Project C02

C02 In-situ atomic scale study of active states during photo-electrochemical water splitting

The goal of this project is to identify electric field and photon-driven mechanisms which allow for running water splitting / oxygen evolution reaction (OER) at the lowest possible overpotential. We have established that during OER a dynamic interface state to water, controlled by correlations, is characteristic for the active state of manganite perovskites. In the 3rd period, the project will apply the developed in-situ environmental TEM and time-resolved X-ray spectroscopy methods to the study of highly active systems and aims at the development of a comprehensive understanding of reaction mechanisms that lead to lowest overpotential in collaboration with theoretical projects.

Fast Mn adatom hopping at the interface of a La1-xSrxMnO3 electrode to H2O is a consequence of partial solvation of surface Mn in liquid H2O. The adatom hopping is revealed by in situ environmental transmission electron microscopy (ETEM) and quantified by image simulation. Such a dynamic interface has a big impact on understanding highly efficient pathways for the oxygen evolution reaction.
G. Lole, V. Roddatis, U. Ross, M. Risch, T. Meyer, L. Rump, J. Geppert, G. Wartner, P. Blöchl and Ch. Jooss, Dynamic observation of Mn-adatom mobility at perovskite oxide catalyst interfaces to water, Nat. Commun. Mat. 1, 68 (2020).