Solvated Electron-Driven Stepwise ORR on Na-Metalated N-Rich Carbon Nitride for Efficient Photocatalytic H2O2 Production.

Solvated electrons (SEs), known for their strong reductive capability, are widely utilized in diverse catalytic reactions. However, their application in photocatalytic oxygen reduction reactions (ORR) for hydrogen peroxide (H2O2) production remains largely unexplored. In this work, a Na-metalated, N-rich poly(heptazine imide)-type carbon nitride (PH-C3N5-Na), synthesized via a NaCl/LiCl molten salt-assisted method is reported, as a novel photocatalyst for in situ SE-driven H2O2 production. The N-rich units and Na into Polymetric carbon nitride (PCN) synergistically narrows the bandgap and facilitates rapid electron transfer, thereby enhancing visible-light absorption and promoting efficient charge separation. Notably, Na metalation enables the generation of solvated electrons under light irradiation, which mediates a stepwise 2e- ORR pathway via superoxide radicals (•O2 -), significantly boosting H2O2 production. As a result, PH-C3N5-Na delivers an impressive H2O2 production rate of 245.51 µmol·h-1, 206 times higher than that of PM-C3N5-550, accompanied by an exceptional apparent quantum efficiency of 54.4% (AQE) at 420 nm. This study presents a new strategy for the rational design of high-performance photocatalysts and unveils the critical role of solvated electrons in enhancing photocatalytic ORR for sustainable H2O2 synthesis.