Boron-Doped Biomass Carbon Nanostructures as Electrocatalysts for the Two-Electron Oxygen Reduction Reaction

Abstract

Highly active B atom dopants were successfully introduced into a biomass carbon matrix as promising electrocatalysts for the two-electron oxygen reduction reaction (2e– ORR) to synthesize hydrogen peroxide (H2O2) by decomposing boron nanosheets with flash Joule heating (FJH) progress. Moreover, the FJH process can greatly improve the graphitization of biomass carbon leading to rapid electron transfer during electrocatalysis. The as-prepared B atom–doped carbon nanomaterial (f-Bs-C) showed greatly enhanced 2e– ORR performance with outstanding H2O2 selectivity (91–94%) at 0.25–0.6 V vs reversible hydrogen electrode (RHE) measured via a rotating ring-disk electrode (RRDE) in an alkaline electrolyte, and the Faradaic efficiency was still greater than 80% during 11 h with a mass activity of 798 mmol gcatalyst –1 h–1 in an actual three-electrode flow cell setup. The overall catalytic performance is preferable to the majority of reported carbon-based catalysts. Density functional theory showed that the O atom connected with B atoms can induce charge density deficiency on the B site acting as high catalytic sites. This research provides an exploration to fabricate heteroatom dopants to enhance the catalytic capability of biomass-based carbon catalysts.