Si Doped CoO Nanorods as Peroxidase Mimics for Colorimetric Sensing of Reduced Glutathione

Si doped CoO nanorods (denoted as Si-CoO) were prepared by the hydrothermal method. The Si-CoO composites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray photoelectron spectra (XPS), etc. The results suggest that Si element uniformly distributed onto CoO nanorods with a diameter of 50–100 nm. The as-prepared Si-CoO nanocomposite possessed an excellent peroxidase-like activity as well as quickly catalyzed the colorless substrate 3,3,5,5-tetramethylbenzidine (TMB) to be oxidized into blue oxTMB by H 2 O 2 only in 20 s, which was easily visually observed. The electron spin resonance (ESR) data confirms that superoxide radicals (•O 2 – ) play a key function in catalytic reaction. On the basis of the peroxidase biomimetic activity of Si-CoO, we constructed a new biosensor for detection of H 2 O 2 and reduced glutathione (GSH) in the range of 1–100 uM with a limit of 0.22 and 0.45 uM, respectively.