Figure 6: Amperometric current-time curves for H2O2 oxidation on the nano-CuO/GCE, at applied potential 0.19 V (versus Ag/AgCl) in 0.01 M NaOH + 0.09 M KCl solution. Concentrations were used in the range between 0.02 μM and 250 μM H2O2. (a) the current-time curves for adding 0.02, 0.06, and 0.2 μM of H2O2. (b) the current-time curves for adding 2, 6, and 20 μM of H2O2. (c) showed versus .