Enhanced Peroxidase-mimicking Activity of Plasmonic Gold-modified Mn3 O4 Nanocomposites through Photoexcited Hot Electron Transfer.

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 Mn3 O4 nanozyme (Mn3 O4 -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 Mn3 O4 conduction band mediated hot electron transfer from photoexcited gold nanoparticles to H2 O2 which undergoes further oxygen-oxygen bond cleavage to yield hydroxyl radical. The surface decoration of plasmonic gold nanoparticles endows Mn3 O4 -Au to be a light-regulated nanozyme.