HERFD XANES and XES study of the structural transformations in working CoFeOx and NiFeOx nanocatalysts for the oxigen evolution reaction

With this experiment, we propose to employ operando HERFD XANES and XES measurements to track the chemical/structural response of size-selected metal oxide nanoparticles (NPs) exposed to oxidizing electrochemical conditions and oxygen evolution reaction (OER) in alkaline electrolyte. In particular, we plan to compare the structure, the composition and their evolution, under OER conditions for a series of CoFeOx and NiFeOx catalysts with well-defined particle sizes. The time-dependent evolution of the oxidation state and the local structure of the transition metal species under working conditions will be followed aiming to observe and rationalize the effect of the particle size and NP composition. In addition to the measurements performed under static conditions, we will explore the response of the catalyst to pulsed reaction conditions, which can provide more details about the charge accumulation in the catalyst and shed new light on the atomistic details of the OER mechanism.