Resumo

KHAN, A. S. A.; AHMED, Riaz  e  MIRZA, M. Latif. Evaluation of Catalytic Activity of Pt and Pt-Ru Catalysts for Electro-oxidation of Methanol in Acid Medium by Cyclic Voltammetry. Port. Electrochim. Acta [online]. 2009, vol.27, n.4, pp.429-441. ISSN 0872-1904.

The cyclic voltammetric study on the electro-oxidation of methanol on 30 % Pt and 20 % Pt +10 % Ru catalysts supported on Vulcan XC-72 was carried out in 0.5 M H₂SO₄. Kinetic parameters such as exchange current density, Tafel slope and heterogeneous rate constants were calculated. The 30 % Pt showed a higher apparent catalytic activity for the electro-oxidation of methanol as compared with 20 % Pt + 10 % Ru catalyst. The presence of Ru did not contribute significantly towards the apparent catalytic activity of a catalyst for the electro-oxidation of methanol but it may be useful to prevent the catalyst from CO poisoning. Thermodynamic parameters, ΔH^*, ΔS^*, and ΔG₂₉₈^* have been evaluated. The values of ΔH^* and ΔG₂₉₈^* were positive showing that the electro-oxidation of methanol is an endothermic and non-spontaneous process

Palavras-chave : methanol; acid medium; cyclic voltammetry; catalytic activity; kinetics; thermodynamic.

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