Metal-Free Nanofibers with Tailored Electronic Structures for Highly Active and Selective Hydrogen Peroxide Electroproduction

Electrocatalytic hydrogen peroxide (H₂O₂) production via two-electron oxygen reduction reaction (2e- ORR) has attracted significant research interest as a promising alternative to the traditional energy-intensive traditional anthraquinone cycling process. However, designing low-cost, highly active, and selective electrocatalysts remains challenging due to the fierce competition from the four-electron reaction pathway. In this study, we engineer the electronic structure of electrospun nanofibers via fluorine and sulfur dual-doping to develop large-scale metal-free electrocatalysts for hydrogen peroxide production. Experimental and theoretical computation results demonstrate the manipulated electronic structures of the carbon active sites after suitable fluorine and sulfur dual-doping, originating from intermolecular charge transfer and electron spin redistribution at the active sites. The optimized catalyst exhibits an onset potential of 0.814 V versus the reversible hydrogen electrode (RHE) in an alkaline medium and a selectivity of 99.1%, outperforming most of the previously reported carbon-based and metal-based counterparts. Density functional theory (DFT) results elucidate the manipulated free energy profiles and kinetic energy barriers in 2e- ORR after fluorine and sulfur dual-doping, confirming the enhanced activity and selectivity in the 2e- ORR pathway for hydrogen peroxide production. This fluorine and sulfur dual-doping strategy on carbon nanofibers from electrospinning provides the pathway to designing and implementing large-scale, low-cost, and highly efficient catalysts for hydrogen peroxide production. Moreover, this strategy also enjoys versatility in the materials for other catalytic fields, such as water splitting, CO₂ reduction, and ammonia production.