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Sodium-ion batteries are considered a top alternative to lithium-ion batteries for large-scale renewable energy storage units due to their low cost and the abundance of sodium-bearing precursors in the earth's mineral deposits. However, the absence of a suitable negative electrode material hinders their development. In this contribution, we report the preparation of nitrogen and phosphorous co-doped...
Functional groups (FGs) in graphene oxide (GO) play an important role in the properties and applications of GO and its related materials. However, there are limited studies about the reversible transformation of FGs in response to external stimuli. In this paper, we report an experimental investigation on the response of FGs to the stimuli of transitional metal compounds. Reversible transformation...
The Dirac bands and flat bands are difficult to coexist because they represent two extreme ends of electronic properties. However, in this paper, we propose a carbon-Kagome-lattice (CKL) family based on first-principles calculations, and the coexistence of Dirac and flat bands are observed in this series of three-dimensional carbon structures. The flat bands are originated from the orbital interactions...
Molecular dynamics simulations with the adaptive intermolecular reactive bond order (AIREBO) potential are performed to study the high-temperature (T) behavior of monolayer graphyne and graphdiyne (MGY and MGDY). During the melting process, MGY and MGDY undergo three continuous phase transitions: (i) transformation into the initial amorphous graphene phase (AGP) starting from 2800 to 2500 K for MGY...
This research explores the surface chemistry of halogen based plasmas on silicon carbide and is aimed at the synthesis of large area graphene-on-insulator films. In these studies, 6H–SiC (0001) substrates were etched using either CF4 and Cl2 based plasmas and then thermally annealed. The resulting surfaces were analyzed using x-ray photoelectron spectroscopy, reflection high energy electron diffraction,...
Described herein is a facile one-pot strategy to synthesize N-doped graphitic carbon-incorporated g-C3N4 by adding slight amount of citric acid into urea as the precursor during thermal polymerization. The obtained materials retained the original framework of g-C3N4 and show remarkably enhanced visible light harvesting and promoted photo-excited charge carrier separation and transfer. The high-resolution...
High-surface-area carbon aerogels are synthesized by pyrolysis of nanocellulose aerogels that are prepared by dissolving of cellulose microcrystalline in NaOH aqueous solutions followed by gelation, regeneration and freeze drying or supercritical CO2 drying. The obtained carbon aerogels are further treated via a CO2 activation process. The result shows that the nanocellulose aerogels dried by supercritical...
A novel and selective electrochemical functionalization of a highly reactive superporous zeolite templated carbon (ZTC) with two different aminobenzene acids (2-aminobenzoic and 4-aminobenzoic acid) was achieved. The functionalization was done through potentiodynamic treatment in acid media under oxidative conditions, which were optimized to preserve the unique ZTC structure. Interestingly, it was...
Here we describe using nanosheets of both graphene and boron nitride, produced by liquid phase exfoliation, as fillers in composite fibres. The fibres were prepared by coagulation spinning using polyvinylalcohol as a matrix. We obtained good quality fibres with diameter and nanosheet volume fraction which could be controlled via the ratio of nanosheet to polymer injection rates. The mechanical stiffness...
To reduce the charge overpotential and improve the cyclability of Lithium–Oxygen (Li–O2) batteries, a novel carbon composite material consisting of graphene and activated carbon (G/AC) is developed for the oxygen electrode (cathode). In the G/AC, the graphene forms a three-dimensional (3D) network with good electrical conductivity and excellent mechanical strength and flexibility, while the AC layer...
Aligned carbon nanofibers (CNFs) were fabricated by electrospinning to evaluate the potential of aligned one-dimensional structure as a supercapacitor electrode. First, randomly oriented polyacrylonitrile (PAN) nanofibers were fabricated, and aligned PAN nanofibers were prepared by increasing the speed of the rotary collector from 250 to 2000 rpm. The prepared PAN nanofibers were carbonized for use...
Three-dimensional (3D) graphene structure exhibits promising potential in thermal interface materials (TIMs) due to the continuous network structure and the high thermal conductivity of graphene. Nevertheless, the very low density and the high porosity of the 3D graphene monoliths usually lead to poor thermal transport performance. To overcome these problems, we fabricated the graphene/carbon nanotube...
Metal-free growth of carbon nanotubes/fibers (CNT/Fs) using chemical vapor deposition (CVD) on semiconducting and insulating substrates is of interest in the context of the construction of nanoscale electronic devices. However, controllable synthesis of CNT/Fs without the aid of metal catalysts is an ongoing challenge. Here we report the direct CVD synthesis of CNT/Fs on the perovskite oxides SrTiO...
We developed a facile hydrothermal method to fabricate the carbon quantum dots (CQDs)/MoS2 composite as hydrogen evolution reduction (HER) catalyst. After irradiation with visible light for 30 min, the CQDs/MoS2 composite (as CQDs/MoS2-L30) performed improved HER activity, featured by a small overpotential of ∼0.125 V at 10 mA cm−2, a high current density, a small Tafel slope of 45 mV/decade and a...
Using density functional theory (DFT) we investigate the changes in electronic and transport properties of graphene bilayer caused by sliding one of the layers. Change in stacking pattern breaks the lattice symmetry, which results in Lifshitz transition together with the modulation of the electronic structure. Going from AA to AB stacking by sliding along armchair direction leads to a drastic transition...
We report on the application of a single layer graphene substrates for the growth of polycrystalline ZnO films with advanced light emission properties. Unusually high ultraviolet (UV) and visible (VIS) photoluminesce was observed from the ZnO/Gr/SiC structures in comparison to identical samples without graphene. The photoluminescence intensity depends non-monotonically on the films thickness, reaching...
In this study, we present a simple and effective mechanical densification method that uses carbon nanotube (CNT) fibers synthesized via a floating-catalyst technique to produce highly dense CNT ribbons. After being infiltrated with epoxy, the resulting cross-linked CNT ribbons exhibited impressive improvements of an increase in strength by 13.5 times and an increase in stiffness by more than 63 times,...
The use of hierarchical assemblies constituted from macroporous structures (e.g., reticulated vitreous carbon, RVC) where the internal pore area is covered with closely spaced nanostructures (e.g., carbon nanotubes, CNT) is proposed for substantially enhancing the energy density of electrochemical capacitors, while maintaining large charge/discharge rates. While the macroscale pores enable storage...
Double-shelled hollow carbon spheres with multiporosity, highly conductive graphite structure and Fe3O4 species was initially prepared (C–C–Fe3O4). The seamless combination between the Fe3O4 species and the porous carbon network leads to a remarkably high capacitivity (1153 F g−1 at 2 A g−1) and good rate capability (514 F g−1 at 100 A g−1) of pseudocapacitive. In addition, the C–C–Fe3O4 assembled...
Stacking order of layered materials strongly influences their electronic properties. Bernal (AB) and rhombohedral (ABC) stacking are much common in few-layer graphenes. Here, we found that AB- and ABC-stacked few-layer graphenes can be well distinguished by whether their highest-frequency shear modes are observed or not in the Raman spectra at room temperature. This method can be expanded to Raman...
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