Montmorillonite-loaded ceria nanocomposites with superior peroxidase-like activity for rapid colorimetric detection of H 2 O 2

An efficient novel colorimetric sensor for H2O2 based on peroxidase-like CeO2-montmorillonite (MMT) nanocomposites that were successfully prepared by a facile one-pot approach, was realized. In comparison with other nanomaterials as peroxidase mimics, the catalytic reaction by the well-dispersed CeO2-MMT nanocomposites was in accordance with typical Michaelis–Menten kinetics, which exhibited a higher affinity to 3,3′,5,5′-tetramethylbenzidine (TMB) and H2O2, bringing about a superior peroxidase-like activity (a distinct blue color change was observed rapidly within 30 s, by the naked eye.) than that of pure CeO2 nanoparticles, MMT and their hybrid materials, respectively. Under the optimized conditions, CeO2-MMT nanocomposites were used to establish a colorimetric biosensor for the detection of H2O2 in a relative wide range of 9 × 10−6 M to 5 × 10−4 M with a lower detection limit of 7.8 × 10−6 M. The sensor was successfully applied in H2O2 detection in milk samples.