ELECTROCATALYTIC PROPERTIES OF GLASSY METALS - COMBINED AUGER-ELECTRON SPECTROSCOPY AND ELECTROCHEMICAL STUDIES OF THE SURFACE-COMPOSITION AND ELECTROCATALYSIS OF CO OXIDATION AT AMORPHOUS PT66SB34 ALLOY

The electrocatalytic activity of Pt66Sb34 rapidly quenched alloy (glassy metal) towards CO oxidation has been investigated. The studies were 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 analysed 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 results show that rapidly quenched Pt66Sb34 is a single-phase alloy of homogeneous composition, free from grain boundaries. The onset of CO oxidation on the alloy is reduced by about 0.2 V in comparison with pure polyoriented Pt. The enhanced catalytic activity of the alloy is due to a synergetic effect. The platinum atoms at the surface provide adsorption sites for CO molecules, while the Sb atoms provide centres at which adsorption of oxygen occurs at more negative potentials than it does at Pt atoms. © 1990.