Liquid-solid interfaces are central to a vast range of energy-related systems and processes. For example, reactions at the mineral-water interfaces effectively controls the transport of contaminants in the environment and, ultimately, are involved in the regulation of atmospheric CO₂. Reactions at electrode-electrolyte interfaces are also a limiting factor in batteries and other energy storage systems. Yet very little is known about most solid-liquid interfaces since they are buried beneath a liquid layer that is opaque to most surface sensitive structural tools. I will present examples of recent work in which we have used and developed phase-sensitive X-ray based scattering techniques to effectively image structures and processes at liquid-solid interfaces. Examples include the imaging of the vertical (i.e., laterally averaged) interfacial structure of mineral-water interfaces from X-ray reflectivity data using phase recovery algorithms; imaging element-specific ion distributions at charged interfaces through phase-sensitive resonant X-ray reflectivity; and the direct imaging of sub-nm high lateral topography and lateral structural variations using X-ray reflection interface microscopy. These observations reveal a high degree of richness and complexity that was previously unobserved, but which can nevertheless be understood based on elementary concepts.

*This work was supported by the Department of Energy, Office of Basic Energy Sciences, Divisions of Chemical Sciences (Geochemistry Research Program), and Materials Sciences (Energy Frontier Research Program).

Argonne Physics Division Seminar Schedule