Ethanol adsorption on platinum catalysts supported on Al2O3 and ZrO2 was studied by temperature-programmed desorption (TPD) and DRIFTS analysis. TPD of ethanol showed that the alumina support favoured the dehydration and decomposition ethanol, besides the water–gas shift reaction. DRIFTS analyses showed different intermediate species on the Pt/Al2O3 and Pt/ZrO2 catalysts. On the Pt/Al2O3 catalyst it was observed formation and decomposition of acetate species. On the Pt/ZrO2 were observed ethoxy species. Catalytic tests of the partial oxidation of ethanol showed that the H2 selectivity was higher on the Pt/Al2O3 compared to the Pt/ZrO2 catalyst. Marked difference was observed for the H2/CO ratio, suggesting preferential WGSR for Pt/Al2O3 and the reverse WGSR for the Pt/ZrO2 catalyst. These results allowed proposing different reaction routes.