The processes of adsorption and oxidation of ethanol on Pt, Pt/Sban and Pt/San electrodes were studied by using cyclic voltammetry and electrochemical quartz crystal micorbalance (EQCM). The results demonstrate that the oxidation of ethanol depends strongly on oxidation states of the electrode surface. Sb adatomes on Pt surface can adsorb oxygen at relatively low potentials and exhibit catalytic effects ofr ethanol oxidation.In contrary, the oxidation of S adatoms consumes oxygen species of Pt electrode surface. As a consequence, the oxidation of ethanol was inhibited by the presence of San. The EQCM studies provide quantitative results of surface mass variation during ethanol oxidation and have thrown new light in elucidating different effects of adatoms Sbad and Sad on Pt electrode surface towards ethanol oxidation.

Key words: CHEMICAL MODIFIED ELECTRODE, ETHANOL, ADSORPTION, ELECTRO-CATALYSIS, ELECTROOXIDATION, CYCLOVOLTAMGRAPH, MICRO-BALANCES, PLATIMUM ELECTRODE