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

摘要

An electrochemical sensor for H_2O_2 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 CuCl_2 solution at -0.4V, 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 H_2O_2 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 0.2nmol L~(-1) (S//V=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 H_2O_2 in real water, which exhibited high analytical sensitivity and reproducibility.