Ag3PO4/AgSbO3 composite as novel photocatalyst with significantly enhanced activity through a Z-scheme degradation mechanism

In this work, a new composite photocatalyst, combined with Ag3PO4 and AgSbO3 (AZA Catalyst), was elaborately designed, successfully synthesized, and characterized by many techniques, such as XRD, UV-DRS, SEM-EDS, XPS, and TEM. Then, the AZA Catalyst was applied for the photocatalytic degradation of Methylene Blue (MB) and tetracycline. The results showed that AZA Catalyst could effectively degrade MB and tetracycline, and the degradation efficiencies were better than that of sole Ag3PO4 and AgSbO3. The photocatalytic properties of AZA Catalyst also exhibited excellent stabilities. In addition, the active species of center dot OH and center dot O-2(-) were demonstrated in the photochemical reaction and played a crucial role to the photocatalytic reaction. Moreover, with the help of advanced characterization (XRD, XPS, ESR, PL, electrochemical analysis) and DFT calculation, the photocatalytic degradation mechanism illustrated that Ag produced in the process of reaction constructed a typical Z scheme path (Ag3PO4/Ag/AgSbO3). Furthermore, due to the work function differences among Ag3PO4, AgSbO3, and Ag, the photogenerated electrons and holes could be effectively transferred and decreased the recombination probability of electrons and holes and thus accelerated the photocatalytic efficiencies of pollutants.