Construction of Mo-Based p-n Heterojunction with Enhanced Oxidase-Mimic Activity for AOPs and Antibiofouling.

Advanced oxidation processes (AOPs) are efficient methods to remove poisonous organic pollutants from water. But in AOPs, additional radical providers, such as H 2 O 2 , persulfate, and permonosulfate, are indispensable, which not only add the risk of secondary pollution but also increase cost and complexity in operation. To resolve this problem, nanozymes with oxidase-mimic activity are a prospective choice, which can convert O 2 in the air to ·OH and degrade organic pollutants. Here, CoMoO 4 /MoS 2 , a nanozyme with excellent oxidase-mimic activity, is synthesized. In the structure, the p-n heterojunction generates between p-type CoMoO 4 and n-type MoS 2 . Energy band analysis and theoretical calculations suggest the p-n heterojunction intensifies adsorption toward O 2 , which improves oxidase-mimic activity. This facilitates the generation of ·OH and improves organic pollutant degradation performance with AOPs. Furthermore, CoMoO 4 /MoS 2 also exhibits an antibiofouling ability due to the existence of ·OH. This work clarifies the connection between the structure and oxidase-mimic activity for nanozymes with the p-n heterojunction. More importantly, a new AOP without additional radical providers is developed based on oxidase-mimic activity.