Methanol oxidation characteristics of rare earth tungsten bronze electrodes doped with platinum

Journal Article · Mon Aug 01 04:00:00 EDT 1988 · J. Electrochem. Soc.; (United States)

DOI:https://doi.org/10.1149/1.2096187· OSTI ID:6452264

Machida, K I; Enyo, M ^[1]; Adachi, G Y; Shiokawa, J ^[2]

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1. Research Institute for Catalysis, Hokkaido Univ., Sapporo 060 (JP)
2. Dept. of Applied Chemistry, Osaka Univ., Yamadaoka, Suita, Osaka 565 (JP)

Rare earth tungsten bronzes, Ln/sub 0.1/WO/sub 3/, and those doped with platinum, PtLn/sub 0.1/WO/sub 3/(Ln = Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, and Yb), were prepared and their electrocatalysis in methanol electro-oxidation was studied in 1.0M CH/sub 3/OH with 0.5M H/sub 2/SO/sub 4/ at 288-323 K. These electrodes revealed generally a redox behavior due to a WO/sub 3//WO/sup 3-/ couple over 0.15-0.45V (RHE) and realized after doped with Pt a higher specific electrocatalytic activity than that of ordinary Pt electrodes. Pt(5 mole percent (m/o))/Ln/sub 0.1/WO/sub 3/ electrodes exhibited a low rest potential of 0.30-0.39V (RHE) in the methanol solution and current density of the oxidation of 20-60 ..mu..Acm/sup -2/ (true) at 0.60V. Also, the heat of activation (10-13 kcal mol/sup -1/) was much lower than that on ordinary Pt electrodes (20 kcal mol/sup -1/). It was found that the electrocatalytic activity depended upon the lattice constants of bronzes, in a similar manner as the redox potential of WO/sub 3//WO/sup 3+/ couple. Further, the electrodes exhibit a much higher activity towards electro-oxidation of CO or of CH/sub 3/OH in the presence of CO as compared with ordinary Pt electrodes. The results suggested a mediatory action of WO/sub 3//WO/sup 3-/ couple, being effective in oxidative removal of impeding reaction intermediates such as adsorbed CO.

• OSTI ID: 6452264
• Journal Information: J. Electrochem. Soc.; (United States), Journal Name: J. Electrochem. Soc.; (United States) Vol. 135:8; ISSN JESOA
• Country of Publication: United States
• Language: English

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