Highly Efficient Degradation of Perfluorooctanoic Acid over a MnOx‐Modified Oxygen‐Vacancy‐Rich In2O3 Photocatalyst

Abstract

AbstractDestructive removal of perfluoroalkyl substances (PFASs) from water has been an emerging concern, as the C−F bond cleavage requires energy‐consuming advanced oxidation approaches. The conventional photocatalyst materials exhibit insufficient PFAS degradation due to either a weak absorption ability towards PFASs or a limited reaction oxygen species (ROS) generation. Herein, In2O3, which has an excellent absorption ability towards perfluorooctanoic acid (PFOA), is chosen as the main catalyst materials. Oxygen vacancies are then generated on the surface of In2O3 to assist the PFOA adsorption. Further depositions of the MnOx cocatalyst on the surface of In2O3 are performed to enhance the ROS generation efficiency. Based on the above design, the MnOx‐modified oxygen‐vacancy‐rich In2O3 photocatalyst shows a remarkably improved PFOA photodegradation and defluorination efficiencies under the solar light irradiation as compared with the pristine and commercial In2O3. The photodegradation pathway of PFOA is investigated. The experimental results from the PFOA adsorption analysis and electron spin resonance (ESR) spectra confirm the enhanced adsorption ability and the higher ROS generation efficiency, respectively. The catalyst is further tested in the presence of different anions and cations, where rapid degradation of PFOA is also observed, indicating the potential of the composite materials applied in the practical treatment of PFAS‐contaminated water.