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Abstract: Methanol electro-oxidation reaction over carbon-supported platinum nanoparticles, including methanol adsorption, apparent reaction order and activation energy, in acidic and alkaline media was investigated comparatively. The results show that the rate constant for methanol adsorption in 1M NaOH is significantly higher than that in 0.5M H2SO4 at the relatively low potential and the COad removal in alkaline media is easier, due to the availability of oxygen-containing species, than in acidic media at the same potential. The apparent activation energy for the MOR in alkaline media is 25.3–14.6kJmol−1, significantly lower than that in acidic media (34.9–28.5kJmol−1). The better MOR activity of Pt/C in alkaline media is attributed to the faster methanol adsorption and the availability of oxygen-containing species. [Copyright &y& Elsevier]

Abstract: To investigate the effect of carbon support adding sequence on Pt particle sizes and Pt utilizations during the polyol process of the electrocatalyst preparation, a series of Pt/C electrocatalysts (different Pt loadings, two kinds of carbon supports−Vulcan XC and Black Pearls 2000) were prepared, namely, Pt/C-a (first reduced Pt ions to form Pt nanoparticles, which subsequently deposited on carbon supports) and Pt/C-b (Pt precursors were first impregnated with carbon supports, then reduced to Pt nanoparticles). The physical properties of the electrocatalysts were characterized by X-ray diffraction, transmission electron microscopy and nitrogen adsorption. The catalytic activities of the electrocatalysts toward the oxygen reduction reaction and the methanol oxidation reaction were characterized by potentiodynamic measurements. The results show that the carbon support adding sequence has significant effects on the Pt particle sizes, especially for the carbon supports with large amount of micropores, as a result, leading to different catalytic activities. [Copyright &y& Elsevier]