Fabrication of dual-phase TiO2/WO3 with post-illumination photocatalytic memory

Abstract

This study describes the synthesis of TiO₂/WO₃ composite systems with a varying concentration of WO₃ by a glucose-template assisted method and demonstrates their round-the-clock photoactivity performance towards the degradation of methanol (MeOH) under illumination and dark conditions. XRD results indicated a biphasic anatase–rutile nature of TiO₂, with tunable concentrations with respect to the WO₃ loading. WO₃ incorporation extended the light absorption of the system towards visible light, increasing the observed photoactivity. The obtained results were further validated using photo-electrochemical investigations such as photocurrent measurements and the impedance response of the systems. Based on the obtained results, the observed round-the-clock photocatalytic efficiency of the catalyst could be related to the formation of new energy levels in the TiO₂ structure due to the incorporation of WO₃ and to the induced oxygen vacancies near the valence band of TiO₂. Such modifications enhanced the overall UV-visible absorption, charge separation and storage of electrons in the TiO₂/WO₃ structure and their subsequent reactions with MeOH towards its degradation under light irradiation and dark conditions.