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 (H₂) and hydrogen peroxide (H₂O₂) 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-C₃N₄) 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 H₂ (941.6 μmol g^-1h^-1 with platinum (Pt) as the cocatalyst) and H₂O₂ (347.6 μmol g^-1h^-1) generation as compared to hollow g-C₃N₄ (TCN) and bulk g-C₃N₄ 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.