Electrocatalytic reduction of hydrogen peroxide at nanostructured copper modified electrode

Abstract

The electrocatalytic reduction of hydrogen peroxide (H₂O₂) has been studied at nanostructured copper (Cu_nano) modified glassy carbon (GC/Cu_nano) electrode in phosphate buffer (pH 7.2). The electrical properties of GC/ Cu_nano modified electrodes were studied by electrochemical impedance spectroscopy (EIS). Surface and electrochemical characterization were carried out by using atomic force microscopy (AFM) and cyclic voltammetry. A well-defined H₂O₂ reduction signal, which is due to mediation of a surface active site redox transition exhibits at the GC/Cu_nano electrode. The Cu_nano is acting as a bridge without the aid of any other electron mediator, which enables the direct electron transfer between the modified electrode and the substrate. The results are compared with bulk copper macroelectrode and emphasized the efficiency of the Cu_nano modified electrode. Systematic investigations were made to optimize the experimental parameter, such as applied potential (E_app) for copper electrodeposition. The calibration curve obtained from chronoamperometric studies was found to be linear in the range 0.5 to 8.0 μM H₂O₂ with a detection limit of ca.10 nM (S/N = 3) at the GC/Cu_nano electrode. The modified electrode is stable for 1 week in phosphate buffer after repetitive measurements.