Origins for the Synergetic Effects of AuCu3 in Catalysis for Oxygen Reduction Reaction

Bimetallic catalysts exhibit a promising prospect as potential alternative catalysts for oxygen reduction reaction because of their distinctively enhanced activities compared to pure monometallic systems. Understanding of the origin of activity enhancement is essential for exploiting any novel bimetallic catalyst. In this work, we used AuCu3 as a model to study the synergetic effects existing among the atoms with strong and weak affinity toward oxygen through density functional theory (DFT) calculation. The results suggest that the combination site of Au and Cu instead of Au-Au or Cu-Cu site provided the best onset potential (0.75 V vs reversible hydrogen electrode (RHE)) for oxygen reduction reaction, which is very close to what has been achieved on Pt(111). And the narrow gap between the onset potentials of AuCu3 and Pt obtained by calculation is consistent with the experimental result. Such results not only explain synergetic effects on bimetallic alloy but also may shed light on designing a novel catalyst for ORR.