Effect of Interfacial Interaction on Electrocatalytic Activity and Durability of Pt-Based Core–Shell Nanocatalysts

Pt-based core–shell nanoparticles have presented a promising generation of high-performance electrocatalysts for proton-exchange membrane fuel cells, with their catalytic performance primarily dependent on the interfacial interaction between the core and Pt shell. Here we systematically investigated the impact of interfacial interaction on electronic structure and electrocatalytic performance by using Pd@Pd–P@Pt core–shell octahedra with precisely controlled shell thicknesses as a well-defined platform. Experimental and theoretical calculation results demonstrate that the Pt–P interfacial interaction would lower the d-band center and increase the vacancy formation energy of Pt sites, thereby substantially enhancing both the activity and durability of the oxygen reduction reaction. Such enhancement effect is highly dependent on the distance between the interface and the Pt sites, which can be tuned via careful manipulation of the shell thickness. Once the shell thickness exceeds 6 atomic layers, the enhancement effect of interfacial interaction on the catalytic performance becomes negligible.