Understanding the electronic properties of hydrogen storage materials with photon-in/photon-out soft-x-ray spectroscopy

摘要

How do we learn about chemisorption and physisorption of hydrides and the kinetics of hydrogen adsorption and desorption? These are profound challenges with us for decades. Soft-x-ray spectroscopy will be will be a unique tool to study the electronic properties of fundamental materials, nanoporous, and complex hydrides and in-situ study the kinetics of hydrogen adsorption and desorption. To facilitate the search for most efficient hydrogen-generation and - storage compounds, a fundamental understanding of the electronic properties is essential. Hydrogen strongly affects the electronic and structural properties of many materials. The electronic structure ultimately determines the properties of matter. Photon-in/photon-out soft-x-ray spectroscopy has been the subject to a revived interest owing to the new generation synchrotron facilities and high performance beamline and instruments. Soft-x-ray absorption spectroscopy (XAS) probes the local unoccupied electronic structure, soft-x-ray emission spectroscopy (XES) probes the local occupied electronic structure, and resonant inelastic soft-x-ray scattering (RIXS) probes the intrinsic low-energy excitations, such as charge transfer, proton energy transfer etc. A number of examples, including some recent experimental findings, then illustrate the potential of XAS and XES applications in hydrogen energy sciences.