NaCl-assisted pyrolysis to construct low metal content multiple-doped 3D porous carbon as oxygen reduction electrocatalysts for Zn-air battery

Oxygen reduction electrocatalysts with multiple heteroatomic doping, abundant defects and porous and layered structures are beneficial for enhancing oxygen reduction reaction (ORR) activity. However, the design and facile preparation of such materials often present great challenges. Herein, Fe, S, N multiple-doped three-dimensional (3D) porous carbon (Fe/S-CN) has been prepared by in-site NaCl template-assisted ball milling and subsequent high-temperature pyrolysis strategy. Due to the multiple doping, abundant defects and porous carbon framework provide rich active sites and rapid mass/electron transport channels, the Fe/S-CN catalyst with low metal content (0.589 wt%) metal species still achieve a high half-wave potential of 0.880 V, exceeding the commercial Pt/C (0.844 V). The Zn-air battery composed of Fe/S-CN catalysts as air cathodes also exhibited excellent performance. This work exhibition a convenient strategy for the fabrication of low-metal ORR catalysts with reciprocity and layered multi-hole and proves its magnificent potential for ORR catalysis and Zn-air batteries.