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

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.