Efficient photocatalytic degradation of tetracycline by Z-scheme ZnWO4/Bi5O7I heterojunction

In this work, Z-scheme ZnWO4/Bi5O7I photocatalysts were synthesized by a simple hydrothermal preparation. It exhibited excellent photocatalytic activity under visible-light irradiation. A total of 96.8 % of tetracycline was degraded within 60 min. The high stability and reusability of the prepared ZnWO4/Bi5O7I heterojunction photocatalysts were demonstrated by ten successive cycling experiments. The hole and superoxide radicals were confirmed to be the primary species responsible for the photocatalytic breakdown of tetracycline based on radical trapping experiments and electron spin resonance analysis. The formation of a Z-scheme heterojunction between ZnWO4 and Bi5O7I was demonstrated. The photocatalytic activity was boosted by the heterostructure, which had a well-matched energy band structure and improved photogenerated charge migration and separation. This work provides a new method to remove pollutants from water.