CeO2@nanogel/Au nanozymes to enhance peroxidase activity for a novel ultrasensitive SERS assay of H2O2 determination

Although the fact that H2O2 is employed in the medical, food, and chemical industries, trace detection of H2O2 remains a difficult and significant problem. For the detection of H2O2 residues, SERS assays based on enzyme inhibition techniques show promise. As a result, we csynthesized CeO2@nanogel/Au nanoparticles with dual enzyme-like capabilities to detect hydrogen peroxide in this study. CeO2 nanozymes possess both peroxidase-like and oxidase-like activities which could oxidize colorless 3,3′,5,5′-tetramethylbenzidine to blue TMB oxide. Surprisingly, after the addition of nanogel, CeO2@nanogel were prepared and both of its dual enzymatic activities decreased, especially the oxidase-like enzymes almost disappeared. To better investigate the enzyme catalytic activity, Au NPs were introduced and CeO2@nanogel/Au nanozymes were self-assembly prepared. Based on the significantly enhancement of CeO2@nanogel/Au nanozymes peroxidase activity, we developed a Raman detection method for H2O2 with TMBox as the probe molecule. The Raman intensity showed good linearity for the concentration of H2O2 in the range of 10-9 M−10−1 M with a correlation coefficient of R2 = 0.9922 and a detection limit of 2.68 × 10-12 M. Thus, the proposed SERS mode sensor exhibited good selectivity and interference resistance, providing a new avenue for environmental monitoring.