Oxygen Evolution on a SrFeO3 Anode: Mechanistic Considerations from Molecular Orbital Theory

Various pathways proposed in the literature for electrochemical oxidation of and evolution have been explored using the ASED‐MO theory and cluster models of the anode surface. The calculations indicate the following. O atoms can be easily formed on the (100) surface as well as on the edge cation sites of a anode by the discharge of OH−, followed by its deprotonation, and electron transfer to the electrode. These O atoms can combine on the edge two‐fold coordinatively unsaturated cation sites to form with a low barrier. On the face cation sites, OH− can be discharged on the O(ads) to form . This species, after dehydrogenation and electron transfer, yields . In either case, the adsorbed is expected to desorb. The calculations indicate that OH− can bind to OH(ads) and, with electron transfer to the electrode, yield weakly adsorbed . While it is expected that OH− is more likely to deprotonate the adsorbed OH, if forms it will yield by dehydrogenation at the electrode surface or by base catalyzed disproportionation. The calculations do not favor the discharge of an OH− on the to form an ozone intermediate.