Photocatalytic degradation of Toluene by three-dimensional monolithic Titanium Dioxide / Cuprous Oxide foams with Z-schemed Heterojunction

Abstract

At present, photocatalytic degradation of volatile organic compounds (VOCs) still faces the problems of low activity of traditional catalysts, insufficient contact between powder catalysts and gases, and easy detachment from the support. To address this challenge, we use a sacrificial template and in-situ growing approach to fabricate a three-dimensional (3D) monolithic photocatalyst with Z-schemed heterojunction. The design combines the TiO₂ and Cu₂O using foamed copper as a substrate. The 3D monolithic TiO₂/Cu₂O foam photocatalyst was used to evaluate its toluene removal efficiency under simulated sunlight and a 15 W UV disinfection lamp. The results show that the photocatalyst outperforms conventional TiO₂ and Cu₂O in toluene removal under both simulated sunlight and ultraviolet (UV) light. After 180 min of irradiation under a 500 W Xe lamp, the TiO₂/Cu₂O foam achieved a removal rate of 90.2% for toluene. This performance improvement is attributed to the unique 3D open internal structure, which enhances the gas-solid mass transfer efficiency. In addition, the formation of Z-schemed heterojunction inside composite materials between TiO₂ and Cu₂O extends the lifetime of photo generated charge carriers, resulting in higher catalyst activity. After four cycles of experiments, its degradation rate is 88.0%, indicating its stability. The degradation pathway, toxicity analysis and catalytic mechanism of the catalytic degradation of toluene by the TiO₂/Cu₂O foam were also explored.