Dataset of "Structural Development on Ru and RuO2 Electrodes during Oxygen Evolution – an operando soft X-ray Absorption Spectroscopy Approach"

Time resolved in-situ X-ray absorption spectroscopy (XAS) in soft X-ray region was used to characterize polarized interphase on Ru and Ru oxide based electrodes under oxygen evolution reaction (OER) conditions. XAS spectra were used to align the type and population of oxygen-containing species formed at electrodes at anodic potentials with local electronic structure of the OER catalyst. The operando soft XAS data do not identify a single rate limiting process at potentials negative to 1.4 V vs Ag/AgCl. Individual intermediates of the oxygen evolution process coexist at the surface at potentials preceding the actual OER onset. The OER is accompanied with redistribution of the electron density resulting for a start of the catalytic cycle reflecting increased population of oxygen vacancies at the surface. The observed spectral behavior indicates a confinement of the OER to the coordination unsaturated sites (cus) at the surface.