Rapidly and highly efficient degradation of tetracycline hydrochloride in wastewater by 3D IO-TiO₂-CdS nanocomposite under visible light

Tetracycline hydrochloride as an environmental pollutant is biologically toxic and highly difficult to degrade. To solve this problem, an efficient catalyst IO-TiO₂-CdS composite with honeycomb-like three-dimensional (3D) inverse opal TiO₂ (IO-TiO₂) and cadmium sulphide (CdS) was synthesized and applied in the degradation of tetracycline hydrochloride in this paper. More than 99% of the tetracycline hydrochloride (30 mg/L) can be degraded by IO-TiO₂-CdS (30 mg) within 20 min under visible light irradiation. Surprisingly, the naphthol rings can be opened and degraded to alkane with a minimum molecular weight of 60, which is the smallest fragment among all publications. The three-dimensional ordered macroporous (3DOM) structure of IO-TiO₂ improves the utilization of light via the slow photon effect. Meanwhile, the addition of CdS enhances the degradation efficiency of tetracycline by broadening the range of absorption spectrum and improving the separation of charge carrier on the catalyst. In addition to the degradation of tetracycline hydrochloride, IO-TiO₂-CdS also shows a good degradation efficiency of Rhodamine B (RhB). This work provides a promising approach to construct visible light response photocatalysts with non-noble metal for efficient degradation of wastewater pollutants.