Insights from the Rigid-Band Model: Tuning Perovskite Electronic Structure for the Oxygen Evolution Reaction

Transition metal oxides exhibit a rich and diverse range of chemistries and physics that has long established their application in a number of electrochemical energy conversion and storage technologies. The ability to design oxides expressly tuned for these applications is rooted in fundamental understanding of the relationships between structure, chemical composition, electronic properties, and electrochemical functionality. In particular, the perovskite family has been a central focus for studying oxygen evolution reaction (OER) electrocatalyst design due to its chemical flexibility and diverse electronic properties. In this work, we probed the valence electronic states for various first-row transition metal perovskite OER catalysts with a range of activities, using combined analysis of X-ray emission, absorption, and photoelectron spectroscopy (XES, XAS, XPS). We examined major compositional design approaches to better understand how to tune perovskite electronic structure – specifically A- and B-site substitutions, oxygen vacancy content, and the double perovskite family. Through these studies, we find clear principles for tuning the metal-oxygen bond strength and identify guiding insights for controlling the mechanism and kinetics on different perovskite surfaces.