CoMoO nanobelts as efficient peroxidase mimics for the colorimetric determination of HO.

CoMoO materials were prepared through a simple hydrothermal method and developed as highly efficient peroxidase mimics for colorimetric determination of HO. Based on the different experimental conditions in the synthesis process, the CoMoO materials present distinct morphologies, structures, surface properties, and peroxidase mimetic activities. Among them, CoMoO 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 HO to generate a blue oxide. In view of the excellent peroxidase mimetic catalytic activity of CoMoO NBs, a rapid, convenient, and ultrasensitive method was successfully established for the visual and colorimetric determination of HO. 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 NBs was illustrated according to the kinetic and active species trapping experiments. The method has a good potential for rapid and sensitive determination of HO for biomedical analysis. Graphical abstract Schematic presentation of the process of CoMoO nanobelts catalyzing the oxidation of peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of HO to generate a typical blue color, which can be applied in rapid and ultrasensitive detection of HO visually.