Enhanced Selectivity in the Electroproduction of H₂O₂ via F/S Dual-Doping in Metal-Free Nanofibers

Electrocatalytic two-electron oxygen reduction (2e⁻ ORR) to hydrogen peroxide (H₂O₂) is attracting broad interest in diversified areas including paper manufacturing, wastewater treatment, production of liquid fuels, and public sanitation. Current efforts focus on researching low-cost, large-scale, and sustainable electrocatalysts with high activity and selectivity. Here a large-scale H₂O₂ electrocatalysts based on metal-free carbon fibers with a fluorine and sulfur dual-doping strategy is engineered. Optimized samples yield with a high onset potential of 0.814 V versus reversible hydrogen electrode (RHE), an almost ideal 2e⁻ pathway selectivity of 99.1%, outperforming most of the recently reported carbon-based or metal-based electrocatalysts. First principle theoretical computations and experiments demonstrate that the intermolecular charge transfer coupled with electron spin redistribution from fluorine and sulfur dual-doping is the crucial factor contributing to the enhanced performances in 2e⁻ ORR. This work opens the door to the design and implementation of scalable, earth-abundant, highly selective electrocatalysts for H₂O₂ production and other catalytic fields of industrial interest.