Fig. 4

a Cyclic voltammograms of DBT–CNT/GCE in a 0.1 M phosphate buffer (pH = 7.0) containing 1000 μM IP at different scan rates, CVs A–F corresponding to 10, 15, 20, 25, 30, and 40 mVs⁻¹ scan rates. b Variation of the electrocatalytic currents versus the square root of the scan rate. c Variation of the scan rate-normalized current (I _p/υ ^1/2) with scan rate. d Tafel plot derived from the rising part of the voltammogram recorded at a scan rate of 10 mVs⁻¹