Fabrication of ternary dual Z-Scheme AgI/ZnIn2S4/BiVO4 heterojunction photocatalyst with enhanced photocatalytic degradation of tetracycline under visible light

In this study, a novel ternary AgI/ZnIn2S4/BiVO4(AZB) composite photocatalyst was successfully prepared by hydrothermal method and in-situ precipitation method. The as-synthesized samples were characterized by XRD, SEM, TEM, XPS and so on, and the photocatalytic activity was evaluated through photocatalytic degradation of tetracycline (TC) under visible light irradiation. When the molar ratio of Bi to Ag was 1:1, the degradation rate of TC can reach 91.44 % within 150 min. The AZB heterojunction demonstrated outstanding efficiency with the apparent reaction rate constants of 0.02118 min−1 for TC removal, was 4.68, 3.27 and 3.27 times higher than that of pure BiVO4, AgI and ZnIn2S4. Based on active species trapping experiments and ESR analysis, a dual Z-Scheme pathways among BiVO4, AgI and ZnIn2S4 for effective separation of photogenerated charges was recommended. This work provided a promising insight for the design of ternary dual Z-scheme heterojunction with multilevel electron transfer to present greater photo-absorption, charge separation, and photodegradation for environmental decontamination.