The effects of Ag doping on crystalline structure and photocatalytic properties of BiVO4

BiVO4 and Ag-doped BiVO4 were hydrothermal synthesized and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction, Raman, X-ray photoelectron spectroscopy (XPS), UV–Vis diffusion reflectance spectroscopy and room-temperature photoluminescence spectra (PL) and photoelectron-chemical measurement. The structural and morphological characterizations reveal that the Ag species, existing as Ag4V2O7 phase, has a significant influence on the morphology and induces a progressive conversion of monoclinic to tetragonal BiVO4. The as-prepared Ag-doped BiVO4 composites exhibit much higher photocatalytic activities for H2 evolution from the ethanol-triethylamine aqueous solution as compared to bare BiVO4. The 4 wt.% Ag-doped BiVO4 possesses the highest photocatalytic activity, and hydrogen production rate of 205 μmol h−1·g−1 can be obtained. The highly improved performance can be attributed to the efficient charge transfer and separation from the coupling effect of Ag4V2O7 semiconductor and monoclinic/tetragonal heterostructured BiVO4 system.