Dual-heteroatom doping to enhance metal-support interaction between CoFe alloys and Vulcan XC-72R for efficient oxygen reduction electrocatalysts

The development of cost-effective, highly-active, and stable oxygen reduction reaction (ORR) electrocatalysts is crucial for advancing fuel cells and metal-air batteries. Herein, we report a two-step thermal treatment strategy for successfully introducing heteroatoms and CoFe alloys onto Vulcan XC-72R to prepare efficient electrocatalysts. Among the synthesized electrocatalysts, the N, F co-doped catalyst (CoFe/NFC) demonstrates optimal ORR performance in alkaline medium. Notably, moderate heteroatom doping generates high specific surface area, large pore volumes, and optimal carbon defects, facilitating both active site accessibility and mass transport. Density functional theory calculations reveal that the N F synergistic effect enhances metal-support interaction and optimizes *OH adsorption energy. Attractively, aluminum-air batteries equipped with CoFe/NFC cathodes present outstanding performance: a peak power density of 187.9 mW/cm 2 , a large specific capacity of 586 mAh/g Al , and stable operation for 720 min at 50 mA/cm 2 . This study offers valuable insights into heteroatom doping strategies, which may facilitate the rational design of carbon-based electrocatalysts with enhanced catalytic performance.