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As reported, the foaming of layered graphene films into porous graphene foams could improve their performance for absorbents, catalysis and supercapacitors. Herein, to emphasize the impact of porous structure on electromagnetic interference (EMI) shielding, the direct comparison between graphene film (G-film) and corresponding microcellular graphene foam (G-foam) in terms of EMI shielding efficiency...
In this work, a dual pass scanning probe microscopy, based on electric force microscopy (EFM), was employed to quantitatively investigate the local electrical conductivity of multi-walled carbon nanotubes (MWNTs). We show that EFM phase signal appears to be directly proportional to the local conductivity. To explain our results we propose a model that take into account the electrically charge tip...
In the past 50 years, a number of synthetic polymer microfibres, such as para-aramid or ultra-high-molecular-weight polyethylene, have been developed, exhibiting remarkable strength. However, their toughness is considerably smaller than that of some natural fibres such as spider silk, thus limiting their performance in applications ranging from surgical devices to vehicle parts. Here, we implement...
A molten salt method has been developed for the synthesis of polymeric carbon nitride nanoseaweeds (CNNSs) using melamine and NaCl/KCl as precursor and eutectic salts, respectively. The resulting CNNSs present uniform shape which are about 20 nm wide and several hundred nanometers long. Moreover, they show excellent water dispersibility and enhanced photoluminescence properties, which make the CNNSs...
Graphene nanoflakes (GNFs) are a stack of 5–20 layers of highly crystalline graphene sheets having a planar size of approximately 100 by 100 nm and low defect concentration. They are produced here through homogeneous nucleation following the plasma decomposition of a carbon source in an inductively coupled thermal plasma reactor. Following synthesis within the plasma reactor, the GNFs are functionalized...
Transverse impact behaviour of graphene sheet (GS) has been studied using molecular dynamics (MD) simulations. One, two and three layers of GS have been impacted with a fullerene rigid projectile in the impact velocity range: 3.5–7.5 km/s. LAMMPS is used for MD simulations using the AIREBO force field. Kinetic energy, displacement, velocity and perforation resistance force of the projectile have been...
In this study, we demonstrate scalable and efficient inkjet printing of graphene flexible transparent conducting films (TCFs). The highly concentrated and stable graphene ink (3.2 mg/mL) that is dominated by 4-layer graphene flakes is achieved by means of shear exfoliation process. The printed graphene TCFs with DC conductivity of ∼4 × 104 S/m (sheet resistance 260 Ω/□ coupled with optical transparency...
While few-layered graphene (FG) has been synthesized by several different arc-discharge methods, its growing mechanism has hardly been studied by experiment. Here, we have investigated systematically its growth mechanism using the arc-discharge method under different environments including helium, oxygen-helium and hydrogen-helium. The results indicate that FG can only be produced in the presence...
We have systematically investigated the structural and magnetic properties of N-doped graphene oxide by density-functional theory. Our results reveal that both the magnetic properties and the defect stability can be significantly affected by the bonding environment. Graphitic N defect has higher formation energy than both pyridinic and pyrrolic N defects. The pyrrolic N becomes more stable when its...
The variety of materials that fall in the diamond category is vast and increasing. From single, to micro to nano-crystalline, diamond can be highly electrically insulating or synthesized to possess varying degrees of conductivity. Diamond in all its forms is without peer in terms of chemical stability exhibits excellent biocompatibility and is famously mechanically robust. Diamond is however, a difficult...
Production of large quantities of graphene sheets with less than 10 layers is extremely difficult due to the lack of a controllable process and method to separate multilayered graphene. Here, we demonstrate a controllable and scalable aqueous arc discharge process that produces high quality bi- and trilayers of graphene. With this process, the number of stacked graphene layers is controlled by adjusting...
Fast growing power densities of modern electronic devices demand high-performance thermal interface materials (TIMs). Owing to the superior thermal conductivity of graphene, composites with graphene fillers dispersed in polymer matrix are expected to be promising TIM candidates. However, the thermal conductivity of graphene-polymer composites is hindered by a high thermal resistance across the interface...
Polymers of intrinsic microporosity (PIMs) are a group of polymers with molecular sieve behaviour due to their rigid, contorted macromolecular backbones. They show great potential in organophilic pervaporation, solvent-resistant nanofiltration and gas and vapour separations. However, they are susceptible to physical ageing, leading to a reduction in permeability over time. An improvement in membrane...
The Cu film is needed for catalysis purposes during graphene syntheses, and its presence leads to direct graphene growth on the Cu surface, thus requiring subsequent cumbersome transfer processes. It is plausible that atomic diffusion processes occurring through the Cu film can be controlled to harvest the graphene grown at the interface between the Cu film and the film-deposited substrate. In our...
In this work, the mixtures of coke aggregates and coal tar pitch were used as starting materials to prepare ultrafine-grain graphites (UGG) by a liquid mixing method for the inhibition of molten salts in molten salt reactor (MSR). The average diameters of coke aggregates for UGG-1 and UGG-2 were respectively 10 and 5 μm. The liquid dispersion technique could effectively prevent fine particles of raw...
Nitrogen-doped reduced graphene oxide aerogel (N-rGO aerogel) with high porosity and ionic conductivity were synthesized by a hydrothermal reduction of graphene oxide with hydrazine and following freezing-dry method. N-rGO aerogel was spray-coated on carboxyl-modified carbon fiber paper with a hydrophilic surface and used as the supercapacitor electrode. Not only can the N-rGO aerogel electrode accelerate...
Large area graphene sheets grown by chemical vapor deposition can potentially be employed as a transparent electrode in photovoltaics if their sheet resistance can be significantly lowered, with minimal loss in transparency. Here, we report the fabrication of a graphene-conducting-carbon-nanotube (CCNT) hybrid material with a sheet resistance considerably lower than neat graphene, and with the requisite...
Dual-doped graphene is synthesized by a facile solvothermal method with the assistance of ionic liquids containing both N and X (X = B, P or S) atoms. All three types of co-doped graphene present excellent catalytic activity, demonstrating preferred four-electron selectivity and low peroxide yields toward oxygen reduction reaction in alkaline solution. Particularly, N, P-graphene exhibits superior...
Recently, graphene and its derivatives as novel metal-free materials have attracted considerable attention in environmental remediation technologies. One of the barriers to practical applications is the mass production of high quality graphene-based catalysts. In this study, high-quality nitrogen-doped graphene (NG) nanomaterials were synthesized by controlled pyrolysis of a mixture of glucose, ferric...
In this paper we report on the study of the buried laser-modified region produced inside single crystal diamond by femtosecond laser irradiation. The cross-section of the modified region was prepared via precise mechanical polishing to investigate its intrinsic structure with Raman spectroscopy, scanning electron microscopy and scanning spreading resistance microscopy. It is found that the opaque...
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