Figure 3
(A) Cyclic voltammograms in a 0.1 M phosphate buffer solution at pH 7.0 of a bare and a GNR-modified GCE in the absence (a and b, respectively) and in the presence (c and d, respectively) of 2.5 mM HQ. Scan rate 0.1 V s−1. (B) Nyquist plots of (a) bare GCE and (b) GNR-modified GCE in 0.1 M phosphate buffer (pH 7) containing 2.5 mM HQ. Amplitude ± 10 mV. Frequency range: 105–10–2 Hz. Applied potential: 0.56 V. Inset: Randles electrical equivalent circuit where Rs (electrolyte resistance), RCT (charge transfer resistance), Cdl (double layer capacitance) and ZW (Warburg impedance).
