Single-Atom Modulated Biocatalytic Selectivity on WSe₂ Clusters

Two-dimensional WSe₂ has garnered significant interest owing to its special electronic properties and high catalytic activity. However, the substrate catalytic selectivity of WSe₂ has still been poorly studied. In this study, ultrasmall M-WSe₂ clusters (M = Cu, Ru, Zn) were designed by a single-atom doping strategy and catalytic selectivity. The Cu-WSe₂ and Zn-WSe₂ clusters show high antioxidant activity, both about a 7.2-fold enhancement higher than the WSe₂ clusters. Meanwhile, Ru-WSe₂ and Cu-WSe₂ prefer to exhibit catalase-like (CAT-like) activities, about 5.6- and 2.5-fold enhancement after single-atom doping. Ru-WSe₂ displays significant peroxidase-like (POD-like) activity with a better affinity than natural HRP, showing a K_m value of 0.43 mM. In contrast, pure WSe₂ clusters exhibit NADH oxidase-like (NOX-like) activity that catalyzes the regeneration of NAD⁺. Density functional theory calculations reveal that catalytic selectivity originates from differential electron transfer around different single atoms as well as d-band center modulation. In vitro cell experiments demonstrated that the M-WSe₂ clusters can modulate the oxidation-reduction balance through single-atom engineering.