Rational Design of Metal-free Doped Carbon Nanohorn Catalysts for Efficient Electrosynthesis of H2O2 from O2 Reduction

Electroreduction of O-2 is a promising method for decentralized H2O2 production. Due to their high selectivity, low cost, and highly tunable properties, O- and N-doped carbon catalysts are appealing for this process. However, the relative effects of O and N dopants on the catalytic performances of carbon are not well understood. In this work, we present highly active and selective 2e(-) O-2 reduction catalysts based on doped carbon nanohorns (CNH) synthesized by the gas-injected arc-in-water (GI-AIW) method. The effects of O and N dopants incorporated during the synthesis and the post-treatment are investigated. We discovered that the selectivity of CNH may be more sensitive to changes in N dopant than to changes in O dopant. Our doped CNH catalyst exhibits an early onset potential of 0.85 V vs RHE, >80% selectivity, and excellent stability even after 5,000 cycles and 12 h of flow electrolysis. Our gas diffusion device can generate H2O2 at a practical concentration of 56 mM per hour, corresponding to a production rate of 0.74 mol h(-1)g(cat)(-1). These results suggest that regulating both O and N dopants is an effective design strategy for an efficient carbon catalyst, which is essential in the electrosynthesis of H2O2 from O-2.