Enhanced Peroxidase‐mimicking Activity of Plasmonic Gold‐modified Mn 3 O 4 Nanocomposites through Photoexcited Hot Electron Transfer

Abstract Enzyme‐mimicking artificial nanomaterials often termed nanozymes have broad applications in many fields, including biosensing, pollutant degradation and cancer diagnosis. Herein, we introduce a plasmonic gold nanoparticle‐modified Mn 3 O 4 nanozyme (Mn 3 O 4 ‐Au). Visible or near infrared light excitation into the plasmonic absorption band of the surface‐bound gold nanoparticles enhances the catalytic oxidation of tetramethylbenzidine (TMB). The mechanism of light‐enhanced peroxidase activity is proposed based on the Mn 3 O 4 conduction band mediated hot electron transfer from photoexcited gold nanoparticles to H 2 O 2 which undergoes further oxygen‐oxygen bond cleavage to yield hydroxyl radical. The surface decoration of plasmonic gold nanoparticles endows Mn 3 O 4 ‐Au to be a light‐regulated nanozyme.