Dependent Relationship between Quantitative Lattice Contraction and Enhanced Oxygen Reduction Activity over Pt–Cu Alloy Catalysts

Abstract

Lattice contraction has been regarded as an important factor influencing oxygen reduction reaction (ORR) activity of Pt-based alloys. However, the relationship between quantitative lattice contraction and ORR activity has rarely been reported. Herein, using Pt-Cu alloy nanoparticles (NPs) with similar particle sizes but different compositions as examples, we investigated the relationship between quantitative lattice contraction and ORR activity by defining the shrinking percentage of Pt-Pt bond distance as lattice contraction percentage. The results show that the ORR activities of Pt-Cu alloy NPs exhibit a well-defined volcano-type dependent relationship toward the lattice contraction percentage. The dependent correlation can be explained by the Sabatier principle. This study not only proposes a valid descriptor to bridge the activity and atomic composition but also provides a reference for understanding the composition-structure-activity relationship of Pt-based alloys.