MoS2 as a cocatalyst applied in advanced oxidation processes for enhancing degradation of organic pollutants: a review

Fenton technology, as a typical advanced oxidation processes (AOPs), can generate reactive oxygen species (ROS) of strong oxidation capacity to degrade organic pollutants, which has attracted wide attention. However, it is accompanied by the slow Fe 3+ /Fe 2+ cycle rate, easy to generate iron sludge and so on. Recently, it has been proven that the inorganic cocatalysts represented by MoS 2 can effectively solve the above problems. Meanwhile, MoS 2 can accelerate the activation of peroxymonosulfate (PMS) and peroxodisulfate (PDS) by Fe 2+ . In this paper, MoS 2 as the cocatalyst in H 2 O 2 + Fe 2+ , PMS + Fe 2+ and PDS + Fe 2+ were comprehensively reviewed. Specially, the cycling processes of Fe 3+ /Fe 2+ in different systems, the cocatalytic effect of MoS 2 by the exposed active sites, the ROS generation mechanism as well as the microscopic mechanism during the reaction were elaborated emphatically. The results indicate that the reductive active sites on the surface of MoS 2 can promote the regeneration of Fe 2+ through the cycle between Fe 3+ /Fe 2+ and Mo 4+ /Mo 5+ /Mo 6+ . Thus, ROS such as ⋅ OH, SO 4 ⋅− and 1 O 2 with strong oxidizing property can be produced to improve the degradation efficiency of organic pollutants. At last, the challenges and developments of MoS 2 cocatalysts in AOPs for practical applications were prospected. This review contributes to a deeper understanding of the cocatalytic effect of two-dimensional metal sulfides in AOPs and facilitates their industrial application.