The preparation and mechanistic study of highly effective PtSnRu ternary nanorod catalysts toward the ethanol oxidation reaction†
Although Pt-based anodes have shown promising electrochemical behaviors toward the ethanol oxidation reaction (EOR) in the direct ethanol fuel cell (DEFC) application, the rational design for optimizing the structures and compositions of catalysts is yet to be fully understood due largely to the lack of mechanistic insights into the catalytic reaction. Herein, we systematically investigated EOR on Pt-based binary (PtSn and PtRu) and ternary (PtSnRu) nanorods with varied atomic ratios to elucidate the effects of chemical composition and structure on the electrochemical behavior. The electrochemical results showed that Sn and Ru in the ternary PtSnRu NRs can effectively promote the EOR performance, both at 0.6 V (I06) and peak potential (Imax), as compared to binary PtSn and PtRu NRs. The enhanced activity at a low potential (I06) corresponded to the strengthened adsorption of water and ethanol on Ru site with a highly energetic d band structure; this at a high potential (Imax) was related to the oxygen-containing species on surface Sn, lowering the oxidation barriers through hydrogen-bond interactions, according to density functional theory-based calculations. The combination of electrochemical experiments on modeled binary and ternary electrodes and theoretical computation offers an effective approach to clarify the complex EOR mechanism and provides information vital to achieving the realistic design of better EOR anodes.