Fabrication of CdS/ZnCr-LDH heterojunctions with enhanced of tetracycline hydrochloride photocatalytic degradation under visible light

Water pollution caused by antibiotics is one of the main problems facing mankind. Photocatalytic degradation is a green, thorough and effective method to remove antibiotics from wastewater, which has broad application prospects. In this study, a Z-scheme photocatalyst constructed by cadmium sulfide (CdS) and ZnCr-layered double hydroxide (ZnCr-LDH) was prepared by hydrothermal method. The properties of the photocatalysts were fully characterized and the photocatalytic performance were evaluated via degradation tetracycline hydrochloride (TCH) under visible light irradiation. The CdS/ZnCr-LDH-5 photocatalyst was very effective for the removal of TCH (84.9%), which is 4.7 times and 2.5 times than that of its precursor ZnCr-LDH and CdS, respectively. The enhanced degradation efficiency of CdS/ZnCr-LDH-5 photocatalyst can be attributed to the high redox ability and charge separation efficiency. Finally, possible degradation pathway and a Z-scheme degradation mechanism was proposed according to the liquid chromatography-mass spectrometry (LC-MS), radial trapping experiments and band energy structure, respectively. This work provides new sights for the design heterojunctions with a Z-scheme charge transfer mechanism for effective photocatalytic degradation antibiotics.