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Mesoporous zinc ferrite (ZnFe2O4)/graphene composites are synthesized using a facile ambient-pressure method, i.e., co-precipitation of metal cations onto graphene oxide followed by solid state reaction to yield ZnFe2O4 nanoparticles anchored on reduced graphene oxide. The resultant ZnFe2O4/graphene composites have large specific surface area with mesopores, and the size of the ZnFe2O4 nanoparticles...
We report an easy strategy to synthesize graphene-wrapped and cobalt oxide-intercalated (GWCI) hybrid nanostructures using microwave irradiation for an extremely durable supercapacitor with ultrahigh energy and power densities. The GWCI hybrid nanostructures that are mechanically protected and squeezed by graphene layers are beneficial for efficiently preventing the detachments of metal oxide nanoparticles...
A reduced graphene oxide (rGO) supported chiral-modified Ni catalyst was synthesized, characterized and employed for asymmetric hydrogenation. The prepared hybrid catalyst could produce each enantiomer with d- or l-tartaric acid as chiral modifier and exhibited a high TOF (20160h−1) and enantioselectivity (enantiomeric excess, 98.5%) for asymmetric hydrogenation of methyl acetoacetate. The high catalytic...
Although there are several reported correlations among structural parameters, Young’s modulus (E), thermal conductivity, electrical resistivity and coefficient of thermal expansion of carbon fibers in the longitudinal direction, a single physical model has not yet been established to explain quantitatively these properties. Here a model of continuous defective graphene nanoribbons (dGNR), which are...
The strongest fibres available today are carbon-based, made from carbon nanotubes (CNTs) or reduced graphene oxide flakes (RGOFs). Carbon fibres (CFs) were first developed half a century ago. Control of the thermal, chemical and mechanical processing allows obtaining desired combination of structure, strength and stiffness. In practical use, CFs are typically incorporated into larger scale systems...
Non-noble metal-containing electrocatalysts were prepared by an electrospinning method and evaluated as oxygen reduction electrocatalysts. Fe- or Co-containing carbon fibers were prepared by pyrolyzing electrospun polyacrylonitrile (PAN) fibers containing the respective metal precursor and are denoted Fe-PAN and Co-PAN, respectively. The Fe- or Co-PAN carbon fibers were acid-leached and subjected...
Graphene oxide (G-O) flakes were used to seed the growth of single crystal graphene islands by chemical vapor deposition (CVD) on Cu foil. Such islands have the G-O seed (which converts to a ‘reduced graphene oxide’ (rG-O) seed due to the CVD growth conditions used) roughly in the center of the islands. The lateral growth of such single crystal graphene islands was studied by carbon isotope labeling...
Herein we discuss the fabrication of ballistic suspended graphene nanostructures supplemented with local gating. Using in situ current annealing, we show that exceptional high mobilities can be obtained in these devices. A detailed description is given of the fabrication of bottom and different top-gate structures, which enable the realization of complex graphene structures. We have studied the basic...
Influences on electronic structure induced by platinum (Pt) deposited on monolayer graphene grown on SiC(0001) are investigated by photoelectron spectroscopy (PES), selected area low energy electron diffraction (μ-LEED) and angle resolved photoelectron spectroscopy (ARPES) techniques at the MAX Laboratory. Stable monolayer graphene electronic properties are observed after Pt deposition and after annealing...
Mesoporous three dimensional hierarchical structure of copper oxide nanowires vertically anchored on graphene substrate was synthesized by a facile and green ‘alkali mediated synthesis’ under microwave irradiation. X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Brunauer−Emmett−Teller surface area tests showed highly crystalline nanowires vertically anchored on...
Nanoscale carbon generally exists as nanodiamond or graphite quantum dot (QD). In this study, we report the first synthesis of the third allotrope carbon QDs with an average size of 2nm through carbonization of sucrose and study their photoluminescence properties. These QDs have a body-centered cubic structure and each lattice point is composed of eight atoms which form a sub-cube (so called C8 crystal...
To meet the needs of targeted drug delivery and medical imaging, uniform mesoporous carbon spheres (UMCS) were functionalized using hyperbranched polyethyleneimine (PEI) covalently linked with fluorescein isothiocyanate (FITC) and folic acid (FA). Folate-receptor-positive KB cancer cells internalized five times more nanoparticles than A549 cells deficient in folate receptors in vitro using flow cytometry...
We demonstrate a very efficient synthesis of vertically-aligned ultra-long carbon nanofibers (CNFs) with sharp tip ends using thermal chemical vapor deposition. Millimeter-scale CNFs with a diameter of less than 50nm are readily grown on palladium thin film deposited Al2O3 substrate, which activate the conical stacking of graphitic platelets. The field emission performance of the as-grown CNFs is...
In this paper, a novel three dimensional field effect transistor (FET) is presented. The transistor is made of graphene foam, which is a complex three dimensional network of single to double layer graphene that is immersed in the ionic liquid. The electrolytic double layer capacitance at the ionic liquid graphene interface provides all-around three dimensional liquid gating of the transistor. The...
We demonstrate that radiation-induced reduced graphene oxide (RrGO) can efficiently function as a hole transporting layer (HTL) for polymer solar cells (PSCs). The solution-processable RrGO was simply obtained by γ-ray irradiation of a graphene oxide (GO) solution dispersed in ethanol and water. Changes in the chemical composition, conductivity, work-function, and morphology in RrGO films that resulted...
radical scavenging efficiencies; the rankings in the scavenging efficiencies, however, were similar for both radicals. The findings in this study that the modified CNT were effective radical scavengers suggested that these CNT have potential applications as antioxidants.
Lithium ion cells comprising actual components of positive electrodes (LiCoO2, LiNixCoyAlz, and LiMn2O4) and negative electrodes (graphite and hard carbon) were assembled for in situ 7Li nuclear magnetic resonance (NMR) experiments. The 7Li NMR measurements of the cells revealed a “relaxation effect” after overcharging: a decrease of the signal assigned to Li metal deposited on the negative electrode...
Graphene can be a corrosion-promotion material because of its high electrical conductivity. This paper aims at eliminating the undesired corrosion-promotion effect of graphene, and reports a promising application of graphene/pernigraniline composites (GPCs) for the corrosion protection of copper. The composites were synthesized by an in situ polymerization-reduction/dedoping process. The synthesized...
Chemical vapor infiltration of activated carbon with tetramethylsilane (TMS) at 200hPa total pressure and a gas phase concentration of 15 (mol-)% TMS in nitrogen is studied. The influence of temperature on the infiltration process is discussed in detail. Up to 873K, the infiltration is performed in the kinetically controlled regime resulting in high loadings up to around 42 (wt.-)%. The modified materials...
Nanostructured carbide-derived carbons (CDCs) were synthesized from hexagonal SiC (α-SiC) and cubic SiC (β-SiC) powders via chlorination at temperatures between 900 and 1200°C. The content of the sp2- and sp3-bonded carbon phases and their crystallinity were analyzed by Raman spectroscopy. The nanocrystalline phases of the synthesized CDCs were observed and characterized by transmission electron microscopy...
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