N, S-Codoped Porous Carbon with Densely Edge Structure for Oxygen Reduction Reaction and Zinc-Air Battery

The sp²-hybridized electronic structure of pristine carbon results in poor kinetic processes in the oxygen reduction reaction (ORR) with a high energy barrier for the proton-coupled electron transfer process. Thus, designing numerous accessible defects by breaking the symmetric structure of carbon materials is conducive to reduce the energy barrier of the ORR. Meanwhile, the heteroatom doping strategy can also modify the electronic properties of neighboring carbon atoms to effectively activate the sp²-hybridized electronic structure of carbon nanomaterials. In this work, a defective carbon nanomaterial with densely accessible S, N-codoped edge structures is synthesized via the sacrificial template method. The as-prepared catalyst (S–N–C-3) shows a high external surface area of 518.5 m²g^–1 with an abundant edge structure. Meanwhile, the metal-free S–N–C-3 material shows an excellent half-wave potential (0.867 V) in alkaline solution. In addition, the discharge voltage of the assembled zinc–air battery from S–N–C-3 remains 1.24 V after 270 h of continuous operation, suggesting its superior durability. The excellent catalytic properties originate from the densely accessible N, S-codoped edge structure. The work would provide ideas for the design and synthesis of metal-free carbon-based electrocatalysts and the mechanism analysis of ORR.