Abstract
In this paper, a vacuum compatible microfluidic device, system for analysis at the liquid vacuum interface, is integrated to hard x-ray absorption spectroscopy to obtain the local structure of K3[Fe(CN)6] in aqueous solutions with three concentrations of 0.5 M, 0.05 M, and 0.005 M. The solutions were sealed in a microchannel 500 μm wide and 300 μm deep in a portable microfluidic device. The Fe K-edge x-ray absorption spectra indicate a presence of Fe(III) in the complex in water, with an octahedral geometry coordinated with 6 C atoms in the first shell with a distance of ∼1.92 Å and 6 N atoms in the second shell with a distance of ∼3.10 Å. Varying the concentration has no observable influence on the structure of K3[Fe(CN)6]. Our results demonstrate the feasibility of using microfluidic based liquid cells in large synchrotron facilities. Using portable microfludic reactors provides a viable approach to enable multifaceted measurements of liquids in the future.
Original language | English |
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Article number | 18LT01 |
Journal | Journal of Physics Condensed Matter |
Volume | 30 |
Issue number | 18 |
DOIs | |
State | Published - Apr 11 2018 |
Externally published | Yes |
Funding
We are grateful for the support from the Pacific Northwest National Laboratory (PNNL) Materials Synthesis and Simulation across Scales Initiative (MS3). The efforts on synchrotron x-ray measurements by Wei Zhang and Feng Wang were supported by the US Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy under the Advanced Battery Materials Research program. We thank Bingwen Liu and Xin Hua for sample and device preparation and Dr Syed Khalid for his assistance in experimental setup in the X18A beamline. We acknowledge helpful comments and suggestions regarding XAFS analysis from John Fulton. The use of the National Synchrotron Light Source was supported by the US DOE, Office of Science, Basic Energy Sciences, under Contract No. DE-SC0012704. PNNL is operated for DOE by Battelle.
Keywords
- SALVI
- aqueous solution
- solvation structure
- x-ray absorption spectroscopy