Native enzymes suffer some disadvantages such as instability in harsh reaction conditions, difficult recovery, etc . In contrast, nanomaterials with enzyme-like activity reveal high stability against pH and temperature changes along with excellent kinetic performances . In fact, with the development of nanoscience, several types of nanomaterials were introduced with unique spectral, optical, catalytic, and stability as a result of the fast development of nanoscience in recent years , some of them reveal significant enzyme-like activity especially peroxidase-like properties with significant advantages over native enzymes for example, high pH and thermal stability, excellent reusability, and high storage stability . Up to now, nanozymes have been utilized in organic dye biodegradation, battery development, sensor, and biosensor design , especially after the first report of COVID-19 , they applied for its clinical sensing . In this field proving the catalytic mechanism of the reaction is an attractive research topic. Hence, herein, kinetics parameters, Km and Vmax, of oxidase-like Ce/Fe-bimetallic nanozymes toward 3,3′,5,5′-tetramethylbenzidine oxidation were determined. The Michaelis-Menten kinetic model was used for the evaluation of the kinetic of the nanozyme-mediated oxidation of 3,3′,5,5′-tetramethylbenzidine. To provide the quantitative and accurate values of kinetics parameters, Km and Vmax, the linear plot of Lineweaver-Burk was constructed.