Monoclinic BiVO4 with regular morphologies: Hydrothermal synthesis, characterization and photocatalytic properties

Monoclinic bismuth vanadate (BiVO4) samples with regular morphologies were prepared by a facile hydrothermal process with Bi2O3 and NH4VO3 as starting materials. The physical and photophysical properties of the as-prepared samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), infrared spectroscopy (IR), and UV–vis diffuse reflectance spectroscopy (UV–vis). It was found that cuboid-like, square plate-like and flower-like BiVO4 could be readily obtained by tailoring the pH values of the reaction suspensions in the presence of CTAB. Both pH value and CTAB played crucial roles in the morphology evolution of the as-prepared samples. The bandgaps (Eg) of cuboid-like, square plate-like and flower-like BiVO4 were 2.39 eV, 2.40 eV and 2.46 eV, respectively. The photocatalytic performance of the as-prepared BiVO4 was much better than that of P25 for photodegradation of methyl orange under sunlight irradiation. The photocatalytic activities of BiVO4 samples were highly related to their crystallinities and shapes.