Electrocatalytic Oxidation and Determination of Hydrogen Peroxide at Poly(N-methylthionine) Electrodes

Poly( N -methylthionine) (PNMTh) was utilized as an electrocatalyst to lower the overpotential of hydrogen peroxide (H 2 O 2 ) oxidation compared with bulk platinum. The electrocatalyst was prepared by potential cycling from a phosphate buffer solution containing N -methylthionine and sodium chloride on a platinum foil electrode. X-ray photoelectron spectroscopy (XPS) demonstrated the formation of the polymer film. Cyclic voltammetry and chronoamperometry showed the PNMTh electrode had an excellent electrocatalytic activity toward H 2 O 2 oxidation. Furthermore, the PNMTh electrode was found to be promising as an amperometric detector for H 2 O 2 . The proposed enzyme-free H 2 O 2 sensor exhibited a wide linear range (1–700 μM), fast response (2 s), low detection limit (0.12 μM), high sensitivity, and long-term stability, plus low cost.