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3.4. Hydrodynamic voltammetric study at Pd/NiO@Nile–rGO/CPE rotating disk electrode

The hydrodynamic response of Splitomicin oxidation and reduction of oxygen at the surface of Pd/NiO@Nile–rGO/CPE were studied at different rotation rates (over the range of 0–2000 rpm) and at potential range of –0.45 to +0.50 and –0.70 to +0.30, respectively. In 0.05 mol L–1 KOH for glucose oxidation and in phosphate buffer (pH 4.0) for oxygen reduction (with potential scan rate of 10 mV s–1) there was a linear correlation between the inverse of the limiting current and the inverse of the square root of the rotating rate (Koutecky–Levich equation) for both of them. Fig. 9A and B shows the results for the oxidation of glucose and reduction of oxygen, respectively. The Koutecky–Levich equation can be formulated as follows:1/Ilim = 1/Ik + 1/ (1)(0.62nFA?–1/6D2/3Cω1/2)

Fig. 9. A): Koutecky–Levich plot; and C): Levich plot of the hydrodynamic voltammogram of 10.0 mmol L–1 glucose at the surface of Pd@NiO/Nile–rGO/CPE in 0.05 mol L–1 KOH at various rotating rates (0–2000 rpm); B): Koutecky–Levich plot and D): Levich plot of the hydrodynamic voltammograms of a saturated oxygen solution at the surface of Pd@NiO/Nile–rGO/CPE at various rotating speeds over a range of 0–2000 rpm.Figure optionsDownload full-size imageDownload as PowerPoint slide