CoMoO 4 nanobelts as efficient peroxidase mimics for the colorimetric determination of H 2 O 2 .

CoMoO ₄ materials were prepared through a simple hydrothermal method and developed as highly efficient peroxidase mimics for colorimetric determination of H ₂ O ₂ . Based on the different experimental conditions in the synthesis process, the CoMoO ₄ materials present distinct morphologies, structures, surface properties, and peroxidase mimetic activities. Among them, CoMoO ₄ nanobelts (NBs) display the best intrinsic peroxidase mimetic abilities due to the high-energy (100) facet exposed, more Co active sites at (100) facet, more negative potential, and larger specific surface area. It can efficiently catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H ₂ O ₂ to generate a blue oxide. In view of the excellent peroxidase mimetic catalytic activity of CoMoO ₄ NBs, a rapid, convenient, and ultrasensitive method was successfully established for the visual and colorimetric determination of H ₂ O ₂ . The method exhibits good selectivity, practicability, stability, and reusability, and has a detection limit of 0.27 μM. The peroxidase mimetic catalytic mechanism of CoMoO ₄ NBs was illustrated according to the kinetic and active species trapping experiments. The method has a good potential for rapid and sensitive determination of H ₂ O ₂ for biomedical analysis. Graphical abstract Schematic presentation of the process of CoMoO ₄ nanobelts catalyzing the oxidation of peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H ₂ O ₂ to generate a typical blue color, which can be applied in rapid and ultrasensitive detection of H ₂ O ₂ visually.