Abstract
The electrooxidation of glucose in alkaline media was studied on glassy carbon (GC) electrodes modified with nickel oxide nanoparticles, which were prepared by taking advantage of the control in the nickel bath deposition medium in addition to controlling the interfacial properties of the underlying GC electrode on which the deposition was done. The Electrodeposition was achieved from a medium containing a certain concentration of nickel and glucose ions, typically 5 mM glucose, for modifying the interfacial properties, which reflected on how the nickel was deposited. The properties of the glassy carbon electrode were also controlled by oxidizing it first before nickel was deposited on it. The combination of these reasons led to the preparation of a highly efficient electrode, designated as GCox/NiOx(glu) , in the electrochemical oxidation of glucose. Given the importance of electrode resistance to poisoning agents. It may achieve high efficiency, but it may lose it in the presence of potential toxins. The oxidation of glucose has been studied in alkaline media that contain halide ions with different concentrations depending on the type of halide. The peak current of glucose oxidation increases five folds at GCox/NiOx(glu) compared to the GC/NiOx (Glu) electrode in which nickel was deposited similarly to the case of GCox/NiOx(glu) but onto unmodified glassy carbon electrode. Also at GCox/NiOx(glu) the potential for glucose oxidation was shifted to more negative potential values. Interestingly, tolerance to poisoning by halides is significant. Susceptibility to poisoning increases in the following way: iodide > bromide > chloride. Upon cycling the potential of the modified electrode in chloride solution containing glucose, the peak current continuously decreases . However, under the experimental condition, the peak current for glucose oxidation after cycling of potential is not less than the value of the current corresponding to the absence of glucose. Thus, the present modified electrode not only enhances the glucose oxidation, but also characterized by high immunity to electrode poisoning by halides.