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In this work we report a method for preparing carbon onions through microwave heating of heavy oil. It was shown that microwave heating of heavy oil mixed with a carbon catalyst at 300 W leads to the growth of a several-centimetre long fractal carbon structure in just 60 s. Scanning electron microscopy (SEM) images showed that the structure is predominantly made of networks of small particles with...
Since lattice strain and charge density affect various material properties of graphene, a reliable and efficient method is required for quantification of the two variables. While Raman spectroscopy is sensitive and non-destructive, its validity towards precise quantification of chemical charge doping has not been tested. In this work, we quantified in-situ the fractional frequency change of 2D and...
Polydiacetylene (PDA) films are shown enabling the combination of graphene transfer and photodetector fabrication into one step. Under the assistance of PDA, centimeter pieces of graphene can be acquired with free of broken or fractures. The constructed PDA/graphene hybrid films demonstrate ultrahigh, gate-tunable responsivity (R) and detectivity (D*) from UV to visible wavelengths, for instance,...
Superlubricity of layered materials, such as graphite, boron nitride, and molybdenum disulfide, is easy to achieve at the nano- or microscale by the formation of ideal incommensurate contact, but it has never been observed at the macroscale due to the size limitations of the contact zone. In the present study, the instantaneous superlubricity of graphite against steel was achieved at the macroscale,...
Presented here is a novel method of reducing the computational cost of analyzing the vibrational properties of a single-walled carbon nanotube (CNT) containing multi-vacancy defects (MVDs), while maintaining a high degree of accuracy. This reduced-order model method is described as modal domain reduction (MDR). In the MDR method, a linearized model of a perturbed CNT is first transformed into modal...
Hexagonal tubular carbon nitride (CN) was successfully fabricated from hexagonal rod-like supramolecular precursor. The supramolecular precursor was synthesized by hydrogen bonded self-assembly of melamine and cyanuric acid, in which cyanuric acid was from in-situ hydrolysis of melamine under haloid acid-assisted hydrothermal environment. The obtained hexagonal tubular CNs not only possess hierarchical...
The enhancement of oxygen reduction reaction (ORR) catalytic activity of non-precious metal catalysts is extremely desirable but still full of challenges. Here, a novel hybrid, core-shell Co/CoNx@C nanoparticles enfolded by Co-N doped carbon nanosheets was successfully prepared by a facile two-step method, including the formation of well-curved porous carbon nanosheets by a facile sintering of trisodium...
Graphene has received abundant attentions in many applications because of its extraordinary properties. Liquid-phase exfoliation is one of the most important methods to obtain graphene from graphite. However, due to strong van der Waals interaction force, it is still extremely challenging to further improve the exfoliation efficiency. Here we report that by carrying out reductions with the oxygenic...
Polymeric carbon nitride (PCN) is a stable semiconducting material with an intermediate band gap (2–3 eV), which is efficient for catalysis and optoelectronics. However, it is still a big challenge to synthesize large-area and transferrable PCN films for applications in solid state optoelectronics. In this work, by using nitrogen-doped graphene (NG) as a van der Waals epitaxial substrate, centimeter-size...
Despite graphene (G) is impermeable to all molecules and with excellent chemical stability, conductive G is cathodic to most metals and can aggravate metal corrosion at exposed metal-coatings interfaces. This effect may accelerate dangerous localized corrosion and potentially impedes its applications in metal protection. Here, we present successful synthesis of nonconductive G (FmG) through the Diels-Alder...
A free-standing, highly flexible and conductive graphene paper (GrP) was fabricated via a simple, green, and inexpensive method. The fabrication process starts with electrochemical exfoliation of graphite as partially oxidized graphene suspension, which is then vacuum-filtered and air-dried. The procedure does not warrant any binders, toxic and corrosive agents, or high temperature. The mechanically...
Stabilization of micro/submicro sized silicon anode has been a challenge for its commercial application as high capacity electrode. Here, we demonstrate a single-step, low temperature (580 °C) synthesis of Si@Ge@C core-shell electrode which can stabilize the micro/submicro Si electrode, and offer high capacity and long life. The Si@Ge@C electrode delivered high specific capacity of ∼900 mAh/g at the...
We explore the potential of the Helium Ion Microscope (HIM) as a tool for direct-write patterning of graphene and describe the underlying processes of graphene milling with image data processing. Controlled helium ion irradiation of suspended graphene conducted while monitoring the mill in-situ revealed the localized formation of nanopores, their growth, and coalescence. We also explore the effects...
Understanding the effect of minor elements such as oxygen and nitrogen on the growth of graphene is crucial to fabrication of graphene single crystals (GSC) with large grain size. In this study, we investigate the nucleation and growth behavior of graphene domains on commercial copper foils as a function of oxygen partial pressure in the chemical vapor deposition (CVD) chamber. To achieve repeatable...
The photoreduction of graphene oxide (GO) with titanium dioxide (TiO2) was exploited to fabricate a UV sensor for real time monitoring of sun exposure. The sensor was fabricated by simultaneous deposition of GO sheets and TiO2 nanoparticles onto interdigitated electrodes using an AC electrophoresis deposition method. Changes in the resistance of the GO sheets decorated with TiO2 nanoparticles during...
Onion-like carbon fullerenes (OLCFs) are a promising material for applications in nanoscale devices, medicine, lubrication and superhard materials. Knowledge of the pyrolysis chemistry of OLCFs helps understanding the thermal-induced erosion of carbon-based resources and spacecraft materials. Here, using first-principle-based ReaxFF atomistic simulations, thermal and dynamical characteristics of supergiant...
Exploring highly efficient non-Pt oxygen reduction reaction (ORR) electrocatalysts is an inevitable trend in the progress of various sustainable energy storage and conversion technologies. Herein, we prepare three kinds of hierarchical porous carbons, derived from hypercrosslinked polyaniline (HCP-An), polypyrrole (HCP-Py) and polymethylbenzene (HCP-MB) through a facile Friedel-Crafts reaction, among...
Single-walled carbon nanohorns (SWNHs) have been shown to be effective photothermal enhancers and drug delivery agents for potential cancer therapy, particularly for the eradication of bladder cancer lesions. In this study, the potential for SWNHs to serve as nanotheranostic vehicles is demonstrated through simultaneous delivery of the chemotherapeutic cisplatin from SWNH cone interiors and imaging...
Spontaneous generation of nanobubbles (NBs) was developed by using a controllable platform of superfast microvortices, based on turbulent jet flows in the presence of graphene oxide (GO) sheets. Very high energy dissipation rates through discharging warm water into cold N2 aqueous solutions resulted in creation of micro/submicro-vortices. Shear stresses in these domains generated gas local supersaturations,...
In the past decades, nanotechnology has stimulated a huge amount of interest and is now used in numerous fields. Carbon nanomaterials, like graphene, carbon nanotubes, and fullerenes, have attracted great attention for their widespread applications in diverse fields because of their excellent mechanical, optical, and thermal properties. With substantial production and use, potential human exposure...
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