Cerium(III)-doped MoS₂ nanosheets with expanded interlayer spacing and peroxidase-mimicking properties for...

Molybdenum disulfide (MoS₂) nanosheets (NSs) with an 8.1 Å interlayer spacing were heavily loaded with cerium(III) ions by a one-step hydrothermal method. The material thus obtained has a strong peroxidase-like (POx-like) activity. The introduction of the large Ce(III) ion enlarges the interlayer distance of MoS₂NSs. It also supports shuttling and transport of substrate, intermediates and electrons. It also increases the specific surface of MoS₂. This results in a larger number of active sites, accelerates the contact between substrate and catalytic surface, and improves the kinetics of the catalytic reaction. The nanomaterial catalyzes the oxidation of colorless 3,3',5,5'-tetramethylbenzidine by hydrogen peroxide (H₂O₂ ) to give a blue-green product with an absorption maximum at 652 nm. The assay has a linear response in the 1-50 μM H₂O₂ concentration range and a 0.47 μM limit of detection. The colorimetric method was applied to real milk samples, and high recoveries (98.4%-108.0%) and repeatability were obtained. Graphical abstractMolybdenum disulfide nanosheets loaded with cerium(III) catalyze the oxidation of colorless 3,3',5,5'-tetramethylbenzidine (TMB) by hydrogen peroxide to give a blue-green product with an absorption maximum at 652 nm.