Nanocrystalline BiVO4:: Preparation by microwave irradiation and photocatalytic properties

Nanocrystalline BiVO4 powders were prepared from aqueous Bi (NO3)(3) and NaVO3 solution by a rapid microwave-assisted method with accurate controlled of microwave irradiation time. The properties of the synthesized BiVO4 powders were investigated by XRD, FFIR, TEM and UV-Vis. When beating 10 min by microwave, pure tetragonal BiVO4 can be obtained. The highly crystalline phases converted irreversibly from tetragonal to monoclinic BiVO4 with prolonged irradiation time. When heating above 40 min by microwave, pure monoclinic BiVO4 can be obtained. X-ray diffraction and FTIR measurements proved the phase transition of BiVO4. These variations in phase structures result in different photocatalytic properties under visible light.