摘要:
V
2O
5/TiO
2 composite films were prepared on pure titanium substrates via micro-arc oxidation (MAO) in electrolytes consisting of NaVO
3. Their morphology and elements were characterized by scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analysis. Phase composition and valence states of species in the films were characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Ultraviolet-visible diffuse reflectance spectra (UV-Vis DRS) were also employed to evaluate the photophysical property of the films. The V
2O
5/TiO
2 composite films show a sheet-like morphology. Not only V
2O
5 phase appears in the films when the NaVO
3 concentration of the electrolyte is higher than 6.10 g/L and is loaded at the surface of anatase, but also V
4+ is incorporated into the crystal lattice of anatase. In comparison with pure TiO
2 films the V
2O
5/TiO
2 composite films exhibit significantly narrow band gap energy. The film prepared in an electrolyte consisting of NaVO
3 with a concentration of 8.54 g/L exhibits the narrowest band gap energy, which is approximately 1.89 eV. The V
2O
5/TiO
2 composite films also have the significantly enhanced visible light photocatalytic activity. The film prepared in an electrolyte consisting of NaVO
3 with a concentration of 8.54 g/L exhibits the best photocatalytic activity and about 93% of rhodamine is degraded after 14 h visible light radiation.