Kinetics of the Electrochemical Reduction of Oxygen on the La0.8Sr0.2MnO3/YSZ Electrode

Electrochemical reduction of oxygen on the La0.8Sr0.2MnO3/YSZ Electrode has been investigated in detail with methods of Low Field Polarization, Cyclic Voltammetry and Potential Step. The results demonstrate that the reduction of oxygen on the LSM+YSZ cathode takes place through two pathways: at low temperatures oxygen reduction takes place at Three Phase Boundary (TPB), in which case the rate determining step is the diffusion of atomic oxygen from the LSM surface to TPB, while at high temperatures the reaction area extends over the whole surface of the LSM electrode and the rate determining step is the charge transfer step. It has also been found that the formation of oxygen vacancy is affected by reaction temperature, oxygen pressure and cathodic potential applied. Oxygen vacancy plays an important role in the electrochemical reduction of oxygen at high temperatures and high oxygen partial pressures.