Manipulating Oxygen Reduction Mechanisms of Platinum with Nonmetallic Phosphorus and Metallic Copper Synergistic Alloying

Abstract Alloying of platinum (Pt) nanostructures with heteroelements, commonly including transition‐metals and nonmetals, is an effective strategy to improve the electrocatalytic performance for oxygen reduction reaction (ORR). However, the distinct mechanisms by which metal/nonmetal alloying improves ORR activity remain unclear. Herein, based on the successful alloying of porous network Pt nanospheres (NSs) with metallic copper (Cu) and non‐metallic phosphorus (P) and systematically integrating the electrochemical tests, density functional theory calculations, and in situ electrochemical Raman spectroscopy, this study reveals that the internal Cu‐alloying is responsible for modulating the binding strength of oxygenated intermediates to lower the free energy barrier of the potential‐determining step (PDS) along the ORR associative mechanism, while the further surface P‐alloying can transform the ORR pathway to dissociative mechanism, in which the PDS has a quite low barrier. As a result, the carbon‐supported P/Cu co‐alloyed porous network Pt nanospheres (P‐PtCu NSs /C) catalyst synthesized by confinement growth and post‐phosphorization demonstrates excellent electrocatalytic ORR activity and stability compared to the commercial Pt/C catalyst both in half‐cells and proton exchange membrane fuel cells. In particular, the hydrogen (H 2 )‐oxygen (O 2 ) single cell with P‐PtCu NSs /C as the cathode catalyst achieves a high mass activity of 0.52 A mg Pt −1 at the voltage of 0.90 V, surpassing the U.S. Department of Energy's current activity target.