N, P, S Co‐Doped Hollow Carbon Supported CuFe Bimetallic Electrocatalysts for Oxygen Reduction in a Wide pH Range

ABSTRACT Design of highly active oxygen reduction reaction (ORR) electrocatalysts under a wide pH condition is essential to achieve the versatile application of conversion devices and energy storage. Herein, we utilize the Kirkendall effect to construct an N, P, S co‐doped hollow carbon supported CuFe bimetallic catalyst (CuFe/NPS‐C). The synergistic effect of CuFe bimetals and the introduction of heteroatoms optimize the adsorption path and regulate the electronic structure, leading to faster ORR kinetics. Additionally, the CuFe/NPS‐C catalyst has abundant micropores and mesopores, along with a hollow structure, providing a large specific surface area, which enables the exposure of more catalytic sites, accelerate transport of O 2 , and thereby promotes high catalytic activity across a wide pH range. Electrochemical tests show that CuFe/NPS‐C exhibits superb catalytic activity at all pH media. Particularly, under neutral conditions, the E 1/2 of CuFe/NPS‐C reaches 0.790 V, which is higher than that of most previously reported catalysts and commercial Pt/C. The open‐circuit voltages of 1.40 and 1.50 V are respectively presented based on the assembled neutral and alkaline zinc‐air batteries (ZABs). Meanwhile, its maximum peak power densities are also greater than those of Pt‐based ZABs, reaching 38.9 and 125.9 mW cm −2 , respectively. Besides, CuFe/NPS‐C‐based batteries achieve charge‐discharge durability of 120 h. This study offers novel insights for the design of co‐doped bimetallic catalysts, paving the way for efficient ORR electrocatalysts applicable at all pH media.