Probing the Local Chemical Environment for Redox Exsolution of Nano- and Endoparticle Electrocatalysts

Metal nanoparticle catalysts dispersed on the surface of a perovskite oxide support show great promise in solid-state electrochemical devices for energy
conversion and electrification of chemical processes involving hydrogen. Breakthrough (electro)catalyst performance and durability have been achieved by direct
growth of nanoparticles from the oxide support by exsolution, and thus exhibit strong anchoring that inhibits agglomeration. Our hypothesis for explaining the
observed results involves transition metals (TM) on interstitial positions in the perovskite structure, where small TM can dissolve into a square-planar configuration
adjacent to A-site vacancies. The potential role of such interstitial solubility of TMs has so far not been addressed in understanding exsolution processes. The
combined in situ XAS and total scattering data of synchrotron experiments will allow for a detailed model of short-range ordering and local distortions in certain
cation environments.