7440-44-0Relevant articles and documents
Aluminium powder as a reactive template for preparation of carbon flakes from CCl4
?imon, Erik,Billik, Peter,Orov?ík, ?ubomír,Nagy, ?tefan,Sasinková, Vlasta,Palou, Martin T.,?krátek, Martin,Trembo?ová, Veronika,Plesch, Gustav
, p. 4599 - 4607 (2020)
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.].
Chemical vapor deposition of methane for single-walled carbon nanotubes
Kong, Jing,Cassell, Alan M.,Dai, Hongjie
, p. 567 - 574 (1998)
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
STRUCTURE OF THE RESIDUAL CARBON MADE BY FLUOROCARBON PYROLYSIS
Fialkov, A. S.,Dobryakov, S. N.,Khorkhorin, A. V.,Tyan, L. S.,Polyakova, N. V.,et al.
, p. 413 - 416 (1990)
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.
Electrical and thermoelectric power measurements of GaInSe2 single crystals
Mobarak
, p. 1259 - 1263 (2009)
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
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
Ermakova,Ermakov,Chuvilin,Kuvshinov
, p. 183 - 197 (2001)
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
The surface decoration and electrochemical hydrogen storage of carbon nanofibers
Yan, Xiaoqi,Gao, Xueping,Li, Ying,Liu, Zhanquan,Wu, Feng,Shen, Yutian,Song, Deying
, p. 336 - 341 (2003)
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.
Magnetotransport in the amorphous carbon films prepared from succinic anhydride
Prasad,Subramanyam
, p. 168 - 176 (2005)
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.
Nanodomain structure of carbon-rich silicon carbonitride polymer-derived ceramics
Mera, Gabriela,Tamayo, Aitana,Nguyen, Hong,Sen, Sabyasachi,Riedel, Ralf
, p. 1169 - 1175 (2010)
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.
Synthesis and characterization of SiC nanowires through a reduction-carburization route
Hu,Lu,Tang,Deng,Jiang,Qian,Yu,Zhou,Liu,Wu
, p. 5251 - 5254 (2000)
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.
Synthesis of 15R polytype of diamond in oxy-acetylene flame grown diamond thin films
Kapil,Mehta,Vankar
, p. 2520 - 2522 (1996)
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.
One-step and template-free preparation of hierarchical porous carbons with high capacitive performance
Zhou, Jin,Zhang, Zhongshen,Li, Zhaohui,Zhu, Tingting,Zhuo, Shuping
, p. 46947 - 46954 (2015)
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.
Few-layer epitaxial graphene grown on vicinal 6H-SiC studied by deep ultraviolet Raman spectroscopy
Kisoda, Kenji,Kamoi, Susumu,Hasuike, Noriyuki,Harima, Hiroshi,Morita, Kouhei,Tanaka, Satoru,Hashimoto, Akihiro
, (2010)
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
Thermal conductivity of hard carbon prepared from C60 fullerene
Smontara,Biljakovic,Staresinic,Pajic,Kozlov,Hirabayashi,Tokumoto,Ihara
, p. 160 - 162 (1996)
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
Carbon-hydrogen bonding in near-frictionless carbon
Johnson,Woodford,Rajput,Kolesnikov,Schleuter,Eryilmaz,Erdemir
, (2008)
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.
Krishnaswamy, J.,Rengan, A.,Narayan, J.,Vedam, K.,McHargue, C. J.
, p. 2455 - 2457 (1989)
Monolayer graphene film/silicon nanowire array Schottky junction solar cells
Xie, Chao,Lv, Peng,Nie, Biao,Jie, Jiansheng,Zhang, Xiwei,Wang, Zhi,Jiang, Peng,Hu, Zhizhong,Luo, Linbao,Zhu, Zhifeng,Wang, Li,Wu, Chunyan
, (2011)
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.
Self-assembly of carbon nanohelices: Characteristics and field electron emission properties
Zhang, Guangyu,Jiang, Xin,Wang, Enge
, p. 2646 - 2648 (2004)
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
Milligan,Jacox
, p. 1387 (1966)
Monolayer graphene growth on Ni(111) by low temperature chemical vapor deposition
Addou, Rafik,Dahal, Arjun,Sutter, Peter,Batzill, Matthias
, (2012)
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.
Fluorination of single-wall carbon nanotubes
Mickelson,Huffman,Rinzler,Smalley,Hauge,Margrave
, p. 188 - 194 (1998)
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
Synthesis of Fe (Co or Ni) loaded mesoporous carbon composites and their adsorption behaviors for methyl orange
Jiang, Tingshun,Fang, Weibing,Zhao, Qian,Liu, Wangping,Zhao, Haibo,Le, Shukun
, p. 5261 - 5270 (2017)
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.
Synthesis and characterization of highly ordered Co-MCM-41 for production of aligned single walled carbon nanotubes (SWNT)
Lim, Sangyun,Ciuparu, Dragos,Pak, Chanho,Dobek, Frank,Chen, Yuan,Harding, David,Pfefferle, Lisa,Haller, Gary
, p. 11048 - 11056 (2003)
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.
DIRECT CURRENT ARC-PLASMA SYNTHESIS OF TUNGSTEN CARBIDES.
Ronsheim,Toth,Mazza,Pfender,Mitrofanov
, p. 2665 - 2674 (1981)
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.
Single-walled nanotubes by the pyrolysis of acetylene-organometallic mixtures
Satishkumar,Govindaraj,Sen, Rahul,Rao
, p. 47 - 52 (1998)
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.
High yield of single-wall carbon nanotubes by arc discharge using Rh-Pt mixed catalysts
Saito, Yahachi,Tani, Yoshihiko,Miyagawa, Norihisa,Mitsushima, Koichi,Kasuya, Atsuo,Nishina, Yuichiro
, p. 593 - 598 (1998)
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.
Liquid-Metal-Enabled Mechanical-Energy-Induced CO2 Conversion
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
, (2021/10/25)
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.
Antibacterial and anticorrosion behavior of bioactive complexes of selected transition metal ions with new 2-acetylpyridine Schiff base
Ashmawy, Ashraf M.,Deghadi, Reem G.,Elsharkawy, Ahmed E.,Mohamed, Gehad G.
, (2022/01/19)
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.
Self-redox reaction of carbon in molten salt for anode materials of lithium/sodium-ion batteries
Chen, Denghui,Ning, Zhiqiang,Song, Qiushi,Xie, Hongwei,Zhao, Hengpeng
, (2022/04/03)
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