Construction of Catalytic Fe₂N₅P Sites in Covalent Organic Framework-Derived Carbon for Catalyzing the Oxygen Reduction Reaction

Abstract

Dual-atom catalysts (DACs) are getting extensive attention in electrocatalysis due to their high metal-loading rate, tunable active centers, and electron states. However, developing dual-metal sites coordinating with different atoms is still under explored. Herein, the highly active Fe2N5P sites supported by P-doped hollow carbons are demonstrated to catalyze the oxygen reduction reaction (ORR). The hollow carbon template was constructed from the core-shelled covalent and metal–organic frameworks, which showed high surface areas and abundant N and P atoms for anchoring dual-Fe atoms. The Fe2@P-HC has catalytic sites of Fe2N5P with a high Fe content of 1.8 wt %, which shows the high catalytic activity and selectivity toward the ORR with a half-wave potential of 0.89 or 0.75 V vs RHE under alkaline or acidic condition in the 4e– pathway. The theoretical calculations reveal that the P atoms in the Fe2N5P sites facilitate the OOH* formation and thus improve the activity. This work provides a strategy to design new catalytic sites from COFs.