Connections between the Speciation and Solubility of Ni(II) and Co(II) in Molten ZnCl2

Simerjeet K. Gill, Jiahao Huang, Julia Mausz, Ruchi Gakhar, Santanu Roy, Fernando Vila, Mehmet Topsakal, William C. Phillips, Bobby Layne, Shannon Mahurin, Phillip Halstenberg, Sheng Dai, James F. Wishart, Vyacheslav S. Bryantsev, Anatoly I. Frenkel

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

Understanding the factors that control solubility and speciation of metal ions in molten salts is key for their successful use in molten salt reactors and electrorefining. Here, we employ X-ray and optical absorption spectroscopies and molecular dynamics simulations to investigate the coordination environment of Ni(II) in molten ZnCl2, where it is poorly soluble, and contrast it with highly soluble Co(II) over a wide temperature range. In solid NiCl2, the Ni ion is octahedrally coordinated, whereas the ZnCl2 host matrix favors tetrahedral coordination. Our experimental and computational results show that the coordination environment of Ni(II) in ZnCl2 is disordered among tetra- A nd pentacoordinate states. In contrast, the local structure of dissolved Co(II) is tetrahedral and commensurate with the ZnCl2 host's structure.

Original languageEnglish
Pages (from-to)1253-1258
Number of pages6
JournalJournal of Physical Chemistry B
Volume124
Issue number7
DOIs
StatePublished - Feb 20 2020

Funding

The authors would like to thank Dr. Klaus Attenkofer for useful discussions on experimental design and help with XAS data collection and Dr. Eli Stavitski for help with XAS data collection. This work was supported as part of the Molten Salts in Extreme Environments Energy Frontier Research Center, funded by the U.S. Department of Energy, Office of Science. BNL, INL, and ORNL are operated under DOE contracts DE-SC0012704, DE-AC07-05ID14517, and DE-AC05-00OR22725, respectively. This research used resources of the ISS (8-ID) and QAS (7-BM) beamlines at the National Synchrotron Light Source II operated by the Brookhaven National Laboratory under Contract No. DE-SC0012704, a U.S. Department of Energy (DOE), Office of Science User Facility. This research used resources of the Oak Ridge Leadership Computing Facility at the Oak Ridge National Laboratory, supported by the Office of Science of the U.S. Department of Energy under contract No. DE-AC05-00OR22725. This work used resources supported, in part, by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Science and Engineering Division, Theoretical Condensed Matter Physics Program contract No. DE-FG02-97ER45623, with computational support from the National Energy Research Scientific Computing Center (NERSC), a U.S. Department of Energy, Office of Science User Facility operated under Contract No. DE-AC02-05CH11231.

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