Surface-Modified Porous Carbon Nitride Composites as Highly Efficient Electrocatalyst for Zn-Air Batteries

Porous carbon nitride (PCN) composites are fabricated using a top-down strategy, followed by additions of graphene and CoSx nanoparticles. This subsequently enhances conductivity and catalytic activity of PCN (abbreviated as CoSx@PCN/rGO) and is achieved by one-step sulfuration of PCN/graphene oxides (GO) composite materials. As a result, the as-prepared CoSx@PCN/rGO catalysts display excellent activity and stability toward both oxygen evolution and reduction reactions, surpassing electrocatalytic performance shown by state-of-the-art Pt, RuO2 and other carbon nitrides. Remarkably, the CoSx@PCN/rGO bifunctional activity allows for applications in zinc-air batteries, which show better rechargeability than Pt/C. The enhanced catalytic performance of CoSx@PCN/rGO can primarily be attributed to the highly porous morphology and sufficiently exposed active sites that are favorable for electrocatalytic reactions.