Dual-channel charge transfer over g–C3N4/g–C3N4/bismuth-based halide perovskite composite for improving photocatalytic degradation of tetracycline hydrochloride

Photocatalytic technology represents a cutting-edge approach for addressing water pollution. The performance of photocatalysts can be improved by constructing of heterojunctions that facilitate the charges transfer between the two components. Herein, we produced a three-component g–C3N4/g–C3N4 isotype heterojunction/bismuth-based halide perovskites (g–C3N4–ISO/BHP) composite using a solvothermal method to grow bismuth-based halide perovskite (BHP) onto the surface of g–C3N4/g–C3N4 isotype heterojunction (g–C3N4–ISO) layers. Several methods were used to investigate crystalline structure, morphology, chemical composition/states, optical characteristics, and charge-carrier dynamics of the three-component composite. The g–C3N4–ISO/BHP composite exhibited superior photocatalytic activity under white LED light with a degradation percentage of 73.2%, which is higher than the mixed-phase g–C3N4–ISO (61.4%) and the bare BHP (62.5%). The control of component content improved the transmission of charges between the composite components. The S-scheme charge transfer mechanism was verified to function on the g–C3N4–ISO/BHP composite as a result of its high compatibility and adequate band structure, resulting in robust redox ability, effective charge carrier separation and extended lifetime. Our study presents a practical approach for constructing three-component composites for efficient photocatalytic water treatment.