Spatially Separated Redox Sites in an RP/In2S3 Photocatalyst for Dual-Channel H2O2 Production in Pure Water

Spatially separated redox site engineering for dual-channel hydrogen peroxide (H2O2) photosynthesis has emerged as a promising strategy for the sustainable production of liquid solar fuels through artificial photosynthesis. Herein, a core–shell heterojunction composed of resorcinol-p-phthalaldehyde (RP) resin and In2S3 nanosheets is constructed to enhance H2O2 formation. The introduction of oxidative and π-conjugated RP kinetically accelerates charge separation and increases the surface charge density of the In2S3 photocatalyst significantly. Thermodynamically, the high redox potential and spatially separated active sites of RP/IS expand the H2O2 generation pathway from a single ORR route to a dual-channel mechanism incorporating both the oxygen reduction reaction (ORR) and water oxidation reaction (WOR). DFT calculations reveal that the synergistic enhancement of O2 and H2O adsorption further facilitates efficient H2O2 production. Upon visible-light irradiation, the optimized RP/IS achieves an impressive H2O2 production rate of 4193 μmol·g–1·h–1 in pure water. This study presents an innovative approach for enhancing H2O2 generation through the modulation of reaction pathways.