These simultaneous electrochemical processes caused a shift of the oxidation peak potential of
around +40 mV in comparison with that shown by the Ni nanoparticles, thereby appearing at +0.45 V.
At higher potentials, between +0.5 and +0.6 V, an anodic current was recorded (III) that is related with the quantitative oxidation of the organic matter. From these voltammograms, a set potential of +540 mV was chosen for the subsequent chronoamperometric measurements (Figure S 4A in the Supporting Information).
From the chronoamperograms, the corresponding calibration curve was constructed (Figure S4B in the Supporting Information) and the estimated analytical parameters are summarized in Table 1.