Explain The Synergistic Effect Of Cyclic Voltammetry

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To demonstrate the synergistic effect of the MWCNTs@PpPD-PB nanocomposites, cyclic voltammetry (CV) was used for characterizing the electrochemical properties of the composites modified GCE in N2 saturated 0.1 M KCl (pH2.7) aqueous solution at a scan rate of 50 mVs-1. Fig. 5 shows the CVs of the pristine GCE, GCE/MWCNTs, GCE/MWCNTs@PpPD, GCE/MWCNTs-PB, and GCE/MWCNTs@PpPD-PB in the absence of H2O2. The reversible pair of redox peaks are observed for MWCNTs-PB (Fig. 5(d)) and MWCNTs@PpPD-PB modified GCE (Fig. 5(e)), whereas no redox pair peaks are indicated to pristine GCE (Fig. 5(a)), MWCNTs (Fig. 5(b)) and MWCNTs@PpPD modified GCE (Fig. 5(c)).
A pair of well-developed redox waves corresponded to the interconversion between PB and PW. Between the observed redox peaks, the peak current of MWCNTs@PpPD-PB modified GCE is much larger than its MWCNTs-PB modified GCE, probably because of high electrical conductivity of the coated pPD polymer on the MWCNTs. After
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10(B) shows the calibration curve of the reduction peak currents vs. the concentration of H2O2. As shown, it presents the linear response region of MWCNTs-PB (Fig. 10(B) (a)) and MWCNTs@PpPD-PB (Fig. 10(B) (b)). The result of MWCNTs-PB modified GCE is similar to that of a previously reported study [67]. Fig. 10(B) (b) shows a linear response range from 0.005 mM to 2.225 mM with a correlation coefficient of 0.9993, and the sensitivity of the sensor was 583.6 µA mM-1 cm-2, which was much higher than that of the previous study estimated from GCE/MWCNTs-PB and GCE/MWCNTs/Ppy/PB. Moreover, the limit of detection of GCE/MWCNTs@PpPD-PB was calculated as 0.95 µM with a signal-to-noise ratio of 3. Table 1 summarizes the electrochemical characteristics of various modified electrodes containing PB for sensing H2O2, indicating that GCE/MWCNTs@PpPD-PB has high sensitivity and a wide linear range in comparison to those of other reported modified electrodes, proving improved electrical conductivity and good

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