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The field emission properties of graphitic nanowalls prepared by a simple microwave-based method are presented. The effects of deposition method on the agglomeration and field emission properties of samples were also studied. Thermal treatment of these samples at 300°C in air and at 1000°C in argon further increased electron emission properties by improving the graphitic order of the samples and removal...
During the past 20years, multiwall carbon nanotubes (MWCNTs) have become an important industrial material. Hundreds of tons are produced each year. This review is a survey of the scientific literature, motivated by industrial requirements and guidelines for environment, health and safety compliance. Sampling, size, area, density, color, crystallinity, as well as purity compared to properties of non-MWCNT...
Conical carbon nanotube (CCNT) arrays were synthesized over a large area of approximately 1cm 2 or more on graphite and tungsten foil substrates. Experimental observations reveal that nucleation is caused by catalyst metal cluster in the initial stages, but the tapered morphology occurs due to the difference in the rates of vertical growth by attachment carbon atoms at edges of growing graphene...
Activated carbon (AC) was modified by hexamethylene diamine (HMDA) to remove low-concentration formaldehyde in air. Results demonstrate that no ammonia or amine compounds give out from the modified AC up to 423K. And the modification significantly improves the adsorption performance of AC for formaldehyde. There exists an optimum loading amount, being around 0.04gHMDA/g AC in this study.
The conformation and electronic structure of hydrogen-treated graphenes are investigated using the density-functional theory (DFT) method. We show that the overall energetics of the hydrogen chemisorption configuration can be analyzed with two energy components: the electronic pairing effect in the hyper-conjugated π electron network and the strain effect in the C–C bond at the boundary between sp...
The characteristics of field-emission current of a graphene nanoribbon along the direction without finite size effect in the graphene sheet have been theoretically studied. After the work function of graphene nanoribbon is assumed not to change with its width, numerical calculations show that field-emission current density at a given external field decreases with decreasing width of nanoribbon. Such...
Novel poly(ether ether ketone) (PEEK)/single-walled carbon nanotube (SWCNT)/glass fiber laminates incorporating polysulfone as a compatibilizing agent were fabricated by melt-blending and hot-press processing. Their morphology, mechanical, thermal and electrical properties were investigated and compared with the behavior of similar non-compatibilized composites. Scanning electron micrographs demonstrated...
The 13 C nuclear magnetic resonance (NMR) and dielectric behavior of rhombohedral C 60 polymer with (003) texturing have been studied. 13 C NMR reveals that sp 3 bonds break from 423 to 523K. This is the temperature region in which depolymerization occurs, as deduced from temperature-resolved X-ray diffractometry. X-ray diffraction also shows the structural transition...
The morphology and thermomechanical properties of composites of poly(methyl methacrylate) (PMMA) and chemically modified graphene (CMG) fillers were investigated. For composites made by in situ polymerization, large shifts in the glass transition temperature were observed with loadings as low as 0.05wt.% for both chemically-reduced graphene oxide (RG-O) and graphene oxide (G-O)-filled composites....
Tannin–formaldehyde carbon aerogels were prepared based on organic gels obtained by sol–gel polymerisation of tannin with formaldehyde that have been dried with supercritical acetone and pyrolysed at 900°C. Tannins drastically reduce the cost of the gels, typically by a factor five, and polymerise in a wide range of pHs, leading to porous carbonaceous materials whose mesopore fraction ranges from...
Core/shell heterostructured conical carbon fibers with silicon-based cores and graphitic carbon sheaths have been grown on silicon carbide (SiC) surfaces exposed to the combustion of methane. The conical carbon fibers (CCFs), which taper from a circular base to a point, appear to form by two simultaneous growth processes, axial tip-growth and radial fiber thickening. Radial fiber thickening results...
We report on the fabrication and transport characteristics of nanoscale stacked-junctions of thin graphite flake. The stacked-junctions were fabricated using a three-dimensional focused-ion-beam milling. By varying the effective in-plane area down to submicron scale, the stacked-junctions with in-plane area A (from 2 down to 0.25μm 2 ) and stack height–length (from 300 to 100nm) along c-axis...
We report here the development of thin film ‘graphite’ electrodes for Li-ion batteries, with near theoretical Li-intercalation/de-intercalation capacity (∼372mAh/g). These films, synthesized by chemical vapor deposition at a relatively low temperature of 1000°C, exhibit strong graphitic order with the basal planes oriented parallel to the Ni current collector. During galvanostatic cycling, in-situ...
Few-layer graphene sheets were prepared by splitting expanded graphite using high-power sonication. Atomic-level calibrated scanning transmission electron microscopy was used to obtain efficient layer statistics, enabling optimization of the experimental conditions. This resulted in a two-step splitting mechanism in which the mean number of layers was first reduced to less than 20 by heating to 1100°C...
Arrays of carbon nanotubes exhibit a polarization dependent radiative absorption at radiofrequencies and this enhanced longitudinal absorbance is attributed to electric field induced intra-band transitions within sp 2 hybridized orbits. This is supported by ab initio calculations.
Jute fibres and corresponding epoxy based composites with sensing abilities could be realized by depositing multi-walled carbon nanotubes (MWCNTs) on the surfaces of jute fibres or fabrics using simple and scalable dip coating. The formation of electrically semiconducting MWCNT networks on jute fibre surfaces was confirmed, which in turn caused the formation of jute/epoxy interphases with highly concentrated...
A novel method was developed to synthesize graphite oxide/TiO 2 composites as a highly efficient photocatalyst by in situ depositing TiO 2 nanoparticles on graphene oxide nano-sheets by a liquid phase deposition, followed by a calcination treatment at 200°C. The two-dimensional porous graphene oxide/TiO 2 composites had specific surface area of 80m 2 g −1 being...
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