Structure-controlled graphene electrocatalysts for high-performance H2O2 production

Abstract

Metal-free carbon materials have emerged as cost-effective and high-performance catalysts for the production of hydrogen peroxide (H₂O₂) through the two-electron oxygen reduction reaction (ORR). Here, we show that 3D crumpled graphene with controlled oxygen and defect configurations significantly improves the electrocatalytic production of H₂O₂. The crumpled graphene electrocatalyst with optimal defect structures and oxygen functional groups exhibits outstanding H₂O₂ selectivity of 92–100% in a wide potential window of 0.05–0.7 V vs. reversible hydrogen electrode (RHE) and a high mass activity of 158 A g⁻¹ at 0.65 V vs. RHE in alkaline media. In addition, the crumpled graphene catalyst showed an excellent H₂O₂ production rate of 473.9 mmol gcat⁻¹ h⁻¹ and stability over 46 h at 0.4 V vs. RHE. Moreover, density functional theory calculations revealed the role of the functional groups and defect sites in the two-electron ORR pathway through the scaling relation between OOH and O adsorption strengths. These results establish a structure-mechanism-performance relationship of functionalized carbon catalysts for the effective production of H₂O₂.