Preparation of nano-copper oxide modified glassy carbon electrode by a novel film plating/potential cycling method and its characterization

An electrochemical sensor for H2O2 determination was prepared by electrodepositing nano-copper oxide on glassy carbon electrode by a novel film plating/potential cycling method. A copper film was first cathodically deposited on the surface of GC in CuCl2 solution at −0.4 V, then a nano-copper oxide film was in situ deposited on the surface of GC by potential cycling at −0.5 to 0.3 V in 0.1 mol L−1 NaOH solution. The mechanism of nano-copper oxide film formation and factors affecting its electrochemical activity were investigated by cyclic voltammetry, electrochemical impedance spectroscopy and scanning electron microscopy. The chronoamperometric detection of H2O2 was carried out at 0.2 V in 0.01 mol L−1 NaOH solution and the linear range was 2–270 nmol L−1 with a detection limit of 0.2 nmol L−1 (S/N = 3), which is lower than that reported in related literatures. The response time to achieve the steady-state current was <1 s. No measurable reduce in analytical performance was found by storing the sensor in ambient condition for 30 days. The sensor was successfully applied to measure H2O2 in real water, which exhibited high analytical sensitivity and reproducibility.