PNNL

Abstract

The electrosynthesis of hydrogen peroxide via a two-electron oxygen reduction reaction enables decentralized H2O2 production. While metal-free carbon catalysts are sustainable and low cost, their performance is hindered by poorly defined active sites and uncontrolled defect states. Here, we resolve these challenges through active site design and catalysts screening using fluorine (F) and nitrogen (N) codoped carbon as model materials. Statistical analysis combined with Density Functional Theoretical calculations reveals that F-induced structural modification and defect passivation optimize OOH* binding, with F-doping and adjacent F atoms predominantly lowering abs(?GOOH*). Experimental results confirm that semi-ionic C–F bonds passivate defects in nitrogen-doped carbon, enhancing catalytic activity and durability. The resulting (N, F)-codoped carbon achieves nearly 100% H2O2 selectivity at 0.5-0.65 V vs. RHE and maintains > 95% across 0.01-0.65 V versus the reversible hydrogen electrode. In an electrolyzer, (N, F)-codoped carbon exhibits an H2O2 yield rate of 74.35 mol gcat. -1 h-1 and sustains 300 mA cm-2 for 105 h with ~95% faradaic efficiency. Coupling 2e? ORR with methanol oxidation further reduces cell voltage and enhances productivity. This work offers an avenue for designing efficient catalysts for industrial H2O2 electrosynthesis.