Activity, short-term stability (poisoning tolerance) and durability of carbon supported Pt–Pr catalysts for ethanol oxidation

Abstract

Pt–Pr/C electrocatalysts were prepared by a modified formic acid method, and their activity for carbon monoxide and ethanol oxidation, their short term stability and durability were compared to that of commercial Pt/C and Pt–Sn/C (3:1) catalysts. By derivative voltammetry (DV) it was found that ethanol electro-oxidation takes place by two main pathways at different potentials. It was observed that, in the presence of Pr, ethanol electro-oxidation takes place mostly through the pathway at lower potential, which is the most interesting for fuel cell application. The Pt–Pr/C catalysts were less tolerant to poisoning by ethanol oxidation intermediate species than Pt/C. Durability test by a repetitive potential cycling under Ar atmosphere revealed a good structural stability of Pt–Pr/C catalysts. A repetitive potential cycling under CO atmosphere carried out on the Pt–Pr/C (1:1) catalyst, instead, indicated a structural change, likely by formation of a core–shell structure.