Synergistic Enhancement of Catalytic Activities in Ligand‐Regulated Carbon Dots‐Ferric Ion Nanozymes via UV‐Enhanced Peroxidase‐Oxidase

ABSTRACT Species of metal ions in carbon dots‐metal ions complex nanozymes boost enzyme‐mimicking activities. However, the relationship between ligand regulation of the catalytic activity of carbon dots‐metal ions complex nanozymes still lacks clarity, which hinders the design of high‐performance nanozymes. Herein, to understand the influence of ligands on nanozyme activities, three kinds of carbon dots‐ferriic ions (CDs‐Fe) nanozymes with three ligands, including allyltriphenylphosphonium bromide (TPP), 1‐hydroxyethane‐1,1‐diphosphonic acid (HEDP), and diethylenetriaminepentaacetic acid (DTPA), are synthesized via sequential hydrothermal carbonization and coordination chemistry. The effects of ligand on peroxidase (POD)‐mimicking and UV‐induced oxidase‐mimicking activities are then systematically evaluated. All CDs‐Fe nanozymes exhibit dual POD‐mimicking and UV‐induced oxidase (OXD)‐mimicking activities. Type of ligand significantly determines catalytic performance, for example, HEDPCDs‐Fe exhibits the highest POD‐mimicking activity (V m 2.68 × 10 −7 M s −1 ), meanwhile TPPCDs‐Fe showing superior UV‐induced OXD‐mimicking activity (V m 2.26 × 10 −7 M s −1 ). Crucially, the synergistic effect of UV‐enhanced POD‐OXD is observed, where UV‐induced processes enhanced POD‐mimicking catalysis, motivating significantly improved reaction kinetics with lower K m (1.05 m m ) and higher V m (5.17 × 10 −7 M s −1 ). POD‐mimicking activity with UV irradiation is 1.93 times that in the dark. Ligand‐regulation strategy of CDs‐Fe nanozyme based on coordination chemistry offers an idea to design and synthesize high catalytic activities of CDs‐metal ions nanozymes.