In situ X-ray photoelectron spectroscopy of electrochemically active solid-gas and solid-liquid interfaces

In this account the application of synchrotron radiation based X-ray photoelectron spectroscopy (XPS) forthe investigation of electrochemically active gas-solid and liquid-solid interfaces will be discussed. Thepotential of Near Ambient Pressure XPS (NAP-XPS) for the estimation of the surface electronic structureof electrochemically active interfaces will be described by two examples. Thereto the oxygen evolutionreaction (OER) over Pt and IrOxanodes will be introduced. In particular the analysis of XP core levelspectra of IrOxrequires the development of an appropriate fit model. Furthermore the design of reactioncells based on proton exchange membranes (PEM) and on electron transparent graphene membranes,which enables the investigation of liquid-gas and liquid-solid interfaces under electrochemical relevantconditions will be discussed. In the last part of this article a perspective to the EMIL project at the syn-chrotron radiation facility BESSY will be given. The purpose of this project is the implementation of twonew beamlines enabling X-ray photoelectron spectroscopy in the X-ray regime from 80 eV–8 keV underreaction conditions. The extension to the so called tender X-ray regime will allow the release of higherkinetic energy photoelectrons which have a higher inelastic mean free path compared to photoelectronsexcited by soft X-ray radiation and therefore will enable the investigation of solid-liquid interfaces underelectrochemical reaction conditions