A hydrogen peroxide sensor based on colloidal MnO2/Na-montmorillonite

A novel amperometric sensor for the determination of hydrogen peroxide was prepared based on the enhanced oxidation of H2O2 at a glassy carbon electrode modified with colloidal MnO2–Na-montmorillonite (nano-MnO2/Na-Mont/GCE). The montmorillonite has been devised to support and dispense the MnO2 nanoparticles. Scanning electron microscopy images (SEM) showed that the MnO2 nanoparticles were homogeneously dispersed in the colloidal Na-montmorillonite. This colloidal dispersion was dried to form a uniform film when added to the surface of GCE. The voltammetric results showed that MnO2 nanoparticles could effectively catalyze the oxidation of H2O2. The dependence of the response current on H2O2 concentration was explored under optimal conditions, and an excellent linear relationship was obtained in the range from 5 × 10− 7 to 7.5 × 10− 3 M with a minimum detectable concentration of 1.5 × 10− 7 M. This sensor has been applied to measure trace concentration of hydrogen peroxide in samples of hair dye.