Enhanced photocatalytic activity of AgVO3/TiO2 nanorod array composite film under visible light irradiation

The novel AgVO3/TiO2 nanorod array composite film (NACF) has been prepared by the hydrothermal and subsequent successive ionic layer adsorption methods. The photocatalytic films were characterised by the scanning electron microscopy (SEM), X-ray diffraction (XRD), photoluminescence (PL), and UV-vis diffuse reflectance spectra (UV-vis DRS). The SEM result showed that AgVO3/TiO2 NACF exhibited a well nanorod array structure, and some AgVO3 nanocrystals were deposited on the TiO2 nanorods. The novel AgVO3/TiO2 NACF showed the enhanced visible photocatalytic activity for degradation of methyl orange (MO) compared with the pure TiO2 nanorod array film. The deposition of AgVO3 nanocrystals on the TiO2 nanorod array led to the improved visible light absorption of the composite film due to the narrow bandgap of AgVO3 (less than 2.5 eV). The contact of AgVO3 and TiO2 resulted in the formation of semiconductor heterostructure, which led to the enhanced separation of photogenerated carriers. The improved visible absorption and efficient separation of photogenerated electron-hole pairs should result in the higher visible activity of composite film compared with pure TiO2 nanorod array film.