Boosting Photosynthetic H₂O₂of Polymeric Carbon Nitride by Layer Configuration Regulation and Fluoride–Potassium Double-Site Modification

Photocatalytic hydrogen peroxide (H2O2) production will become a burgeoning strategy for solar energy utilization by selective oxygen reduction reaction (ORR). Polymeric carbon nitride (PCN) shows relatively high two-electron ORR selectivity for H2O2 production but still limited low H2O2 production efficiency due to slow exciton dissociation. Herein, we constructed a heptazine/triazine layer stacked carbon nitride heterojunction with fluorine/potassium (F/K) dual sites (FKHTCN). The introduction of F/K not only can regulate layer components to enhance the charge separation efficiency but, more importantly, also optimize the adsorption of surface oxygen molecules and intermediate *OOH during H2O2 production. Consequently, FKHTCN efficiently improves the photocatalytic H2O2 production rate up to 3380.9 μmol h–1 g–1, nearly 15 times higher than that of traditional PCN. Moreover, a production–utilization cascade system was designed to explore their practical application in environmental remediation. This work lays out the importance of engineering a layer-stacked configuration and active sites for enhancing photocatalysis.