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

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.