Facile fabrication of hierarchical BiVO4/TiO2 heterostructures for enhanced photocatalytic activities under visible-light irradiation.

BiVO₄/TiO₂ nanocomposites were fabricated by a facile wet-chemical process, followed by the synthesis of TiO₂ hierarchical spheres via hydrothermal method. The BiVO₄/TiO₂ nanocomposites were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV-Vis diffuse reflectance spectroscopy and X-ray photoelectron spectroscopy. The results showed that prepared TiO₂ presented hierarchical spherical morphology self-assembled by nanoparticles and an anatase-brookite mixed crystal phase. The introduction of monoclinic BiVO₄ components retained the hierarchical structures and expanded the light response to around 510 nm. Type II BiVO₄/TiO₂ heterostructured nanocomposites exhibited improved photocatalytic degradation towards methylene blue under visible-light irradiation, especially for the composite photocatalysts with atomic Ti/Bi = 10, which showed double degradation rate than that of pure BiVO₄. The enhanced photocatalytic mechanism of the heterostructured BiVO₄/TiO₂ nanocomposites was discussed as well. [ABSTRACT FROM AUTHOR]