MoS2/CoFe2O4 heterojunction for boosting photogenerated carrier separation and the dominant role in enhancing peroxymonosulfate activation

Abstract

• MoS 2 /CoFe 2 O 4 (MC) had high carriers separation capacity and migration efficiency. • Photoinduced electron-hole pairs played important roles in PMS activation. • Norfloxacin over MC/PMS/Vis could be completely degraded after only 15 min. Utilizing peroxymonosulfate (PMS) to produce a catalytic system in which multiple active species coexist is a promising tactic to enhance the oxidation capacity of photocatalytic systems. Here, a MoS 2 /CoFe 2 O 4 heterojunction (MC) was constructed for PMS activation to degrade norfloxacin (NFX) in water under visible light irradiation. MC exhibited a higher visible light response, excellent separation capacity and migration efficiency of photoinduced charge, and superior catalytic performance in the MC/PMS/Vis system for the decomposition of NFX. After only 15 min of reaction, the degradation efficiency of NFX by the MC/PMS/Vis system reached 95.0%. This degradation efficiency was far greater than that of pure MoS 2 and CoFe 2 O 4 under identical conditions. In addition, after the 5th reuse, the degradation efficiency still exceeded 93.0%. The separation and transfer mechanism of photogenerated carriers was explored in detail using photoelectrochemical and X-ray photoelectron microscopy (XPS). More importantly, the NFX degradation pathway, intermediate toxicity assessment, and MC/PMS/Vis system reaction mechanism were proposed. Therefore, this work might provide new insight into the mechanism by which MC activates PMS under visible light, which is of importance for creating environmentally friendly catalytic methods for the efficient degradation of organic wastewater.