Fig. 2 shows the effect of varying the NaCl concentrations in the electrolyte, which contained also 0.1 mol L−1 oxalic acid. In the absence of chloride, i.e., in pure oxalic acid solution, 2a [26], the oxidation peak of silver is rather broad (half-width of about 0.069 V). Additionally, the peak current decays in subsequent cycles [26], which is a result of diffusional loss of silver ions into the bulk solution. The addition of 0.3 mmol L−1 (Fig. 2b) NaCl causes the appearance of a shoulder at lower overpotentials, which grows into a single peak, larger and narrower (half-width of 0.027 V), when the concentration of NaCl is greater than 0.6 mmol L−1 (Fig. 2c). The presence of NaCl in the solution of oxalic acid increases the stability of the oxidation peak of silver, since the charge associated with the redox processes decreases more slowly. In Fig. 2a–g only the first two cycles are shown, but even after 10 cycles the current remains stable. Moreover, the presence of NaCl (0.1 mol L−1) in the solution of oxalic acid shifts the silver oxidation peak by about 0.180 V. Also, in 0.1 mol L−1 NaCl (without oxalic acid) the oxidation overpotential decreases by around 0.100 V, which cannot be caused by changes in pH.