Evaluation of the Sensor Response.
The sensor responses for all composites were assessed using glucose as standard COD analyte. Figure 1A shows the voltammetric response of the Ni-based sensor. Two well-defined redox peaks at +0.32 V (peak I) and +0.41 V (peak II) vs Ag/AgCl, in the forward and backward potential scan, respectively, were recorded in 0.1 NaOH background electrolyte solution, which can be assigned to the oxidation/reduction of the Ni(II)/Ni(III) redox pair.