Synthesis of a double type-II CdS/Zn2In2S5/g-C3N4 heterojunction photocatalyst for the photodegradation of tetracycline under visible light

Herein, the ternary CdS/Zn2In2S5/g-C3N4 (CdS/ZIS/CN) heterojunction photocatalyst was successfully prepared via a one-pot method for photodegradation of tetracycline (TC) under visible light irradiation. The surface morphology, structure and optical properties of the prepared photocatalytic material were analyzed by XRD, SEM, TEM, UV–vis DRS, FT-IR and PL. Moreover, the experimental results exhibited that the ternary CdS/ZIS/CN photocatalyst revealed excellent photocatalytic activity compared with g-C3N4. In this work, 94.73% of TC (20 mg/L, pH=11) was degraded by 0.5 g/L 30CdS/ZIS/CN within 60 min of visible light irradiation. Additionally, the degradation rate of the photocatalyst decreased by about 9.41% after the fourth cycle, indicating its high stability and reusability. Subsequently, a possible double type-II mechanism of photodegradation was eventually provided based on active radical capture experiments. The current investigation provided a promising strategy to construct the high-efficiency heterojunction photocatalyst to degrade antibiotic contaminants.