Synthesis of visible-light sensitive M-BiVO4 (M = Ag, Co, and Ni) for the photocatalytic degradation of organic pollutants

A series of M-BiVO4 (M = Ag, Co, and Ni) particles were successfully prepared by amorphous heteronuclear complex precursor. The particles were characterized using X-ray diffraction analysis (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), UV-vis diffuse reflectance spectroscopy and Raman spectra. The results showed that the crystallized M-BiVO4 had a monoclinic phase with the hybrid metals, namely Co and Ni being attached on BiVO4 particles in the form of oxides mainly. The M-BiVO4 photocatalysts were responsive to visible light. Photodegradation of both methyl blue and 2,4-dichlorophenol over M-BiVO4 composites was observed at wavelength > 420 nm. Co-BiVO4 exhibited the best photocatalytic efficiency, with a decoloration percent of about 85% after 2-h irradiation (at lambda > 420 nm). Nearly 90% of 2,4-dichlorophenol was removed in 5 h. Electron paramagnetic resonance (EPR) study confirmed that superoxide and hydroxide radicals were formed under light irradiation and might be responsible for the degradation of the organic compound. (C) 2011 Elsevier B.V. All rights reserved.