Abstract
An electrochemical sensor for H2O2 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 H2O2, the modified electrode (CuO/APGE) exhibits significant oxidation of H2O2 with starting potential around +0.05 V (vs. Ag/AgCl) which dramatically decreases the overpotential of H2O2 oxidation. Under the optimal experiment conditions, the electrocatalytic response current of this sensor was proportional to the H2O2 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 H2O2 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.
Highlights
Hydrogen peroxide is an important chemical because it has attractive features like anti-bacterial property, decolorizing and oxidizing agent.[1]
The oxidation peak current of the voltammetric responses of the activation of the pencil graphite electrodes (APGE) in different solution divided on the oxidation peak current of the unmodified pencil graphite electrode (PGE) was given as an enhancement factor
These results indicate that this electrochemical sensor has a good stability and reproducibility, as required for the determination of H2O2
Summary
Hydrogen peroxide is an important chemical because it has attractive features like anti-bacterial property, decolorizing and oxidizing agent.[1]. During repetitive cyclic potential scanning in the alkaline solution of 0.1 mol L-1 NaOH, CuO nanocubes were formed on the APGE. The repetitive cyclic voltammograms for the electrochemical deposition of CuO nanocubes on the APGE in 0.1 mol L-1 NaOH are shown in the Supplementary Information (Figure S1).
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