Hierarchical construction of a new Z-scheme Bi/BiVO4-CdS heterojunction for enhanced visible-light photocatalytic degradation of tetracycline hydrochloride

Developing cost-effective photocatalysts with efficient electron hole separation efficiency and excellent light absorption performance for the remediation of organic pollutants from wastewater is highly desirable. Herein, a new Z-Scheme Bi/BiVO4-CdS heterojunction with leaf-like morphology has been successfully fabricated for the first time and its application as a photocatalyst for the degradation of tetracycline hydrochloride (TCH) has been explored. Compared with BiVO4 and Bi/BiVO4, the as-prepared Bi/BiVO4-CdS exhibits improved light absorption capacity and electron-hole separation efficiency, and it has a superior performance of photocatalytic degradation of TCH. The degradation ratio of TCH by Bi/BiVO4-CdS based photocatalysis reaches 85.5% within 30 min. The rate constant of TCH degradation for Bi/BiVO4-CdS is 1.32 and 1.18 times of the BiVO4 and Bi/BiVO4, respectively. In addition, Bi/BiVO4-CdS displays a high stability without obvious decay for its TCH degradation efficiency (<5%) during four recycles. The ESR characterization and reactive species trapping experiments indicates that the generated h(+), center dot O-2(-) and center dot OH from Bi/BiVO4-CdS based photocatalysis are responsible for TCH degra- dation. Since several intermediates are identified by HPLC-MS, the pathways for Bi/BiVO4-CdS based photocatalytic degradation of TCH are proposed.