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Dissipative Particle Dynamics (DPD) simulations were used to investigate the conformation of polyvinyl pyrrolidone (PVP) grafted on carbon nanotubes (CNT) and the physical adsorption of the PVP under shear flow. The behavior of PVP on the surface of CNTs was illustrated after the physical adsorption of PVP on the CNT reached equilibrium in an aqueous medium. It was found that PVP molecules prefer...
The friction coefficients of diamond and hydrogen-free diamond-like carbon films were reported to be in an intermediate range, from 0.2 to 0.4, in oxygen atmosphere, but the mechanism has not been explored. Herein, by using first-principles calculations, we attempt to fill this gap by providing atomistic insights into the bonding behaviors of oxygen atom(s) at interfaces constructed by two self-mated...
In the current work, graphene oxide (GO) and sulfonated graphene oxide (SGO) were synthesized and composited with Nafion to increase the water uptake (WUP) and ion exchange capacity (IEC) of the cast membranes. Ionic polymer-metal composite (IPMC) soft actuators in protonated form were fabricated based on the cast pure Nafion, Nafion/GO and Nafion/SGO membranes. The effects of incorporating GO and...
Metal intercalation to graphite produces various types of superconductors. The highest superconducting transition temperature Tc (onset temperature, Tconset, of 11.5 K) was found in Ca intercalated graphite, denoted CaC6. Tconset increased up to 15.1 K at 7.5 GPa, implying a positive pressure dependence. However, no new metal-intercalated graphite superconductors with Tconset higher than 11.5 K at...
In non-aqueous Li–O2 batteries, relatively large amounts of discharge products are formed on air cathodes. As such, the expansion of air cathodes is a critical issue that remains to be solved. Here, we report the fabrication of highly porous free-standing graphene paper by introducing macropores within the paper using polystyrene colloidal particles as a sacrificial template. The as-prepared macroporous...
In present work, we demonstrate a synchronous carbonization and graphitization process to produce nanoporous graphitic carbon materials, using glucose as carbon source, and Ni-Dimethylglyoxime-complex, Ni(dmgH)2, as graphitization agent. The carbon samples exhibit good graphitic feature at the low carbonization temperature of 800 °C, with the BET surface area of 584 m2 g−1, and pore volume of 0.76 cm...
A series of phosphorus (P) modified graphitic carbon nitride (P–C3N4) were facilely prepared by direct thermolysis of melamine and hexachlorotriphosphazene. Based on the results of XPS and 31P NMR analyses, it is deduced that there is replacement of C atoms located at the bay and edge terminal positions by P atoms. The P–C3N4 materials are easy-to-handle, stable, and metal-free. They function well...
A strategy for the preparation of metal oxide-carbon composite powders with yolk-shell structure by simple spray pyrolysis is introduced. Mn–Sn–O–C composite powders with yolk-shell structure representing the first target material are prepared by one-pot spray pyrolysis and their formation mechanism is evaluated. Phase separation of polyvinylpyrrolidone (PVP), Sn, and Mn components during the drying...
A general and straightforward strategy was developed for fabricating transition metal carbide (TMC)/carbon (C) core/shell nanospheres (NSs) by laser ablation of transition metals in acetone/ethanol liquid. Various TMC/C core/shell NSs such as TaC/C, NbC/C, HfC/C, and MoC/C core/shell NSs were successfully fabricated, highlighting the generality of this method. Crucially, this approach is green, facile,...
The mechanism of graphitic ordering of atomic C on Ni was investigated at temperatures ranging from room temperature to 550 °C. The C/Ni films were prepared by ion beam sputtering. Their structure has been determined by Rutherford backscattering spectrometry/nuclear reaction analysis, X-ray photoelectron spectroscopy, Raman spectroscopy and cross-sectional transmission electron microscopy. A temperature-induced...
A large scale 3D interconnected hierarchical porous carbon monolith was developed by a novel synthetic approach from the 2nd most abundant natural polymer, lignin. This newly derived carbon monolith possess desirable microstructure and high conductivity that enables the fabrication of a binder-/conductive additive-free thick electrode. The carbon monolith delivered simultaneously excellent areal/volumetric...
Wide angle X-Ray scattering was used to measure the progression of alignment when stretching carbon nanotube (CNT) sheets. The nanotubes were grown by an aerogel chemical vapor deposition process and drawn onto a drum rotating at a draw rate of 15 m/min to form a sheet. Samples were cut from this sheet at 0°, 10°, 25°, 45° and 90° with respect to the drawing direction. Samples stretched along the...
A novel model called Surface Shell Formation (SSF) is developed which predicts soot maturity based on the equilibrium nanostructure of poly aromatic hydrocarbons (PAHs) inside soot primary particles. The characteristic isotropic core-graphitic shell internal nanostructure of soot primary particles is used to distinguish nascent from mature soot primary particles. A new sectional soot model is developed...
Nitrogen-doped multiwalled carbon nanotubes (CNx-MWCNTs) with bamboo structures have been unzipped via a helical mechanism, and nitrogen-doped graphene oxide nanoribbons (CNx-GONRs) with a multifaceted microstructure have been obtained. CNx-GONRs have then been exposed to nitrogen and/or sulfur precursors at high temperatures to obtain doped graphene nanoribbons. The effects of single-doping, two-step-doping,...
The influence of humidity on the NH3 detection capability of S- and N-containing nanoporous carbons was examined for the first time. To investigate the role of water on the electrical performance of the sensors, the sensing tests were carried out using a flow of NH3 diluted in moist air. The same tests were also carried out by performing a 2 h prehumidification prior to the exposure of the carbons...
The chemical vapor deposition of monolayer graphene on metal foils and thin films typically yields graphene that appears to be continuous and complete but that actually contains a high density of pinhole defects. These pinhole defects can be present at densities greater than 1 μm−2 and are problematic for many applications, ranging from the implementation of graphene in electronics to its use as a...
We demonstrate that the thickness uniformity of chemical vapor deposited graphene monolayers strongly depends on the pre-annealing conditions of the copper foils used as substrates. We show that pre-annealing of copper foils under specific conditions leads to (111)-oriented smooth copper surfaces, while other conditions lead to corrugated surface morphologies. The differences in the morphologies of...
Binder-free, graphitic, hierarchically porous carbon nanofiber (CNF) electrodes with in-situ encapsulated Co–Ni catalysts are synthesized with electrospinning as an efficient oxygen electrode for Li–O2 batteries (LOBs). The inherently interconnected, graphitic network makes it unnecessary to include binders and carbon additives, therefore eliminating the possible side reactions from binder and facilitating...
The complex heterogeneous nature of chars has confounded the complete analysis of the Raman spectra of these materials. The additional shoulders observed on the defect (D)-band and high intensity valley between the D and graphitic (G)-bands represent the primary regions of uncertainty. In this paper the effects of various vacancy and substitution defects in a coronene parent molecule have been systematically...
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