The occurrence of the Volmer-Tafel sequence is frequently discounted due to the anticipation of a large activation barrier for this type of reaction . An alternative oxygen evolving mechanism which features active involvement of lattice oxygen has been known since the 1980s. The experimental evidence conclusively shows that in many cases (regardless of pH) the produced oxygen molecule may contain at least one oxygen atom originating from the catalysts lattice . The nature of this behavior has been most systematically studied in materials intended for alkaline water electrolysis (such as Ni based perovskites) . These materials show an enhancement of the overall oxygen evolving activity if the lattice oxygen activation contributed to the overall oxygen evolution process. This behavior of the Ni-based perovskites was attributed to a stabilization of oxygen surface vacancies which in turn can be affected by the chemical element at the A site of the perovskite structure .