Water purification using solar energy: effect of sulphur on photocatalytic properties of TiO2

Abstract

The present work considers the effect of sulphur on several properties of titanium dioxide (TiO₂) including electronic structure, defect disorder and photocatalytic properties. While the reports on the mechanism of sulphur incorporation into the TiO₂ lattice are conflicting, there is a consensus that sulphur leads to reduction of band gap and enhanced photocatalytic performance. The latter effect suggests that light absorption, which is determined by an electronic structure, plays the key role in the conversion of the light energy into the chemical energy that is required for photocatalytic decomposition of organic contaminants in water. Analysis of the reported data suggests that different processing procedures result in different doping mechanisms. It is argued that most of the experimental data reported so far are not well defined and, therefore, are not compatible. Consequently, the progress in the science of photocatalysis requires collection of empirical data that are well defined.