Operando HERD-XAS at perovskite high entropy oxides during the oxygen evolution reaction

The oxygen evolution reaction (OER) is the limiting process in the hydrogen production, which could serve as sustainable energy storage. To improve the sluggish kinetics of the OER, high entropy perovskite oxide electrocatalyst are promising candidates. Operando x-ray absorption spectroscopy studies are needed to track changes in oxidation state and atomic structure as function of applied potential during the OER for this new class of compositionally complex materials. We focus on epitaxial thin-film HEOs as a well-defined system to reveal the fundamental composition-structure-function relation under operation condition, i.e. the key scientific insight needed for rational design of future catalysts based on this complex chemical composition providing a baseline for “ideal” electrical and compositional properties for OER catalysts.