Pt catalysts modified with Bi: Enhancement of the catalytic activity for alcohol oxidation in alkaline media

Abstract

Recent developments on anion-exchange membranes for fuel cell application renewed the interest in the study of alcohol oxidation at high pHs for applications in anion-exchange membrane direct alcohol fuel cells (AEM-DAFC). Although platinum is still the most studied catalyst for oxidation of alcohols in alkaline media, the introduction of one or more metals in order to increase the oxophilicity of the catalyst is a common approach in the development of improved materials for these reactions. In this manuscript, we report the enhancement of the catalytic activity of Pt/C toward ethanol, methanol, and propanol oxidation in alkaline media by simple adsorption of Bi surface. The activity was checked by cyclic voltammetry, and the reaction products and intermediates were analyzed by “in situ” infrared spectroscopy. The presence of Bi was shown to increase the activity of Pt toward the oxidation of the referred alcohols by acting as a third body (impeding surface poisoning) and also by an electronic effect (on water adsorption at the surface).