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A self-standing porous carbon nanofiber (PCNF) matrix with controllable shallow hierarchical mesoporous structure on ∼40 nm of the top layer and microporous network in the fiber bulk has been prepared by electrospinning technology coupled with Mg(NO3)2 treatment in a one-step carbonization without further treatment. By regulating the heating rate during carbonization, PCNF with high specific surface...
The rational design and preparation of hierarchically porous carbons feature high on the wish list of academia and industry alike. However, creating interconnected pores of distinct dimensions is no easy task. Starting from the precursor design, we present a novel synthesis strategy of porous carbons that much enhances the pore interconnectivity. The 500 °C pyrolysis of chelated Mg and Fe nitrilotriacetates...
The blending of the matrix-forming polymer with the labile polymer (polymer blending) for designing carbon materials is reviewed. The organic template techniques are classified into three, on the basis of their purposes, pore structure control in the resultant carbons (membranes and fibers), preparation of hollow carbon nanofibers by spinning, and improvement in processability, particularly spinnability...
Ising model with the anisotropy is abstracted based on a nano-graphene sandwich-like structure. The system consists of a ferromagnetic middle layer and two antiferromagnetic layers on the top and under the bottom. Multiple spin states are employed to the analysis of magnetic behavior for graphene-like molecules. The effective-field theory with correlations has been successfully applied to this, and...
In this study, we demonstrated that carbon films with nanoscale roughness and controllable thickness can be produced by high temperature treatment of the polyacrylonitrile (PAN) film fabricated through dip-coating from 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) solution. Specifically, ultrasmooth (root mean squared average roughness between 1 and 3 nm), crack-free carbon films were produced. In our...
A nano-graphene bilayer is described by a transverse Ising model with single-ion anisotropy. The upper layer consists of spin 3/2 with an antiferromagnetic exchange coupling, whereas the bottom layer composes of spin 5/2 with a ferromagnetic exchange coupling. Based on the effective-field theory with correlations the general formula for the magnetization is given. Magnetic properties of the system...
Developing economical and commercially available materials to replace precious and nondurable platinum based catalysts is a very important issue in contemporary fuel cell technology. Nanostructured carbon materials have the potential to reduce the costs, improve the fuel tolerance and scalability; however, they are limited presently by their relatively low catalytic activity. Herein, we have synthesized...
Nitrogen-doped carbon aerogels (NCAs) were prepared by introducing tripolycyanamide during the synthesis of organic aerogel precursors, and the effects of the nitrogen content on the pore structure of NCAs and the photovoltaic properties of dye-sensitized solar cells (DSSCs) based on NCA counter electrodes (CEs) were studied. With the increase of nitrogen-doped concentration, the pore size of NCAs...
A hybrid nano-urchin structure consisting of spherical onion-like carbon and MnO 2 nanosheets is synthesized by a facile and environmentally-friendly hydrothermal method. Lithium-ion batteries incorporating the hybrid nano-urchin anode exhibit reversible lithium storage with superior specific capacity, enhanced rate capability, stable cycling performance, and nearly 100% Coulombic efficiency...
An asymmetric supercapacitor with high energy and power densities has been fabricated using MnO 2 /carbon nanofiber composites as positive electrode and activated carbon nanofibers as negative electrode in Na 2 SO 4 aqueous electrolyte. Both electrode materials are freestanding in nature without any conductive additives or binders and exhibit outstanding electrochemical performances...
Graphene sheet is used to modify mesoscopic carbon materials through electrostatic induced self-assembly and applied as a Pt-free counter electrode (CE) in a thiolate/disulfide redox couple based dye-sensitized solar cell (DSSC). The electrochemical characterization are carried out with Electrochemical impedance spectroscopy and Tafel polarization, which indicates that the catalytic activity of mesoscopic...
Porous poly(vinylidene fluoride) fibers were prepared by electrospinning from solutions in dimethylformamide, poly(ethylene oxide) (PEO) and water. The PVDF fiber mats were then converted into electrospun carbon fiber paper using a low temperature chemical stabilization treatment (“dehydrofluorination”) followed by carbonization at 1000°C. The resulting self-supporting carbon fiber paper exhibits...
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