Constructing oxygen-deficient Cu/WO3/TNT heterojunction film for improved photocatalytic decomposition of toluene and bacteria: From bench-scale study to enlarged reactor test

Abstract

A robust and active photocatalyst that can effectively decompose indoor air pollutants is highly demand. In this study, we have fabricated Cu and WO₃ modified titania nanotube (Cu/WO₃/TNT) with oxygen vacancies to enhance photocatalytic decomposition of toluene and bacteria under light irradiation. The roles of WO₃ and Cu modification on TNT film have been investigated through photoelectrochemical (PEC) measurements and photocatalytic decomposition of pollutants. The results demonstrate that the deposition of Cu (about 2.5 %) and WO₃ (about 1.1 %) onto TNT film, as well as concurrent formation of oxygen vacancies, effectively enhance PEC response and photocatalytic activity of TNT film. Under UV–visible light irradiation, the optimized Cu/WO₃/TNT catalyst can effectively degrade toluene by approximately 95.0 % in 90 min, while over 99.9 % of E. coli bacteria can be inactivated by the photocatalyst under visible light irradiation. Both Cu/WO₃ deposition and oxygen vacancy formation improve light absorption and charge carrier separation of the TNT film for pollutants degradation. Oxygen plays a crucial role in the toluene degradation process, with O₂/^•O₂⁻ activation considered as a key step for subsequent oxidation of toluene or benzyl radical. Whereas, the main oxidants for bacteria inactivation during the process are identified as ¹O₂ and h⁺. Scaled-up experiments (∼1.0 m³ reactor for toluene degradation and ∼ 0.1 m³ reactor for gas phase bacteria inactivation) prove that the the optimized Cu/WO₃/TNT film is a promising photocatalyst for indoor air purification under UV–visible light irradiation.