In‐Plane Topological‐Defect‐Enriched Graphene as an Efficient Metal‐Free Catalyst for pH‐Universal H2O2 Electrosynthesis

Abstract

AbstractDeveloping efficient metal‐free catalysts to directly synthesize hydrogen peroxide (H2O2) through a 2‐electron (2e) oxygen reduction reaction (ORR) is crucial for substituting the traditional energy‐intensive anthraquinone process. Here, in‐plane topological defects enriched graphene with pentagon‐S and pyrrolic‐N coordination (SNC) is synthesized via the process of hydrothermal and nitridation. In SNC, pentagon‐S and pyrrolic‐N originating from thiourea precursor are covalently grafted onto the basal plane of the graphene framework, building unsymmetrical dumbbell‐like S─C─N motifs, which effectively modulates atomic and electronic structures of graphene. The SNC catalyst delivers ultrahigh H2O2 productivity of 8.1, 7.3, and 3.9 mol gcatalyst−1 h−1 in alkaline, neutral, and acidic electrolytes, respectively, together with long‐term operational stability in pH‐universal electrolytes, outperforming most reported carbon catalysts. Theoretical calculations further unveil that defective S─C─N motifs efficiently optimize the binding strength to OOH* intermediate and substantially diminish the kinetic barrier for reducing O2 to H2O2, thereby promoting the intrinsic activity of 2e‐ORR.