Hydrothermal synthesis and photocatalytic activities of stabilized bismuth vanadate/bismuth tungstate composites

Bismuth vanadate/bismuth tungstate (BVO/BWO) composites in various BVO fractions (f(V)) were synthesized through hydrothermal reaction. Morphology analysis of the composites showed that rod-like BVO structures were partially deposited on flake-ball (FB) BWO particles. In addition, surface structures of BWO, BVO and BVO/BWO were studied in energy-resolved distribution of electron traps and conduction band-bottom (CBB) position by household reversed double-beam photoacoustic spectroscopy (PAS) and single-beam PAS, respectively. Apparent CBB of BVO/BWO was ca. 0.4 eV anodically shifted from BWO and almost similar to BVO. Moreover, photocatalytic oxygen liberation under irradiation of UV-vis and visible lights demonstrated that photocatalytic activities of the BVO/BWO composites were depended on f(V) and calcined BVO/BWO composites in which BVO was stabilized on BWO showed enhancement of photocatalytic activity comparing to a pristine BVO. The prolonged and the highest active photocatalyst under visible light was calcined 0.80 f(V) due to BVO stabilization on FB-BWO particles.