Efficient Oxidation of Ethanol at Ru@Pt Core-Shell Catalysts in a Proton Exchange Membrane Electrolysis Cell

Abstract

Efficient electrochemical oxidation of ethanol in fuel cells and electrolysis cells is important for generating power and hydrogen, respectively, from renewable resources. PtRu alloys are most widely employed as catalysts because they provide high activities at low potentials. However, they produce acetic acid as the main product from ethanol, which results in low faradaic and overall efficiencies. In contrast, Pt provides high selectivity for the complete oxidation of ethanol to CO _2 , but low activities. Ru@Pt core–shell nanoparticles can improve efficiency by delivering higher activity than Pt and enhanced formation of CO _2 relative to PtRu. Here, Ru@Pt catalysts have been prepared by depositing Pt onto a commercial carbon-supported Ru catalyst. The influence of the amount of Pt deposited has been investigated in H _2 SO _4 (aq) at ambient temperature and in a proton exchange membrane cell at 80 °C. Activities for ethanol oxidation were intermediate between those for commercial Pt and PtRu catalysts, providing higher currents than Pt at low potentials, and higher currents than PtRu at high potentials. Faradaic yields of CO _2 (38%–48%) were greatly increased relative to the PtRu alloy catalyst (11%). This will optimize the efficiency of ethanol oxidation in PEM electrolysis and fuel cells.