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/BiVO 4 -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 BiVO 4 and Bi/BiVO 4 , the as-prepared Bi/BiVO 4 -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/BiVO 4 -CdS based photocatalysis reaches 85.5% within 30 min. The rate constant of TCH degradation for Bi/BiVO 4 -CdS is 1.32 and 1.18 times of the BiVO 4 and Bi/BiVO 4 , respectively. In addition, Bi/BiVO 4 -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 + , •O 2 – , and •OH from Bi/BiVO 4 -CdS based photocatalysis are responsible for TCH degradation. Since several intermediates are identified by HPLC-MS, the pathways for Bi/BiVO 4 -CdS based photocatalytic degradation of TCH are proposed.