Revealing the intrinsic peroxidase-like catalytic mechanism of O-doped CoS 2 nanoparticles.

CoS 2 nanoparticles (NPs) have shown promise as potential peroxidase (POD)-like catalysts, but the catalytic molecular mechanisms are largely unknown. Moreover, no study has adequately explored the influence of O-doping induced by the inevitable oxidation of CoS 2 on their POD-like activity. Here, O-doped CoS 2 NPs were prepared by a one-step method, and their intrinsic POD-like catalytic mechanism was investigated with a combined experimental and theoretical approach. The hydroxyl radical (˙OH) and the superoxide radical (O 2 ˙ - ) have been found to play significant roles in the POD-like activity, and ˙OH is the major radical. The O-doping could reduce the transition-state energy barrier of H 2 O 2 dissociation, thus promoting the decomposition of H 2 O 2 to ˙OH and inducing the formation of O 2 ˙ - . Therefore, O-doping is an effective method for enhancing the catalytic activity of CoS 2 NPs. Furthermore, due to the excellent oxidation property of ˙OH and O 2 ˙ - , this nanozyme exhibited efficient catalytic activity towards the degradation of organic dyes with H 2 O 2 . This manuscript provides a new inspiration for designing more promising anion-defective transition-metal sulfide nanozymes for different applications.