Enhanced peroxidase-like activity of Cu–Cu2O composite film through PtPd immobilization for colorimetric glucose detection

In this study, Cu–Cu2O/PtPd nanocomposites were synthesized and characterized for their peroxidase-like enzyme activity. X-ray diffraction and energy dispersive X-ray spectroscopy analyses confirmed the successful synthesis of the nanocomposites, which exhibited a flower-like morphology and a more uniform dispersion than Cu–Cu2O. The catalytic activity of Cu–Cu2O/PtPd was evaluated using the chromogenic substrate 3,3′,5,5′-tetramethylbenzidine (TMB), finding that Cu–Cu2O/PtPd outperformed Cu–Cu2O. The optimal temperature and pH for the catalytic activity of Cu–Cu2O/PtPd were determined to be 40 °C and pH 4.0, respectively. A kinetic analysis revealed that Cu–Cu2O/PtPd followed Michaelis–Menten kinetics and exhibited a higher affinity toward TMB than the horseradish peroxidase enzyme. The catalytic mechanism of Cu–Cu2O/PtPd involved the generation of hydroxyl radicals, which facilitated the oxidation of TMB. Furthermore, the Cu–Cu2O/PtPd nanocomposite was successfully applied for the colorimetric detection of glucose, demonstrating a linear range of 8–90 μM, a detection limit of 2.389 μM, and high selectivity for glucose over other sugars.