Synthesis, Properties, and Visible Light Photocatalytic Activity of Nonstoichiometric Titanium Dioxide-Based Composites

Abstract

We have synthesized oxide composites based on TiO2 modified with aliovalent cations, W6+, Co3+, Cu2+, and Fe3+, in the range 5–30 wt %. Its deviation from stoichiometry is increased by active generation of Ti3+ cations during vacuum calcination at temperatures from 500 to 800°C. The photocatalytic activity (PCA) of the composites for dye degradation reactions under illumination with visible light exceeds that of analogous samples calcined in air. The PCA of the synthesized materials is an intricate function of their composition and structure. The highest PCA, which considerably exceeds the PCA of TiO2 of similar origin and that of the commercially available Degussa P-25 TiO2, is offered by the optimal compositions of the W- and Cu-modified samples for ferroin and methylene blue degradation and the Co- and Fe-modified samples for aniline degradation.