Abstract
Peroxidase‐mimicking Ag–Cu/CQDs nanocomposites were successfully synthesized
via
a green approach, in which CQDs acted as both reducing and stabilizing agents for the simultaneous formation of AgNPs and CuNPs. The resulting nanozyme system exhibited a synergistic catalytic effect, arising from enhanced electronic interactions between Ag and Cu by CQDs, thereby increasing peroxidase‐like activity. This activity of Ag–Cu/CQDs was demonstrated through the catalytic oxidation of colorless 3,3′,5,5′‐tetramethylbenzidine (TMB) substrate to blue TMB
ox
via the generation of hydroxyl radicals (OH
•
) in the presence of H
2
O
2
. Based on this principle, a colorimetric glucose (GL) detection method was developed by coupling glucose oxidase (GOx) with Ag–Cu/CQDs as nanozyme catalysts. The reaction mechanism consists of two main steps: (i) the oxidation of GL by GOx generates H
2
O
2
, and (ii) Ag–Cu/CQDs catalyze the decomposition of H
2
O
2
, generating OH
•
, and then oxidize TMB to blue TMB
ox
. The established system exhibited excellent catalytic performance for detecting H
2
O
2
and GL, achieving detection limits of 0.14 and 0.06 mM, respectively, which are lower than those reported for some nanozyme‐based GL sensors. Furthermore, the developed assay successfully analyzed human urine samples, yielding recoveries ranging from 100.0% to 104.3%. Compared with natural peroxidase enzymes, Ag–Cu/CQDs have significant advantages, including simple synthesis, high stability, and cost‐effectiveness, making them promising candidates for biosensor applications.