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We report a novel far-infrared (FIR) thermal reduction process to effectively reduce graphene oxide films for supercapacitor electrode applications. The binder-free graphene oxide films used in this study were produced by electro-spray deposition of a graphene oxide colloidal solution onto stainless steel current collectors. The reduction of graphene oxide was performed using a commercial FIR convection...
A transparent, gas barrier film comprised of poly(vinyl alcohol) (PVA) and graphene oxide (GO) is synthesized through combined methods of solution blending and isothermal recrystallization. The recrystallized PVA/GO film with only 0.07vol% GO gives an O2 transmission rate <0.005ccm−2day−1 and an O2 permeability <5.0×10−20cm3cmcm−2Pa−1s−1; hence, it is far superior to other blend polymer/inorganic...
The carbonization of a newly reported two-dimensional zeolitic imidazolate framework (ZIF-L) with leaf-like morphology was investigated by TG, SEM, XRD and XPS. ZIF-L flakes were thermally stable at up to 200°C, and completely transformed into an amorphous carbonaceous material after heat treatment in nitrogen at 550°C. A carbon composite membrane was then prepared by deposition of ZIF-L flakes on...
A series of highly nanoporous carbons have been prepared by converting benzoate–metal complexes, including zinc benzoate, magnesium benzoate and aluminium benzoate through a template carbonization process. The carbonization temperature plays a pivotal role in determining the carbon structures as well as the resultant electrochemical behaviors in supercapacitors. The carbon–Zn-900 sample derived from...
A semi-classical kinetic model for the electronic response of a single-walled carbon nanotube (SWCNT) is combined with the Molecular Dynamics (MD) method to simulate propagation of fast protons through the nanotube, with the initial kinetic energies between 1 and 100keV. Instead of the continuum potential based on the Thomas–Fermi–Moliere model that was used in our previous work, we introduce here...
Polyacrylonitrile-based carbon fiber bundles, with two sides fixed, were heated in a graphitization furnace with temperature profiles similar to those used in the preparation of carbon/carbon composites. The microstructure of the microvoids formed was characterized by small-angle X-ray scattering and high resolution transmission electron microscopy (HR-TEM). Results showed that the average radius...
The chemical kinetics of propane pyrolysis in chemical vapor deposition (CVD) is investigated in 1074 reactions consisting of 285 species to understand chemistry of CVD from propane. The reaction mechanism is modeled in a perfectly stirred reactor and a continuous tubular reactor, to produce a 0-D and a 1-D propane pyrolysis model, respectively. The concentration profiles of gas-phase products in...
We report an efficient one-step approach to reduce and functionalize graphene oxide (GO) during the in situ polymerization of phenol and formaldehyde. The hydrophilic and electrically insulating GO is converted to hydrophobic and electrically conductive graphene with phenol as the main reducing agent. Simultaneously, functionalization of GO is realized by the nucleophilic substitution reaction of...
Direct fabrication of graphene on solid carbon coated nickel surface was realized by laser irradiation at room temperature. High-quality graphene was obtained rapidly, e.g. 28.8cm2/min. Arbitrary patterns designed by computer aided design (CAD) software were fabricated directly on Ni substrates without additional mask or setup. Raman mapping results showed that monolayer/bilayer graphene regions accounted...
A novel method is developed for low temperature synthesis of carbon encapsulated spherical Fe7S8, equiaxed Fe3O4 and spherical porous FeOOH nanocrystals with a core–shell structure via a solid–solid reaction of ferrocene with (NH4)2S2O8, (NH4)2Cr2O7 and NH4ClO4 in an autoclave, respectively. Samples were characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy...
We demonstrate the direct growth of carbon nanotube (CNT) forests on metallic titanium (Ti) coatings by single-step chemical vapor deposition. This was achieved by catalyst engineering, which involves a novel design of Fe/Ti/Fe nanostructure sputtering coated on SiO 2 /Si wafers. The Fe sublayer, an additional catalyst added to the conventional catalyst/support design, plays a key role in...
In contrast with traditional methods of observation, synchrotron radiation X-ray computed tomography (SR-CT) is an advanced technique that allows direct three-dimensional (3D) and non-destructive observation of microstructures in materials. High-resolution in situ observations (0.7μm/pixel) of fractures in short carbon fiber/epoxy composites are achieved using the SR-CT technique, and the mechanical...
In this paper, the nanojoining method of graphene sheets (GSs) by ion beam irradiation is proposed and the joining process is researched by classical molecular dynamics simulations. We demonstrate that the carbon ion beam irradiation should result in the joining of overlapped GSs. And it is found that these joining processes are attributed to two different mechanisms. In addition, the influences of...
Multi-layer graphene sheets have been synthesized by a time-efficient microwave autoclave method and used to form composites in situ with single-walled carbon nanotubes. The application of these composites as flexible free-standing film electrodes was then investigated. According to the transmission electron microscopy and X-ray diffraction characterizations, the average d-spacing of the graphene–single-walled...
An easy method to synthesize a strongly coupled cobalt ferrite/carbon nanotube (CoFe 2 O 4 /CNT) composite with oxygen bridges between CoFe 2 O 4 and reduced carbon nanotubes (CNTs) by calcining the precursor material was reported. The precursor was prepared by an electrostatic self-assembly of the exfoliated Co(II)Fe(II)Fe(III)-layered double hydroxide (CoFeFe-LDH)...
SiO 2 -matrix composites filled with 2, 5 and 10wt.% multiwalled carbon nanotubes (MWCNTs) were prepared to evaluate the dielectric properties and microwave attenuation performances over the full X-Band (8.2–12.4GHz) at a wide temperature ranging from 100 to 500°C. On the basis of the conductivity induced by the structure of the MWCNT, the transport of migrating and hopping electrons in the...
The thermal transport properties of graphene nanoribbons (GNRs) with pentagon–heptagon defect (PHD) are studied by using first principles calculations in combination with non-equilibrium Green’s function approach. The results show that the PHD effect on thermal conduction in armchair-oriented GNR is stronger than that in zigzag-oriented GNR. The out-of-plane acoustic mode is almost reflected by the...
Mesoporous carbon (MC), prepared by the carbonization of phenol resin using ethylene glycol as a pore forming agent, was used as the catalyst of the counter electrode in dye-sensitized solar cells (DSCs) fabricated by a paste coating method at low temperature, where a non-ionic surfactant, Triton X100, was used as a modifier of the paste. Fractal dimensions (D F ) were used to evaluate the...
A Mo/Si slurry was coated onto the surface of Al/Si-coated carbon fiber reinforced carbon (C/C) composites and vacuum-sintered to form a fused double-layered coating. The effect of the Al content (6 and 10 mass%) in the Al/Si layer on the oxidation resistance of the composites was investigated. Results indicate that the presence of Al effectively prevents liquid Si infiltration into the composites...
Large-scale few-layer graphene (FLG) films were prepared by an industrial single-roller melt spinning technique based on molten alloy quenched carbon self-segregation using nickel and carbon as precursors. A formation mechanism of FLG based on rapid diffusion and non-equilibrium segregation of carbon is discussed. This ultra-fast thin film preparation technique can be extended and used to produce...
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