Oxygen reduction reaction cyclic voltammogram

The catalytic activity of the PANI for the oxygen reduction reaction was first characterized by using a film PANI electrode as the working electrode in oxygen-and argon-saturated 1 M HC1 solution. Fig. 1 shows cyclic voltammograms in these two solutions. 

Figure 8. Blank cyclic voltammogram of R-poly electrode in parallel with hydrogen oxidation reaction, oxygen reduction reaction and ethanol oxidation reaction. For neither of these cases Pt surface cannot be considered as clean or static.

For mixed lanthanide-transition metal clusters, Yukawa et al. have synthesized an octahedral [SmNi6] cluster by the reaction of Sm3+ and [Ni(pro)2] in nonaque-ous medium [66-68]. The six [Ni(pro)2] ligands use 12 carboxylate oxygen atoms to coordinate to the Sm3+ ion, which is located at the center of an octahedral cage formed by six nickel atoms. The coordination polyhedron of the central Sm3+ ion may be best described as an icosahedron. The [SmNir, core is stable in solution but the crystal is unstable in air. The cyclic voltammogram shows one reduction step from Sm3+ to Sm2+ and six oxidation steps due to the Ni2+ ions. Later, similar [LaNis] and CjdNif> clusters were also prepared. 

The reaction is further slowed down if some electrolyte species adsorb onto the catalyst surface. Figure 11.8 shows the cyclic voltammograms for O2 reduction on a Pt electrode in either 0.1 M perfluorosulfonimide (CF3SO2NFISO2C4F9) (PFSI), 0.1 M FI3PO4, or 0.1 M PFSI + 20 mM FI3PO4 [42]. The oxygen reduction was an irreversible wave, and the peak currents in the three electrolyte solution were similar. Flowever, the half-wave potential (the potential at 85% of the peak... 

The basic idea of this technique is that a linear potential sweep (of low rate) is applied to the disk electrode, while cyclic voltammograms (of a relatively high sweep rate) are measured at the ring. The results of such experiments can lead to the creation of a 3D map , which may reveal the electroactive intermediates or products that are formed in the electrode process(es) taking place on the disk. The applicability of the proposed technique is demonstrated here by considering the oxygen reduction process at the gold 0.5 mol dm sulphuric acid electrode as an illustrative model reaction. 

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