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Potassium ion batteries (KIBs) are drawing intensive attention as the next-generation energy storage technology, owning to their similar electrochemical properties to lithium system and rich abundance of potassium resources. The carbonaceous materials with low cost, nontoxicity and high safety have been considered as promising candidates for KIBs anodes. However, they still suffer from several problems,...
By taking advantage of the structural tunability of ionic liquids (ILs), a series of imidazolium ILs were employed as precursors to prepare carbon dots (IL-CDs) and as regulators to control their properties. The simultaneous formation of hydrophilic CDs (IL-HCDs) and organophilic CDs (IL-OCDs) is achieved in hydrothermal reaction system by undergoing sulfuric acid carbonization. The quantum yields...
Fluorescent carbon quantum dots (C-CQDs) with graphitic structure were synthesized by chemical vapor deposition (CVD) for the first time. With this approach, the synthesized C-CQDs exhibit excellent crystaline graphitic nature with an average diameter of 3.5 nm and rich of hydrophobic CH3 terminal groups. Optical band gap of the C-CQDs was determined to be 3.16 eV, whereas low-lying HOMO/LUMO energy...
A novel three-dimensional (3D) magnetic carbon framework (MCF) is developed and applied as an efficient absorbent for the removal of lead from aqueous medium. The MCF adsorbent was designed with Prussian blue (PB), amylopectin and polyurethane (PU) sponge serving as iron and carbon precursors at a calcination temperature of 450 °C. The framework is characterized by scanning electron microscopy (SEM),...
We have demonstrated a nonlinear behavior for the bandgap opening of doped graphene by controlling the concentration of B and N co-dopants. X-ray absorption and emission spectra reveal that the bandgap increases from 0 to 0.6 eV as the concentration of BN dopants is increased from 0 to 6%, while the bandgap closes when the doping concentration becomes 56%. This nonlinear behavior of bandgap opening...
We report semiconducting behavior of monolayer graphene enabled through plasma activation of substrate surfaces. The graphene devices are fabricated by mechanical exfoliation onto pre-processed SiO2/Si substrates. Contrary to pristine graphene, these graphene samples exhibit a transport gap as well as nonlinear transfer characteristics, a large on/off ratio of 600 at cryogenic temperatures, and an...
A ferrate functionalized graphene-based composite is prepared by growth of hydrous ferric oxide (FeOOH) on the polyethylene glycol (PEG) modified graphene oxide (GO) sheets. The obtained GO–PEG–FeOOH composite is characterized by ATR-FTIR, TEM, AFM, XPS and ICP-MS. The PEGylation significantly changes the surface property of the bare graphene oxide, which not only generates a nano-bio-interface for...
Natural graphite was modified by oxidation with a mixture of sulfuric acid (98%) and hydrogen peroxide (30%) with a volume ratio of 1:1, followed by a heat treatment under argon at 900°C for 3h to overcome its disadvantages of the presence of active surface groups and volume changes produced by the intercalation/deintercalation of Li ions. Results showed that the graphitic layers of the expanded graphite...
We present prominent photoresponse of bio-inspired graphene-based phototransistors sensitized with chlorophyll molecules. The hybrid graphene-chlorophyll phototransistors exhibit a high gain of 10 6 electrons per photon and a high responsivity of 10 6 A/W, which can be attributed to the integration of high-mobility graphene and the photosensitive chlorophyll molecules. The charge transfer...
Ordered mesoporous carbons were prepared by pyrolysis of polymer blends, which were formed by the organic–organic self-assembly of resorcinol–formaldehyde pre-polymers and tri-block copolymers under acidic conditions. The tri-block copolymer mixtures of F127 and P123 were used as structure-directing agents. The samples were characterized by X-ray diffraction, transmission electron microscopy and nitrogen...
Pristine graphene flakes, with ∼12% monolayers, are directly exfoliated from natural graphite, and noncovalently modified by an amorphous–crystalline block copolymer, polyvinylcyclohexane-b-polyethylene-b-polyvinylcyclohexane (PVCH-b-PE-b-PVCH). The PE block selectively crystallizes on the graphene surface, while the PVCH block extends freely and stabilizes the graphene flakes in the aliphatic and...
A two-dimensional TiO 2 /carbon nanowall composite material was fabricated by growing carbon nanowalls on a Ti sheet with hot filament chemical vapor deposition, followed by metal–organic chemical vapor deposition using titanium isopropoxide as TiO 2 precursor and argon as carrier gas. Scanning electron microscopy showed that TiO 2 was uniformly coated on the entire carbon...
A novel carbon nanotube (CNT)/polystyrene (PS) hybrid miniemulsion was synthesized by an in situ process. The structure of composites in the prepared miniemulsion was characterized by scanning and transmission electron microscopes. The lubricating property of this emulsion as an additive in water-based fluid was investigated by a four-ball tribo-tester. Results confirmed that the anti-wear performance...
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