Revealing the intrinsic peroxidase-like catalytic mechanism of O-doped CoS2 nanoparticles

CoS2 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 CoS2 on their POD-like activity. Here, O-doped CoS2 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 H2O2 dissociation, thus promoting the decomposition of H2O2 to OH and inducing the formation of O-2(-). Therefore, O-doping is an effective method for enhancing the catalytic activity of CoS2 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 H2O2. This manuscript provides a new inspiration for designing more promising anion-defective transition-metal sulfide nanozymes for different applications.