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Abstract: Graphene single nanosheet (GNS) is synthesized from graphite by chemical oxidation and thermal exfoliation at 1000 °C and confirmed by X-ray diffraction analysis. Scanning electron and transmission electron microscope images clearly show the lateral expansion of graphite sheet and uniform dispersion of Pt nanoparticles on GNS. Fourier transform infrared and X-ray photoelectron spectroscopy analyses are conducted for surface properties of GNS such as oxygenated functional groups. Cyclic voltammetric analysis shows that electrochemical active surface areas (ECSAs) for Pt/GNS, commercial Pt/Vulcan XC-72 carbon black and Pt-incorporated onto commercial carbon black (Pt/CB) prepared in the laboratory are 33.1 m2 g−1, 23.5 m2 g−1 and 22.5 m2 g−1, respectively. Because of significant restacking of Pt/GNS sheets, carbon black (CB) with different content is intercalated between Pt/GNS as a spacer. The ECSAs of Pt/GNS, Pt/GNS/CB20, Pt/GNS/CB30 and Pt/GNS/CB40 are evaluated to be 31.5 m2 g−1, 28.6 m2 g−1, 38.8 m2 g−1 and 30.4 m2 g−1, respectively. The cell performance highly depends on CB content and Pt/GNS/CB with 30 wt.% of CB content shows the best cell performance of 400 mA cm−2. [Copyright &y& Elsevier]

Abstract: Antimony doped tin oxide supported on carbon black (ATO/C) has been synthesized using an in situ co-precipitation method, and platinum–ATO/C nanoparticles have been prepared using a consecutive polyol process to enhance the catalyst activity for the methanol oxidation reaction. The Pt–ATO/C electrocatalyst is characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microcopy (SEM), energy dispersive X-ray spectroscopy (EDS) and cyclic voltammetry. The Pt–ATO/C catalyst exhibits a relatively high activity for the methanol oxidation reaction compared to Pt–SnO2/C or commercial Pt/C catalyst. This activity can be attributed to the high electrical conductivities of the Sb-doped SnO2, which induces the electronic effects with Pt catalysts. Pt–ATO/C is a promising methanol oxidation catalyst with high activity for the reaction in direct methanol fuel cells. [Copyright &y& Elsevier]