Construction of Au/Cu hierarchically organized particles with dual-functional enzyme-like activity

Nanozymes are defined as mimic enzymes with both unique nanostructures and catalytic activity. Inspired by natural enzymes, herein, we reported a dual-functional nanozyme of Au/Cu hierarchically organized particles (Hops) with excellent polyphenol oxidase-like (PPO-like) and peroxidase-like (POD-like) activities, which could rapidly oxidize refractory toxic phenolic pollutants and serve as a sensitive tool to detect biologically energy-supplying substances. Au/Cu Hop nanozymes exhibited excellent catalytic activity and recyclability and were stable under extreme conditions. Notably, Au/Cu Hop nanozymes had higher substrate affinity and 6.37 times higher V max compared with natural laccase for hydroquinone oxidation reaction at the same mass concentration. Furthermore, the cascade reaction system was constructed based on the POD-like activity of Au/Cu Hops to detect glucose concentration with a low detection limit of 5 µmol L−1. Significantly, we demonstrated the formation of dual-catalytic active sites by Cu-S clusters on the surface of Au/Cu Hops by the molecular dynamics simulations and revealed the mimic enzyme catalysis pathway by the density functional theory calculation. This work has important implications for the construction and application of dual-functional mimetic enzymes.