Interaction mechanism between multi-layered MoS₂ and H₂O₂ for self-generation of reactive oxygen species

Elucidating the generation mechanism of reactive oxygen species (ROS) is essential for advanced oxidation processes with respect to environmental and biological sciences. Herein, self-generation of ROS such as hydroxyl radicals (·OH), superoxide radicals (O₂^•-) and singlet oxygen (¹O₂) from the interaction between multi-layered flowerlike MoS₂ nanosheets and H₂O₂ is presented. The results demonstrate that H₂O₂ can exfoliate multi-layered MoS₂ into quantum dots and promote a 2H to 1 T phase change accompanied by the dissolution of MoS₂ to produce H⁺, MoO₄^2- and SO₄^2-. Electron spin resonance (ESR) spectroscopy confirm the production of ·OH, superoxide radicals O₂^•- and ¹O₂ in the MoS₂/H₂O₂ system. The calculation data based on density functional theory (DFT) indicate that the 1 T-MoS₂ can lower the free energy profiles for stepwise catalytic decomposition of H₂O₂ to produce ROS as compared to 2H-MoS₂.