Chemical and Electrochemical Reduction of H₃PMo₁₂O₄₀ and Its Utilization as an Inexpensive Anode Catalyst for H₂-O₂ Fuel Cells at Room Temperature

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The catalytic activity of H₃PMo₁₂O₄₀ (PMO) was enhanced by a chemical reduction treatment (CRT) and a subsequent electrochemical reduction treatment (ERT) with the hydrogen pump method for use in the hydrogen oxidation reaction in fuel cells, and the underlying mechanism was discussed. Both CRT and ERT with the hydrogen pump method can eliminate the suspicion that the improved catalytic activity was only due to precipitation of Pt in the vicinity of the catalyst. Catalyst of excellent quality was produced by keeping the anode containing PMO at a negative potential vs. SHE in acid for a given period during ERT. The activity per weight of the PMO catalyst after ERT is about 20% that of Pt catalyst (20 wt.% Pt/Vulcan XC72), and the numerical value of activity will change further in the future depending on experimental conditions. The new catalyst works well even in strong acids. Furthermore, a Pt free H₂-O₂ fuel cell using PMO and H₅PMo₁₀V₂O₄₀ as the anode and cathode, respectively, was constructed.