Enhanced visible light photocatalytic degradation of rhodamine B by Z-scheme CuWO4/g-C3N4 heterojunction

The g-C3N4-based heterojunction photocatalysts have aroused worldwide attention for improving photogenerated charge carrier's lifetime and photocatalytic activity. In this study, a series of CuWO4/g-C3N4 composites were prepared by a simple hydrothermal method, and then its structural characteristics were analyzed using XRD, SEM, FT-IR, UV-vis DRS, XPS, and N-2 adsorption-desorption techniques. The photocatalytical activities of CuWO4/g-C3N4 composites were clearly evaluated by the photodegradation experiments of rhodamine B (RhB). The obtained results shown that CuWO4/g-C3N4 composite with the mass ratio of 10% CuWO4 displayed the highest degradation efficiency (93%) for RhB within 150 min in the photodegradation processes, which corresponded well with the pseudo-first-order kinetics. Obviously, the construction of Z-scheme CuWO4/g-C3N4 heterojunction can effectively improve photocatalytical efficiency, which is owing to fast separation of electron-hole pairs and enhancement of redox ability. Besides, the photodegradation efficiency can still keep more than 80% after four cycles, and then the reaction mechanism of photocatalysis was fully discussed to prove the formation of Z-scheme system. This work provides a certain theoretical foundation for the designation and research of g-C3N4-based Z-scheme heterojunction photocatalyst.