Novel C3N4/Zn1−xCdxS heterostructures with adjustment of the band gap and their visible light photocatalytic properties

In this study, C3N4/Zn1−xCdxS (0 ≤ x ≤ 1) heterostructures with adjustment of the band gap were successfully prepared by calcination and a hydrothermal synthesis method. The photocatalytic properties of C3N4/Zn1−xCdxS composite photocatalysts were evaluated by the photocatalytic degradation of RhB under visible light irradiation. The results showed that the combination of the two semiconductor photocatalysts (C3N4 and Zn1−xCdxS) greatly enhanced the photocatalytic degradation efficiency of RhB compared to the pure C3N4 and Zn1−xCdxS under visible light irradiation. Among them, the 0.1C3N4/Zn0.8Cd0.2S composite photocatalyst exhibited the highest photocatalytic activities with the degradation efficiency of RhB arriving to 97.9% within 90 min. The remarkable photocatalytic activity of the 0.1C3N4/Zn0.8Cd0.2S composite photocatalyst was mainly attributed to the appropriate band structure and the effective separation of photogenerated electron–hole pairs. Additionally, a possible basic mechanism of the composite semiconductor photocatalytic process was also discussed. Moreover, it was also investigated that O2˙− and h+ were the main reactive oxidative species in this photocatalytic process of the degradation of RhB on the 0.1C3N4/Zn0.8Cd0.2S heterostructure photocatalyst.