K–N Bridge-Mediated charge separation in hollow g-C3N4 Frameworks: A bifunctional photocatalysts towards efficient H2 and H2O2 production

The development of bifunctional photocatalysts for enhancing hydrogen (H 2 ) and hydrogen peroxide (H 2 O 2 ) production from water is essential in addressing environmental and energy issues. However, the practical implementation of photocatalytic technology is still constrained by the inadequate separation of photo-generated charge carriers. Herein, potassium (K) atoms are introduced into the interlayers of graphitic carbon nitride (g-C 3 N 4 ) with a hollow hexagonal structure (K-TCN) and are coordinated with N atoms in adjacent layers. The presence of K–N coordination serves as a layer bridge, facilitating the separation of charge carriers. The hollow hexagonal structure reduces the distance over which photogenerated electrons migrate to the surface, thereby enhancing the reaction kinetics. Consequently, the optimized K-TCN exhibits a dramatically improved photocatalytic H 2 (941.6 μmol g −1 h −1 with platinum (Pt) as the cocatalyst) and H 2 O 2 (347.6 μmol g −1 h −1 ) generation as compared to hollow g-C 3 N 4 (TCN) and bulk g-C 3 N 4 nanosheet (CN) without K–N bridge under visible light irradiation. The unique design holds promising potential for developing highly efficient bifunctional photocatalysts towards producing renewable fuels and value-added chemicals.