Photothermal-enabled single-atom catalysts for high-efficiency hydrogen peroxide photosynthesis from natural seawater

Hydrogen peroxide (H₂O₂) is a powerful industrial oxidant and potential carbon-neutral liquid energy carrier. Sunlight-driven synthesis of H₂O₂ from the most earth-abundant O₂ and seawater is highly desirable. However, the solar-to-chemical efficiency of H₂O₂ synthesis in particulate photocatalysis systems is low. Here, we present a cooperative sunlight-driven photothermal-photocatalytic system based on cobalt single-atom supported on sulfur doped graphitic carbon nitride/reduced graphene oxide heterostructure (Co-CN@G) to boost H₂O₂ photosynthesis from natural seawater. By virtue of the photothermal effect and synergy between Co single atoms and the heterostructure, Co-CN@G enables a solar-to-chemical efficiency of more than 0.7% under simulated sunlight irradiation. Theoretical calculations verify that the single atoms combined with heterostructure significantly promote the charge separation, facilitate O₂ absorption and reduce the energy barriers for O₂ reduction and water oxidation, eventually boosting H₂O₂ photoproduction. The single-atom photothermal-photocatalytic materials may provide possibility of large-scale H₂O₂ production from inexhaustible seawater in a sustainable way.