- Aluminium powder as a reactive template for preparation of carbon flakes from CCl4
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Abstract: This work presents a simple procedure for the preparation of 2D carbon flakes by a catalyst-free redox reaction in the range of 400–600?°C at atmospheric pressure. Tetrachloromethane (CCl4) was reduced by aluminium flakes (Al), which also serve as a?template for carbon flakes, for either 60?min or 120?min. Gaseous aluminium chloride (AlCl3) was released from the?synthesis. According to BET analysis, the prepared carbon flakes exhibit a mesoporous structure with surface area in?the?range of 300–500?m2?g?1. The 2D morphology and amorphous character was confirmed by XRD, Raman spectra and TEM analyses. In addition, SEM and TEM images revealed the carbon flakes are composed from carbon layers which can be also folded. A?mechanism of their formation was also proposed. At?higher reaction temperature, e.g., 700?°C, 1D carbon nanostructures with worm-like morphology was obtained. Graphic Abstract: [Figure not available: see fulltext.].
- ?imon, Erik,Billik, Peter,Orov?ík, ?ubomír,Nagy, ?tefan,Sasinková, Vlasta,Palou, Martin T.,?krátek, Martin,Trembo?ová, Veronika,Plesch, Gustav
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- Preparation of a platelike carbon nanomaterial using MgO as a template
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A carbon nanomaterial in the form of hollow hexagonal platelets with shells of disordered graphene layers has been synthesized through CH4 pyrolysis on pseudomorphic hexagonal MgO platelets 1-2 μm in average size, followed by dissolution of the magnesium oxide. The material has a specific surface area above 1300 m2/g, specific pore volume of 3.23 cm 3/g, and resistivity of 0.08 Ω cm. Pleiades Publishing, Ltd., 2012.
- Davydov,Kryukov,Gerya,Izvol'skii,Rakov
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- Chemical vapor deposition of methane for single-walled carbon nanotubes
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We report the synthesis of high-quality single-walled carbon nanotubes (SWNT) by chemical vapor deposition (CVD) of methane at 1000°C on supported Fe2O3 catalysts. The type of catalyst support is found to control the formation of ind
- Kong, Jing,Cassell, Alan M.,Dai, Hongjie
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- A novel emulsion-based replica method for the synthesis of mesoporous carbon
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We present a novel approach for the synthesis of large-pore mesoporous carbon with a highly porous structure, based on an oil/water (O/W) emulsion templating method. For the formation of oil-in-water emulsions with nanoscale oil droplets, polyvinylpyrrolidone was used as an emulsifier. Mesoporous carbon materials with large mesopores were successfully synthesized via a three-step process: (1) polymerization in the oil-in-water emulsion, (2) filtration, and (3) carbonization. We confirmed that the pore size of the carbon can be significantly reduced through a modified O/W emulsion method. The mesoporous carbon materials prepared without an activation step exhibited an appreciable surface area (705 m2/g) and a noticeable capacitive performance of ～100 F/g at 2.0 A/g. We believe that the approach presented here can be widely applied to the synthesis of mesoporous carbon using various carbon sources, and the structural properties of the mesoporous carbon can be improved through proper optimization.
- Kang, Jin Kyeong,Xiong, Wei,Kang, Ji Hoon,Kang, Jukyoung,Kim, Seok,Jung, Yongju
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- STRUCTURE OF THE RESIDUAL CARBON MADE BY FLUOROCARBON PYROLYSIS
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Fluorocarbon defluorination products show an anusual temperature dependence for the paramagnetic susceptibility in the range 77-300 K after pyrolysis at 650-1000 deg C, which is explained from dynamic equilibrium between the formation and dissociation of free radicals involving a bond eergy of 11.22 kJ/mole.The ESR line width initially increases with temperature but then decreases.The width of the inhomogeneously broadened line has been calculated as a function of the frequencies of the static and dynamic spin exchange, which shows that at low temperatures there is alocal increase in the radical concentration, but at higher temperatures, the dynamic exchange averages out this dipole spin-spin interaction.A suggestion confirmed by x-ray structures analysis is that the products contain a linear form of carbon.
- Fialkov, A. S.,Dobryakov, S. N.,Khorkhorin, A. V.,Tyan, L. S.,Polyakova, N. V.,et al.
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- Electrical and thermoelectric power measurements of GaInSe2 single crystals
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A single crystal of GaInSe2 was prepared from melt using a vertical Bridgman technique. The crystal was characterized by X-ray diffraction and Energy dispersive X-ray fluorescence spectrometer (EDXRF). Electrical conductivity, hall effect, and
- Mobarak
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- Formation of carbon nanoparticles by the condensation of supersaturated atomic vapor obtained by the laser photolysis of C3O2
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A new technique is suggested for obtaining nanoparticles from highly supersaturated vapor resulting from the laser photolysis of volatile compounds. The growth of carbon nanoparticles resulting from C3O2 photolysis has been studied in detail. Absorbing UV quanta (from an Ar-F excimer laser), C3O2 molecules decompose to yield atomic carbon vapor with precisely known and readily controllable parameters. This is followed by the condensation of supersaturated carbon vapor and the formation of carbon nanoparticles. These processes have been investigated by the laser extinction and laser-induced incandescence (LII) methods in wide ranges of experimental conditions (carbon vapor concentration, nature of the diluent gas, and gas pressure). The current and ultimate particle sizes and the kinetic parameters of particle growth have been determined. The characteristic time of particle growth ranges between 20 and 1000 μs, depending on photolysis conditions. The ultimate particle size determined by electron microscopy is 5-12 nm for all experimental conditions. It increases with increasing total gas pressure and carbon vapor partial pressure and depends on the diluent gas. The translational energy accommodation coefficients for the Ar, He, CO, and C3O 2 molecules interacting with the carbon particle surface have been determined by comparing the LII and electron microscopic particle sizes. A simple model has been constructed to describe the condensation of carbon nanoparticles from supersaturated atomic vapor. According to this model, the main process in nanoparticle formation is surface growth through the addition of separate atoms to the nucleation cluster. The nucleus concentrations for various condensation parameters have been determined by comparing experimental and calculated data.
- Gurentsov,Eremin,Schulz
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- Decomposition of methane over iron catalysts at the range of moderate temperatures: The influence of structure of the catalytic systems and the reaction conditions on the yield of carbon and morphology of carbon filaments
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Decomposition of high-purity methane in the presence of α-Fe-based catalysts to produce filamentous carbon was studied at 650°-800°C. Filamentous carbon was formed at temperatures not lower than 680°C in the presence of both bare α-Fe and catalysts based
- Ermakova,Ermakov,Chuvilin,Kuvshinov
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- Synthesis of SiC nanorods using floating catalyst
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The beta-silicon carbide (β-SiC) nanorods have been synthesized by a floating catalyst method. Iron particles, decomposed from ferrocene vapor while being carried into the reaction chamber by the flowing gases, are very tiny. These small Fe particles act as catalyst to promote the growth of SiC nanorods in the SiCl4-C6H6-H2-Ar system at 1100-1200°C. The diameters of the β-SiC in the products are less than 100 nm, and the SiC nanorods with uniform diameters are single crystals with the stacking faults on the {111} crystal planes.
- Zhang, Yingjiu,Wang, NanLin,He, Rongrui,Chen, Xihua,Zhu, Jing
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- The surface decoration and electrochemical hydrogen storage of carbon nanofibers
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The tube-like carbon nanofibers (CNF) with cone-shaped structure were synthesized by catalytic pyrolysis of methane over Ni/MgO catalyst at 550°C for 30 min. The outer diameter of CNF with a rough surface increased to ～ 50-80 nm due to the deposition of Ni-P alloy particles in a ball shape. In the dark field under the selected electron diffraction, the Ni-P alloy particles with fine crystallites existed along the outer surface of CNF, like chain morphology. The heat treatment of CNF decorated with Ni-P alloy particles led to higher crystallization of surface alloy particles. The maximum discharge capacities of the composites with Ni-P content of 76.3 wt % before and after heat treatment were 101 and 149 mA h/g, respectively.
- Yan, Xiaoqi,Gao, Xueping,Li, Ying,Liu, Zhanquan,Wu, Feng,Shen, Yutian,Song, Deying
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- Growth of graphene layers on HOPG via exposure to methyl radicals
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The interaction of methyl radicals with hot HOPG (highly oriented pyrolytic graphite) surfaces under single-collision conditions has been studied by scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS). Methyl radicals were generated by thermal decomposition of azomethane N2(CH3)2. Significant carbon deposition under elevated surface temperature conditions was observed if substrates were used which had been decorated by nanometer sized defects prior to methyl radical exposure. Graphene layers as well as protrusions were observed to be formed depending on the defect. No carbon deposition was observed for surface temperature below 800 °C. Largest sticking probabilities of up to 10 -6 were observed for HOPG (highly oriented pyrolytic graphite) surfaces prestructured with hexagonal nanometer sized etch pits. Here, the initially resulting mono-atomic layers are pinned by the hole periphery and exhibit a densely packed hexagonal atomic structure corresponding to the graphite basal plane. For surfaces held at 1000 °C, the lateral growth rate of a graphene layer around a single hole can exceed 230 A?2/s at a CH3· flux of 3×1017 molecules/cm2s. The deposition kinetics switches from 2D to 3D growth prior to completion of the first graphene layer. A growth mechanism based on CH3· decomposition and hydrogen desorption is proposed.
- Wellmann, Ralf,B?ttcher, Artur,Kappes, Manfred,Kohl, Ulrich,Niehus, Horst
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- Magnetotransport in the amorphous carbon films prepared from succinic anhydride
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In this paper, we report the low-temperature electrical conductivity of amorphous carbon films prepared from an organic precursor succinic anhydride at different pyrolysis temperatures (700-980 °C). The films prepared at low temperatures show activation behavior. The films prepared at 900 °C and above show metal-like behavior, with positive temperature coefficient and a resistivity hump below about 25 K in the R-T behavior. The metal-like behavior at low temperatures was suppressed by the application of a magnetic field. The magnetoconductance in the metal-like films at low and high field limits were analyzed in terms of weak localization and electron-electron interaction models. Negligible magnetoconductance was observed at higher temperatures.
- Prasad,Subramanyam
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- One-step replication and enhanced catalytic activity for cathodic oxygen reduction of the mesostructured Co3O4/carbon composites
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Mesostructured Co3O4/C composites of high surface area have been synthesized via a one-step replica route by co-nanocasting cobalt and carbon precursors into mesoporous silica, in which the Co3O 4 nanoparticles are homogeneously dispersed in the mesoporous structure of carbon substrates. The mesostructured composites showed relatively high catalytic activities for oxygen reduction reaction (ORR), and that with a Co loading content of 4.3 at% exhibited the best electrochemical performance for ORR. The relatively high catalytic activity is attributed to the effects of the redox couples (Co3+/Co2+) together with the contribution from the conductive mesoporous carbon substrate.
- Wang, Yongxia,Cui, Xiangzhi,Chen, Lisong,Wei, Chenyang,Cui, Fangming,Yao, Heliang,Shi, Jianlin,Li, Yongsheng
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- Nanodomain structure of carbon-rich silicon carbonitride polymer-derived ceramics
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The presence of nanodomains in polymer-derived ceramics constitutes one of the most intriguing features of this class of materials. In the present work, the nanostructure of novel carbon-rich silicon carbonitride (SiCN) ceramics synthesized via thermolysis of poly(methylphenylsilylcarbodiimide), -[Ph(CH 3) Si-NCN]n-, at 1300°, 1500°, 1700°, and 2000°C is investigated by micro-Raman spectroscopy, X-ray powder diffractometry, and small-angle X-ray scattering (SAXS). The structural information obtained from these experimental methods is combined together with theoretical modeling of the SAXS data to obtain a detailed model of the temperature-dependent evolution of nanodomains comprised of free carbon, SiC, and Si3N4 in SiCN-based ceramics.
- Mera, Gabriela,Tamayo, Aitana,Nguyen, Hong,Sen, Sabyasachi,Riedel, Ralf
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- Synthesis of diamondlike films by an electrochemical method at atmospheric pressure and low temperature
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A technique of carbon film synthesis based on an electrochemical process was developed. A solution of acetylene in liquid ammonia was employed as the electrolyte. Films were deposited at the metallic anode. Two types of films were produced. Films of type I are transparent and fragile, whereas those of type II are black and plastic. The films were investigated by the electron diffraction method and Raman spectroscopy. The electron diffraction data for type I films demonstrate the films' high degree of crystallinity. Values of lattice plane spacings agree with data on cubic diamond modifications. The Raman spectrum of type I films shows a line at 1334 cm-1 (full width at half-maximum equal to 15 cm-1), inherent in that of diamond and an essentially amorphous carbon component. Spectra of the type II films do not feature the Raman peak of diamond.
- Novikov,Dymont
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- Synthesis and characterization of SiC nanowires through a reduction-carburization route
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Cubic silicon carbide (3C-SiC) nanowires were synthesized through a reduction-carburization route by using silicon powders and tetrachloride (CCl4) as Si and C sources, and metallic Na as the reductant at 700 °C. The as-prepared SiC nanowires were characterized and studied by X-ray powder diffraction, transmission electron microscopy, X-ray photoelectron spectra, Raman backscattering, and photoluminescence spectra at room temperature. The SiC nanowires produced from the present route typically have diameters of 15-20 nm and lengths of 5-10 μm. The influencing factors of the formation of the SiC nanowires were discussed and a possible growth mechanism for the SiC nanowires was proposed.
- Hu,Lu,Tang,Deng,Jiang,Qian,Yu,Zhou,Liu,Wu
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- Electronic properties of grains and grain boundaries in graphene grown by chemical vapor deposition
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We synthesize hexagonal shaped single-crystal graphene, with edges parallel to the zig-zag orientations, by ambient pressure CVD on polycrystalline Cu foils. We measure the electronic properties of such grains as well as of individual graphene grain bound
- Jauregui, Luis A.,Cao, Helin,Wu, Wei,Yu, Qingkai,Chen, Yong P.
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- Synthesis of 15R polytype of diamond in oxy-acetylene flame grown diamond thin films
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15R polytype of diamond has been synthesized using a specially designed oxy-acetylene flame system along with 3C diamond and cubic carbon on polycrystalline molybdenum substrates. X-ray diffraction has been used to detect the 15R phase as the dominant phase in these films. Rapid changes in the substrate temperature during the growth process are expected to be responsible for the growth of these phases.
- Kapil,Mehta,Vankar
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- The development of carbon nanotubes/RuO2·χH2O electrodes for electrochemical capacitors
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Carbon nanotubes were refluxed with nitric acid to create acid sites on the surface. After such treatment, amorphous or nano-scale crystalline RuO2·χH2O can be adhered to the surfaces of carbon nanotubes by a simple method. RuO2·χH2O became more amorphous with decreasing the fraction of carbon nanotubes. The capacitance can be enhanced significantly by the adherence. When the weight fraction of RuO2·χH2O in the composite electrodes reached 75%, a specific capacitance of 560 Fg-1 was achieved. On the other hand, carbon nanotubes/RuO2·χH2O capacitors exhibit excellent power delivery behavior. So the processing of carbon nanotubes/RuO2·χH2O composite electrodes is a new attempt to fabricate supercapacitors with both high energy and high power density.
- Ma,Wei,Xu,Liang,Wu
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- One-step and template-free preparation of hierarchical porous carbons with high capacitive performance
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Considering the wide application of hierarchical porous carbon materials (HPCs), one-step and template-free preparation of HPCs is very attractive. In this work, HPCs are prepared by direct carbonization of phenolic resin carboxylic salt xerogels. The morphology and porosity of the prepared carbon materials are characterized by scanning electron microscopy, transmission electron microscopy and nitrogen adsorption/desorption. The obtained HPCs possesses typically hierarchical porosity combined interconnected mesopores and highly accessible micropores with short diffusion length. Due to its unique hierarchical pore texture, the prepared carbon materials shows superior capacitive performance with high specific capacitance, excellent rate capability, and good long-term cycle stability in both KOH and N(C2H5)4BF4/acetonitrile electrolyte. Remarkable energy densities of 29.1 and 6.1 W h kg-1 are delivered by HPC-9d in organic and KOH electrolyte, respectively. At a very high power density of 10000 W kg-1, the energy densities of HPC-9d still reach up to 14.4 and 4.5 W h kg-1 in organic electrolyte and KOH electrolyte, respectively, suggesting the prepared HPCs possess both high energy density and high power density.
- Zhou, Jin,Zhang, Zhongshen,Li, Zhaohui,Zhu, Tingting,Zhuo, Shuping
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- Catalytic growth of single-wall carbon nanotubes from metal particles
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Single-walled carbon nanotubes (SWNTs) have been synthesized at milligram per hour rates by the catalytic decomposition of both carbon monoxide and ethylene over a supported metal catalyst known to produce larger multiwalled nanotubes. Under certain conditions, there is no termination of nanotube growth, and production appears to be limited only by the diffusion of reactant gas through the product nanotube mat that covers the catalyst. Further development of the catalyst geometry to overcome the diffusion limitation may allow bulk catalytic production of SWNTs by supported metal catalysts.
- Hafner, Jason H.,Bronikowski, Michael J.,Azamian, Bobak R.,Nikolaev, Pavel,Rinzler, Andrew G.,Colbert, Daniel T.,Smith, Ken A.,Smalley, Richard E.
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- Few-layer epitaxial graphene grown on vicinal 6H-SiC studied by deep ultraviolet Raman spectroscopy
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Few layer epitaxial graphenes (1.8-3.0 layers) grown on vicinal 6H-SiC (0001) were characterized by deep ultraviolet Raman spectroscopy. Shallow penetration depth of the probe laser enabled us to observe G-peak of graphene without subtraction of the SiC s
- Kisoda, Kenji,Kamoi, Susumu,Hasuike, Noriyuki,Harima, Hiroshi,Morita, Kouhei,Tanaka, Satoru,Hashimoto, Akihiro
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- Electrodeposited Ni(OH)2 nanoflakes on graphite nanosheets prepared by plasma-enhanced chemical vapor deposition for supercapacitor electrode
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Graphite nanosheets have been grown on Ni foam by radio-frequency plasma-enhanced chemical vapor deposition, which are used as substrates for electrodepositon of Ni(OH)2 with a porous and 3D nanostructure. The Ni foam/graphite nanosheets/Ni(OH)2 electrode has a high specific capacitance of 1667 F g-1 and the specific capacitance can maintain 93.3% after 700 cycles at the current density of 60 A g-1 in 1 M KOH.
- Wang, Xin,Wang, Yayu,Zhao, Cuimei,Zhao, Yunxiao,Yan, Baoyu,Zheng, Weitao
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- Thermal conductivity of hard carbon prepared from C60 fullerene
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We report measurements of thermal conductivity in 30-350 K range of hard fullerene-based carbon. The material has been prepared from C60 fullerene under pressure and has an unusual combination of large hardness and relatively high electrical co
- Smontara,Biljakovic,Staresinic,Pajic,Kozlov,Hirabayashi,Tokumoto,Ihara
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- Controlled particle generation in an inductively coupled plasma
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By injecting pulses of acetylene into an inductive argon/helium discharge, carbon clusters with diameters in the range of 10-50 nm are produced. These particles cause an instability of the plasma, which becomes visible as an oscillation of the emission intensity. The particles are analyzed ex situ using atomic force microscopy and scanning electron micrographs. A unique linear dependence between particle size and oscillation time period is found. Thereby the oscillation phenomenon can serve as monitor signal to control the size of plasma produced particles.
- Schulze,Von Keudell,Awakowicz
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- Carbon-hydrogen bonding in near-frictionless carbon
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The uniquely low friction behavior of near-frictionless carbon (NFC) as compared to conventional diamondlike carbon (DLC) is determined by the bonding within the film. Inelastic neutron scattering (INS) and Fourier transform infrared (FTIR) spectroscopy were used to probe the bonding environment of carbon and hydrogen; both INS and FTIR can probe the whole sample. Previous work has focused on surface studies; the present results show that in the film as a whole the majority of the hydrogen is adjacent to s p3 -bonded carbon. In addition this work has determined the absence of any molecular hydrogen in NFC.
- Johnson,Woodford,Rajput,Kolesnikov,Schleuter,Eryilmaz,Erdemir
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- Melt Casting LiFeP O4: II. Particle Size Reduction and Electrochemical Evaluation
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LiFeP O4 was prepared using a melt casting technique of Li 2 C O3 and FeP O4 precursors at 1000°C. The product was characterized by X-ray diffraction and is of the olivine structure with a minor amount of Li4 P2 O7 impurity. The synthesis, based on a molten procedure, provides a route to large-scale synthetic practices and reduced cost through the use of inexpensive precursors and short reaction times. The large particle sizes of the LiFeP O4 crystals obtained from the melt casting were reduced to 200 nm by a series of successive milling techniques without affecting the purity of the sample. A subsequent carbon coating on this milled material with a variety of carbon precursors was capable of producing samples with high capacities and electrochemical results similar to that of commercial LiFeP O4 powders. These results indicate that the melt casting procedure could be a competitive synthetic technique for the large-scale production of LiFeP O 4.
- MacNeil,Devigne,Michot,Rodrigues,Liang,Gauthier
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- CO2turned into a nitrogen doped carbon catalyst for fuel cells and metal-air battery applications
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Heteroatom doped metal-free catalysts are one of the most promising replacements for platinum for the alkaline oxygen reduction reaction (ORR). Due to the lack of metal atoms, they are extremely stable and environmentally friendly. However, production of carbon nanomaterials can have a very high CO2footprint. In this study, we present ORR catalysts made directly from CO2viamolten salt CO2electrolysis. The deposited carbon powder is doped with nitrogen using pyrolysis in the presence of dicyandiamide. The effect of molten carbonate electrolyte composition towards the final ORR activity in 0.1 M KOH is studied. A thorough physico-chemical study of the starting carbons and N-doped catalysts is presented with SEM and TEM imaging, BET analysis, Raman and X-ray photoelectron spectroscopy as well as the rotating disk electrode method. The onset potential and half-wave potential of the better catalyst were ?50 and ?175 mVvs. SCE in 0.1 M KOH, respectively.
- ?mits, Kri?jānis,?utka, Andris,Kruusenberg, Ivar,Lo?s, Jānis,Mikli, Valdek,Ratso, Sander,Vītola, Virgīnija,Walke, Peter Robert
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- Monolayer graphene film/silicon nanowire array Schottky junction solar cells
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Schottky junction solar cells were constructed by combining the monolayer graphene (MLG) films and the Si nanowire (SiNW) arrays. Pronounced photovoltaic characteristics were investigated for devices with both p-MLG/n-SiNWs and n-MLG/p-SiNWs structures. Due to the balance between light absorption and surface carrier recombination, devices made of SiNW arrays with a medium length showed better performance and could be further improved by enhancing the MLG conductivity via appropriate surface treatment or doping. Eventually, a photoconversion efficiency up to 2.15% is obtained by the means of filling the interspace of SiNW array with graphene suspension.
- Xie, Chao,Lv, Peng,Nie, Biao,Jie, Jiansheng,Zhang, Xiwei,Wang, Zhi,Jiang, Peng,Hu, Zhizhong,Luo, Linbao,Zhu, Zhifeng,Wang, Li,Wu, Chunyan
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- Lanthanide complexes of 3-methoxy-salicylaldehyde: Thermal and kinetic investigation by simultaneous TG/DTG-DTA coupled with MS
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The reaction of a lanthanide(III) nitrate (Ln = Pr, Nd, Gd, Dy, Er) with 3-methoxy-salicylaldehyde(3-OCH3-saloH), afforded neutral complexes of the general formula [Ln(3-OCH3-salo)3], which were characterized by means of elemental analysis, FT-IR spectra, TG-DTA curves, and magnetic measurements. The released products, due to the thermal decomposition were analyzed by on-line coupling MS spectrometer to the thermobalance in argon, allowed to prove the proposed decomposition stages. In order to confirm the stability scale provided on the basis of the onset decomposition temperature, a kinetic analysis of the three decomposition stages was made using the Kissinger equation, while the complex nature of the decomposition kinetics was revealed by the isoconvertional Ozawa-Flynn-Wall method.
- Papadopoulos, Christos,Kantiranis, Nikolaos,Vecchio, Stefano,Lalia-Kantouri, Maria
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- Self-assembly of carbon nanohelices: Characteristics and field electron emission properties
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The fabrication of self-assembled carbon nanohelices (CNH) on iron needles using microwave plasma assisted chemical vapor deposition was discussed. The microstructures and morphologies of CNH were investigated using scanning electron microscopy, high-reso
- Zhang, Guangyu,Jiang, Xin,Wang, Enge
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- New heterometallic pivalates with FeIII and ZnII ions: Synthesis, structures, magnetic, thermal properties
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Techniques for synthesizing Zn(II)-Fe(III) heterometallic molecular complexes [Fe2Zn4O2(Piv)10] (1), [Fe4Zn3O3(Piv)12(H2O)]·1.5Et2O (2) and [Fe3Zn2O2(Piv)9(1,10-phen)] (3) (where HPiv is pivalic acid, 1,10-phen – C12H8N2) have been developed. It has been found that recrystallization of the solid product formed from reaction mixture of Fe(NO3)3, Zn(NO3)2, KOH and HPiv (in the 3:2:13:34 ratio) in water (?Reagent A?) from acetone results in hexanuclear complex 1, whereas thermolysis of ?Reagent A? at 130 °C in air followed by crystallization of the thermolysis products from ether makes it possible to isolate complex 2. It has been found that dissolution of thermolyzed ?Reagent A? in MeCN in the presence of 1,10-phenanthroline leads to formation of complex 3. The structures of complexes 1–3 were determined by single crystal X-ray diffraction analysis. The doublet M?ssbauer spectra of complexes 1 and 2 correspond to high-spin Fe3+ ions in an octahedral environment of oxygen atoms, while the non-equivalence of the environment of iron ions in compound 3 (FeO6 and FeO4N2) is reflected by two observed doublets with different intensities. Based on the results of magnetic data simulation and quantum-chemical calculations, it has been shown that antiferromagnetic exchange coupling exists in complexes 1 and 2 (J12 = ?3.05 cm?1 for 1 and J12 = ?0.4, J13 = ?13.5, J23 = ?3.6, J24 = ?27.2 and J34 = ?30.1 cm?1 for 2). The value of the exchange integral between pairs of metal ions correlates with the Fe-O distances and the Fe-O-Fe angles in the bridging oxo ligands. Processes of thermal destruction have been studied for complexes 1 and 2 in argon atmosphere in the temperature range of 25–500 °C.
- Lutsenko, Irina A.,Kiskin, Mikhail A.,Efimov, Nikolay N.,Ugolkova, Elena A.,Maksimov, Yurii V.,Imshennik, Vladimir K.,Goloveshkin, Alexander S.,Khoroshilov, Andrey V.,Lytvynenko, Anton S.,Sidorov, Aleksey A.,Eremenko, Igor L.
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- Diamondlike carbon deposition on silicon using radio-frequency inductive plasma of Ar and C2H2 gas mixture in plasma immersion ion deposition
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Diamondlike carbon (DLC) was deposited on silicon using a plasma immersion ion deposition (PIID) method. Inductive radio-frequency plasma sources were used to generate Ar and C2H2 plasmas at low gas pressures ranging from 0.04 to 0.93 Pa. The film stress and hardness were sharply dependent upon bias voltage at an operating pressure of 0.04 Pa. A maximum hardness of 30 GPa and compressive stress of 9 GPa was observed at a pulsed bias of -150 V bias (carbon energy of 80 eV). The mechanical properties of DLC films are correlated with UV Raman peak positions which infer sp3-bonded carbon contents.
- Lee,He,Walter,Nastasi,Tesmer,Tuszewski,Tallant
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- Monolayer graphene growth on Ni(111) by low temperature chemical vapor deposition
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In contrast to the commonly employed high temperature chemical vapor deposition growth that leads to multilayer graphene formation by carbon segregation from the bulk, we demonstrate that below 600 °C graphene can be grown in a self-limiting monolayer growth process. Optimum growth is achieved at ～550 °C. Above this temperature, carbon diffusion into the bulk is limiting the surface growth rate, while at temperatures below ～500 °C a competing surface carbide phase impedes graphene formation.
- Addou, Rafik,Dahal, Arjun,Sutter, Peter,Batzill, Matthias
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- Growth of carbon nanowires and nanotubes via ultrarapid heating of ethanol vapor
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A method is proposed for producing carbon nanomaterials by ultrarapid heating of vapors of organic compounds to high temperatures, and an experimental setup for implementing this method is described. The starting reagents used are ethanol and mixtures of ethanol with water, glycerol, and ferrocene. At heater temperatures of 1500-2000°C and substrate temperatures of 600-1000°C, carbon nanowires and nanotubes are obtained. The nanowires attain 100 μm in length and range in thickness from 30 to 150 nm. The nanotubes have bamboo or fish-bone structures, with a thickness from 20 to 50 nm. The deposition of nanotubes on supported catalysts (iron, nickel, gold, and others) is also examined. It is shown that, under certain conditions, selective deposition of carbon nanotubes (nanowires) onto catalyst-coated parts of the substrate is possible.
- Red'kin,Malyarevich
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- Fluorination of single-wall carbon nanotubes
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Purified single-wall carbon nanotubes (SWNTs) were fluorinated at several different temperatures. Product stoichiometries were determined and electron microscopy was used to verify whether or not the fluorination was destructive of the tubes. SWNTs fluori
- Mickelson,Huffman,Rinzler,Smalley,Hauge,Margrave
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- Synthesis of Fe (Co or Ni) loaded mesoporous carbon composites and their adsorption behaviors for methyl orange
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Mesoporous carbon (CMK-3) was synthesized by hard template method using SBA-15 as template and sucrose as carbon source. The magnetic mesoporous carbon materials (Fe/CMK-3, Co/CMK-3, Ni/CMK-3) were prepared by a simple impregnation method. The samples were characterized by XRD, SEM, TEM, N2 physical adsorption, and the adsorption process was investigated by varying the contact time, temperature, pH, adsorbent dose and initial dye concentration. The results showed that the maximum adsorption capacity of methyl orange (MO) on the Fe/CMK-3, Co/CMK-3 and Ni/CMK-3 were 187, 157 and 166 mg · g-1, respectively. The equilibrium data were described using the Langmuir and Freundlich isotherms. It was found that the equilibrium data were best represented by the Langmuir isotherm model. The experimental data were fitted well by the pseudo-second-order kinetic model. Thermodynamic analysis revealed that the adsorption was an exothermic and spontaneous process. The negative eliv ΔSθ suggested decreasing in randomness of adsorbent species. The adsorbents are easy to be recycled in the magntic field.
- Jiang, Tingshun,Fang, Weibing,Zhao, Qian,Liu, Wangping,Zhao, Haibo,Le, Shukun
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- In situ-grown carbon nanotube array with excellent field emission characteristics
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In situ catalytic thermal decomposition method was used for producing aligned multiwalled carbon nanotubes (MWNTs) in bulk quantities on stable and electrically conducting substrates. Very low turn-on electric fields of 0.75 V/μm and low threshold fields of ～1.6 V/μm (for current density of 10 mA/cm2) were obtained from the MWNT arrays grown on TiN substrate. Furthermore, large emission current densities of 1-3 A/cm2 were obtained at reasonably low fields of less than ～8 V/μm. These enhanced emission properties are tentatively attributed to the oriented and high-density nature of the emitting carbon nanotube structure and the high-conductivity, stable nature of the TiN substrate onto which the nanotubes are attached.
- Rao,Jacques,Haddon,Zhu,Bower,Jin
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- Synthesis and characterization of highly ordered Co-MCM-41 for production of aligned single walled carbon nanotubes (SWNT)
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Highly ordered cobalt substituted MCM-41 samples were synthesized and characterized for application as catalytic templates for producing aligned single walled carbon nanotubes (SWNT). Highly reproducible Co-MCM-41 samples were successfully synthesized using alkyl templates with 10, 12, 14, 16, and 18 carbon chain lengths by direct incorporation of cobalt into the siliceous MCM-41 framework using a hydrothermal method; the pore size and the pore volume can be controlled precisely. The local environment of cobalt as determined by UV-vis spectroscopy is a mixture of tetrahedral and distorted tetrahedral structures similar to those observed in Co3O4. Cobalt atoms are uniformly distributed in the pores (about 30-40/pore) at nearly atomic dispersion probed by XAFS. Incorporation of cobalt into siliceous MCM-41 improves the structure, most likely by dehydroxylation and/or knitting the defective structure of the amorphous silica polymer. The optimum crystallization temperature and time were 100?°C and 4 days for siliceous MCM-41 and 6 days for Co-MCM-41, respectively. Co-MCM-41 is very stable against reducing and oxidation conditions at temperatures under 750?°C. The catalytic templates showed over 90% selectivity to SWNT with up to 4 wt % carbon yield. The growth of SWNT in the pores of Co-MCM-41 was confirmed by Raman spectroscopy and TEM. The catalytic template maintained its structure after successive reaction cycles, which suggests that Co-MCM-41 is a very stable template for producing SWNT under harsh reaction conditions.
- Lim, Sangyun,Ciuparu, Dragos,Pak, Chanho,Dobek, Frank,Chen, Yuan,Harding, David,Pfefferle, Lisa,Haller, Gary
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- The carbon phases formed during pyrolysis of gaseous hydrocarbons in reaction volume of a fluidized bed apparatus
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In view of the kinetic laws of hydrocarbon pyrolysis, three mechanisms of the carbon phase formation are considered: the mechanism of individual atoms, the two-stage model of growth, and the mechanism of agglomerate. The macrostructure is investigated by
- Kurbakov
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- DIRECT CURRENT ARC-PLASMA SYNTHESIS OF TUNGSTEN CARBIDES.
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Chemical reactions which occur in a thermal plasma between fine powders of tungsten and graphite and between powdered tungsten and methane have been studied. When using a commercial d. c. torch and a standard reactor design, the conversion to tungsten carbide is relatively poor. With a specially designed reactor operating in a transferred-arc mode, nearly complete conversion to carbide results when operating at the same power level and with methane as a reactant. Crystal structures and particle morphologies have been studied with electron microscopy and X-ray diffraction. Several initial stages of the particle-particle and particle-gas reactions have been determined. A number of interesting composite particles corresponding to intermediate reaction steps has been observed.
- Ronsheim,Toth,Mazza,Pfender,Mitrofanov
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- Structural Evolution from Metal-Organic Framework to Hybrids of Nitrogen-Doped Porous Carbon and Carbon Nanotubes for Enhanced Oxygen Reduction Activity
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A series of hybrids of nitrogen-doped graphitic porous carbon and carbon nanotubes (NGPC/NCNTs) are readily prepared in a stepwise manner by using a typical metal-organic framework (MOF-5) and urea as the carbon and nitrogen precursors, and nickel as the graphitization catalyst, respectively. These NGPC/NCNTs hybrids have demonstrated prominent catalytic activities toward oxygen reduction reaction (ORR) in alkaline medium. Compared to the benchmark Pt/C catalyst, the optimized NGPC/NCNT-900 (annealed at 900 °C) exhibits superior catalytic activity, durability and methanol tolerance, which makes it one of the best ORR electrocatalysts derived from MOFs. The promising properties in NGPC/NCNT-900 are mainly attributed to synergistic contributions of its unique hybrid structure, rich nitrogen doping, high graphitic degree, and large surface area. This attractive route for the preparation of NGPC/NCNTs holds promise for general use of a great number of available and yet rapidly growing MOFs in constructing high-performance carbon-based ORR electrocatalysts.
- Zhang, Linjie,Wang, Xiuyun,Wang, Ruihu,Hong, Maochun
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- Single-walled nanotubes by the pyrolysis of acetylene-organometallic mixtures
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Gas-phase pyrolysis of acetylene along with a metallocene or with a binary mixture of metallocenes in flowing Ar or Ar + H2 at 1100°C yields single-walled carbon nanotubes. Pyrolysis of Fe(CO)5-acetylene mixtures in Ar at 1100°C also gives single-walled nanotubes. The diameter of the nanotubes is generally around 1 nm, showing thereby that on pyrolysis under the dilute conditions employed, the organometallic precursors give rise to very fine metal particles essential for the formation of such nanotubes.
- Satishkumar,Govindaraj,Sen, Rahul,Rao
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- Preparation of hollow carbon nanospheres at low temperature via new reaction route
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Hollow carbon nanospheres were obtained at 200°C via a new reaction route, by using magnesium, hexachloroethane and aluminum trichloride as starting materials and benzene as solvent. The products were characterized with X-ray diffraction pattern, transmission electron microscope, high-resolution transmission electron microscope images and Raman spectrum. The reaction conditions are easy to be maintained and controlled. They may provide a new method to produce other carbonaceous materials. A possible mechanism of reaction was proposed.
- Ni, Youbao,Shao, Mingwang,Tong, Yanhua,Qian, Guixiang,Wei, Xianwen
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- High yield of single-wall carbon nanotubes by arc discharge using Rh-Pt mixed catalysts
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Single-walled carbon nanotubes (SWNT) were produced using binary mixtures of the platinum-group metals as catalysts by arc evaporation in helium gas. Transmission electron microscopy and Raman scattering spectroscopy revealed that the production yield of SWNTs was remarkably enhanced when a Rh-Pt mixture was used as a catalyst. The density of SWNTs in raw soot was as high as that obtained from Fe-Ni and Y-Ni. The distribution of diameters of SWNTs was narrow (1.28±0.07 nm). The merit of this catalyst is that it is free from magnetic metals.
- Saito, Yahachi,Tani, Yoshihiko,Miyagawa, Norihisa,Mitsushima, Koichi,Kasuya, Atsuo,Nishina, Yuichiro
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- Methane Decomposition on the Surface of Molybdenum Nanoparticles at Room Temperature
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Abstract: The decomposition of methane on molybdenum nanoparticles was studied experimentally at room temperature. The molybdenum nanoparticles were synthesized in the gas phase using UV laser photolysis of Mo(CO)6 vapor in a flow reactor. The working part of the flow reactor was equipped with quartz windows for introducing the radiation from a pulsed Nd:YaG laser operating at the fourth harmonic (266 nm) at a frequency of 10 Hz. Methane was used as a carrier gas. As a result of irradiation of a mixture of methane with Mo(CO)6 vapors in the gas phase at room temperature, nanoparticles with sizes of 2–50 nm were synthesized. The phase composition of the nanoparticles included pure molybdenum, molybdenum carbide Mo2C, and molybdenum oxide MoO3. During the reaction, the hydrogen yield was measured with a VG-7 highly sensitive hydrogen analyzer based on a semiconductor metal–dielectric sensor. The measured H2 concentration varied from 5 to 25 ppm depending on the concentration of Mo(CO)6. The possibility of methane decomposition on molybdenum nanoparticles at room temperature was discussed based on the obtained data.
- Eremin, A. V.,Grigoriev, Yu. V.,Gurentsov, E. V.,Khmelenin, D. N.,Kolotushkin, R. N.
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- Synthesis, evaluation, and kinetic assessment of Co-based catalyst for enhanced methane decomposition reaction for hydrogen production
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In this work, the development of 10, 30, and 50?wt.% Co/TiO2–Al2O3 catalysts for catalytic methane decomposition reaction has been reported to produce pure hydrogen. The synthesis of Co particles on the surface of mesoporo
- Al Mesfer, Mohammed K.,Danish, Mohd,Shah, Mumtaj
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- Liquid-Metal-Enabled Mechanical-Energy-Induced CO2 Conversion
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A green carbon capture and conversion technology offering scalability and economic viability for mitigating CO2 emissions is reported. The technology uses suspensions of gallium liquid metal to reduce CO2 into carbonaceous solid products and O2 at near room temperature. The nonpolar nature of the liquid gallium interface allows the solid products to instantaneously exfoliate, hence keeping active sites accessible. The solid co-contributor of silver–gallium rods ensures a cyclic sustainable process. The overall process relies on mechanical energy as the input, which drives nano-dimensional triboelectrochemical reactions. When a gallium/silver fluoride mix at 7:1 mass ratio is employed to create the reaction material, 92% efficiency is obtained at a remarkably low input energy of 230 kWh (excluding the energy used for dissolving CO2) for the capture and conversion of a tonne of CO2. This green technology presents an economical solution for CO2 emissions.
- Tang, Junma,Tang, Jianbo,Mayyas, Mohannad,Ghasemian, Mohammad B.,Sun, Jing,Rahim, Md Arifur,Yang, Jiong,Han, Jialuo,Lawes, Douglas J.,Jalili, Rouhollah,Daeneke, Torben,Saborio, Maricruz G.,Cao, Zhenbang,Echeverria, Claudia A.,Allioux, Francois-Marie,Zavabeti, Ali,Hamilton, Jessica,Mitchell, Valerie,O'Mullane, Anthony P.,Kaner, Richard B.,Esrafilzadeh, Dorna,Dickey, Michael D.,Kalantar-Zadeh, Kourosh
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- Self-redox reaction of carbon in molten salt for anode materials of lithium/sodium-ion batteries
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Preparation of carbonaceous anode with excellent electrochemical performance is important for the utilization of lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). Herein, carbon powder was synthesized from CaCO3 and CaC2 in CaCl2-NaCl molten salt. The reaction mechanism was discussed in thermodynamics and kinetics. Microstructure of the carbon powder was systemically characterized. Electrochemical performance of the carbon powder was evaluated as anode materials of LIBs and SIBs. The results showed that molten salt can transfer the carbonization process from a solid-solid process to a liquid-solid process. The kinetic barrier of CaO layers on the raw materials was removed in molten salt. The products exhibited better lithium (reversible capacity of ~480 mAhg?1 after 200 cycles and reversible capacity of ~250 mAh·g?1 at 1000 mAg?1) and sodium (reversible capacity of ~290 mAhg?1 after 200 cycles and reversible capacity of ~180 mAh·g?1 at 5000 mA·g?1) storage performance than commercial graphite. This method was easy and efficient to recover more than 70 wt% of carbon in the raw materials within 15 min
- Chen, Denghui,Ning, Zhiqiang,Song, Qiushi,Xie, Hongwei,Zhao, Hengpeng
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- A new organic-inorganic hybrid compound (C10H28N4)[CuCl4][BF4]2: Structural, optical, thermal studies and DFT-TDDFT calculations
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The new organic-inorganic hybrid compound 1,4-bis (3-aminiopropyl) piperazine-1,4-dium bis(tetrafluoroborate) tetrachlorocuprate (II) was synthesized and determined by X-ray diffraction analysis. The structure consists of two isolated [BF4]? tetrahedrons, [CuCl4]2- square plane and tetra organic cations, held together by hydrogen bonds, forming a three-dimensional network. Different types of contacts have been quantified through the calculations of Hirshfeld surfaces percentages and described by fingerprint plots. The vibrational, optical and thermal properties have been also investigated by Infrared spectroscopy, UV–Vis absorption, Photoluminescence and TG-DTA measurements, respectively. The titled compound exhibits absorption features attributed to the Ligand-to-Metal Charge Transfer (LMCT) phenomena and a blue light emission appealing to some optoelectronic applications. Moreover, Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TDDFT) calculations have been performed in order to more accurately infer the experimental finding, and great agreement has been provided.
- Elleuch, Slim,Hadaoui, Souhir,Kefi, Riadh,Ouerghi, Zeineb
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- Antibacterial and anticorrosion behavior of bioactive complexes of selected transition metal ions with new 2-acetylpyridine Schiff base
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Successful preparation of Schiff base 4-(4-aminophenoxy)-N-(1-(pyridin-2-yl)ethylidene)aniline derived from refluxing of 4,4-oxydianniline with 2-acetylpyridine within 2?h in 1:1 molar ratio was performed. Different transition metal complexes were synthesized by reacting metal chlorides with the formed ligand in 1:1 molar ratio. Structural features of the complexes were obtained from different tools such as infrared (IR), 1H-nuclear magnetic resonance (1H-NMR), ultraviolet–visible (UV-vis), molar conductivity, thermogravimetric (TG)/differential thermogravimetric (DTG), microanalysis, and mass spectrometry. All complexes had an octahedral structure and Schiff base acted as a neutral bidentate ligand that linked to metal centers via N-azomethine and N-pyridine atoms. Cr(III), Fe(III), and Ni(II) complexes were electrolytes while other complexes were nonelectrolytes. The molecular structure of Schiff base was optimized theoretically and its HOMO and LUMO energies were dictated by B3LYP/DFT calculations. The in vitro antibacterial activity versus some selected bacteria species showed that all prepared compounds were biologically active except Fe(III) complex against certain species and Co(II) complex had the highest biological activity values. Molecular docking was used to determine effective binding modes between ligand and its [Co(L)(H2O)2Cl2]·4H2O complex with active sites of 4WJ3, 4ME7, 4K3V, and 3T88 receptors. The strongest binding of Co(II) complex was with the 4ME7 receptor with lowest binding energy value ?25.4?kcal mol?1. Schiff base as corrosion inhibitors for mild steel in 1.0-M HCl had been investigated using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PP), and electrochemical frequency modulation (EFM). The results showed that the inhibitor acts as a mixed-type inhibitor. The inhibition efficiency increases with increasing inhibitor concentration to its maximum of 97.5% at 1?×?10?3?M solution. The adsorption model obeys the Langmuir isotherm, and Gibbs free energy was around ?40 kJ/mol, indicating that it is spontaneously and chemically adsorbed on the surface. SEM/EDX results proved the sticking of a barrier film on the mild steel sample.
- Ashmawy, Ashraf M.,Deghadi, Reem G.,Elsharkawy, Ahmed E.,Mohamed, Gehad G.
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- Biochemical Characterization and Antimicrobial Activity against Some Human or Phyto-Pathogens of New Diazonium Heterocyclic Metal Complexes
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String of vanadium (IV), zirconium (IV), palladium (II), platinum (IV) and uranium (VI) chelates of 2-cyano-2-[(2-nitrophenyl)hydrazono]thioacetamide (Cnphta) were prepared and characterized by physicochemical, spectroscopic and thermal analyses. The form
- El-Attar, Mohamed S.,Elshafie, Hazem S.,Sadeek, Sadeek A.,El-Farargy, Ahmed F.,El-Desoky, Sameh I.,El-Shwiniy, Walaa H.,Camele, Ippolito
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- Non-oxidative Decomposition of CH4 Over CeO2 and CeO2–SiO2 Supported Bimetallic Ni–Mo Catalysts
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The development of highly active and durable catalysts for H2 production through CH4 decomposition process is still a great challenge. In this study, CeO2 and CeO2–SiO2 supported bimetallic Ni–Mo cata
- Aboul-Enein, Ateyya A.,Aboul-Gheit, Noha A. K.,Ahmed, Hanan A.,Awadallah, Ahmed E.,Solyman, Sanaa M.
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- High-Performance Asymmetric Supercapacitors Based on Monodisperse CuO@C Polyhedron Nanocomposites
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Herein, CuO nanocrystals spatially embedded inside carbon polyhedron (CuO@C) derived via morphology-preserved transformation of metal–organic frameworks (MOFs) are utilized for high-performance asymmetric supercapacitors (SCs). Using a conventional MOF (several micrometers in size), pore-filling with polymer inside MOF (polymer@MOF) via vapor-phase polymerization (VPP) process was achieved that amount of polymer used for VPP can be readily adjusted to control the carbon content of CuO@C after thermolysis and subsequent oxidation processes. When monodisperse and nano-sized MOF is used for CuO@C (denoted as nCuO@C_1), it presents superior electrochemical performance because monodispersity and smaller size reduce interfacial resistance and promote mass-transport property, respectively. Asymmetric SC of nCuO@C_1 with carbon sphere (CS) as a counter electrode presents excellent energy density of 55.47 Wh/kg and long-term stability of 88.7% at 5000 cycles, comparable to the best MO-based asymmetric SCs derived from MOFs.
- Kim, Hee Soo,Kang, Min Seok,Heo, Incheol,Yoo, Won Cheol
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p. 649 - 657
(2021/03/18)
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- Carbon dots conjugated nanocomposite for the enhanced electrochemical performance of supercapacitor electrodes
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Naturally, a combination of metal oxides and carbon materials enhances the electrochemical performance of supercapacitor (SC) electrodes. We report on two different materials with highly conductive carbon dots (CDs) and a Co0.5Ni0.5Fe2O4/SiO2/TiO2nanocomposite with a high power density, a high specific surface area, and a nanoporous structure to improve power and energy density in energy storage devices. A simple and low-cost process for synthesizing the hybrid SC electrode material Co0.5Ni0.5Fe2O4/SiO2/TiO2/CDs, known as CDs-nanocomposite, was performedviaa layer-by-layer method; then, the CDs-nanocomposite was loaded on a nickel foam substrate for SC electrochemical measurements. A comparative study of the surface and morphology of CDs, the Co0.5Ni0.5Fe2O4/SiO2/TiO2nanocomposite and CDs-nanocomposite was carried out using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), BET surface area, and Raman spectroscopy. The synthesized CDs-nanocomposite electrode material displayed enhanced electrochemical performance, having a high specific capacitance of 913.7 F g?1at a scan rate of 5 mV s?1and capacitance retention of 72.2%, as well as remarkable long-life cyclic stability over 3000 cycles in the three-electrode setup and 1 M KOH electrolyte. It also demonstrated a superior energy density of 130.7 W h kg?1. The improved electrochemical behavior of the CDs-nanocomposite for SC electrodes, together with its fast and simple synthesis method, provides a suitable point of reference. Other kinds of metal oxide nanocomposites can be synthesized for use in energy storage devices.
- Abd Elkodous, M.,Kawamura, Go,Matsuda, Atsunori,Youssry, Sally M.
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p. 39636 - 39645
(2021/12/31)
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- Hollow, mesoporous, eutectic Zn1?xMgxO nano-spheres as solid acid-base catalysts for the highly regio-selectiveO-methylation of 1,2-diphenols
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The highly regio-selectiveO-methylation of catechol with dimethyl carbonate (DMC), catalyzed by a solid acid-base catalyst, is an environmentally friendly chemical process for industrial production of guaiacol. However, a guaiacol yield below 84% and high reaction temperature above 280 °C limit its industrial application. Here, hollow, mesoporous Zn1?xMgxO nano-spheres with a eutectic structure, denoted as Zn1?xMgxO HMNSs (x= 0.012-0.089), are facilely fabricatedviathe calcination of Mg2+/Zn2+ion-adsorbing carbon spheres at 500 °C in air. In theO-methylation of catechol with DMC at 180 °C, Zn1?xMgxO HMNSs (x= 0.052) afford guaiacol in 95.5% yield with a complete catechol conversion. Furthermore, 89.0-95.3% mono-ether yields with high 1,2-diphenol conversions (94.5-100%) are also obtained for the other 1,2-diphenols bearing -CH3and -Br groups. Moreover, a plausible mechanism for highly selectiveO-methylation of catechol with DMC is proposed, in which the single-site activation and double-site activation of phenolic hydroxyls by the basic oxygen of Mg-O afford guaiacol and veratrole, respectively.
- Liu, Jie,Ma, Xuebing,Wang, Xuri,Xie, Guangxin,Yin, Zuyong,Zhang, Jianing
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p. 7454 - 7466
(2021/11/23)
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- Nickel nanoparticle/carbon catalysts derived from a novel aqueous-synthesized metal-organic framework for nitroarene reduction
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Carbon-supported, non-noble metal-based catalysts derived from metal-organic frameworks (MOFs) are attractive alternatives to noble metal-based systems, but typical syntheses of the starting MOFs are not desirable from an environmental and practical perspective (e.g., they rely on non-innocuous organic solvents and long reaction times). Here, we report the preparation of a Ni-based MOF in aqueous medium, at moderate temperature (95 °C) and in a short reaction time (2 g?1 depending on the carbonization temperature applied to the MOF, as well as high Ni contents (between ～36 and 57 wt%). Notwithstanding the latter, the metal was homogeneously distributed throughout the carbon matrix in the hybrid and was quite resistant to extensive agglomeration and sintering, even at temperatures as high as 1000 °C. With increasing carbonization temperature, the Ni component was seen to go through different crystal phases, i.e., Ni3C phase → Ni hexagonal close-packed phase → Ni face-centered cubic phase. The results of the catalytic tests suggested the former and latter phases to be the most active towards the reduction of 4-NP, with catalytic activity values as high as 0.039 mol4-NP molNi?1 min?1.
- Martín-Jimeno, F. Julian,Martínez-Alonso, Amelia,Paredes, Juan I.,Suárez-García, Fabián,Tascón, Juan M. D.
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- One-step preparation of sodium alginate-based porous carbon for the adsorption of bisphenol a in water
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In this study, sodium alginate (SA) was used as a carbon precursor and K2CO3 as an activator to prepare SA-based porous carbon (SAC) with high specific surface area in one step. The optimal product was SAC-1 which had good thermal stability, high carbon content and SBET of 1073.40 m2 g-1, and the highest adsorption capacity for bisphenol A (BPA). Additionally, the obtained adsorption experimental data accorded with the pseudosecond- order kinetics and Langmuir model, and the saturated adsorption capacity of SAC-1 for BPA was 632.91 mg g-1 at 308 K. Thermodynamic analysis showed that the adsorption process was a spontaneous endothermic process. Moreover, SAC-1 exhibited strong resistance to acid, alkali, coexistence of ions, and interference of organic matter. Furthermore, it showed good renewable performance through five cycles of experiments. Therefore, SAC-1 prepared by a simple one-step method had good adsorption and regeneration properties, which can efficiently remove organic pollutants form the water environment.
- Chen, Aixia,Xie, Yaping,Wei, Xiao,Chen, Bei,Pang, Jiaju
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p. 1101 - 1109
(2021/02/03)
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- Biochemical Characterization, Phytotoxic Effect and Antimicrobial Activity against Some Phytopathogens of New Gemifloxacin Schiff Base Metal Complexes
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String of Fe(III), Cu(II), Zn(II) and Zr(IV) complexes were synthesized with tetradentateamino Schiff base ligand derived by condensation of ethylene diamine with gemifloxacin. The novel Schiff base (4E,4′E)-4,4′-(ethane-1,2-diyldiazanylylidene)bis{7-[(4Z
- Mohamed, Amira A.,Elshafie, Hazem S.,Sadeek, Sadeek A.,Camele, Ippolito
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- Ru3+, Mn2+, Co2+, Ni2+, Cu2+, and Zn2+ uni-metallic complexes of 3-(-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl) methylene) hydrazono)indolin-2-one, preparation, structure elucidation and antibacterial activity
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Ru3+, Mn2+, Co2+, Ni2+, Cu2+, Zn2+ uni-metallic complexes of dihydrazone derived from the condensation of 3-hydrazonoindolin-2-one with 4-formyl antipyrine were synthesized. The resulted dihydrazone and its chelated compounds structurally characterized basing on spectroscopic tools (NMR, FT-IR, EAS, ESI-MS) thermo-gravimetric, elemental, magnetic and molar conductance measurements. This structural elucidation leads us to conclude that the dihydrazone has been performed as a neutral bidentate chelator linked the Ru3+, Mn2+, Co2+, Ni2+, Cu2+, Zn2+ ions via the carbonyl and azomethine of isatin moiety adopting regular or distorted octahedral structures around the central metallic ions. The structural description of dihydrazone and its chelated compounds have been endorsed basing on the Density Functional Theory calculations. The optimized geometry, global reactivity descriptors, and LUMO-HOMO orbitals and of the molecules have been calculated by the DFT-B3LYP method and 6e311G(d,p) basis set. The molecular electrostatic potential picture has been painted utilizing the same level of theory to envision the molecules charge distribution and chemical reactivity. The DFT studies of the designated compounds revealed small HOMO-LUMO gap which is a strong indication to the large reactivity these compounds. The TG analysis has confirmed the complexes chemical formulae and assured that the thermo-degradation processes occur in three or four steps ended with the formation of metal oxide or carbon-contaminated metal oxide residues. The In-vitro antibacterial of dihydrazone and its chelated compounds have been evaluated against E. coli, P. aeruginosa, K. pneumonia and B. subtilis, the observed antibacterial result denoted that Cu2+ and Zn2+ complexes have a good activity in comparation with the free dihydrazone.
- Selim, Quad M.,Shakdofa, Adel M. E.,Shakdofa, Mohamad M. E.
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- Synthesis, Structure, DFT, and Biological Activity of Metal Complexes of Norfloxacin and Metformin Mixed Ligand
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Abstract: A new series of mixed ligand metal complexes has been synthesized by the reaction of Co(II), Ni(II), Cu(II), Zr(IV), Pd(II), and Cd(II) with norfloxacin (NOR) and metformin hydrochloride (MF) in 1 : 1 : 1 molar ratio. The complexes have been characterized by FT-IR, UV-Vis, and 1H NMR spectra, TG/DTG and elemental analysis, molar conductance, and magnetic susceptibility data. According to FT-IR, NOR chelates with metal ions as a bidentate ligand via one oxygen of the carboxylate group and pyridone oxygen, and MF chelates with metal ions via two imine groups. Complexes have been identified as electrolytes. Electronic and magnetic data have indicated the octahedral structure for all complexes except square planar Pd(II) complex. Antibacterial and antifungal activities of the compounds have been tested against several species, and have indicated higher inhibition against micro-organisms for the metal complexes than the mixed ligands.
- Abbass, L. M.,El-Shwiniy, W. H.,El-Telbany, M.,Sadeek, S. A.,Zordok, W. A.
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p. 1774 - 1782
(2021/11/01)
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- Facile synthesis of porous Co3O4nanoflakes as an interlayer for high performance lithium-sulfur batteries
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The “shuttle effect” of long-chain polysulfides and the low conductivity of elemental sulfur lead to the inferior cycling stability of lithium-sulfur batteries and imped their practical applications. Herein, Co3O4nanoflakes with uniform macro pores distribution were synthesizedviafacile oil bath and calcination methods. Coupled with super P and coated on common polypropylene separators, they were expected to hinder the migration of lithium polysulfides (LiPSs) and accelerate the redox kinetics of polysulfides. Coin cells assembled with the Co3O4-super P interlayer exhibited a capacity of 760 mA h g-1at 1 C, maintained 598 mA h g-1after 350 cycles, and the decay rate of discharge capacity was only about 0.062% per cycle. Such high performance can be attributed to the synergistic effects between polar Co3O4and conductive super P. The facile fabrication method and high performance make the Co3O4-super P interlayer a feasible material to apply in lithium-sulfur batteries.
- Lu, Yi-Ming,Wu, Qi-Long,Yang, Jin-Lin,Zeng, Xiang-Tian,Zhao, Shi-Xi,Zheng, Xiao-Xiao
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p. 5677 - 5683
(2020/05/13)
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- Solar Reforming of Biomass with Homogeneous Carbon Dots
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A sunlight-powered process is reported that employs carbon dots (CDs) as light absorbers for the conversion of lignocellulose into sustainable H2 fuel and organics. This photocatalytic system operates in pure and untreated sea water at benign pH (2–8) and ambient temperature and pressure. The CDs can be produced in a scalable synthesis directly from biomass itself and their solubility allows for good interactions with the insoluble biomass substrates. They also display excellent photophysical properties with a high fraction of long-lived charge carriers and the availability of a reductive and an oxidative quenching pathway. The presented CD-based biomass photoconversion system opens new avenues for sustainable, practical, and renewable fuel production through biomass valorization.
- Achilleos, Demetra S.,Durrant, James R.,Kasap, Hatice,Markushyna, Yevheniia,Reisner, Erwin,Savateev, Aleksandr,Yang, Wenxing
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supporting information
p. 18184 - 18188
(2020/09/04)
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- Tumor Microenvironment Stimuli-Responsive Fluorescence Imaging and Synergistic Cancer Therapy by Carbon-Dot–Cu2+ Nanoassemblies
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A method is developed to fabricate tumor microenvironment (TME) stimuli-responsive nanoplatform for fluorescence (FL) imaging and synergistic cancer therapy via assembling photosensitizer (chlorine e6, Ce6) modified carbon dots (CDs-Ce6) and Cu2+. The as-obtained nanoassemblies (named Cu/CC nanoparticles, NPs) exhibit quenched FL and photosensitization due to the aggregation of CDs-Ce6. Their FL imaging and photodynamic therapy (PDT) functions are recovered efficiently once they entering tumor sites by the stimulation of TME. Introducing of Cu2+ not only provides extra chemodynamic therapy (CDT) function through reaction with hydrogen peroxide (H2O2), but also depletes GSH in tumors by a redox reaction, thus amplifying the intracellular oxidative stress and enhancing the efficacy of reactive oxygen species (ROS) based therapy. Cu/CC NPs can act as a FL imaging guided trimodal synergistic cancer treatment agent by photothermal therapy (PTT), PDT, and thermally amplified CDT.
- Chen, Qiao,Li, Zhongjun,Lin, Hengwei,Liu, Chuang,Sun, Shan,Tang, Zhongdi,Wu, Aiguo
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supporting information
p. 21041 - 21048
(2020/09/17)
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- Methane Decomposition Nickel Catalysts Based on Structured Supports
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Abstract: New methane degradation nickel catalysts based on original and modified layered double hydroxides and multilayer carbon nanotubes have been synthesized. The synthesized systems have been characterized by a set of physicochemical methods, namely, X-ray diffraction (XRD) analysis, scanning electron microscopy, Raman spectroscopy, and the thermal method. The catalytic activity of the synthesized catalysts in the temperature range of 550–850°С has been studied. It has been shown that in the methane decomposition reaction, the sample with a modified Ni-containing layer exhibits two regions of catalytic activity (550–650 and 700–850°С), whereas the sample based on carbon nanotubes is characterized by a single region (700–850°С) and the system based on a layered double hydroxide does not show activity in the entire temperature range.
- Gubanov, M. A.,Ivantsov, M. I.,Knyazeva, M. I.,Kryuchkov, V. A.,Kulikov, A. B.,Kulikova, M. V.,Maksimov, A. L.,Nikitchenko, N. V.,Pimenov, A. A.
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p. 1043 - 1051
(2020/10/02)
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- Enhanced kinetics of MgH2 via in situ formed catalysts derived from MgCCo1.5Ni1.5
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Magnesium hydride is highly desirable for hydrogen storage due to the high energy density and good reversibility; however, poor thermodynamic and kinetics during dehydrogenation are the main issues for application. Here, to improve the dehydrogenation properties of Mg/MgH2 system, we prepare an Mg/MgH2–MgCCo1.5Ni1.5 composite by ball-milling and hydriding combustion method, in which the in situ decomposition products of MgCCo1.5Ni1.5 compound plays catalytic effect for the de/hydrogenation of the formed MgH2 from Mg. Compared with pure MgH2, the MgH2–MgCCo1.5Ni1.5 composite exhibits a lower initial hydrogen releasing temperature and a faster hydrogen reaction, of which it starts desorbing H2 at 217 °C, 160 °C lower than that of the MgH2. Even at 150 °C, the Mg–MgCCo1.5Ni1.5 composite can reabsorb 5.5 wt% H2 within 60 min. Moreover, the apparent activation energy of the dehydrogenation of composite is reduced to 39.6 kJ/mol from 162.8 kJ/mol. XRD and TEM analyses confirm the formation of Mg2NiH4, MgC0.5Co3 and C during hydrogenation reaction process, where the dehydrogenation of Mg2NiH4 can induce the MgH2 to release hydrogen, the MgC0.5Co3 has a catalytic effect in the composite reaction, and the formed carbon materials help the dispersion of the composite particles.
- Ding, Zhenmin,Zhang, Lu,Fu, Yaokun,Wang, Wenfeng,Wang, Yu,Bi, Jia,Li, Yuan,Han, Shumin
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- Directing nitrogen-doped carbon support chemistry for improved aqueous phase hydrogenation catalysis
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Selective hydrogenations in the aqueous phase are an important transformation in the context of developing biorefinery concepts. In this report the application and optimisation of nitrogen-doped carbon (NDC) supported Pd nanoparticles as hydrogenation catalysts is discussed in the context of directing support (e.g. N) chemistry for improved catalytic performance in the aqueous phase. As a demonstrative example, the aqueous phase hydrogenation of phenol to cyclohexanone (e.g. a platform for polyamide production) is utilised. Catalyst supports were prepared based on an initial hydrothermal synthesis to yield NDC xerogels (from biomass precursors), the chemistry of which (e.g. functionality) was directed using a secondary thermal carbonisation (Tc) step at different temperatures (i.e. 350, 550, 750, 900 and 1000 °C). After Pd introduction, it was found that size, dispersion and electronic structure of the formed nanoparticles is affected by the surface chemistry of the NDC. This consequently led to higher turn-over frequency (TOF) and stability of the prepared catalysts compared to a "nitrogen-free"carbon supported Pd and a commercial, carbon supported Pd (Pd/AC) catalyst. Pd/NDC 900 (featuring predominantly quaternary and pyridinic N) catalysed the complete conversion of phenol at 99% selectivity to cyclohexanone, with excellent stability over 11 recycles and no discernible catalyst sintering or leaching (in contrast to the commercial catalyst). High catalytic stability, activity and selectivity make the Pd/NDC 900 catalyst highly applicable for aqueous phase hydrogenation reactions, whilst the general principle opens scope for support tailoring for application (e.g. biorefinery hydrogenations) and the development of structure/activity relationships.
- Bosilj, Monika,Fischer, Anna,Melke, Julia,Rustam, Lina,Thomann, Ralf,White, Robin J.
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p. 4794 - 4808
(2020/08/21)
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- Uniformly distributed ruthenium nanocrystals as highly efficient peroxidase for hydrogen peroxide colorimetric detection and nitroreductase for 4-nitroaniline reduction
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Here, we report highly dispersed small ruthenium nanoparticles (NPs) anchored onto a porous carbon (Ru/PC) with a clean catalytic surface and explore their excellent peroxidase-like activity for 3,30,5,50- tetramethylbenzidine oxidation mediated by H2O2, which allows sensitive colorimetric detection of H2O2 with a low detection limit of 3.8 lM. Moreover, it is also found that the Ru/PC has a high nitroreductase-like activity for 4-nitroaniline reduction triggered by NaBH4.
- Feng, Shiya,Ming, Mei,Wang, Mingzhu,Wang, Xue,He, Daiping,Jiang, Ping,Chen, Yuyun
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supporting information
p. 12347 - 12350
(2020/10/30)
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- Uncovering the actual inner-filter effect between highly efficient carbon dots and nitroaromatics
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High performance sensors can be produced by adequately designing the chemical structure and uncovering the actual detection mechanism. In this study, a fluorescent probe was synthesized for various nitroaromatic molecules, including stereochemically varied nitrophenols and nitroaniline. A systematic investigation of the influence of various analytes on the luminescence behavior of the as-synthesized carbon dot (CDs) revealed the inner-filter effect to be the major detection mechanism. The extinction coefficient and spectral overlap were found to be the critical parameters for high sensitivity and good selectivity rather than the functional groups of the CDs and analytes.
- Chung, Jin Suk,Hur, Seung Hyun,Jana, Jayasmita,Lee, Hye Jin
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- Fabrication of flexible microsupercapacitors with binder-free ZIF-8 derived carbon films via electrophoretic deposition
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Miniaturized power supplies, such as microsupercapacitors, are highly demanded in micro-electro mechanical systems (MEMS) and micro portable microdevices due to their superior cyclability, high power density, and considerable energy. In this study, we utilize ZIF-8 derived carbon as a source of active material to fabricate flexible microsupercapacitors via a simple electrophoresis method. The deposited ZIF-8 derived carbon particles with high surface area play a decisive role in achieving high electrochemical performances. The simple and straightforward process of electrophoretic deposition using ZIF-8 derived carbon particles generates porous carbon films on microsupercapacitors, which leads to a superior electrochemical performance.
- Henzie, Joel,Kim, Jeonghun,Kim, Minjun,Li, Jing,Li, Yang,Na, Jongbeom,Park, Teahoon,Wang, Jie,Xie, Huaqing,Yamauchi, Yusuke,Yi, Jin Woo,Young, Christine
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p. 176 - 181
(2020/04/27)
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- Synthesis, spectroscopic, thermal, structural investigations and biological activity studies of charge-transfer complexes of atorvastatin calcium with dihydroxy-p-benzoquinone, quinalizarin and picric acid
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The charge-transfer interactions between n-electron donor, atorvastatin calcium (ATC) and the electron acceptors, 2,5-dihydroxy-1,4-benzoquinone (DHBQ), 1,2,5,8-tetrahydroxy-9,10-anthraquinone (quinalizarin, Quiz), and 2,4,6-trinitrophenol (picric acid, P
- Niranjani, S.,Venkatachalam, K.
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- Synthesis, Structural characterization, thermal, molecular modeling and biological studies of chalcone and Cr(III), Mn(II), Cu(II) Zn(II) and Cd(II) chelates
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A number of new Cr(III), Mn(II), Cu(II) Zn(II) and Cd(II) chelates of (E)-3-(4-(dimethyl-amino)phenyl)-1-(pyridin-2-yl)prop-2-en-1-one were synthesized. The structures were elucidated by elemental and thermal analysis as well as spectral techniques (mass, IR, and electronic spectra) and magnetic measurements. The IR data suggested that the investigated chalcone acted as a bidentate ligand via the O and N atoms of the C[dbnd]O and C[dbnd]N groups, respectively. The spectral plus magnetic data revealed the formation of octahedral structures for all chelates while Cu(II) chelate has the square planar geometry. The kinetic and thermodynamic parameters of the thermal decomposition stages have been evaluated. Molecular orbital calculations have been performed to confirm the geometry of the isolated compounds. The in vitro antimicrobial activities of the chalcone and its metal chelates have been performed against some bacterial strains. The data indicated that all the metal chelates demonstrated a higher activity than the free chalcone. The anticancer activity of the mentioned metal chelates is evaluated against MCF7 cell. These compounds exhibited a moderate and weak activity against the tested cell line. The results were correlated with the experimental data.
- Diab, H. A.,El-Gamil, Mohammed M.,El-Nahass, Marwa N.,Fayed, Tarek A.,Gaber, M.
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- Stable High-Pressure Methane Dry Reforming Under Excess of CO2
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Dry reforming of methane (DRM), the conversion of carbon dioxide and methane into syngas, offers great promise for the recycling of CO2. However, fast catalyst deactivation, especially at the industrially required high pressure, still hampers this process. Here we present a comprehensive study of DRM operation at high pressure (7–28 bars). Our results demonstrate that, under equimolar CH4 : CO2 mixtures, coke formation is unavoidable at high pressures for all catalysts under study. However, under substoichiometric CH4 : CO2 ratios (1 : 3), a stable high pressure operation can be achieved for most catalysts with no sign of deactivation for at least 60 hours at 14 bars, 800 °C and 7500 h?1. In addition to the enhanced stability, under these conditions, the amount of CO2 abated per mol of CH4 fed increases by a 50 %.
- Ramirez, Adrian,Lee, Kunho,Harale, Aadesh,Gevers, Lieven,Telalovic, Selvedin,Al Solami, Bandar,Gascon, Jorge
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p. 5919 - 5925
(2020/09/17)
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- Sacrificial agent-free photocatalytic H2O2evolutionviatwo-electron oxygen reduction using a ternary α-Fe2O3/CQD?g-C3N4photocatalyst with broad-spectrum response
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Ultrathin g-C3N4nanosheets have been fabricatedviaa two-step calcination regulated by melamine precursors at a high heating rate (30 °C min?1). The resulting g-C3N4nanosheets were further employed as carriers for the growth of carbon quantum dots (CQDs) and (110) exposed α-Fe2O3through the PVP-enabled adsorption effects by a solvothermal process. It was discovered that the so fabricated ternary photocatalyst α-Fe2O3/CQD?g-C3N4presented a broad-spectrum absorption range (up to 800 nm) and particularly enhanced active sites of photogenerated electrons for highly efficient photocatalytic oxygen reduction toward H2O2evolution in pure water. A H2O2production rate of 1.16 μM min?1could be expected for the developed photocatalyst under visible light irradiation, which is about 19 times faster than that of pure ultrathin g-C3N4. Herein, the loaded Fe2O3could transform the H2O2evolution from two-step single-electron reduction into one-step two-electron one, as verified by the various active species experiments and rotating ring-disk electrode tests. This work presents a new perspective in designing ultrathin g-C3N4through a simple method of precursor-regulated calcination, which features more outstanding advantages than the conventional exfoliation of bulk g-C3N4towards ultrathin g-C3N4. More importantly, it provides an optimized photocatalytic reaction route of two-electron oxygen reduction for efficient H2O2production in pure water under visible light irradiation, without the need for noble metals or organic sacrificial agents.
- Chen, Xi,Feng, Luping,Jiang, Jie,Wang, Hua,Yan, Tingjiang,Zhang, Chunxian,Zhang, Lixiang,Zhang, Wenwen
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supporting information
p. 18816 - 18825
(2020/10/02)
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- Nano-Azo Ligand and Its Superhydrophobic Complexes: Synthesis, Characterization, DFT, Contact Angle, Molecular Docking, and Antimicrobial Studies
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Metal complexes of the 2,2'-(1,3-phenylenebis(diazene-2,1-diyl))bis(4-aminobenzoic acid) diazo ligand (H2L) derived from m-phenylenediamine and p-aminobenzoic acid were synthesized and characterized by different spectral, thermal, and analytical tools. The H2L ligand reacted with the metal ions Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) as 1: 1 stoichiometry. All complexes displayed an octahedral geometry according to the electronic and magnetic moment measurements. The IR spectra revealed the binding of the azo ligand to the metal ions via two azo nitrogen atoms and protonated carboxylate O in a neutral tetradentate manner. Both IR and 1H NMR spectra documented the involvement of the carboxylate group without proton displacement. The thermal studies pointed out that the complexes had higher thermal stability comparable with that of the free ligand. SEM images revealed the presence of the diazo ligand and its Cd(II) complex in a nanostructure form. The contact angle measurements proved that the Cd(II) complex can be considered as a superhydrophobic material. The molecular and electronic structure of H2L and [Cd(H2L)Cl2].H2O were optimized theoretically, and the quantum chemical parameters were calculated. The biological activities of the ligand, as well as its metal complexes, have been tested in vitro against some bacteria and fungi species. The results showed that all the tested compounds have significant biological activities with different sensitivity levels. The binding between H2L and its Cd(II) complex with receptors of the crystal structure of S. aureus (PDB ID: 3Q8U), crystal structure of protein phosphatase (PPZ1) of Candida albicans (PDB ID: 5JPE), receptors of breast cancer mutant oxidoreductase (PDB ID: 3HB5), and crystal structure of Escherichia coli (PDB ID: 3T88) was predicted and given in detail using molecular docking.
- Mahmoud, Walaa H.,Mohamed, Gehad G.,Refaat, Ahmed M.
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- A molten calcium carbonate mediator for the electrochemical conversion and absorption of carbon dioxide
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High-temperature molten salts are an excellent electrolyte to bring about redox reactions at a rapid rate without using rationally designed nano-structured catalysts. However, the large-scale electrolyzer is constrained by the use of expensive and resource-deficient lithium salts. Using Earth-abundant CaCO3 releases the pressure of using strategic lithium resources, but the low solubility of CaO in molten carbonates disables the capability of capturing CO2. In addition, the separation of carbon from water-insoluble CaO and CaCO3 consumes a large amount of acids. To tackle these challenges, we report a CaCO3-containing molten carbonate electrolyzer to prevent the use of lithium salts, and a molten CaCl2 dissolver to separate carbon from CaO that is soluble in molten CaCl2 and can capture CO2 by carbonization. More importantly, we develop a salt-soluble-to-water-insoluble approach for producing ultrafine CaCO3 using molten salt as a soft template. Overall, this study opens a pathway to use cheap and Earth-abundant molten CaCO3 as a mediator to convert CO2 to oxygen at a cost-effective inert anode, with value-added carbon at the cathode, and ultrafine CaCO3 through a salt-to-solution process.
- Chen, Xiang,Qu, Jiakang,Tang, Diyong,Wang, Dihua,Xie, Hongwei,Yin, Huayi,Zhao, Haijia,Zhao, Zhuqing
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p. 7946 - 7954
(2020/12/01)
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- Catalytic transfer hydrogenation of bio-based furfural by palladium supported on nitrogen-doped porous carbon
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Highly porous carbon was prepared via a zeolite hard templating route. Subsequent melamine treatment produced nitrogen-functionalized carbon (NPC), which was used as a support to anchor Pd nanoparticles (Pd/NPC) of sizes 2–4 nm using the chemical reduction method. Various analytical techniques were used to characterize the textural properties, structure, and chemical nature of the catalyst. Pd/NPC was then employed as a catalyst for the transfer hydrogenation of biomass-derived furfural (FF) to furfuryl alcohol (FFA) with alcohol as a hydrogen donor, and the effect of temperature, hydrogen donor species, reaction time, and catalysts loading were investigated. The Pd/NPC catalyst was reusable up to five times without any apparent loss of its activity and selectivity. A possible mechanistic pathway for the catalytic transfer hydrogenation of FF over Pd/NPC catalyst was proposed.
- Puthiaraj, Pillaiyar,Kim, Kyoungsoo,Ahn, Wha-Seung
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- SYSTEM AND METHOD FOR PYROLYSIS USING A LIQUID METAL CATALYST
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A process for decomposing a hydrocarbon-containing composition includes feeding the hydrocarbon-containing composition to a reactor containing a catalytically active molten metal or a catalytically active molten metal alloy, wherein the metal or alloy cat
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Paragraph 0106
(2019/02/28)
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- Synthesis of functionalized carbon microspheres and their catalyst activity in C—O and C—N bond formation reactions
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Disclosed herein is a simple process for functionalization/grafting of carbon microspheres obtained from bagasse with various active functional groups onto it and use of the same as catalyst for various organic reactions, having very high selectivity and conversion rate.
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Page/Page column 6
(2019/02/14)
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- Significantly enhanced photocatalytic performance of mesoporous C@ZnO hollow nanospheres via suppressing charge recombination
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Mesoporous C@ZnO hollow nanospheres were prepared by carbon sphere template. The influence of defects and surface state on photocatalytic performance was studied. The photocatalytic activity of C@ZnO nanospheres without treatment is the worst, that of the sample via pickling and annealing is secondary, and the pickling sample is the best. The improved performance can be attributed to the reduction of defects, which suppress the charge recombination. This work helps us better understand the important effects of defects on photocatalytic properties, and provides us with a feasible way to improve the UV photocatalytic activity of ZnO and other metal oxide.
- Zhu, Kexin,Jin, Changqing,Jian, Zengyun,Wei, Yongxing,Nan, Ruihua,Zhang, Chi,Hu, Lin
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p. 102 - 105
(2019/01/04)
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- Improved capacitance of NiCo2O4/carbon composite resulted from carbon matrix with multilayered graphene
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The optimized electric and ionic conductivity of metal oxides with pseudo-capacitive properties can greatly improve their electrochemical performances and can effectively amplify their applications in super-capacitors. Carbon spheres with multilayered graphene formed in their matrix are prepared by annealing them with sodium metal and they are combined with NiCo2O4 spheres by a simple hydro-thermal treatment. Structures and electrochemical performances of resulted samples are examined with X-ray diffraction, Raman scattering spectra, X-ray photoelectron spectroscopy, infrared spectroscopy, electron microscopy, gas physisorption, cyclic voltammetry and electrochemical impedance spectra, respectively. The largest specific capacitance of resulted composites is measured about 920 F g?1 at 1 A g?1, which is about 3.7 times larger than that of pure carbon spheres and 2.8 times larger than that of pure NiCo2O4 spheres. The formation of multilayered graphene in the matrix of carbon spheres not only increases the high specific capacitance based on electric double layers, but also makes metal oxides combined with them display greatly increased pseudo-capacitance. The electric and ionic conductivity of resulted composites with various weight ratios of NiCo2O4 and carbon spheres are respectively investigated and their effects on their electrochemical performances are also discussed.
- Xu, Zijie,Yang, Liu,Jin, Qiaoran,Hu, Zhonghua
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p. 376 - 383
(2018/11/30)
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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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- A study on decomposition of environmentally noxious gas with simultaneous synthesis of metal oxide powder in transferred DC thermal plasma
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Carbon dioxide was directly decomposed by a transferred DC thermal plasma and the effects of plasma induced current on the decomposition efficiency were investigated. The thermal plasma system was operated in a way that the metal oxide particles could be simultaneously produced from an anodic bulk metal (Zn) placed on a carbon crucible, so as to continuously consume atomic and molecular oxygens (O and O2) generated from the CO2 decomposition. As the induced current increased from 120 to 160 A by 20 A, the decomposition efficiency increased almost linearly from 53 to 68 %. The amount of ZnO particles produced from the bulk also increased and the particle crystallinity was improved. Although the concentration of carbon monoxide in the effluent was sharply increased at 160 A, further destruction can be done by re-circulating the effluent to plasma chamber.
- Choi, In-Chang,Kim, Heon Chang
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p. 449 - 452
(2019/01/10)
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- Reversible Nature of Coke Formation on Mo/ZSM-5 Methane Dehydroaromatization Catalysts
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Non-oxidative dehydroaromatization of methane over Mo/ZSM-5 zeolite catalysts is a promising reaction for the direct conversion of abundant natural gas into liquid aromatics. Rapid coking deactivation hinders the practical implementation of this technology. Herein, we show that catalyst productivity can be improved by nearly an order of magnitude by raising the reaction pressure to 15 bar. The beneficial effect of pressure was found for different Mo/ZSM-5 catalysts and a wide range of reaction temperatures and space velocities. High-pressure operando X-ray absorption spectroscopy demonstrated that the structure of the active Mo-phase was not affected by operation at elevated pressure. Isotope labeling experiments, supported by mass-spectrometry and 13C nuclear magnetic resonance spectroscopy, indicated the reversible nature of coke formation. The improved performance can be attributed to faster coke hydrogenation at increased pressure, overall resulting in a lower coke selectivity and better utilization of the zeolite micropore space.
- Kosinov, Nikolay,Uslamin, Evgeny A.,Meng, Lingqian,Parastaev, Alexander,Liu, Yujie,Hensen, Emiel J. M.
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supporting information
p. 7068 - 7072
(2019/04/17)
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- Direct Non-Oxidative Methane Conversion in a Millisecond Catalytic Wall Reactor
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Direct non-oxidative methane conversion (DNMC) has been recognized as a single-step technology that directly converts methane into olefins and higher hydrocarbons. High reaction temperature and low catalyst durability, resulting from the endothermic reaction and coke deposition, are two main challenges. We show that a millisecond catalytic wall reactor enables stable methane conversion, C2+ selectivity, coke yield, and long-term durability. These effects originate from initiation of the DNMC on a reactor wall and maintenance of the reaction by gas-phase chemistry within the reactor compartment. The results obtained under various temperatures and gas flow rates form a basis for optimizing the process towards lighter C2 or heavier aromatic products. A process simulation was done by Aspen Plus to understand the practical implications of this reactor in DNMC. High carbon and thermal efficiencies and low cost of the reactor materials are realized, indicating the technoeconomic viability of this DNMC technology.
- Oh, Su Cheun,Schulman, Emily,Zhang, Junyan,Fan, Jiufeng,Pan, Ying,Meng, Jianqiang,Liu, Dongxia
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supporting information
p. 7083 - 7086
(2019/04/27)
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- An Efficient Photocatalyst Based on Black TiO2 Nanoparticles and Porous Carbon with High Surface Area: Degradation of Antibiotics and Organic Pollutants in Water
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Porous carbon (PC) materials with high surface area can separate electron–hole pairs and adsorb organic pollutants more effectively. A series of nanocomposites were prepared by anchoring black TiO2 nanoparticles (BTN) onto PC through a calcination process. Chemical and structural features of samples were examined by X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, powder X-ray diffraction (P-XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses. The resulting adsorption-photocatalysis synergistic effect led to a dramatically improved photocurrent for BTN@PCs, thus indicating the high photocatalytic performance toward water-soluble organic species. For instance, the degradation of tetracycline under visible light reached 90 %, which is higher than that for activated carbon doped onto BTN (57 %) without any additional agents. Moreover, the degradation of other antibiotics (such as oxytetracycline and ciprofloxacin) and methylene blue were also studied, thus showing that this system has the potential to be used for water treatment.
- Fang, Yu,Li, Yuanyuan,Zhou, Feng,Gu, Peiyang,Liu, Jiadi,Chen, Dongyun,Li, Najun,Xu, Qingfeng,Lu, Jianmei
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p. 474 - 480
(2019/06/11)
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- Highly selective CO removal by sorption enhanced Boudouard reaction for hydrogen production
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The development of an energy-efficient and cost-effective technology for the purification of a hydrogen rich stream to achieve a CO concentration below 10 ppm, suitable for low temperature fuel cell applications, is one of the major objectives of energy research. Here we report the sorption enhanced Boudouard (SEB) reaction as an effective route for pure hydrogen production on metal-free catalysts by the highly selective removal of CO and CO2 from a hydrogen rich stream, where CaO serves as both a catalyst and a CO2 sorbent. We reveal that the in situ generated oxygen vacancy by CO adsorption on CaO catalyzes the sorption enhanced Boudouard reaction, hence the Boudouard reaction and CO2 removal occur simultaneously in a single step. The capture of CO2 in the presence of H2 by the solid sorbent shifts the chemical equilibrium towards complete CO conversion. The results demonstrate a remarkable decrease in the CO concentration from 0.5% in a hydrogen rich stream to less than 5 ppm, suitable for low temperature fuel cells. It avoids a subsequent preferential oxidation process or methanation reaction, as well as an additional CO2 capture process. The feasibility of applying the sorption enhanced Boudouard reaction in the production of highly pure hydrogen (CO content less than 10 ppm) was demonstrated by multicycle tests of Boudouard-carbonation/regeneration on Ca-based oxides with stable cyclic operation.
- Rout, Kumar R.,Gil, María V.,Chen, De
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p. 4100 - 4107
(2019/08/12)
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- Mesoporous carbon supported ultrasmall palladium particles as highly active catalyst for Suzuki-Miyaura reaction
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A fast and efficient eco-friendly two-step preparation of a palladium-containing mesoporous carbon catalyst (C1) from green and readily available carbon precursors (phloroglucinol and glyoxal), a porogen template (pluronic F-127) and PdCl2 is described. Catalyst C1 contains ultra-small Pd nanoparticles (1.2 nm) uniformly dispersed in the carbon network and shows an outstanding activity for Suzuki-Miyaura reactions in pure water: extremely low amounts of palladium (10 μequiv. in most cases) are sufficient to afford almost palladium-free products (containing 0.25 ppm of precious metal without further purification steps).
- Enneiymy, Mohamed,Le Drian, Claude,Ghimbeu, Camelia Matei,Becht, Jean-Michel
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- Pore-structure-directed CO2 electroreduction to formate on SnO2/C catalysts
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Electrochemical reduction of carbon dioxide (CO2) to value-added chemicals and fuels has attracted great interest, although it suffers from low energy efficiency and selectivity. Herein, we discover that the pore structure of a supported catalyst significantly affects the products and efficiency of the electrochemical CO2 reduction reaction (CO2RR). Three-dimensional (3D) porous carbon (PC) sheets with abundant micropores and macropores and mesopore-dominant activated carbon (AC) have been used to construct electrocatalysts with uniformly dispersed SnO2 nanoparticles. SnO2/PC exhibits efficient formate production from the electrochemical CO2RR with a high faradaic efficiency of 92% and partial current density of 29 mA cm-2 at -0.86 V, ranking as a top-tier Sn-based catalyst. Importantly, systematic investigation and comparison with SnO2/AC show that the space-confinement effect of micropores enhances CO2RR selectivity towards formate by inhibiting proton transfer to active sites and thus suppressing the HER process, while the 3D sheet structure with abundant macropores provides mass and charge transport highways, making more active sites accessible for an effective CO2RR and thus a larger current density. These findings shed light on the design of efficient electrocatalysts via engineering pore structures for diverse applications.
- He, Yeheng,Jiang, Wen-Jie,Zhang, Yun,Huang, Lin-Bo,Hu, Jin-Song
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p. 18428 - 18433
(2019/08/13)
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- P-doped mesoporous carbons for high-efficiency electrocatalytic oxygen reduction
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Chemically modified carbonaceous materials have attained utmost attention in the fields of renew-able energy storage and conversion, due to the controllable physicochemical properties, tailorable micro-/nanostructures, and respectable stability. Herein, P-doped mesoporous carbons were syn-thesized by using F127 as the soft template, organophosphonic acid as the P source and phenolic resin as the carbon source. Small amounts of iron species were introduced to act as a graphitization catalyst. The synthesized carbons exhibit the well-defined wormhole-like pore structure featuring high specific surface area and homogenously doped P heteroatoms. Notably, introducing iron spe-cies during the synthesis process can optimize the textural properties and the degree of graphitiza-tion of carbon materials. The doping amount of P has an important effect on the porous structure and the defect degree, which correspondingly influence the active sites and the oxygen reduction reaction (ORR) activity. The resultant material presents superior catalytic activity for the ORR, together with remarkably enhanced durability and methanol tolerance in comparison with the commercial Platinum catalyst, demonstrating the possibility for its use in electrode materials and electronic nanodevices for metal-air batteries and fuel cells.
- Zhao, Hui,Hu, Zhong-Pan,Zhu, Yun-Pei,Ge, Li,Yuan, Zhong-Yong
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p. 1366 - 1374
(2019/08/07)
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- Synthesis, characterization, and in vivo anti-cancer activity of new metal complexes derived from isatin-N(4)antipyrinethiosemicarbazone ligand against ehrlich ascites carcinoma cells
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The current study aimed to synthesize new metal coordination complexes with potential biomedical applications. Metal complexes were prepared via the reaction of isatin-N(4)antipyrinethiosemicarbazone ligand 1 with Cu(II), Ni(II), Co(II), Zn(II), and Fe(III) ions. The obtained metal complexes 2-12 were characterized using elemental, spectral (1H-NMR, EPR, Mass, IR, UV-Vis) and thermal (TGA) techniques, as well as magnetic moment and molar conductance measurements. In addition, their geometries were studied using EPR and UV-Vis spectroscopy. To evaluate the in vivo anti-cancer activities of these complexes, the ligand 1 and its metal complexes 2, 7 and 9 were tested against solid tumors. The solid tumors were induced by subcutaneous (SC) injection of Ehrlich ascites carcinoma (EAC) cells in mice. The impact of the selected complexes on the reduction of tumor volume was determined. Also, the expression levels of vascular endothelial growth factor (VEGF) and cysteine aspartyl-specific protease-7 (caspase-7) in tumor and liver tissues of mice bearing EAC tumor were determined. Moreover, their effects on alanine transaminase (ALT), aspartate transaminase (AST), albumin, and glucose levels were measured. The results revealed that the tested compounds, especially complex 9, reduced tumor volume, inhibited the expression of VEGF, and induced the expression of caspase-7. Additionally, they restored the levels of ALT, AST, albumin, and glucose close to their normal levels. Taken together, our newly synthesized metal complexes are promising anti-cancer agents against solid tumors induced by EAC cells as supported by the inhibition of VEGF and induction of caspase-7.
- El-Saied, Fathy,El-Aarag, Bishoy,Salem, Tarek,Said, Ghada,Khalifa, Shaden A.M.,El-Seedi, Hesham R.
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