Vacuum compatible flow-cell for high-quality in situ and operando soft X-ray photon-in–photon-out spectroelectrochemical studies of energy materials

Abstract

Soft X-ray spectroscopy is a powerful method to investigate materials on an element selective level with respect to their atomic and electronic structure. However, its application is technically challenging for in situ or operando investigations of materials for electrochemical applications. Herein, we present a spectroelectrochemical flow-cell designed to enable state-of-the-art electrochemical characterization while being installed in a vacuum chamber for the direct accessibility of the electroactive sample to soft X-rays. An overview of the application of soft X-ray photon-in–photon-out spectroscopic studies to electromaterials is provided, along with discussions of experimental and technical considerations specific to this highly sensitive mode of analysis. Application of the cell for the in situ spectroelectrochemical characterization of an electrodeposited nickel oxide water electrooxidation catalyst is demonstrated.