Efficient degradation of pollutants by Bi2WO6/BiOCl heterojunction activated peroxymonosulfate: Performance and mechanism

The coupling of photocatalysis and peroxymonosulfate (PMS) induced advanced oxidation processes can be realized as an efficient strategy for the purification of dye wastewater. However, developing a suitable catalyst with both visible light photo-response and high PMS activation efficiency remains challenging. In this paper, a series of type-II Bi2WO6/BiOCl heterojunction composite photocatalysts were synthesized via a simple solvothermal method, which combine the benefits of visible photocatalysis and massive generation of active oxygen species generated by activating PMS. Compared with single pure Bi2WO6 and BiOCl, the composite photocatalyst coupled with PMS system showed better degradation performance for Rhodamine B (RhB). The optimized Bi2WO6/BiOCl (BCW) photocatalyst showed a degradation efficiency up to 97.5% for RhB within 25 min under visible light irradiation as well as exhibited good stability. The excellent photocatalytic performance can be attributed to the synergistic effect of the construction type-II heterostructure and photocatalytically activated PMS. On the one hand, the type-II heterostructure construction facilitated the separation of photogenerated charges. On the other hand, the photocatalytically activated PMS produces more active species and promotes the degradation of pollutants. Furthermore, the intermediates products of RhB degradation were also studied by high performance liquid chromatography-mass spectrometry (LC-MS). Overall, this work provides new insights into the fabrication of type-II photocatalyst in photocatalytic-PMS activation system, which can realize high-efficient purification of dye wastewater.