67 research outputs found
Spectroscopic characterization of graphene films grown on Pt (111) surface by chemical vapor deposition of ethylene
This work reports the peculiar properties of a graphene film prepared by the
chemical vapor deposition (CVD) of ethylene in high vacuum on a well oriented
and carefully cleaned Pt(111) crystal surface maintained at high temperature.
In-situ and ex-situ characterization techniques (low energy electron
diffraction, high resolution electron energy loss spectroscopy, scanning
electron microscopy and Raman micro-spectroscopy) used here indicate the
prevalence of single layer regions and the presence of two different
orientations of the graphene sheets with respect to the Pt(111) substrate. In
most of the deposited area evidence is found of a compressive stress for the
graphene lattice, as a net result of the growth process on a metal substrate.
This graphene film grown on Pt(111) exhibits a lower degree of order and of
homogeneity with respect to the exfoliated graphene on Si/SiO2, as it is found
generally for graphene on metals, but several characterization techniques
indicates a better quality than in previous deposition experiments on the same
metal substrate.Comment: 18 pages, 5 figures, Journal of Raman spectroscopy 201
One-step electrodeposition synthesis of silver-nanoparticle-decorated graphene on indium-tin-oxide for enzymeless hydrogen peroxide detection
Silver-nanoparticles-decorated reduced graphene oxide (rGO) was electrodeposited on indium tin oxide (ITO) by a cyclic voltammetry method. The results of X-ray diffraction, Fourier-transform infrared transmission spectroscopy and Raman spectroscopy confirmed the simultaneous formation of cubic phase silver nanoparticles and reduction of GO through the electrodeposition process. Field emission scanning electron microscope images showed a uniform distribution of nanometer-sized silver nanoparticles with a narrow size distribution on the RGO sheets, which could only be achieved using silver ammonia complex instead of silver nitrate as precursor. The composite deposited on ITO exhibited notable electrocatalytic activity for the reduction of H2O2, leading to an enzymeless electrochemical sensor with a fast amperometric response time less than 2 s. The corresponding calibration curve of the current response showed a linear detection range of 0.1 mM to 100 mM (R2 = 0.9992) while the limit of detection was estimated to be 5 μM
Fabrication of graphene from graphene oxide by ultrasonication with high Li storage capability
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