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Graphene nanoribbons (GNRs) with tubular shaped thin graphene layers were prepared by partially longitudinal unzipping of vapor-grown carbon nanofibers (VGCFs) using a simple solution-based oxidative process. The GNR sample has a similar layered structure to graphene oxide (GO), which could be readily dispersed in isopropyl alcohol to facilitate electrophoretic deposition (EPD). GO could be converted...
Carbon nanotubes (CNTs) have one of the highest production volumes among carbonaceous engineered nanoparticles (ENPs) worldwide and are have potential uses in applications including biomedicine, nanocomposites, and energy conversion. However, CNTs possible widespread usage and associated likelihood for biological exposures have driven concerns regarding their nanotoxicity and ecological impact. In...
Non-metallic fractions of FR-3 type waste printed circuit boards were pyrolyzed at high temperatures. The resultant char at 600°C was used to prepare activated carbons by physical and chemical activation. The influence of pyrolysis temperature on char yields, and activation conditions on the burn-off and porous properties of the activated carbons were investigated. Results show that char yields decrease...
We developed a multiscale scheme using molecular dynamics (MD) and finite element (FE) methods for evaluating the effective thermal conductivity of graphene epoxy nanocomposites. The proposed hierarchical multiscale approach includes three different scales. First, we used MD simulations for the investigation of thermal conduction in graphene epoxy assembly at atomic scale. Our results suggest that...
Piezoresistivity (change of the volume electrical resistivity with strain) in continuous carbon fiber polymer-matrix structural composites allows electrical-resistance-based strain/stress sensing. Uniaxial through-thickness compression is encountered in fastening. As shown for a 24-lamina quasi-isotropic epoxy-matrix composite, compression results in (i) strain-induced reversible decreases in through-thickness...
Hybrid silica–carbon nanotube (CNT) particles with a radial symmetry were produced by the growth of nanotubes onto spherical, mesoporous silica gel particles using the floating catalyst chemical vapour deposition (FC-CVD) method. Characterisation of the hybrid particles, using electron microscopy, Raman spectroscopy and thermogravimetry showed the geometry and porosity of the silica particles to influence...
Tensile tests were performed on carbon nanofibers in situ a transmission electron microscope (TEM) using a microelectromechanical system (MEMS) tensile testing device. The carbon nanofibers tested in this study were produced via the electrospinning of polyacrylonitrile (PAN) into fibers, which are subsequently stabilized in an oxygen environment at 270°C and carbonized in nitrogen at 800°C. To investigate...
Carbon foams were synthesized using an asphaltene pitch as a carbon precursor. The effects of foaming conditions and carbonization on the pore structures and physical properties of the carbon foams were investigated. Results indicate that the average pore size and density of as-synthesized carbon foams were about 150μm and 800kg/m 3 , respectively. The compressive strength of the carbon foam...
Wide-bandgap multilayer oxygenated graphene (MLOG) is used as the recombination barrier layer (RBL) in dye-sensitized solar cell (DSSC). The MLOG is derived from multilayer graphene synthesized by chemical vapor deposition (CVD) and oxygenated with high density/low power oxygen plasma. We observe 19% improvement in photoconversion efficiency of the DSSC with MLOG RBL, as compared with DSSC without...
Reduced graphene oxide (RGO) with different amounts of wrinkling were synthesized in a water–ethylene glycol (EG) system with different volume ratios. The obtained RGO were characterized by X-ray powder diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, scanning and transmission electron microscopy, thermogravimetric analyze, and Brunauer–Emmett–Teller N 2 adsorption–desorption...
We have prepared multiwalled carbon nanotube (MWCNT)/In 2 O 3 composites using a simple impregnation method. The precursor compound indium(III) chloride (InCl 3 ) was used to cover the surface of MWCNTs and distilled water was used as solvent. The applied mass ratio was 4:1 (In 2 O 3 /MWCNT), and during the calcination process different temperatures (300, 350...
A simple route for the Sn-assisted synthesis of carbon nanocoils (CNCs) by chemical vapor deposition of acetylene on polycrystalline BaSrTiO 3 (BST) substrates is reported. In this study, high-quality CNC forests have been synthesized on BST substrates with the presence of Sn. The morphologies and qualities of the CNCs were characterized by scanning electron microscopy, transmission electron...
Effective thermal conductivity of composites of graphite foam infiltrated with phase change materials (PCM) was investigated numerically and experimentally. Graphite foam, as a highly-conductive, highly-porous structure, is an excellent candidate for infiltrating PCM into its pores and forming thermal energy storage composites with improved effective thermal conductivity. For numerical simulation,...
This work describes a novel approach to fabricate horizontal nanotube interconnects with dimensions comparable to state-of-the-art copper interconnects. The interconnects consist of carbon nanotubes bundles with wall density ≈10 13 cm −2 , wire lengths of tens of micrometers and wire diameters scalable to 50nm. The nanotubes are first grown vertically, inside vias with diameters ranging...
Porous graphene obtained by chemical vapor deposition (CVD) using porous MgO sheets as template is demonstrated to exhibit a high reversible capacity (1723 mAh g -1 ), excellent high-rate capability and cycling stability for Li-ion batteries. The simple CVD approach offers a new way for large-scale production of porous graphene materials for energy storage.
In the present work, nitrogen-containing carbon particles were synthesized by a two-step microwave carbonization. Nitrogen was introduced into the carbon particles via the addition of urea solution during microwave-assisted hydrothermal carbonization. The nitrogen content was easily controlled by varying the urea concentration. Carbon microspheres of over 90% carbon content by atomic ratio were obtained...
The viscoelastic behavior of binderless carbon black compacts under dynamic compression (0.2–10.0Hz, static strain 1.0–2.5%, deformation amplitude 9.4–16μm and packing density 0.18–0.45g/cm 3 ) is governed by the solid part of the compact, with the elastic character dominating the viscous character. The viscous character increases with increasing aggregate size, while the elastic character...
Nanoporous carbon (NPC) is structurally complex yet poorly understood, particularly the topological defects such as pentagon rings. Here we propose a computational approach that links the topological defects to structure factor S(q) measured from X-ray experiments. The essence of this method is to generate a large dataset of realistic NPC models by virtual synthesis procedures, from which both the...
Multi-wall carbon nanotubes (MWCNTs) prepared by chemical vapor deposition, were pretreated by ball milling, chemical activation and ammoxidation and the influence of the pretreatment on their electrochemical capacitance was investigated. Results show that MWCNTs can be shortened and broken by ball milling and chemical activation, and as a result their surface area and pore volume are increased. However,...
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