Photocatalytic oxidation of toluene and isopropanol by LaFeO₃/black-TiO₂

Large amount of volatile organic compounds (VOCs) are emitted from industrial, mobile, and domestic sources, causing adverse effects on human health and environment. Among VOCs, toluene and isopropanol (IPA) are commonly used as solvent, soldering flux, and spray paint and their emissions need to be reduced. Several VOCs abatement technologies are available to reduce VOC emission and photocatalytic oxidation of VOC is regarded as a viable technique due to its advantage of utilizing solar energy. TiO₂ has been investigated for its oxidation capability toward VOCs because of its good photocatalytic activity. However the utilization is limited to UV due to its wider bandgap; furthermore, its fast recombination rate of electron-hole pair reduces the oxidation rate of VOCs. Black-TiO₂ and perovskite-type photocatalyst such as LaFeO₃ can be applied to enhance photocatalytic activity due to narrower bandgap and longer electron-hole pair lifetime. In this study, black-TiO₂ and LaFeO₃ are prepared and investigated for their photocatalytic oxidation rates toward toluene and IPA. Results show that toluene removals achieved with black-TiO₂ and LaFeO₃ are 89% and 98% while IPA removals are 90% and 94%, respectively. Both photocatalysts show better photocatalytic activity than TiO₂ and good absorption capability toward visible light. [Figure not available: see fulltext.].