Hydrothermal synthesis of Zn-doped BiVO4 with mixed crystal phase for enhanced photocatalytic activity
A monoclinic-tetragonal mixed phase Zn-doped BiVO4 photocatalyst was successfully prepared by a simple hydrothermal synthesis method. The photocatalyst was characterized by XRD, SEM, XPS, UV-Vis DRS, PL, photocurrent response, LSV and EIS. The results showed that the crystal phase changed from monoclinic to tetragonal, and the morphology changed from flake to microsphere by Zn doping. When the doping level reached 2.5%, the monoclinic-tetragonal mixed heterostructure was formed, and the photo-degradation rate of RhB reached 96% after 90 min, which was much higher than that of pure BiVO4. The improvement of photocatalytic performance is mainly due to the effective separation of photogenerated electron-hole pairs in Z-scheme heterojunction. The radical-capture experiments confirmed that superoxide radicals (·O2-) and photoproduction hole (h+) are the main active substances, and the probable degrading mechanism was investigated.