Experimental and DFT Investigation of the Synergistic Mechanism for Photogenerated Charge Separation: Enhancing the Catalytic Performance of the g-C3N4/Bi2WO6 Composite

With the advancement of industrialization, the contamination of aquatic environments by organic pollutants has become increasingly severe, highlighting the urgent need for efficient and stable visible light-driven photocatalysts. In this study, g-C 3 N 4 /Bi 2 WO 6 composite photocatalysts were synthesized via hydrothermal synthesis method. Experimental results show that the g-C 3 N 4 /Bi 2 WO 6 composite achieves degradation efficiencies of 95.7% for Rhodamine B and 86.5% for ciprofloxacin, with reaction rate constants enhanced by factors of 1.98 to 12.8 compared to the individual components. Furthermore, the catalyst retains high activity after three consecutive cycles, indicating excellent recyclability and structural stability. Combined theoretical calculations and experimental characterizations reveal that a built-in electric field at the heterojunction interface, in synergy with interfacial orbital hybridization, promotes a direct Z-scheme charge transfer mechanism. This mechanism not only reduces the band gap, extending visible-light absorption, but also enables efficient separation of photogenerated carriers while preserving strong redox capabilities. This work establishes a robust theoretical and experimental foundation for the rational design of high-performance visible-light-responsive photocatalytic materials.