Abstract:A composite catalyst Nafion-Pt-H_xMoO₃ was prepared on a glassy carbon by cyclic voltammetry methods in sulfuric acid solution containing Na₂MoO₄, H₂PtCl₆ and Nafion, and its activity for the methanol oxidation was studied with Pt-H_xMoO₃ as comparison. It is found that the electrocatalytic activity and the stability of Pt-H_xMoO₃ are improved by the Nafion. The activity of Pt-H_xMoO₃ reaches its maximum when the content of Nafion in the preparation solution is 0.012%(mass fraction). In this case the oxidation peak current of methanol on Nafion-Pt-H_xMoO₃ is 1.76 times larger than that on Pt-H_xMoO₃ and keeps unchanged when the potential is set at 0.3 V (vs Hg-Hg₂SO₄) for 5 000 s in 1 mol/LCH₃OH+0.5 mol/L H₂SO₄ solution. The results from energy dispersive spectroscopy show that the content of Nafion in the composite is 0.57%. The results from scanning electron spectroscopy show that the composite of Nafion-Pt-H_xMoO has a gain size of about 90 nm and distributes more uniformly than Pt-H_xMoO₃.

Key words: platinum-hydrogen molybdenum bronze; Nafion; electrodeposition preparation; methanol oxidation