In-situ synthesis of Z-scheme CeO2@WO3 heterojunction with aromatic rings as electron medium for efficient photocatalytic degradation of perfluorobutane sulfonate

Abstract

Photocatalytic technology has been proven to be a simple and effective method for degrading recalcitrant organic pollutants. In this study, a series of Z-scheme heterojunction nanocomposites composed of CeO₂ and terephthalic acid-modified WO₃ was prepared and further used as photocatalysts for perfluorobutane sulfonate (PFBS) degradation. In this design, terephthalic acid was used as an electron recombination center and heterojunction mediator, which effectively enhances the migration ability of electron–hole pairs and the physicochemical stability of the catalyst. In addition, in situ synthesis of CeO₂ onto the WO₃ surface by the coordinate bond between terephthalic acid and Ce ions can avoid CeO₂ agglomeration. As a result, the CeO₂@WO₃ photocatalyst exhibits excellent PFBS degradation ability (94% for CeO₂@WO₃ vs. 19% for CeO₂). After the fifth cyclic degradation experiment, the CeO₂@WO₃ photocatalyst still maintains stable degradation efficiency. Furthermore, the reaction mechanism of the PFBS in CeO₂@WO₃ photocatalytic process was analyzed by free radical trapping experiment and liquid chromatography tandem mass spectrometry (LC-MS) technique. This study provides new insights for constructing Z-scheme heterojunction and demonstrates that CeO₂@WO₃ photocatalysts possess a promising prospect for degrading PFBS pollutants.