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An electrochemical sensor for H 2 O 2 determination was prepared by electrodepositing copper oxide nanoparticles on the activated pencil graphite electrodes. At first, a study has been made of the optimum conditions for chemical activation of the pencil graphite electrodes (APGE) and then the activated pencil graphite electrode was modified with copper oxide nanoparticles (CuO/APGE) and used as a non-enzymatic hydrogen peroxide sensor. The morphology of the modified electrode surface was investigated by scanning electron microscopy (SEM). Upon the addition of H 2 O 2 , the modified electrode (CuO/APGE) exhibits significant oxidation of H 2 O 2 with starting potential around +0.05 V (vs. Ag/AgCl) which dramatically decreases the overpotential of H 2 O 2 oxidation. Under the optimal experiment conditions, the electrocatalytic response current of this sensor was proportional to the H 2 O 2 concentration in the range of 5.0 × 10 −6 to 1.6 × 10 −3 mol L -1 with a detection limit down to 0.21 µmol L -1 (signal/noise = 3). The sensitivity was calculated to be 4.75 µAL mmol -1 . The electrochemical active surface area and the catalytic rate constant of hydrogen peroxide electro-oxidation were calculated. The H 2 O 2 sensor exhibited a low detection limit, a good signal reproducibility (relative standard deviation (RSD), n = 4) 2.36% and the accurate measurements in milk as the real sample.

Nickel oxide nanostructure network electrodes have been fabricated via metal electrodeposition into a silica template on Ni foam as a three-dimensional metal electrode. The metal oxide nanostructure on three-dimensional electrodes provides a pathway to a very high surface area of electrode built on a cheap commercially available material. These electrodes were characterized by electrochemical impedance spectroscopy, field emission scanning electron microscopy, energy-dispersive X-ray analysis and X-ray diffraction pattern. The electrochemical properties of the electrodes, such as the electrochemical active area and some kinetic parameters, were investigated. The prepared electrode was applied as an amperometric sensor for hydrogen peroxide determination in low potential. The presented electrode shows good sensitivity and stability. Finally, the proposed electrochemical sensor was successfully applied to determine H 2 O 2 in milk and the method has been validated using independent estimation by the classical potassium permanganate titration method.Electronic supplementary material The online version of this article (

A copper oxide nanowire network electrode has been fabricated through an electrodeposition procedure using mesoporous silica film as the template on Ni foam.