Valence-engineering modulation of MoS₂ clusters for enhancing biocatalytic activity

Earth-abundant MoS₂ with the advantages of a stable structure, tunable bandgap, and easy shear has great potential for applications in the fields of catalysis, biomedicine, and so on. However, the biocatalytic activity of MoS₂ remains little investigated and is insufficient for biomedical applications. In this work, we develop ultra-small and water-soluble MoS₂ clusters with superior antioxidant activity and enzyme-like activity <i>via</i> valence-engineering modulation with Ce doping. Compared with pure, Re-, Tl-, and Nd-MoS₂ clusters, Ce-MoS₂ clusters exhibit about 1.7-fold enhanced antioxidant activity. Moreover, superoxide dismutase (SOD)-like activity of Ce-MoS₂ clusters is about 30-fold higher than that of MoS₂ clusters. In addition, the Ce-MoS₂ clusters are evidenced to possess ultra-high clearance performance for reactive oxygen species and reactive nitrogen radicals (RONS), especially ˙OH and O₂˙^-. The comprehensive analyses of valence evolution and the energy level structure indicate that the enhanced biocatalytic activity is attributed to the synergistic effect of valence engineering of Mo⁴⁺/Mo⁶⁺ and energy-level engineering in MoS₂ clusters <i>via</i> Ce doping. This work provides a universal approach to improve the biocatalytic activity of MoS₂ clusters <i>via</i> valence engineering modulation, which exhibits great potential in the field of biomedical application, especially inflammatory diseases.