The technique of cyclic voltammetry has been applied to study reduction and oxidation phenomena which are observed at low oxygen partial pressures during steady state current-overpotential measurements of the Au, O2(g)/Fe implanted yttria-stabilized zirconia interface. The redox potential (EO) of the observed redox couple is in close agreement with the thermodynamic potential of coexistent Fe2O3 and Fe3O4 phases. Hence in the forward sweep of the cyclic voltammogram, defined for negatively swept potential, part of the Fe3+ is reduced to Fe2+. The peak currents in the voltammogram result from a redox reaction which is rate limited by the diffusion of electrons or electron holes in the Fe implanted YSZ surface to the implanted Fe ions rather than by the diffusion of the Fe ions themselves.
van Hassel, B. A., & Burggraaf, A. J. (1992). Characterization of Fe implanted yttria-stabilized zirconia by cyclic voltammetry. Solid state ionics, 51(3-4), 175-181. https://doi.org/10.1016/0167-2738(92)90196-V