ELECTROCATALYTIC OXIDATION OF FORMIC-ACID AND METHANOL AT THE AMORPHOUS PT66SB34 ELECTRODE

The electrocatalytic activity of Pt{sub 66}Sb{sub 34} rapidly quenched alloy (glassy metal) towards oxidation of HCOOH and CH{sub 3}OH has been investigated. The studies have been carried out in an apparatus in which combined surface analysis electrochemistry experiments can be performed. The electrodes were cleaned by standard UHV procedures, and their surface composition was analyzed using Auger electron spectroscopy before each electrochemical experiment. The electrocatalytic activity of the material has been directly correlated with the surface composition of the alloy. The rapidly quenched Pt{sub 66}Sb{sub 34} is a single-phase alloy of homogeneous composition, free from grain boundaries. No surface segregation or leaching of alloy elements were observed during experiments which lasted several hours. Its surface composition displayed a long term stability. The rate of CH{sub 3}OH and HCOOH oxidation at this material is about 5 to 20 times higher than that at a pure, smooth, polyoriented Pt electrode. It has been shown that the enhanced catalytic activity of the glassy alloy is a complex function of electronic, geometric, and synergistic effects.