Indium-modified Ga2O3 hierarchical nanosheets as efficient photocatalysts for the degradation of perfluorooctanoic acid

Abstract

More and more attention has been redirected to per- and polyfluorinated alkyl substances (PFASs), particularly perfluorooctanoic acid (PFOA), owing to their ecotoxicity and environmental risks. As one of the major emerging and persistent contaminants in the environment, the current treatment processes could not remove PFOA efficiently. The recent advances in heterogeneous photocatalysis have demonstrated high efficiencies in degrading persistent contaminants, which provides an alternative approach for PFOA removal. Notably, Ga₂O₃-based photocatalysts exhibited great potential for PFOA remediation due to their high oxidizing capability and energy sustainability. Thus, Ga₂O₃ hierarchical nanosheets modified by a series of transition metals were rationally developed, and applied as heterogeneous photocatalysts for fast and efficient PFOA degradation. Noteworthily, the indium modified Ga₂O₃ hierarchical nanosheets achieved prominent PFOA decomposition activity, which can completely degrade 20 mg L⁻¹ PFOA within 1 hour. The In–Ga₂O₃ hierarchical composites have dramatically enhanced the degradation kinetics for PFOA, which was 7.8 times higher than that of pristine Ga₂O₃. With in-depth mechanism investigation, we have demonstrated that In modification can not only enhance light harvesting and suppress photogenerated carrier recombination, but also favor the improvement of the adsorption ability for PFOA through the coexistence of monodentate and bidentate/bridging coordination modes. The transition metals–modification strategy paves the way for fabricating high-performance nanoscale photocatalysts for the removal of PFASs in water.