, Dina A.,Yoshizawa, Kazunari
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- New Compounds and Phase Selection of Nickel Sulfides via Oxidation State Control in Molten Hydroxides
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Molten salts are promising reaction media candidates for the discovery of novel materials; however, they offer little control over oxidation state compared to aqueous solutions. Here, we demonstrated that when two hydroxides are mixed, their melts become fluxes with tunable solubility, which are surprisingly powerful solvents for ternary chalcogenides and offer effective paths for crystal growth to new compounds. We report that precise control of the oxidation state of Ni is achievable in mixed molten LiOH/KOH to grow single crystals of all known ternary K-Ni-S compounds. It is also possible to access several new phases, including a new polytope of β-K2Ni3S4, as well as low-valence KNi4S2 and K4Ni9S11. KNi4S2 is a two-dimensional low-valence nickel-rich sulfide, and β-K2Ni3S4 has a hexagonal lattice. Moreover, using KNi4S2 as a template, we obtained a new layered binary Ni2S by topotactic deintercalation of K. The new binary Ni2S has a van der Waals gap and can function as a new host layer for intercalation chemistry, as demonstrated by the intercalation of LiOH between its layers. The oxidation states of low-valence KNi4S2 and Ni2S were studied using X-ray absorption spectroscopy and X-ray photoelectron spectroscopy. Density functional theory calculations showed large antibonding interactions at the Fermi level for both KNi4S2 and Ni2S, corresponding to the flat-bands with large Ni-dx2-y2 character.
- Balasubramanian, Mahalingam,Chung, Duck Young,Kanatzidis, Mercouri G.,Mandia, David J.,Park, Hyowon,Wen, Jianguo,Yakovenko, Andrey,Yu, Lei,Zhou, Xiuquan
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supporting information
p. 13646 - 13654
(2021/09/11)
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- Thermal stability and reduction mechanism of LiNi0.8Co0.1Mn0.1O2 and LiNi0.5Co0.2Mn0.3O2 cathode materials studied by a Temperature Programmed Reduction
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The temperature Programmed Reduction method was applied to analyze the structural and thermal behavior of LiNixCoyMnzO2 (x = 0.5 and 0.8). All reduction phases of LiNi0.5Co0.2Mn0.3O2 powder were transitioned above 843 K. For LiNi0.8Co0.1Mn0.1O2 powder, three reduction steps are starting at 661 K. It contributes to the transition to Ni2+, Co2+, Ni0, and Co0 phases, respectively. It was consistent with the reduction mechanism of LiNiO2 and LiCoO2. In delithiated NCM523, only a structural change from H1 to M is observed, which does not significantly affect thermal stability. For delithiated NCM811, the TPR result was sharply reduced to 536 K in the H2-H3 structural transition. When charged to 4.4 V, it decomposes into a NiO-like phase at 507 K. The reducing phase was verified through X-ray diffraction after all decomposition steps of the TPR results. As a result, the TPR method can confirm the reduction mechanism and thermal stability of the cathode material.
- Bakenov, Zhumabay,Kim, Jun-Sik,Kim, Sung-Soo,Lim, Seong-Hyeon,Umirov, Nurzhan,Yeon, Seon-Young
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- Synthesis, characterization, potential antimicrobial, antioxidant, anticancer, DNA binding, and molecular docking activities and DFT on novel Co(II), Ni(II), VO(II), Cr(III), and La(III) Schiff base complexes
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In this study, five novel complexes for Co(II), Ni(II), VO(II), Cr(III), and La(III) ions were synthesized from a tridentate NNO monobasic chelating Schiff base ligand, (Z)-2-((pyridin-2-ylimino)methyl)phenol (HL). Spectral and analytical tools were applied to elucidate the structural compositions of the new compounds. Then, geometry optimization was conducted for all the syntheses by the Gaussian 09 program via the density functional theory method to obtain optimal structures and the most essential parameters. Moreover, the biochemical behaviors of all the syntheses were explored based on the reactivity, which was tested against various cancer cell lines (HepG-2, MCF-7, and HCT-116). The complexes exhibited an interestingly antiproliferative potential against human cancer cell lines, and the cytotoxicities of the new complexes were arranged to follow the order: VOL > CrL > NiL > LaL > CoL > HL. The antioxidant behaviors of the complexes were studied using the DPPH assay, and VOL showed the maximum antioxidant activity, followed by LaL. The antibacterial activities of the HL ligand and its complexes were studied. Moreover, the binding nature of the complexes with calf thymus DNA (CT-DNA) was investigated based on the spectrophotometric absorption titration, viscosity, and gel electrophoresis methods. The binding ability of the complexes with CT-DNA was proposed to be just intercalation or replacement mode. The intrinsic binding constant Kb was calculated and arranged based on the following order: VOL (5.2 × 105) > CrL (3.6 × 105) > NiL (3.3 × 105) > LaL (3.0 × 105) > CoL (1.12 × 105) mol?1?dm?3. Docking investigations were performed using the receptors of COVID-19's main protease viral protein (PDB ID: 6LU7) and Escherichia coli (gram [–ve] bacteria [PDB ID: 1fj4]).
- Abdalla, Ehab M.,Abdel-Rahman, Laila H.,Al-Farhan, Badriah Saad,Basha, Maram T.,Shehata, Mohamed R.
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- Synthesis, dft calculations, antiproliferative, bactericidal activity and molecular docking of novel mixed-ligand salen/8-hydroxyquinoline metal complexes
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Despite the common use of salens and hydroxyquinolines as therapeutic and bioactive agents, their metal complexes are still under development. Here, we report the synthesis of novel mixed-ligand metal complexes (MSQ) comprising salen (S), derived from (2,2′-{1,2-ethanediylbis [nitrilo(E) methylylidene]}diphenol, and 8-hydroxyquinoline (Q) with Co(II), Ni(II), Cd(II), Al(III), and La(III). The structures and properties of these MSQ metal complexes were investigated using molar conductivity, melting point, FTIR,1H NMR,13C NMR, UV–VIS, mass spectra, and thermal analysis. Quantum calculation, analytical, and experimental measurements seem to suggest the proposed structure of the compounds and its uncommon monobasic tridentate binding mode of salen via phenolic oxygen, azomethine group, and the NH group. The general molecular formula of MSQ metal complexes is [M(S)(Q)(H2O)] for M (II) = Co, Ni, and Cd or [M(S)(Q)(Cl)] and [M(S)(Q)(H2O)]Cl for M(III) = La and Al, respectively. Importantly, all prepared metal complexes were evaluated for their antimicrobial and anticancer activities. The metal complexes exhibited high cytotoxic potency against human breast cancer (MDA-MB231) and liver cancer (Hep-G2) cell lines. Among all MSQ metal complexes, CoSQ and LaSQ produced IC50 values (1.49 and 1.95 μM, respectively) that were comparable to that of cisplatin (1.55 μM) against Hep-G2 cells, whereas CdSQ and LaSQ had best potency against MDA-MB231 with IC50 values of 1.95 and 1.43 μM, respectively. Furthermore, the metal complexes exhibited significant antimicrobial activities against a wide spectrum of both Gram-positive and-negative bacterial and fungal strains. The antibacterial and antifungal efficacies for the MSQ metal complexes, the free S and Q ligands, and the standard drugs gentamycin and ketoconazole decreased in the order AlSQ > LaSQ > CdSQ > gentamycin > NiSQ > CoSQ > Q > S for antibacterial activity, and for antifungal activity followed the trend of LaSQ > AlSQ > CdSQ > ketoconazole > NiSQ > CoSQ > Q > S. Molecular docking studies were performed to investigate the binding of the synthesized compounds with breast cancer oxidoreductase (PDB ID: 3HB5). According to the data obtained, the most probable coordination geometry is octahedral for all the metal complexes. The molecular and electronic structures of the metal complexes were optimized theoretically, and their quantum chemical parameters were calculated. PXRD results for the Cd(II) and La(III) metal complexes indicated that they were crystalline in nature.
- Abdalla, Ehab M.,Abdel Rahman, Laila H.,Al-Farhan, Badriah Saad,Basha, Maram T.,El-Ezz, Doaa Abou,El-Saghier, Ahmed M. M.,Marzouk, Adel A.,Shehata, Mohamed R.
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- Syntheses, characterization and oxygen evolution reaction (OER) electrocatalytic properties of M(II) based bromo-salophen complexes
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Efficient oxygen evolution reaction catalyst can be prepared via controlled decomposition method, and there is still minimal mechanistic understanding of such method. Here, we introduce a 3-Bromo-salophen ligated nickel(II) and copper(II) complexes as a precursor to obtain a Ni and Cu-based oxygen evolution reaction electrocatalyst via the controlled decomposed method. In our case, the unique O,N chelation mode of the 3-Bromo-salophen ligand (bis[2-bromosalicylydene]-1,2-iminophenylenediamine) was used to synthesize M(II) complexes. By regulating the decomposition conditions, we successfully obtained varied structures. The designing of a nonprecious, highly efficient and long-lasting oxygen evolution reaction electrocatalyst for electrochemical water splitting is a current emergency for reducing energy demand in the future. In this study, we found cost-effective decomposed products of NiO and CuO which are prepared by a simple one-step chemical precipitate method at high temperature (500 °C). The chemical composition, structure and morphology of the decomposed products NiO and CuO were confirmed by PXRD, FTIR and SEM spectroscopy. The decomposed products were loaded onto a glassy carbon electrode by a drop-casting method. For the oxygen evolution reaction, the complexes as well as their decomposed products, NiO and CuO achieve an ultralow over-potential exhibit onset lower potential 1.5 V in 0.1 M KOH solution.
- Gautam, Chiteri,Kumar, Pramod,Sharma, Vinod Kumar,Singh, Anar,Singh, Ashish Kumar,Singh, Ayushi
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- The composition dependent structure and catalytic activity of nanostructured Cu-Ni bimetallic oxides
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Nanostructured bimetallic oxides have received a great amount of attention in the field of catalysis. Here, the influence of composition on the structure and catalytic activity of CuO/NiO bimetal oxides is reported. Oxides with different ratios of Cu : Ni (0 : 100, 25 : 75, 50 : 50, 75 : 25 and 100 : 0) were prepared via a hydrothermal process and subsequently heat-treated at 600 °C for 4 h. XRD and Raman spectroscopic analysis clearly indicated the co-existence of NiO and CuO phases in the bimetallic oxides. Electron microscopy studies revealed a reduction in particle size for the bimetallic oxide compared to the monometallic oxide. The highest catalytic activity with good recyclability for the reduction of 4-nitrophenol was observed with Cu50Ni50-600, having a rate constant of 5.08 × 10-3 s-1. Cyclic voltammetry investigations confirmed the high reactivity of Cu50Ni50-600 for 4-nitrophenol, showing a high oxidation current peak compared to that of other samples. The results show that the presence of CuO and NiO enhances the catalytic activity by their synergetic effect, unlike the monometal oxides. This journal is
- Preethi, S.,Sundramoorthy, Ashok K.,Suresh Babu, K.,Vivek, S.
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p. 9691 - 9698
(2020/07/03)
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- Water Soluble Nickel – metformin ternary complexes: Thermal, DNA binding and molecular docking studies
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The Nickel (II) complexes [Ni(Cl)2(metf)(o-phen)] (1), [Ni(Cl)2(metf)(opda)] (2), [Ni(Cl)2(metf)(en)](3), [Ni(Cl)2(metf)(2,2'-bipy)](4), (metf = metformin, o-phen = ortho-phenanthroline, opda = ortho-phenylenediamine, en = ethylenediamine, 2–2′ bipy = 2–2′ bipyridyl) were synthesized and characterized using LC–MS, elemental analysis, molar conductance measurements, TGA-DTA, IR spectroscopy, magnetic moment measurements and electronic spectroscopy. The central Ni2+ was found to be in octahedral geometry. The DNA interaction of these complexes have been studied by UV–visible absorption studies, fluorescence emission technique and viscosity measurement. The complexes showed absorption hyperchromism in UV–visible spectra with calf thymus DNA. The binding constants from UV–visible absorption studies were 7.42 × 104, 0.74 × 104, 3.19 × 104, 5.9 × 104 M?1 for 1, 2, 3 and 4, respectively and Stern-Volmer quenching constants from fluorescence studies were 0.16, 0.41, 0.23, 0.18, respectively. Viscosity measurements revealed that the binding of the complexes with DNA could be surface binding, mainly due to groove binding. The highest DNA cleavage activity of the complexes is recorded for complex 1. The complexes were docked in to B-DNA sequence, 5′(D*AP*CP*CP*GP*AP*CP* GP*TP*CP*GP*GP*T)-3′ retrieved from protein data bank (PDB ID: 423D), using Discovery Studio 2.1 software. C Docker Intectraction energy of 1, 2, 3 and 4 complexes is 32.027, 31.427, 35.393 and 30.521 respectively. The highest docking score is seen for complex 3.
- Rajeshwari,Vasantha,Kumar,Shekhar,Lakshmi
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- Anti-hepatocellular carcinoma, antioxidant, anti-inflammation and antimicrobial investigation of some novel first and second transition metal complexes
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New coordination compounds of some selected metal ions from the first and second transition metals series with a Schiff base were synthesized and characterized. The Schiff base is derived from 4-Aminoantipyrine and 3-(hydroxyimino) butan-2-one. The compounds were characterized by different analysis tools like; elemental analysis, mass spectra, Fourier transform infrared (FTIR) as well as electronic spectra, magnetic measurements, molar conductance and thermal analysis technique. All complexes were formed with 1:1 (metal: ligand) stoichiometry except Mn (II) where 1:2 (Mn: ligand) is formed. Schiff base ligand interacted as a tridentate ligand by using the nitrogen atoms of the imine and the oximato groups and the carbonyl oxygen atom as donor groups with all studied metal ions except copper (II) and manganese (II) where the carbonyl oxygen is not shared in the coordination. These complexes show various physicochemical properties. X-ray powder diffraction shows different crystal systems; Cd (II) complex: hexagonal, Cu (II) complex: orthorhombic; and [Ni (II), Mn (II), Rh (III) & Pd (II)] complexes: monoclinic. All compounds showed potent cytotoxicity against the growth of human liver cancer cell lines. The square planar Pd (II) complex was more active than those of octahedral geometries of all other synthesized complexes. Cd (II) complex has the highest microbial growth inhibition than the rest of the prepared complexes. The docking active sites interactions were evaluated using the selected proteins EGFR tyrosine kinase and protein crystal structure of GlcN-O-P synthase. in vitro antioxidant assay revealed potent free radical scavenging activity of the three synthesized Cu (II), Pd (II) and Rh (III) complexes that exceeded the standard ascorbic acid. Pd (II) complex shows the most significant inhibition denaturation percent.
- Hassan, Safaa S.,Khalf-Alla, Perihan A.
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- Synthesis, Crystal Structures, and Thermolysis Studies of Heteronuclear Transition Metal Aluminum Alcoholates
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Heteronuclear alcoholate complexes [M{Al(OiPr)4}2(bipy)] (2-M, M = Fe, Co, Ni, Cu, Zn) and [M{Al(OcHex)4}2(bipy)] (3-M, M = Fe, Co, Ni, Zn) are formed by adduct formation of [M{Al(OiPr)4}2] (1-M, M = Fe, Co, Ni, Cu, Zn) with 2,2'-bipyridine and transesterification reaction with cHexOAc. According to crystal structure analyses, in 2-M and 3-M the central transition metal ion M2+ is coordinated by two chelating Al(OR)4– moieties and one bipyridine ligand in an octahedral arrangement. Treating 1-Cu with 2,2'-bipyridine leads to a reduction process, whereat the intermediate [Cu{Al(OiPr)4}(bipy)2][Al(OiPr)4] (4) could be structurally characterized. During conversion of the iso-propanolate ligands in 1-Cu to cyclohexanolate ligands, Cu2+ is reduced to Cu+ forming [Cu{Al(OcHex)4}(py)2] (5). UV/Vis-spectra and results of thermolysis studies by TG/DTA-MS are reported.
- Küsel, Sebastian,Krautscheid, Harald
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- New perspective of a nano-metal preparation pathway based on the hexahydro-closo-hexaborate anion
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Today, metal-based nanomaterials play an increasingly important role in the energy, environment, medical and health fields. In order to meet the needs of various fields, it is necessary to continuously develop advanced technologies for preparing metal-based materials. Inspired by previous research, the results of a proof-of-concept experiment show that the hexahydro-closo-hexaborate anion (closo-[B6H7]?) in the borane cluster family has properties similar to NaBH4.Closo-[B6H7]?can not only convert common precious metal ions such as Au3+, Pd2+, Pt4+and Ag+to the corresponding zero-valence state, but also convert some non-precious metals such as Cu2+and Ni2+to the zero-valent or oxidation state.Closo-[B6H7]?moderate reduction to cause rapid aggregation of metal-based materials is not easy compared with NaBH4. Compared withcloso-[B12H12]2?,closo-[B6H7]?achieves the conversion of Pt4+to Pt0under ambient conditions, and its reduction performance extends to non-precious metals. The excellent stability and easy modification characteristics determine the universality of thecloso-[B6H7]?reduction strategy for metal ions.
- Liu, Jun,Zhang, Haibo,Zhao, Xue
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p. 33444 - 33449
(2020/09/21)
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- Synthesis, characterization, antiproliferative of pyrimidine based ligand and its Ni(II) and Pd(II) complexes and effectiveness of electroporation
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In the study, a new Schiff base (ligand) was obtained using 4-aminopyrimidine-2(1H)-one, the starting material, and 2,3,4-trimethoxy benzaldehyde. Ni(II) and Pd(II) complexes were obtained from the reaction of the ligand and NiCl2·6H2O, PdCl2(CH3CN)2 (1:1 ratio). These compounds were characterized using the elemental and mass analysis, 1H, 13C-NMR, FT-IR, UV-Vis, magnetic susceptibility, thermal analysis, and the X-ray diffraction analyses. The antiproliferative activities of the synthesized ligand, Ni(II) and Pd(II) complexes were identified on the HepG2 (human liver cancer cells) cell line and their biocompatibility was tested on the L-929 (fibroblast cells) cell line by the MTT analysis method. Furthermore, the effects of electroporation (EP) on the cytotoxic activities of synthesized compounds were investigated in HepG2 cancer cells. According to the MTT findings of the study, the ligand did not exhibit an antiproliferative activity while its Ni(II) and Pd(II) complexes exhibited an antiproliferative activity. Moreover, it was observed that the antiproliferative activity of the Pd(II) complex was stronger than that of the Ni(II) complex. The combined application of EP + compounds is much more effective than the usage of the compounds alone in the treatment of HepG2 cancer cells. The EP increased the cytotoxicity of the Ni(II) and Pd(II) complexes by 1.66, and 2.54 times, respectively. It was concluded that Ni(II) and Pd(II) complexes may contribute as potential anti-cancer agents for the treatment of hepatocellular carcinoma and yield promising results in the case of being used in ECT. Communicated by Ramaswamy H. Sarma.
- Alk??, Mehmet E?ref,Buldurun, Kenan,Turan, Nevin,Alan, Yusuf,Y?lmaz, ünzile Kele?temur,Mantarc?, Asim
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- Enhancing the Stability of Aromatic PCN Pincer Nickel Complexes by Incorporation of Pyridine as the Nitrogen Side Arm
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New PCNPy pincer nickel complexes have been synthesized through a short synthetic route. Incorporating pyridine as the nitrogen side arm facilitated the C–H activation in the PCN ligand and allowed the cyclometallation with nickel to take place at room temperature. Pyridine also enhanced the stability of β-hydrogen-containing alkyl complexes. Also, the symmetric NCN nickel complex with pyridine side arms was successfully obtained giving a rare example of such type of complexes to be prepared through direct C–H activation. Furthermore, preliminary results showed that the (PCNPy)Ni–Br is active in Kumada coupling reactions particularly the coupling of aryl halides with aryl Grignard reagents.
- Mousa, Abdelrazek H.,Chakrabarti, Kaushik,Isapour, Ghodsieh,Bendix, Jesper,Wendt, Ola F.
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p. 4270 - 4277
(2020/11/30)
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- Preparation of highly dispersed Ni1-xPdx alloys for the decomposition of chlorinated hydrocarbons
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A convenient procedure to synthesize highly dispersed Ni1-xPdx alloys has been developed. The procedure is based on thermal decomposition in the reducing atmosphere of specially synthesized multicomponent precursor. The formation of single-phase solid solutions in the entire range of palladium concentrations was confirmed by powder XRD. The alloys have a porous structure composed of grains whose size depends on the synthesis temperature. The study of the catalytic properties of Ni1-xPdx alloys (5 wt% Pd) showed their high activity in the 1,2-dichloroethane decomposition process. After 5 h of catalytic experiment the yield of carbon material was 160 gС/gcat for Ni1-хPdх. This is more than 3 times higher than the yield of reference samples (porous Ni, Ni–Co, Ni–Cu). The carbon material formed has a segmented fibrous structure. It is characterized by high morphological uniformity. The specific surface area of the obtained carbon material is 580 m2/g.
- Rudneva, Yuliya V.,Shubin, Yury V.,Plyusnin, Pavel E.,Bauman, Yury I.,Mishakov, Ilya V.,Korenev, Sergey V.,Vedyagin, Aleksey A.
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p. 716 - 722
(2019/01/04)
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- NiRh nanosponges with highly efficient electrocatalytic performance for hydrogen evolution reaction
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The development of Ni-based nanoalloys has been extensively explored due to their low cost, high activity, and durability in the hydrogen evolution reaction (HER). Structural design of Ni-based nanoalloys is a promising approach to attain excellent electrocatalytic activity as well as stability of these catalysts. This study reports a facile method to prepare NixRhy nanosponges while using NaBH4 as a reducing agent without any surfactant. The ratio of Ni and Rh has been changed to obtain various NixRhy electrocatalysts (Ni, Ni3Rh1, Ni1Rh1, Ni1Rh3, and Rh), respectively. Among the prepared catalysts, Ni1Rh3 electrocatalyst exhibits a high electrocatalytic activity with an overpotential of 48 mV at a current density of ?10 mA cm?2 and a superior stability even after 2000 cycles of CV in 0.5 M H2SO4 electrolyte. In addition, the Ni1Rh3 electrocatalyst shows good electrocatalytic activity in 1.0 M KOH electrolyte compared to commercial Pt/C (20 wt% of Pt) (c-Pt/C). Moreover, the overall water splitting system of the Ni1Rh3 cathode and the commercial RuO2 anode is evaluated, not only exhibiting excellent performance with a potential of 1.52 V at a current density of 10 mA cm?2, but also proving very stable operation for over 100,000 s in 1.0 M KOH electrolyte.
- Nguyen, Ngoc-Anh,Nguyen, Van-Toan,Shin, Sangho,Choi, Ho-Suk
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p. 163 - 173
(2019/03/14)
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- Electrochemical promotion of Bi-metallic Ni9Pd core double-shell nanoparticles for complete methane oxidation
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Electrochemical promotion of Ni9Pd nanoparticles (NPs)with low Pd content (Ni:Pd = 9:1 atomic ratio)supported on yttria-stabilized zirconia (YSZ)solid-electrolyte was evaluated for the first time for complete methane oxidation. Electron Energy Loss Spectroscopy (EELS)showed a Pd core with a Ni first shell surrounded by 3–4 nm layer of Pd outer shell. This core double-shell structure of Ni9Pd NPs enhanced the catalytic activity and stability compared to mono-metallic Pd and Ni NPs under open-circuit. The reversible electrochemical promotion of Ni9Pd was obtained upon positive polarization between 425 and 500 °C. At 425 °C, the reaction rate increase reached 240% corresponding to apparent Faradaic efficiency of 25. On Ni9Pd NPs the reaction exhibited electrophobic behavior, i.e., the rate increased with anodic polarization, under all experimental conditions of this study. The results demonstrate the advantage of using Ni9Pd bi-metallic nanoparticles with core double-shell structure for methane complete oxidation due to the synergetic effect between Pd and Ni and very low amount of expensive Pd phase. EPOC with this type of highly dispersed and low noble metal content catalysts may find a way in the real world catalytic converters for gas exhaust treatment.
- Hajar, Yasmine M.,Venkatesh, Balaji,Houache, Mohamed S.E.,Liu, Hanshuo,Safari, Reza,Prabhudev, Sagar,Botton, Gianluigi A.,Baranova, Elena A.
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p. 127 - 135
(2019/05/10)
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- Identification of an Active NiCu Catalyst for Nitrile Synthesis from Alcohol
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Development of heterogeneous catalysts for alcohol transformation into nitriles under oxidant-free conditions is a challenge. Considering the C-H activation on α-carbon of primary alcohols is the rate-determining step, decreasing the activation energy of C-H activation is critical in order to enhance the catalytic activity. Several NiM/Al2O3 bimetallic catalysts were synthesized and scrutinized in catalytic transformation of 1-butanol to butyronitrile. Ni-Cu was identified as a suitable combination with the optimized Ni0.5Cu0.5/Al2O3 catalyst exhibiting 10 times higher turnover frequency than Ni/Al2O3 catalyst. X-ray absorption spectroscopy (XAS) and high angle annular dark field scanning transmission electron microscopy (HAADF-STEM) revealed that the NiCu particles in the catalyst exist in the form of homogeneous alloys with an average size of 8.3 nm, providing an experimental foundation to build up a catalyst model for further density functional theory (DFT) calculations. Calculations were done over a series of NiM catalysts, and the experimentally observed activity trend could be rationalized by the Br?nsted-Evans-Polanyi (BEP) principle, i.e., catalysts that afford reduced reaction energy also feature lower activation barriers. The calculated activation energy (Ea) for C-H activation with coadsorbed NH3 dropped from 63.4 kJ/mol on pure Ni catalyst to 49.9 kJ/mol on the most active NiCu-2 site in NiCu bimetallic catalyst, in good agreement with the experimentally measured activation energy values. The Ni0.5Cu0.5/Al2O3 catalyst was further employed to convert 11 primary alcohols into nitriles with high to near-quantitative yields, at a Ni loading 10 times less than that of the conventional Ni/Al2O3 catalyst.
- Wang, Yunzhu,Furukawa, Shinya,Yan, Ning
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p. 6681 - 6691
(2019/07/12)
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- Kinetics and Mechanism of Thermal Decomposition of Bis(Η3-Allyl)Nickel Complexes
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Abstract: The kinetics of thermal decomposition of bis(η3-allyl) nickel complexes in various media is studied. The specific features of the mechanism are determined, including the combination of the stages of trans-cis isomerization of Niall2 and the bimolecular decomposition of the cis-isomer with diallyl formation. The effect of autocatalytic decomposition of complexes with metallic nickel is been detected. The qualitative dependences of the process rate on the nature of the solvent and the structure of the allyl ligand are determined. The activation parameters of individual steps, consistent with quantum chemical calculations, are found.
- Flid,Zamalyutin,Shamsiev,Katsman
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p. 113 - 117
(2019/05/27)
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- Interstitial nitrides revisited – A simple synthesis of MxMo3N (M = Fe, Co, Ni)
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The efficient synthesis of polycrystalline filled beta-Mn structured Ni2Mo3N, and the eta-carbides Fe3Mo3N and Co3Mo3N, by a single heating of metal powders at 975 °C under a hydrogen-nitrogen mixture is reported. Rietveld analysis of high-resolution X-ray powder diffraction data shows that the reduction-nitridation of NiMoO4 produces Ni2Mo3N and nickel; Ni3Mo3N is not obtained in this way and its existence is disproved.
- Conway, Jack O.,Prior, Timothy J.
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- Compound, thin film-forming material, and thin film manufacturing method
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A novel compound represented by the general formula (I) or (II) below: [in the formula, each of R1 and R2 independently represent a C1?12 hydrocarbon group, and Si(R3)3 is optionally substituted for a hydrogen atom in the hydrocarbon group; however, R1 and R2 are different groups; R3 represents a methyl or ethyl group; M represents a metal atom or silicon atom; and n is an integer from 1 to 4].
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Page/Page column 31-32
(2019/04/26)
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- Hierarchical Hollow Nanoprisms Based on Ultrathin Ni-Fe Layered Double Hydroxide Nanosheets with Enhanced Electrocatalytic Activity towards Oxygen Evolution
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The oxygen evolution reaction (OER) is involved in various renewable energy systems, such as water-splitting cells and metal–air batteries. Ni-Fe layered double hydroxides (LDHs) have been reported as promising OER electrocatalysts in alkaline electrolytes. The rational design of advanced nanostructures for Ni-Fe LDHs is highly desirable to optimize their electrocatalytic performance. Herein, we report a facile self-templated strategy for the synthesis of novel hierarchical hollow nanoprisms composed of ultrathin Ni-Fe LDH nanosheets. Tetragonal nanoprisms of nickel precursors were first synthesized as the self-sacrificing template. Afterwards, these Ni precursors were consumed during the hydrolysis of iron(II) sulfate for the simultaneous growth of a layer of Ni-Fe LDH nanosheets on the surface. The resultant Ni-Fe LDH hollow prisms with large surface areas manifest high electrocatalytic activity towards the OER with low overpotential, small Tafel slope, and remarkable stability.
- Yu, Le,Yang, Jing Fan,Guan, Bu Yuan,Lu, Yan,Lou, Xiong Wen David
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supporting information
p. 172 - 176
(2017/12/29)
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- Ice Melting to Release Reactants in Solution Syntheses
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Aqueous solution syntheses are mostly based on mixing two solutions with different reactants. It is shown that freezing one solution and melting it in another solution provides a new interesting strategy to mix chemicals and to significantly change the reaction kinetics and thermodynamics. For example, a precursor solution containing a certain concentration of AgNO3 was frozen and dropped into a reductive NaBH4 solution at about 0 °C. The ultra-slow release of reactants was successfully achieved. An ice-melting process can be used to synthesize atomically dispersed metals, including cobalt, nickel, copper, rhodium, ruthenium, palladium, silver, osmium, iridium, platinum, and gold, which can be easily extended to other solution syntheses (such as precipitation, hydrolysis, and displacement reactions) and provide a generalized method to redesign the interphase reaction kinetics and ion diffusion in wet chemistry.
- Wei, Hehe,Huang, Kai,Zhang, Le,Ge, Binghui,Wang, Dong,Lang, Jialiang,Ma, Jingyuan,Wang, Da,Zhang, Shuai,Li, Qunyang,Zhang, Ruoyu,Hussain, Naveed,Lei, Ming,Liu, Li-Min,Wu, Hui
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supporting information
p. 3354 - 3359
(2018/02/21)
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- Supported Ru?Ni Catalysts for Biogas and Biohydrogen Conversion into Syngas
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Catalytic properties of monometallic Ni and bimetallic Ru–Ni supported on Al2O3, CaO–Al2O3, and MgO–Al2O3 have been studied in mixed reforming of methane. Physicochemical properties of the
- Mierczynski,Ciesielski,Zakrzewski,Dawid,Mosinska,Kedziora,Maniukiewicz,Dubkov,Gromov,Szynkowska,Witonska,Shtyka,Maniecki
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p. 509 - 513
(2018/08/17)
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- On the influence of the titanium source on the composition and structure of novel titanoniobates
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Systematic variation of the titanium source and the reaction temperature applied during hydrothermal synthesis led to crystallization of four new titanoniobates: {[Ni(cyclam)]4[Ti2Nb8O28]}n·～28nH2O (I), K[Ni(cyclam)]3[TiNb9O28]·xH2O; x = 18 (II), x = 14 (III) and x ～ 10 (IV). These are the first titanoniobates with Ni2+-centered amine complexes acting as counter cations and additionally, this is the first report of transition metal complexes expanded by monotitanoniobates. While I is obtained using Ti(OiPr)4, II-IV are formed using K2TiO(C2O4)·2H2O as the educt. The presence of oxalate anions seems to influence the coordination environments of the Ni2+ cations that are octahedrally coordinated in I, and in a square-planar environment in II-IV. The titanium source also affects the degree of substitution of NbV by TiIV. Temperature-dependent syntheses demonstrate that the formation of I does not depend on the reaction temperature, while the formation of II-IV is clearly affected by this parameter. Regarding the arrangement of crystal water molecules, patterns of different dimensionalities ranging from 0D to 3D are formed which can be classified as water clusters. Each compound exhibits a pronounced plateau in the thermogravimetric curves after the removal of crystal H2O molecules. Rehydration experiments after water removal proved that except for compound III, the re-integration of water was successful.
- Dopta, Joanna,Grzanna, Sven,N?ther, Christian,Bensch, Wolfgang
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p. 15103 - 15113
(2018/11/10)
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- Hafnocene-based Bicyclo[2.1.1]hexene Germylenes - Formation, Reactivity, and Structural Flexibility
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2,5-Disilylsubstituted germole dianions 1 react with hafnocene dichloride to give hafnocene-based bicyclo[2.1.1]hexene germylenes 3. Their formation proceeds via hafnocene-germylene complexes 2 that were identified by NMR and UV spectroscopy. Germylenes 3 are stabilized by homoconjugation between the empty 4p(Ge) orbital and the ?€-bond of the innercyclic C2? - C3 double bond. This interaction can be understood as σ2, ?€-coordination of the butadiene part to the dicoordinated germanium atom that leaves the 16e- hafnocene moiety electronically unsaturated. We demonstrate that this new class of germylenes might serve as ligand to a variety of low-valent transition-metal complexes. The structure of the germylene ligand in complexes with Fe(0), Ni(0), and Au(I) and in reaction products with N-heterocyclic carbenes showed an intriguing structural flexibility that allows to accommodate different electronic situations at the ligating germanium atom. The origin of this structural adaptability is the interplay between the topological flexible unsaturated germanium ring and the hafnocene group.
- Dong, Zhaowen,Bedbur, Katja,Schmidtmann, Marc,Müller, Thomas
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supporting information
p. 3052 - 3060
(2018/03/08)
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- Synthesis, characterization, antimicrobial activity and DFT studies of 2-(pyrimidin-2-ylamino)naphthalene-1,4-dione and its Mn(II), Co(II), Ni(II) and Zn(II) complexes
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A pyrimidine-based ligand, 2-(pyrimidin-2-ylamino)naphthalene-1,4-dione (L), has been synthesized by the reaction of 2-aminopyrimidine with 2-hydroxy-1,4-napthoquinone. Reaction of the ligand with Ni(II), Co(II), Mn(II) and Zn(II) acetate gave the corresponding metal complexes which were characterized by spectroscopic techniques, (infrared, electronic), elemental analysis, room-temperature magnetometry, conductance measurements and thermogravimetry-differential scanning calorimetry (TG-DSC) analyses. The room-temperature magnetic data and electronic spectral measurements of the complexes gave evidence of 4-coordinate square planar/tetrahedral geometry. The thermal analyses values obtained indicated the monohydrate complexes. The antimicrobial screening of the compounds showed mild to very good results. The Mn(II) complex showed the best result within in the range of 11.5–29 mm. The electronic, structural and spectroscopic properties of the complexes were further discussed using density functional theory. Molecular docking studies showed significant binding affinity with the drug targets and the metal complexes have potentials to be used as drugs.
- Chioma, Festus,Ekennia, Anthony C.,Ibeji, Collins U.,Okafor, Sunday N.,Onwudiwe, Damian C.,Osowole, Aderoju A.,Ujam, Oguejiofo T.
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p. 455 - 464
(2018/05/03)
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- Structural designing, spectral and computational studies of bioactive Schiff's base ligand and its transition metal complexes
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Transition metal complexes of Mn(II) and Ni(II) have been synthesized with novel bioactive Schiff's base ligand. Schiff's base ligand i.e. benzoylacetone-bis(2-amino-4-methylbenzothioazole) has been synthesized via condensation reaction between 2-amino-4-
- Gautam, Seema,Chandra, Sulekh,Rajor, Hament,Agrawal, Swati,Tomar, Praveen Kumar
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- Catalytic behavior of magnetic Ni–Zn alloy
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Ni–Zn alloy with various compositions of zinc was synthesised using a sodium borohydride-assisted chemical reduction method. The as-synthesised Ni–Zn alloy samples were annealed at 673?K for 2?h in nitrogen atmosphere. The atomic absorption spectroscopy measurement reveals the zinc-rich composition in all alloy samples. Field emission scanning electron microscopy shows that the surface morphology of Ni–Zn alloys has a flake-like nature. The X-ray diffraction pattern of as-synthesised samples shows the presence of nickel hydroxide while the annealed samples show formation of Ni2Zn11 phase. The phase transition temperature of as-synthesised Ni–Zn alloy was observed using differential scanning calorimetry and crystallization temperature changes with zinc composition was also examined. The room temperature magnetic behaviour of both as-synthesised and annealed samples was studied using vibrating sample magnetometer. This shows that as-synthesised samples have a weak ferromagnetic nature and annealed samples have a soft ferromagnetic nature. The decreasing magnetization value and Curie temperature with zinc composition was observed. The catalytic activity of Ni–Zn alloy was studied for the reduction of 4-nitrophenol. The rate constant value changes with zinc composition in the alloy.
- Dhanapal,Dhanavel,Revathy,Narayanan,Stephen
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p. 4149 - 4161
(2018/03/21)
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- Ni-Catalyzed Regioselective Alkylarylation of Vinylarenes via C(sp3)-C(sp3)/C(sp3)-C(sp2) Bond Formation and Mechanistic Studies
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We report a Ni-catalyzed regioselective alkylarylation of vinylarenes with alkyl halides and arylzinc reagents to generate 1,1-diarylalkanes. The reaction proceeds well with primary, secondary and tertiary alkyl halides, and electronically diverse arylzinc reagents. Mechanistic investigations by radical probes, competition studies and quantitative kinetics reveal that the current reaction proceeds via a Ni(0)/Ni(I)/Ni(II) catalytic cycle by a rate-limiting direct halogen atom abstraction via single electron transfer to alkyl halides by a Ni(0)-catalyst.
- Kc, Shekhar,Dhungana, Roshan K.,Shrestha, Bijay,Thapa, Surendra,Khanal, Namrata,Basnet, Prakash,Lebrun, Robert W.,Giri, Ramesh
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supporting information
p. 9801 - 9805
(2018/08/06)
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- Selective hydrogenolysis of Α–O–4, Β–O–4, 4–O–5 C–O bonds of lignin-model compounds and lignin-containing stillage derived from cellulosic bioethanol processing
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Benzyl phenyl ether (BPE), phenethyl phenyl ether (PPE) and diphenyl ether (DPE) have been selected as model compounds of the most abundant and significant ether linkages found within the complex structure of lignin (e.g. α–O–4, β–O–4, and 4–O–5, respectively). The catalytic hydrogenolysis of these compounds has been carried out using several Ru, Pd and Ni catalysts supported over different metal oxides (e.g. Al2O3, ZrO2, TiO2) and carbon materials (e.g. active carbon, multiwall carbon nanotubes). The conversion of these compounds at relevant hydroprocessing conditions (150?°C, 25?bar-g in H2 atmosphere) is much dependent on the labile nature of the relevant ether bonds of the selected model compounds. Conversion levels for the three compounds increases in the following order: DPE (4–O–5 linkage)??Pd?>?Ru). The catalytic systems with easier reducible species performes better in the conversion of the dimer models. Besides, a preliminary study on the catalytic depolymerization of a real lignin stream (lignin-containing 2G bioethanol plants stillage) has been carried out. Detailed characterization by 13C-1H heteronuclear single-quantum correlation spectroscopy (HSQC) showed that on 5?wt.% Ru/C it is possible to achieve 50% desapearance of the most abundant lignin ether bond (i.e. β–O–4) and liquid yields above 50?wt.%.
- Gómez-Monedero,Ruiz,Bimbela,Faria
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- Catalytic Aerial Oxidation of Biomass-Derived Furans to Furan Carboxylic Acids in Water over Bimetallic Nickel–Palladium Alloy Nanoparticles
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Bimetallic Ni1?xPdx (0.10≤x≤0.75) alloy nanoparticle catalysts were synthesised and successfully employed for the catalytic aerial oxidation of biomass-derived furans, such as 2-furfuraldehyde (furfural), 2-furfuryl alcohol (furfuryl alcohol), 5-hydroxymethyl-2-furfural (5-HMF), 5-methyl-2-furfural (MF) and 5-methyl-2-furfuryl alcohol (MFA), to selectively afford the corresponding furan carboxylic acids (2-furoic acid, furan-2,5-dicarboxylic acid (FDCA) and 5-methyl-2-furoic acid (MFCA)) in water at 80 °C. Among the studied Ni1?xPdx nanoparticle catalysts, Ni0.90Pd0.10 nanoparticle catalyst outperformed the others, achieving high yields of the corresponding furan carboxylic acid products. The presence of Ni in the Ni1?xPdx nanoparticle catalysts was advantageous, because it not only enhanced the catalytic activity for the facile oxidation of biomass-derived furans using aerial oxygen to achieve high catalytic turnover, but also provided excellent stability to the Ni0.90Pd0.10 nanoparticle catalyst towards air and water and thus significantly enhanced its recyclability (up to 10 catalytic runs). The experiments revealed that the catalytic oxidation of 5-HMF proceeded by the initial oxidation of the formyl group to carboxylic acid, and, subsequently, the conversion of alcohol to carboxylic acid via the formyl group to form FDCA. Moreover, the one-pot direct transformation of fructose to furan carboxylic acid products (such as FDCA) was also achieved by using the Ni0.90Pd0.10 nanoparticle catalyst.
- Gupta, Kavita,Rai, Rohit K.,Dwivedi, Ambikesh D.,Singh, Sanjay K.
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p. 2760 - 2767
(2017/07/28)
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- 3D hierarchical Ni(PO3)2 nanosheet arrays with superior electrochemical capacitance behavior
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A novel electrode material, three-dimensional (3D) hierarchical Ni(PO3)2 nanosheet arrays, is explored via a rational topotactic strategy combining hydrothermal growth with subsequent phosphorylation treatment. The as-synthesized Ni(PO3)2 nanosheet arrays self-supported on activated carbon cloth (Ni(PO3)2@ACC) exhibit superior electrochemical capacitive behaviors to a Ni(OH)2 analogue with similar structural characteristics. The areal and mass specific capacitances of the arrays are as high as 4.43 F cm-2 at a current density of 2 mA cm-2 and 2237 F g-1 at ～1 A g-1, respectively, which is comparable to the best reported results for Ni-based and Me-POx battery-type electrodes. Furthermore, even at a high rate of 10 mA cm-2, the arrays maintain ～90% charge retention after 2000 cycles, suggesting their robust stability and their very promising applications for energy storage.
- Liu, Qiao,Chen, Chongyi,Zheng, Jinju,Wang, Lin,Yang, Zuobao,Yang, Weiyou
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supporting information
p. 1421 - 1427
(2017/02/05)
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- [NiEn3]CrO4: Structure, thermal properties, and pseudomorphism
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The crystal structure of [NiEn3]CrO4 (En is ethylendiamine), C6H24CrN6NiO4 is studied: a = 9.0408(5) ?, c = 9.7466(4) ?, V = 689.92(8) ?3, space group P63/mmc, Z = 2, dx = 1.704 g/cm3, Ni–N 2.133(9) ?, ∠N–Ni–N 82.4(5)°. The thermal properties are determined. When it is heated in a hydrogen atmosphere, a mixture of nanocrystalline Ni and Cr2O3 powders with coherent scattering regions of 59 nm and 90 nm respectively is formed. It is demonstrated that thermal decomposition products consist of pseudomorphic particles that inherit the sizes and shapes of initial [NiEn3]CrO4 single crystals.
- Khranenko,Komarov, V. Yu.,Gerasimov, E. Yu.,Zadesenets,Maksimovsky,Gromilov
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p. 1448 - 1452
(2018/01/05)
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- Synthesis, spectroscopic, and thermal investigations of metal complexes with mefenamic acid
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The novel metal complexes with empirical formulae M(mef)2·nH2O (where M = Mn(II), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II); mef is the mefenamic ligand) were synthesized and characterized by elemental analysis, molar conductance, FTIR-spectroscopy, and thermal decomposition techniques. All IR spectra revealed absorption bands related to the asymmetric (as) and symmetric (s) vibrations of carboxylate group. The Nakamoto criteria clearly indicate that this group is bonded in a bidentate chelate mode. The thermal behavior of complexes was studied by TGA methods under non-isothermal condition in air. Upon heating, all compounds decompose progressively to metal oxides, which are the final products of pyrolysis. Cu(II), Zn(II), and Cd(II) complexes were also characterized by the coupled TG-FTIR technique, which finally proved the path and gaseous products of thermal decomposition. Additionally, the coupled TG-MS system was used to determine the principal volatile products of thermolysis and fragmentation processes of Mn(mef)2·3H2O and Co(mef)2·2H2O.
- Kafarska, Karolina,Gacki, Micha?,Wolf, Wojciech M.
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- Ni(II) and Cu(II) complexes with ONNO asymmetric tetradentate Schiff base ligand: synthesis, spectroscopic characterization, theoretical calculations, DNA interaction and antimicrobial studies
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A novel Schiff base, namely Z-3-((2-((E)-(2-hydroxynaphthyl)methylene)amino)-5-nitrophenylimino)-1,3-dihydroindin-2-one, was synthesized from the condensation of 2-hydroxy-1-naphthaldehyde and isatin with 4-nitro-o-phenylenediamine. It was structurally characterized on the basis of 1H NMR, 13C NMR and infrared spectra and elemental analyses. In addition, Ni(II) and Cu(II) complexes of the Schiff base ligand were prepared. The nature of bonding and the stereochemistry of the investigated complexes were elucidated using several techniques, including elemental analysis (C, H, N), Fourier transform infrared and electronic spectroscopies and molar conductivity. The thermal behaviours of the complexes were studied and kinetic–thermodynamic parameters were determined using the Coats–Redfern method. Density functional theory calculations at the B3LYP/6-311G++ (d, p) level of theory were carried out to explain the equilibrium geometry of the ligand. The optimized geometry parameters of the complexes were evaluated using LANL2DZ basis set. The total energy of highest occupied and lowest unoccupied molecular orbitals, Mullikan atomic charges, dipole moment and orientation are discussed. Moreover, the interaction of the metal complexes with calf thymus DNA (CT-DNA) was explored using electronic spectra, viscosity measurements and gel electrophoresis. The experimental evidence indicated that the two complexes could strongly bind to CT-DNA via an intercalation mechanism. The intrinsic binding constants of the investigated Ni(II) and Cu(II) complexes with CT-DNA were 1.02?×?106 and 2.15?×?106?M?1, respectively, which are higher than that of the standard ethidium bromide. Furthermore, the bio-efficacy of the ligand and its complexes was examined in vitro against the growth of bacteria and fungi to evaluate the antimicrobial potential. Based on the obtained results, the prepared complexes have promise for use as drugs. Copyright
- Abdel-Rahman, Laila H.,Abu-Dief, Ahmed M.,Moustafa,Hamdan, Samar Kamel
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- B-cation partial substitution of double perovskite La2NiTiO6 by Co2 +: Effect on crystal structure, reduction behavior and catalytic activity
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La2NiTi0.9Co0.1O6 and La2Ni0.9Co0.1TiO6 perovskites were obtained by partial substitution of either Ti4 + or Ni2 + from double perovskite La2NiTiO6 by Co2 +. The Rietveld analysis demonstrated that all as-synthesized samples have orthorhombic symmetry and space group Pbnm. Quantitative phase analysis using Rietveld refinement of XRD profiles after temperature programmed reduction showed that the reduction of La2NiTiO6 was modified by partial substitution of either Ni2 + or Ti4 + by Co2 +, being more evident for the La2NiTi0.9Co0.1O6. The activity of all catalysts for steam reforming of methane was attributed to both the reduction degree of two-valence metals and the metal-support interaction.
- Tuza, Pablo V.,Souza, Mariana M.V.M.
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- Selective hydrogenation of unsaturated carbonyls by Ni-Fe-based alloy catalysts
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Ni-Fe alloy catalysts prepared by a simple hydrothermal method and subsequent H2 treatment exhibited the greatest activity and selectivity for the hydrogenation of biomass-derived furfural to furfuryl alcohol among the examined second metals, such as Al, Ga, In, Co, and Ti. This work reveals that the alloying of Ni and Fe is a key factor in achieving highly selective hydrogenation of the CO moiety in unsaturated carbonyl substrates. We found that decreasing the temperature of H2 treatment (i.e. decreasing the crystallite size), e.g. Ni-Fe(2)HT-573 K (TOF = 952 h-1), increased the activity compared to that over Ni-Fe(2)HT-673 (TOF = 375 h-1) for furfural hydrogenation. This result suggests that a low-coordinated Ni-Fe alloy was imperative for the catalytic cycle. Moreover, the effect of the metal/support interface was critical; despite the high catalytic performance of Ni-Fe/TiO2, Ni-Fe/Al2O3, and Ni-Fe/CeO2, Ni-Fe supported on SiO2, taeniolite, and hydrotalcite catalysts were ineffective. Vibrational studies using FT-IR measurement confirmed that furfural was physically adsorbed on the surface of the Ni-Fe alloy catalyst via an η1(O) configuration. The synthetic scope of the Ni-Fe catalytic system was very broad; various types of unsaturated carbonyls, such as unsaturated aromatics, unconjugated aliphatics, and a large substituent, were selectively converted into the corresponding unsaturated alcohols.
- Putro, Wahyu S.,Kojima, Takashi,Hara, Takayoshi,Ichikuni, Nobuyuki,Shimazu, Shogo
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p. 3637 - 3646
(2017/08/21)
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- Coordination chemistry and oxidative addition of trifluorovinylferrocene derivatives
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Complexes using trifluorovinylferrocene and 1,1′-bis(trifluorovinyl)ferrocene as ligands can be obtained by the reaction with a series of fragments of transition metal complexes. Formation of [Pt(η2-trifluorovinylferrocene)(PPh3)2] (1), [{Pt(PPh3)2}2(η2-1,1′-bis(trifluorovinyl)ferrocene)] (2) and [Pt(η2-1,1′-bis(trifluorovinyl)ferrocene)(PPh3)2] (3) were achieved by ligand substitution in [Pt(η2-CH2?=?CH2)(PPh3)2]. Treatment of eneacarbonyldiiron with trifluorovinylferrocene provided [Fe(CO)4(η2-trifluorovinylferrocene)] (4). Photolytically activated reactions of [MnCp(CO)3] and [MnCp′(CO)3] (Cp′?=?C5H4CH3) afforded [MnCp(CO)2(η2-trifluorovinylferrocene)] (5a) and [MnCp′(CO)2(η2-trifluorovinylferrocene)] (5b) respectively. [Ni(η2-trifluorovinylferrocene)(Cy2P(CH2)2PCy2)] (6) could be obtained by reaction with [Ni(COD)2] and Cy2P(CH2)2PCy2. Furthermore the C[sbnd]F bond activation by oxidative addition in the presence of lithium iodide yielding two isomers of [PtI{η1-difluorovinylferrocene}(PPh3)2] (7a/7b) is presented. Molecular structures of 1, 4 and 7a were elucidated using X-ray single crystal diffraction. The spectroscopic and structural data of these complexes prove the powerful π acceptor abilities of these ligands.
- Heinrich, Darina,Schmolke, Willi,Lentz, Dieter
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p. 105 - 112
(2016/11/11)
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- Strategy to improve phase compatibility between proton conductive BaZr0.8Y0.2O3-δ and nickel oxide
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BaZr0.8Y0.2O3-δ (BZY20) is a promising candidate as an electrolyte in protonic ceramic fuel cells (PCFCs), and nickel (Ni) is known to show good electrode properties for the anode reaction. However, their compatibility seems to be questionable, since during the co-sintering process for cell fabrication, a second phase of BaY2NiO5 formed due to a reaction between BZY20 and NiO. The results in this work revealed that BaY2NiO5 was unstable against high temperature (1500 and 1600 °C), and could also be reduced in a hydrogen atmosphere at 600 °C. The products of these reactions may affect fuel cell performance. A systematic work was then performed to provide fundamental insight into the reactivity between BZY20 and NiO, which was found to be impacted significantly by the compositional homogeneity of the BZY20 powder used for cell fabrication, and also the BaO activity during the co-sintering process. It is concluded that improving the compositional homogeneity of BZY20, by elevating the final heating temperature for BZY20 from 1300 to 1600 °C in this work, and choosing a proper sintering strategy may improve effectively the phase purity of the cell.
- Han, Donglin,Otani, Yuki,Noda, Yohei,Onishi, Takayuki,Majima, Masatoshi,Uda, Tetsuya
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p. 19288 - 19297
(2016/03/01)
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- Development of heterogeneous Ni-Ni complex/HPA-RNi catalyst for hydrogenation of benzene
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Raney nickel (RNi) was modified by (NH4)3PMo12O40 heteropoly acid (HPA) to give supported HPA-RNi through exchange of ammonium ion. A homo binuclear Ni-Ni complex was synthesized to form Ni-Ni complex/HPA-RNi heterogeneous catalyst, which was used for liquid phase benzene hydrogenation. The complex and the catalyst are well characterized and the heterogeneous catalyst thus prepared was found to be highly active at lower hydrogen pressures of 2.8-3.5 MPa and at moderate temperatures of 393-473 K. The catalyst was 100 % selective towards the formation of cyclohexane. The reaction rates of benzene reduction were considerably higher (1.4-5.0 times) compared to standard hydrogenation catalysts and comparable to those of noble metal catalysts reported in the literature. The catalyst was found to be thermally and chemically stable at higher temperatures and have shown that the hydrogenation of 100 h did not affect the nature of the catalyst.
- Lal, Sunder,Pant, Deeptiraj
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p. 1447 - 1452
(2016/05/09)
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- New bulk nickel phosphide catalysts for glycerol hydrogenolysis to 1,2-propanediol
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Transitional metal phosphides were found to have outstanding activity and stability in catalytic hydrotreatments. The bulk trinickel phosphide catalyst with the smallest phosphorus content among the nickel phosphides were synthesized by a hydrothermal method followed by an annealing treatment, and the resulting bulk trinickel phosphide catalysts presented a high purity and morphology of hexagonal prisms. The optimized synthesis conditions include a P:Ni ratio of 3 to 1 and a pH value of 5 in the hydrothermal synthesis stage and a calcination temperature of 773 K in the annealing treatment. The synthesized trinickel phosphides exhibited a low-temperature activity to selective glycerol hydrogenolysis and the high selectivity to 1,2-propanediol.
- Shi, Guojun,Su, Lijun,Jin, Kai
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p. 180 - 183
(2015/02/19)
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- Facile synthesis of crumpled ZnS net-wrapped Ni walnut spheres with enhanced microwave absorption properties
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Controllable magnetic-dielectric hybrids with cores of walnut-like Ni and shells of ultra-thin and crumpled ZnS nets have been successfully synthesized by a facile two-step approach. The morphology, microstructure and microwave absorption properties of the as-synthesized core-shell Ni/ZnS composites were investigated by scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, transmission electron microscopy and network analysis. The shapes and microwave absorption properties of Ni/ZnS can be tuned by the hydrothermal temperatures. The core-shell Ni/ZnS composites present significantly enhanced microwave absorption compared with pristine Ni walnuts. When the reaction temperature was 60°C, the reflection loss (RL) could be as low as -42.4 dB at 12.3 GHz. Moreover, the effective bandwidth (RL -10 dB) can be recorded in the 11.3-15.6 GHz range with the absorber thickness of only 2.2 mm. The excellent microwave absorption properties were attributed to impedance match, the synergetic effect between the dielectric loss and magnetic loss, interfacial relaxation and conduction loss of unique cross-linked ZnS shells. These results suggest that the as-synthesized crumpled ZnS net-wrapped Ni composites may be an attractive candidate for microwave absorption application.
- Zhao, Biao,Shao, Gang,Fan, Bingbing,Zhao, Wanyu,Chen, Yongqiang,Zhang, Rui
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p. 9806 - 9814
(2015/03/05)
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