The role of the subsurface cation in multilayered catalysts during the oxygen evolution reaction

To store sustainable energy in the form of hydrogen, the efficiency of water electrolysis must be improved. Specifically, the overpotential of the oxygen evolution reaction (OER) must be reduced while high stability of the catalyst must be maintained. Perovskite oxides (ABO3) are considered promising earth-abundant catalysts for the OER in alkaline media. However, an inverse relationship between activity and stability seems to exist. We propose the use of subsurface engineering to enhance the activity of LaCoO3 layers without doping of soluble elements to overcome the activity-stability trade-off. When using LaNiO3 as a subsurface, a complex interplay between Ni and Co results in high OER activities. We propose the use of HERFD XAS to study this interplay in an operando experiment during the OER.