Characterization of Fe-CDs/Mn-CeO2 and Its Colorimetric Sensing Studies of H2O2, Glu, and GSH

This study systematically investigated the characterization of 2Fe-CDs/12Mn-CeO2 composites and the colorimetric sensing properties of H2O2, glucose (Glu), and glutathione (GSH). The morphology, structure, and optical properties of the 2Fe-CDs/12Mn-CeO2 composite were analyzed in detail by XRD, FT-IR, SEM, TEM, XPS, and Raman spectroscopy, and its formation was supported by multiple complementary characterization techniques. The catalytic efficiency (kcat/Km) of the nanozyme is 152-fold higher than natural HRP under optimal conditions and remains 59-fold higher even after temperature normalization to 25 °C. In the colorimetric sensing experiments, the detection limits of Fe-CDs/Mn-CeO2 were 0.21 μM, 2.7 μM, and 0.63 μM for H2O2, Glu, and GSH, respectively. Rapid and accurate determination of the concentrations of these biomolecules can be achieved by observing the color changes after Fe-CDs/Mn-CeO2 reaction with the objects to be measured. The experimental results show that Fe-CDs/Mn-CeO2 have high sensitivity and selectivity for H2O2, Glu, and GSH, which provides a solid theoretical and experimental basis for the application of Fe-CDs/Mn-CeO2 in the field of biosensing and medical diagnosis.