A hydroxyl-induced carbon nitride homojunction with functional surface for efficient photocatalytic production of H2O2

Scalable solar-driven H 2 O 2 evolution from water holds great promise for industrial applications. Efficient H 2 O 2 generation relies on excellent spatial charge separation but simultaneously suffers from severe surface H 2 O 2 backreaction, which becomes a bottleneck for scalable H 2 O 2 evolution. Herein, a hydroxyl-induced carbon nitride (CN) homojunction coherently optimizes the bulk charge separation and suppresses surface backreaction. Surface hydroxyls provide extra electron accommodation bands for electron extraction from the bulk to the surface which are visually observed with KPFM and rationalized by DFT calculations. 2e - oxygen reduction reaction (ORR) kinetic became more favorable than 4e - ORR in the presence of hydroxyl, showing suppressed H 2 O 2 decomposition. This homojunction achieves a 4.5-fold improvement in H 2 O 2 production compared to pristine CN, and an apparent quantum yield (AQY) of 2.1 % at 500 nm in water. This work demonstrates a strategy for coherently improving spatial charge separation and surface reaction kinetics, which is applicable for various photocatalytic reactions.