Ceria-based peroxidase-mimicking nanozyme with enhanced activity: A coordination chemistry strategy

Ceria nanomaterials have been reported to possess multienzyme properties (oxidase, superoxide dismutase, catalase, and phosphatase mimetic). In this work, we constructed a new synthesis strategy of ceria-based nanomaterials bearing excellent peroxidase mimic behaviors. An effective coordination chemistry strategy was used by chelating transition metals ions onto ceria nanorods and then the fabricated materials are applied to regulate the peroxidase mimicking activity. Owing to the efficient synergistic effect between metal ions and CeO2 nanorods, the as-prepared M/CeO2 (M = Fe3+, Co2+, Mn2+, Ni2+, Cu2+, Zn2+) exhibited promising intrinsic peroxidase activity toward a classical peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H2O2 and showed excellent affinity to TMB because of the existence of surface carboxyl groups serve as substrate binding sites. We found that Mn(II)/CeO2 exhibit the highest peroxidase mimicking activity. Based on these findings, a sensitive and selective colorimetric method based on Mn(II)/CeO2 was successfully applied to the detection of H2O2 and glucose with detection limits of 2 mu M and 8.6 mu M. This study not only demonstrates that metal-chelated nanoceria exhibits high-activity enhancement of peroxidase-mimic property, but also provides a promising strategy to regulate the catalytic activity of nanozymes.