A surface plasmon-enhanced nanozyme-based fenton process for visible-light-driven aqueous ammonia oxidation

Abstract

By incorporating glucose oxidase-like activity and surface plasmon resonance (SPR) of Au nanoparticles (AuNPs), a novel nanozyme-Fenton system is designed, i.e., ultrasmall AuNPs and α-FeOOH microcrystals are grown on porous carbons for constructing a nanozyme-Fenton catalyst. AuNPs can catalytically oxidize glucose with oxygen for producing H₂O₂ (the crucial reagent in Fenton process) and gluconic acid (regulating the pH of micro-environment). Due to the SPR effect, the interaction between the glucose molecules and oscillating local electromagnetic fields contributes to the activation of the glucose molecules, promoting the reaction with O₂ in close proximity, thus enhancing the production of H₂O₂. The heat released from AuNPs by absorbing light energy can increase the system temperature to the optimum condition of the enzymatic reaction. Hot electrons from plasmon-excited AuNPs promote charge separation at the Au/α-FeOOH interface, leading to efficient cycling of Fe³⁺/Fe²⁺. Besides, growing these α-FeOOH nanocrystals on the porous structures of carbon frameworks is beneficial for the electron transfer between the carbon and α-FeOOH, and this restricts the leaching of iron ions. This study can provide a novel path for the development of a Fenton-like reaction based on a photo-induced surface plasmon-enhanced nanozyme-Fenton catalyst to improve the ˙OH production efficiency.