(308a) Understanding Dynamic Materials for Electrocatalytic Processes

Electrochemical processes provide a unique set of parameters to optimize catalyst material and reactor performance, including fine tuning via modified electronic structures, applied electric potentials, and solvent effects. In addition, they enable operation at atmospheric temperature and pressure, produce few pollutants, and provide a mechanism for storage and conversion of vital renewable electricity sources. However, these unique reaction environments also commonly induce rearrangement of the catalyst electronic and geometric structures, such that the operational catalyst active sites do not resemble the pristine synthesized materials.

We use controlled material syntheses and advanced spectroscopy techniques to monitor dynamic behavior of catalysts in response to electrocatalytic reaction conditions. We have developed several iridium-based perovskite materials to establish electronic structure effects associated with systematic changes in composition, crystallinity, and strain. We use these materials to elucidate trends in structural reorganization and degradation mechanisms induced by reaction operating conditions, exemplified with water splitting reactions in acidic conditions. Particularly for water oxidation, the development of active and stable catalysts has been a longstanding challenge. Imaging and scattering techniques reveal active site moieties and short-range order at the surface of these restructured iridate catalysts that have previously been considered largely amorphized. We also investigate non-platinum group metal-based catalysts for water oxidation in acidic conditions and compare the durability of these respective material systems. With this work, the Seitz lab aims to exploit electrochemical processes and reaction environments to understand and harness catalyst material dynamics to achieve enhanced activity, selectivity, and stability for sustainable production of fuels and chemicals.