| Abstract [eng] |
In recent years, electrophoretic deposition (EPD) method has been widely employed to produce composite coatings. Especially, this versatile, fast and low-cost technique has been shown to be more effective than other deposition techniques for manipulating graphene layers in liquid suspensions with the aim to produce graphene-based composite materials for catalytic, sensing, energy storage and environmental applications. EPD of graphene oxide (GO) sheets on metals is an attractive coating method. The negatively-charged GO only allows the anodic EPD process, which makes it difficult to achieve high-quality coating layers due to oxygen gas bubbling and electrochemical oxidation of metal substrates. However, GO sheets with nanometric thickness and size in the range of a few micrometers have an atomically flat and big surface which could be charged positively by adsorption of metal ions on it. Silver nanoparticles (Ag NPs) have been proposed as great electrocatalyst, owning to their excellent conductivity and large specific surface area. Thus, the aim of this work was to impose the positive charge to GO sheets by using Ag+ ions and successfully perform the cathodic EPD of GO-Ag nanocomposite on Cu electrode surface (GO-Ag/Cu). Afterwards, comprehensively characterize it and carry out the studies of hydrogen peroxide (H2O2) electrochemical reduction. The nature of GO-Ag/Cu nanocomposite coatings was confirmed by using ultraviolet-visible diffuse reflectance (UV-vis) and Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. The electrochemical behavior of GO-Ag/Cu electrode was investigated by cyclic voltammetry and chronoamperometry in 0.1 M phosphatic buffer (pH 7.0) solution. In summary, it was found that electrophoretically deposited GO-Ag/Cu composite coating has been characterized with a strong GO nanosheets and Ag NPs synergetic effect. Therefore, the specific surface area and electrocatalytic activity of the resulting GO-Ag/Cu composite coating were effectively enhanced towards the electrochemical reduction of H2O2. Was noticed, that GO-Ag/Cu electrode had a fast linear amperometric (R2 = 0.991) response (< 3 s), when concentration of H2O2 in neutral solution changed from 44 µM to 468 µM. The limit of detection was estimated 30,9 µM, when S/N = 3. Hence, GO-Ag/Cu nanocomposite electrode can be utilized to fabricate electrochemical sensors with high selectivity, sensitivity and fast amperometry response time. |
