Characterization and mechanism analysis of Mo-N-co-doped TiO2 nano-photocatalyst and its enhanced visible activity

In this study, Mo-N-co-doped TiO2 nano-photocatalysts have been synthesized through hydrolysis-precipitation method, combined with sonication posttreatment. The resulting materials were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and UV-vis diffuse reflectance spectroscopy (UV-vis DRS). XRD showed that co-doping with Mo and N favored the formation of anatase and retarded the growth of crystallite size. XPS revealed that N was incorporated into the lattice of TiO2 through substituting oxygen atoms and coexisted in the forms of beta-N and gamma-N in co-doped TiO2. Meanwhile, Mo was also incorporated into the lattice of TiO2 through substituting titanium atoms and existed in the form of Me. DRS indicated that the light absorbance in visible region was improved by co-doping with Mo and N, leading to a narrower band gap and higher visible light photocatalytic activity for the degradation of phenol than that of pure and N-doped TiO2. The enhanced visible light photocatalytic activity of Mo-N-co-doped TiO2 nano-photocatalyst was attributed to the small crystallite size, narrow band gap and intense light absorbance in visible region. This study provides a new method to synthesize visible light active TiO2-based photocatalyst. (C) 2011 Elsevier Inc. All rights reserved.