Ru-specific promotion in electrodeposited Pt-based bimetallic catalysts for isopropanol electrooxidation

Isopropanol/acetone is a promising electroactive liquid organic hydrogen carrier pair due to its high hydrogen storage capacity (3.4 wt%), low toxicity, and large-scale availability. The slow electrocatalytic oxidation of isopropanol is the bottleneck for the isopropanol/acetone pair's energy-storage applications. Platinum-based catalysts have shown distinguished catalytic activity in this reaction but suffer from catalyst poisoning and performance degradation. Second-metal doping, especially ruthenium, is considered a common strategy to enhance catalytic performance. To clarify whether the enhancement originates from a general bimetallic effect or a ruthenium-specific promotion, this study prepared platinum-ruthenium and platinum-rhodium catalysts with varying metal ratios via electrodeposition and evaluated them for isopropanol electrooxidation. Electrochemical analysis reveals that ruthenium doping is superior to rhodium doping, and that a 1 : 1 atomic ratio is optimal. Kinetic and thermodynamic investigations reveal that both alterations in the electronic structure and ruthenium-specific oxygen affinity contribute to the enhanced efficiency and stability of bimetallic catalysts in the oxidation of isopropanol, with the latter being more pronounced.