Surface protonation and oxygen evolution activity of epitaxial La1−xSrxCoO3 thin films

As an alternative electrode material, transition metal oxides are promising candidates due to multivalent nature and oxygen vacancies present in the structure with facilitate redox reactions. The aim of this study is to explore the intrinsic mechanism of oxygen evolution reaction (OER) using two-dimensional thin film La1−xSrxCoO3 electrode as a model. Herein, we report a planar two-dimensional model La1−xSrxCoO3 electrode grown on a Nb-SrTiO3 single-crystal substrate via pulsed laser deposition. The two-dimensional La1−xSrxCoO3 films offer different oxygen evolution activities at different pH electrolyte solutions. The mechanisms behind the variations of the oxygen evolution activity were discussed after comparing the oxygen evolution activity before and after treatments of the electrodes and measurements by various test methods. The results of this study offer a promising, low-cost electrode material for the efficient OER and a sustainable production of hydrogen fuel.