X-ray absorption spectroscopy is an invaluable tool in probing co-ordination environment of targeted elements in all forms of matter. Due to low penetration depths of few nanometers for electrons compared to hundreds of microns for X-ray photons, X-ray absorption measurements done by measuring total electron yield (TEY) and X-ray fluorescence (XRF) together can provide both interfacial and bulk co-ordination environments. We report on a simple and inexpensive set-up for collecting simultaneously TEY and XRF signals from an inverted pendant drop of electrolyte solutions. The set-up is tested with an aqueous solution of rare-earth element-europium. The X-ray absorption near edge structure (XANES) and the extended X-ray absorption fine structure (EXAFS) data obtained from the solution show remarkable differences in their TEY and XRF signals. The differences directly indicate variations in Eu<sup>3+</sup> coordination environments near air-water interfaces compared to the bulk solutions. Simultaneous surface and bulk sensitivities, low volume requirements (less than 1 ml) of solutions, straight forward and quick alignment procedures of the set-up make it attractive and distinct from conventional way of collecting X-ray absorption measurements from solutions. This work and the use of the Advanced Photon Source, a U. S. Department of Energy (DOE) Office of Science User Facility at Argonne National Laboratory, is based upon work supported by the U. S. DOE, Office of Science, Office of Basic Energy Science, Division of Chemical Sciences, Biosciences and Geosciences, under contract No DE-AC02-06CH11357.

Inverted pendant drop set-up for X-ray absorption spectroscopy of electrolyte solutions and their surfaces

249th National Meeting (2015)

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