A novel platform based on graphene/poly(3,4-ethylenedioxythiophene)/iron (III) hexacyanoferrate (II) composite film for electrocatalytic reduction of H2O2

A new platform for electrocatalysis of hydrogen peroxide (H2O2) based on graphene and poly(3,4-ethylenedioxythiophene) as support to iron (III) hexacyanoferrate (II) was developed. The platform was constructed by electropolymerizing PEDOT and Fe4III[FeII(CN)6]3 (FeHCF) onto the graphene modified electrode. Surface morphology and electrochemical properties of the composite film modified gold electrode were investigated by scanning electron microscopy (SEM), scanning electrochemical microscopy (SECM), cyclic voltammetry (CV), and amperometry. The Graphene/PEDOT/FeHCF modified electrode showed an excellent electrocatalytic activity toward hydrogen peroxide (H2O2) reduction with a diminution of the overpotential of about 400 mV, compared to the process at an unmodified electrode. Cyclic voltammetry and amperometry experiments indicated that the H2O2 reduction reaction involves two electrons and a catalytic rate constant (kcat) about of 4.0 × 106 mol−1 L s−1. The electrochemical sensor presented better performance in 0.1 mol L−1 phosphate buffer solution (PBS) at pH 7.0. Under optimized conditions, a linear response range from 18 up to 10,000 μmol L−1 was obtained with a sensitivity of 0.26 μA L μmol−1 and limit of detection of 1.0 μmol L−1. The proposed method was effectively applied for the determination of H2O2 in antiseptic mouthwash samples and the results were in agreement with those obtained by a comparative method described in the literature.