Au@CuxOS yolk-shell nanomaterials with porous shells act as a new peroxidase mimic for the colorimetric detection of H^sub 2^O^sub 2

In this research, Au@CuxOS yolk-shell nanomaterials with porous shells were prepared by an ion-exchange route and characterized by scanning electron microscopy (SEM) as well as transmission electron microscopy (TEM). Then, the as-prepared Au@CuxOS yolk-shell nanomaterials were proposed as an outstanding peroxidase-like mimic for the first time, which could be used as a colorimetric probe for the determination of H2O2. The enhanced intrinsic peroxidase mimic activity was much higher than that of horseradish peroxidase (HRP), Au nanoparticles, and Au@Cu2O core-shell nanomaterials due to the special yolk-shell structure and the synergistic cooperation between the AuNP core and the CuxOS shells. The catalytic property of the resulting nano-alloy followed a symbolical Michaelis–Menten model. Further studies also exhibited a ping-pong mechanism of the enzyme catalytic reaction. Under the optimized conditions, colorimetric determination for H2O2 was carried out and the results showed a linear response range from 0.1 to 32 μM along with a limit of detection of 0.03 μM (S/N = 3). Due to the high catalytic activity, this assay promised wide application in clinical diagnosis, food safety, and environmental monitoring.