7440-02-0

Kinetic regularities of the chemical vapor deposition of nickel layers from bis-(ethylcyclopentadienyl)nickel

Protopopova,Alexandrov

, p. 742 - 746 (2012)

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.

Magnetic properties of nanometric nickel particles

Broto,Ousset,Rakoto,Askenazy,Dufor,Brieu,Mauret

, p. 263 - 265 (1993)

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.

Russell, A. S.,Carver, J. C.

, p. 210 - 211 (1938)

Supercapacitor electrodes with high-energy and power densities prepared from monolithic NiO/Ni nanocomposites

Lu, Qi,Lattanzi, Michael W.,Chen, Yunpeng,Kou, Xiaoming,Li, Wanfeng,Fan, Xin,Unruh, Karl M.,Chen, Jingguang G.,Xiao, John Q.

, p. 6847 - 6850 (2011)

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

Effect of nickel precursors on the performance of Ni/AlMCM-41 catalysts for n-dodecane hydroconversion

Fang, Kegong,Ren, Jie,Sun, Yuhan

, p. 51 - 58 (2005)

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

Fabrication and magnetic properties of nickel dodecahedra

Zhao, Lijun,Zhao, Lei,Zhang, Guangshu

, p. 5913 - 5919 (2014)

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.

One-step synthesis of carbon nanotubes with Ni nanoparticles as a catalyst by the microwave-assisted polyol method

Liu, Xian-Song,Hu, Feng,Zhu, De-Ru,Jia, Dao-Ning,Wang, Peng-Peng,Ruan, Zheng,Cheng, Chun-Hao

, p. 2829 - 2832 (2011)

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.

Cyclic voltammetry study of the NiP electrodeposition

Crousier, J.,Hanane, Z.,Crousier, J-P.

, p. 261 - 266 (1993)

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.

Comparison of the magnetic properties of metastable hexagonal close-packed Ni nanoparticles with those of the stable face-centered cubic Ni nanoparticles

Jeon, Yoon Tae,Moon, Je Yong,Lee, Gang Ho,Park, Jeunghee,Chang, Yongmin

, p. 1187 - 1191 (2006)

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.

Enhanced electrochemical performance of nanoplate nickel cobaltite (NiCo2O4) supercapacitor applications

Yedluri, Anil Kumar,Kim, Hee-Je

, p. 1115 - 1122 (2019)

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.

Magnetic field effects in electrochemical reactions

Bund,Koehler,Kuehnlein,Plieth

, p. 147 - 152 (2003)

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.

Electrocodeposition of nickel nanocomposites using an impinging jet electrode

Thiemig, Denny,Bund, Andreas,Talbot, Jan B.

, p. D510-D515 (2007)

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.

Magnetophoresis behaviour at low gradient magnetic field and size control of nickel single core nanobeads

Benelmekki,Montras,Martins,Coutinho,Martinez, Ll.M.

, p. 1945 - 1949 (2011)

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.

Watt. G. W.,Davies, D. D.

, p. 3753 - 3755 (1948)

Aqueous solutions of colloidal nickel: Radiation-chemical preparation, absorption spectra, and properties

Ershov

, p. 1715 - 1721 (2000)

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.

Amperometric detection of hydrogen peroxide at nano-nickel oxide/thionine and celestine blue nanocomposite-modified glassy carbon electrodes

Noorbakhsh, Abdollah,Salimi, Abdollah

, p. 6312 - 6321 (2009)

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

Paravano, G.

, p. 1194 - 1198 (1952)

SURFACE STATE,CATALYTIC ACTIVITY AND SELECTIVITY OF NICKEL CATALYSTS IN HYDROGENATION REACTIONS

Yasuaki Okamoto,Yuriko Nitta,Toshinobu Imanaka,Shiichiro Teranishi

, p. 998 - 1007 (1980)

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.

Ammonia-assisted fabrication of flowery nanostructures of metallic nickel assembled from hexagonal platelets

Ni, Xiaomin,Zheng, Huagui,Yang, Qing,Tang, Kaibin,Liao, Guangxuan

, p. 677 - 682 (2009)

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

Fabrication of Ni-coated Al2O3 powders by the heterogeneous precipitation method

Li, Guo-Jun,Huang, Xiao-Xian,Guo, Jing-Kun

, p. 1307 - 1315 (2001)

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.

Electrooxidation of methanol on NiMn alloy modified graphite electrode

Danaee,Jafarian,Mirzapoor,Gobal,Mahjani

, p. 2093 - 2100 (2010)

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.

Polar symmetry and intercalation of new multilayered hybrid molybdates: [M2(pzc)2(H2O)x][Mo 5O16] (M = Co, Ni)

Yan, Bangbo,Maggard, Paul A.

, p. 4721 - 4727 (2006)

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.

Alkalization of the near-cathode layer in electrodeposition of nickel from a chloride electrode

Balakai,Arzumanova,Balakai

, p. 65 - 71 (2010)

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.

Hydrangea-like NiCo-based Bimetal-organic Frameworks, and their Pros and Cons as Supercapacitor Electrode Materials in Aqueous Electrolytes

Li, Qiaoqin,Wang, Xiaoqin,Yang, Nana,He, Fan,Yang, Yufei,Wu, Bohua,Chu, Jia,Zhou, Anning,Xiong, Shanxin

, p. 1022 - 1030 (2019)

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.

Magnetic nanochains of metal formed by assembly of small nanoparticles

Liu, Chen-Min,Guo, Lin,Wang, Rong-Ming,Deng, Yuan,Xu, Hui-Bin,Yang, Shihe

, p. 2726 - 2727 (2004)

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.

Autoclave Synthesis of Finely Divided Nickel Powders

Belousov, O. V.,Belousova, N. V.,Borisov, R. V.,Romanchenko, A. S.,Zeer, G. M.

, p. 1463 - 1468 (2021/11/24)

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.

Self-assembled Ni/NiO impregnated polyaniline nanoarchitectures: A robust bifunctional catalyst for nitrophenol reduction and epinephrine detection

Ramadoss, Manigandan,Chen, Yuanfu,Ranganathan, Suresh,Giribabu, Krishnan,Thangavelu, Dhanasekaran,Annamalai, Padmanaban,Vengidusamy, Narayanan

, (2021/02/26)

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.

Synthesis, physical and electrochemical properties of CoMn2O4: application to photocatalytic Ni2+ reduction

Kaci,Nasrallah,Kebir,Guernanou,Soukeur,Trari

, p. 1693 - 1712 (2021/01/20)

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.