Hollow TiO2 spheres with improved visible light photocatalytic activity synergistically enhanced by multi-stimulative: Morphology advantage, carbonate-doping and the induced Ti3 +

Abstract

Great efforts have been devoted to improve the photocatalytic activity of TiO2 in the visible light region. Rational design of the external structure and adjustment of intrinsic electronic status by impurity doping are two main effective ways to achieve this purpose. A facile one-pot synthetic approach was developed to prepare C-doped hollow TiO2 spheres, which simultaneously realized these advantages. The synthesized TiO2 exhibits a mesoporous hollow spherical structure composed of fine nanocrystals, leading to high specific surface area (~180m2/g) and versatile porous texture. Carbonate-doping was achieved by a post-thermal treatment at a relatively low temperature (200°C), which makes the absorption edge red-shifted to the visible region of the solar spectrum. Concomitantly, Ti3+ induced by C-doping also functions in improving the visible-light photocatalytic activity by reducing the band gap. There exists a synergistic effect from multiple stimulatives to enhance the photocatalytic effect of the prepared TiO2 catalyst. It is not out of expectation that the as-prepared C-doped hollow TiO2 spheres exhibits an improved photocatalytic activity under visible light irradiation in organic pollutant degradation.