Heterogeneous electrocatalysis over metal oxide generally occur via the Mars and van Krevelen (MVK) mechanism , where reductant reacts with the surface oxygen of the metal oxide. In our case, there's possibility that while oxygen evolution is occurring, oxygen vacancies/defects are generated on catalyst surface due to lattice oxygen removal. These defects are filled up by solvent or gaseous phase molecular oxygen, indicating dynamic exchange of oxygen. To further corroborate the dynamic exchange behavior, we scanned the R-LSCO electrode again after keeping it in the electrolyte for some time. Interestingly, the original electrochemical behaviour is attained as evident by blue trace in Figure . Overall, the RRDE studies confirms the evolution of lattice oxygen, exchange of lattice oxygen with the solvent and the methanol assisted water oxidation reaction.