Z-Scheme ZnV2O4/g-C3N4 Heterojunction Catalyst Produced by the One-Pot Method for the Degradation of Tetracycline under Visible Light

Abstract

A novel Z-scheme ZnV2O4/g-C3N4 composite catalyst was prepared using a one-pot calcination method, and the photodegradation performance of the ZnV2O4/g-C3N4 heterojunction was studied under simulated sunlight condition. Under visible-light treatment, the ZnV2O4/g-C3N4 catalyst showed excellent catalytic activity in the degradation of tetracycline (TC), and compared with pure g-C3N4 and ZnV2O4, its photocatalytic degradation efficiency was significantly improved. The performances of the ZnV2O4/g-C3N4 catalyst were compared under different ZnV2O4 loading rates, catalyst dosage, pollutant concentrations, and initial pH values of the solution. The experimental results showed that the 35 wt % ZnV2O4/g-C3N4 (35ZVO/CN) had the best photocatalytic activity. The appreciable improvement in performance was mainly due to the construction of the Z-scheme structure between ZnV2O4 and g-C3N4, which promoted the effective separation of charge carriers. In addition, a possible mechanism of the photodegradation process of 35ZVO/CN was discussed based on the energy band position analyses and active radical capture experiments. That superoxide radical was the main reaction specie confirmed the Z-scheme mechanism. By forming the Z-scheme heterojunction, the efficiency of charge separation and transfer was improved, and the catalyst had strong oxidation and reduction abilities. This research provided a new enlightenment for the construction and synthesis of a low-cost Z-scheme heterojunction photocatalyst and the treatment of antibiotics in water.