Integrated Two-in-one Strategy for Efficient Neutral Hydrogen Peroxide Electrosynthesis via Phosphorous Doping in 2D Mesoporous Carbon Carriers.

Herein, we demonstrate a two-in-one strategy for efficient neutral electrosynthesis of H2O2 via two-electron oxygen reduction reaction (2e-ORR), achieved by synergistically fine-modulating both the local microenvironment and electronic structure of indium (In) single atom (SA) sites. Through a series of finite elemental simulations and experimental analysis, we highlight the significant impact of phosphorous (P) doping on an optimized 2D mesoporous carbon carrier, which fosters a favorable microenvironment by improving the mass transfer and O2 enrichment, subsequently leading to an increased local pH levels. Consequently, an outstanding 2e-ORR performance is observed in neutral electrolytes, achieving over 95% selectivity for H2O2 across a broad voltage range of 0.1 to 0.5 V vs RHE. In a flow cell, the production rate of H2O2 exceeds 22.54 mol gcat-1 h-1 while maintaining high stability at industrial-level current densities. These results are comparable to, if not better than, those achieved under alkaline conditions. Further analysis, both experimental and theoretical, indicates that the P dopant occupies the second coordination sphere of the In SA, which shows optimized OOH* binding strength for an enhanced 2e- ORR kinetic.