In situ synthesis of Z-scheme Ag3PO4/CuBi2O4 photocatalysts and enhanced photocatalytic performance for the degradation of tetracycline under visible light irradiation

The Ag3PO4/CuBi2O4 (ACBO) composites with a small quantity of Ag3PO4 nanoparticles (0.5-10 wt.%) were synthesized by an in situ precipitation method and characterized by XRD, SEM, EDS, TEM, BET, XPS, UV-vis absorption spectra, PL, EIS and ESR analysis. Obviously, all the ACBO photocatalysts exhibited significantly enhanced photocatalytic performances. Meanwhile, ACBO with 5 wt.% content of Ag3PO4 (ACBO-5) showed the highest photocatalytic activity, which is around 2.79 and 2.16-fold higher than that of pristine Ag3PO4 and CuBi2O4, respectively. The enhanced photocatalytic activity could be due to the efficient separation of photogenerated electron-hole pairs through the formation of Z-scheme system composed of Ag3PO4, Ag and CuBi2O4, in which a small quantity of reducible Ag nanoparticles acted as the charge transmission-bridge. Moreover, the high photocatalytic stability of as-synthesized ACBO heterojunction photocatalyst was obtained through five successive cycling experiments. Finally, a possible photocatalytic mechanism was also discussed. (C) 2017 Elsevier B.V. All rights reserved.