Insights into the Corrosion of Pd-Pt-Co Core-Shell Nanocubes and Their Evolved Heterostructures as Active Methanol Oxidation Reaction Electrocatalysts.

Unraveling the corrosion dynamics of nanocrystal electrocatalysts is crucial for their rational design and practical application. Meanwhile, top-down corrosion processes can lead to the formation of novel heterostructures with enhanced physicochemical properties for catalytic applications. Herein, we encapsulate Pt and PtCo shells on Pd nanocubes to systematically study the distinct corrosion behaviors induced by transition metal incorporation. The results reveal that the core of Pd@PtCo nanocubes undergoes dominant etching at the terraces, in stark contrast to the corner-focused corrosion on the Pd cores observed in Pd@Pt nanocubes. Mechanistic insights were obtained through transmission electron microscopy analysis, revealing corrosion-induced concave Pd@PtCo nanocubes with abundant atomic steps. These unique heterostructures exhibit exceptional performance in the methanol oxidation reaction, achieving mass and specific activities 10 and 27 times higher, respectively, than those of commercial catalysts. These results enhance our understanding of the corrosion dynamics in noble-metal heterostructures and provide valuable insights into the development of efficient and durable electrocatalysts.