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The speciation of doped-nitrogen (pyridinic N, pyrrolic N, graphitic N and amino N) was controlled by ferric ion catalysis for improving fluorescence of nitrogen-doped carbon dots (NCDs). Comparing to the synthesis of NCDs without ferric ion catalysis, the present strategy induces two following effects: (1) an increase of pyrrolic N and a decrease of pyridinic N; (2) a more well-organized arrangement...
A flexible conductive cotton fabric was demonstrated by formulation and deposition of a graphene oxide (GO) dispersion onto a cotton fabric by vacuum filtration. The deposited GO amount was controlled by the concentration and volume of the GO dispersion. The GO was reduced by a hot press method at 180 °C for 60 min, and no chemical reductant was needed in both the deposition and reduction processes...
Aerographite is a lightweight 3D nanocarbon network which offers covalent interconnections for polymer nanocomposites (PNCs). Here, the electrical and mechanical properties of neat Aerographite and Aerographite-based PNCs are investigated in detail. The Aerographite filler networks consist of hollow, graphitic tubes of μm-sized diameters and nm-sized wall thicknesses. Different densities of Aerographite...
Rechargeable Zn-air batteries are under intensive studies because of their high-energy density, low cost, and safety. However, their wide application is prevented by several remaining technical issues, one of which is the lack of suitable bifunctional cathodic catalysts for oxygen reduction reaction (ORR) during discharging and oxygen evolution reaction (OER) during charging. Due to low material cost...
In this paper, aligned graphene sheets (AGS) embedded in PDMS (AGS@PDMS) has been prepared by repeated spin-coating (SC) technique. The triboelectric nanogenerator (TENG) based on the AGS@PDMS film is fabricated and its electric output is investigated systematically with different contents of filling graphene sheets and different spin-coating layers. The PDMS embedded with AGS is compared with that...
Many novel two-dimensional (2D) allotropes of carbon have been predicted to be (meta)stable at 0 K, however, their thermal stability and mechanical properties at finite temperatures remain unclear. In this study, the mechanical properties and fracture behaviors of five newly predicted monatomic thick carbon sheets (C31, C33, δ-graphyne (GY), γ-GY, C63, and graphene) are investigated using molecular...
Here, we report a rapid and straightforward microwave method to synthesize a multilayered and interconnected three-dimensional graphene-carbon nanotube-iron oxide (3D G-CNT-Fe2O3) heteronanostructure for a flexible and wideband high-performance electromagnetic interference (EMI) shielding film. The single integrated 3D G-CNT-Fe2O3 heteronanostructure that consists of carbon nanotubes, graphene sheets...
We demonstrate a general and facile method to fabricate all-solid-state flexible micro-supercapacitors (MSCs) with micropatterned multi-walled carbon nanotube (MWNT) electrodes via mask-free micro-plasma-jet etching in ambient conditions. Localized pulsed plasma jet etches the MWNTs rapidly and produces the interdigitated electrode patterns by scanning. This mask-free patterning technique is easy...
We investigate local doping concentration modulation of graphene flakes on a SiO2/Si substrate that has been exposed to the same chemicals in device fabrication using tip-enhanced Raman spectroscopy (TERS). By spectral line scanning across the edge of graphene, it is observed that the D peak enhancement is localized in the vicinity of the edge boundary, and the TERS spatial resolution of ∼228 nm is...
Fast external heating rates in graphite oxide thermal exfoliation have been reported to be advantageous for generating high surface area graphene-based materials for a variety of applications. The study yields the surprising result that the surface area and porosity developed in reduced graphite oxide under some conditions are independent of instrument-set external heating rates. The true “total”...
We demonstrate that a simple spectrophotometric method can be efficiently applied for the characterization of structural and chemical stability and adsorption properties of composite graphene oxide (GO) films in various solutions. The immersion stability of GO layer-by-layer (LbL) self-assembled with a polycation into ultrathin multilayered films was studied in water and in concentrated salty, acidic...
We report the nonlinear optical properties of graphene oxide (GO), reduced graphene oxide (rGO), sulfonated graphene oxide (S-rGO), and sparingly sulfonated water soluble graphene (WSG), measured under ultrafast (100 fs) and short pulse (300 ps, 50 ns) laser excitations at 800 nm, employing the open aperture Z-scan technique. The samples exhibit typical third order nonlinear optical behaviour including...
The physical and chemical properties of graphene are highly related to its nanostructure. Yet, existing preparation methods cannot easily obtain free-standing 3-D graphenic materials with controllable morphology. Here we report a growth strategy for graphenic materials with various micron- and nano-architectures by templating γ-alumina, which was transformed from morphology-controllable boehmite....
Herein, zirconium diboride (ZrB2) is reinforced with silicon carbide (SiC) and carbon nanotube (CNT) to provide enhanced structural stability and oxidation protection against extreme thermal (>2400 °C) and oxidative environments. The ablation resistance of ZrB2-based composites was evaluated using plasma arc-jet with a heat-flux of 2.5 MW/m2 for 30 s, and the decreased oxidation-rate (from 0.77 μm/s...
Carbon fiber reinforced multilayered pyrocarbon-silicon carbide ((PyC-SiC)n) matrix (C/(PyC-SiC)n) composites were prepared by means of layer-by-layer deposition of PyC and SiC via chemical vapor infiltration. Effects of the number of PyC-SiC sequences (n = 1, 2 and 4) on matrix microstructure, electrical conductivity, mechanical and electromagnetic interference (EMI) shielding performance of C/(PyC-SiC)...
Molecular models for graphene reinforced polymer composites are developed to study the enhanced mechanical and tribological properties of the composites by introduction of graphene as reinforcements. Strain constant method is applied to evaluate the Young's modulus and shear modulus of the polymer composites. A layer model containing iron atoms as the top nanorod and the graphene reinforced polymer...
Chemical modification and functionalization of graphene is of great interest to alter its intrinsic properties. Among various methods, wet chemical oxidation is widely used for obtaining large quantities of graphene oxide or reduced graphene oxide. It is also often used as an intermediary step for further functionalization of the graphene. This work presents a microscopic study of the oxidation of...
Free-standing, intergrown and covalently-bonded structures of three-dimensional (3D) graphene may have great advantages in electric and thermal transport properties for energy applications, but the desired symmetry and periodicity are rather hard to design and produce. Here we use an organic-inorganic template to grow an inverse.opal graphene structure by chemical vapor deposition. The symmetry-controlling...
A novel type of substrate for quantitative surface enhanced Raman spectroscopy (SERS) composed of chemical vapor deposition (CVD) graphene and in-situ fabricated rounded gold nanoparticles (AuNPs) was designed. SERS was measured on samples of different concentrations of Rhodamine 6G (R6G) on the AuNPs/graphene substrates using a low power 632.8 nm laser. Finite element simulations were carried out...
Metal-free catalysts have attracted more attention due to their highly active in catalytic oxidation reactions. The outstanding stability and catalytic activity of a single-atom Si incorporated N4 centers in graphene (Si-GN4) are investigated using first-principles calculations. It is found that the Si-GN4 configuration can be stable at high temperature, the positively charged Si dopant as the active...
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