P and O Co‐Doped Pt‐Co Octahedral Nanocrystals as Highly Active and Stable Electrocatalysts for Oxygen Reduction Reaction

Abstract

The development of high active and stable Pt‐M (M = transition metals) electrocatalysts for oxygen reduction reaction (ORR) is crucial for the commercialization of proton exchange membrane fuel cells (PEMFCs). The main challenge of Pt‐M electrocatalysts is their instability, mainly due to the leaching of M. In this study, we report the design of P and O co‐doped octahedral PtCo alloy on Ketjen carbon black (Px‐Oct PtCo/C) through a seed‐mediated synthesis. In‐situ FTIR spectroscopy revealed that P0.61‐Oct PtCo/C has the lowest d‐band center, thereby enhancing the catalytic activity. The strong interaction formed by chemical bond between O and Co in Px‐Oct PtCo/C, observed by EXAFS spectra effectively inhibited the dissolution of Co and improved the ORR stability. The mass activity and specific activity of P0.61‐Oct PtCo/C can reach 0.61 A mgPt‐1 and 2.4 mA cm‐2, respectively, which is 4.1 times and 10.9 times higher than that of commercial Pt/C. After 50,000 potential cycles, the loss of mass activity is only 25%, surpassing the DOE 2025 target of less than 40% loss after 30,000 cycles. This study offers an alternative approach to enhancing the activity and durability of Pt‐M electrocatalysts for the ORR.