A wheel-like polyoxometalate for haloperoxidase-inspired antibiofouling with H₂O₂in situ provided by electrocatalysis

Biofouling is the adherence of micro-organisms on submerged surfaces, which is a common phenomenon presenting a serious hazard to industry and public health. Nanozymes with haloperoxidase mimic activity are promising options to combat biofouling because HBrO generated by them can kill micro-organisms effectively. However, in haloperoxidase mimic nanozyme-involved antibiofouling, massive H2O2 injection is a requisite, which causes secondary pollution. To achieve self-sufficient H2O2 supply in antibiofouling, a wheel-like polyoxometalate (POM) compound, Ni16Mo16P24, was synthesized. As an artificial nanozyme, Ni16Mo16P24 shows excellent haloperoxidase mimic activity. In the electrocatalytic oxygen reduction reaction (ORR), it shows typical two-electron character and H2O2 production rate reaches 1394.5, 1245.5 and 1053 mM g(-1) h(-1) at 0.1, 0.3 and 0.5 V (vs. RHE) in neutral electrolyte. With H2O2 produced by electrocatalysis, Ni16Mo16P24 accelerates the conversion from Br- to HBrO and achieves "additional H2O2 free" antibiofouling. For bifunctional Ni16Mo16P24, the structure-activity connection is clarified for haloperoxidase mimic activity and electrocatalytic H2O2 production property. More importantly, an environmentally friendly antibiofouling strategy is developed.