Redox Buffering and Corrosion in Molten Chloride Salts Dictated by Chlorobasicity.
7 affiliations
- 1Department of Nuclear Engineering and Engineering Physics, University of Wisconsin-Madison, Madison, Wisconsin53706, United States.
- 2Chemistry Division, Brookhaven National Laboratory, Upton, New York11973, United States.
- 3Department of Chemistry, University of Tennessee-Knoxville, Knoxville, Tennessee37996, United States.
- 4Department of Material Science and Chemical Engineering, Stony Brook University, Stony Brook, New York11794, United States.
- 5Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee37830, United States.
- 66IJCLab, CNRS/IN2P3, Université Paris-Saclay, 91405Orsay, France.
- 7National Synchrotron Light Source-II, Brookhaven National Laboratory, Upton, New York11973, United States.
Abstract
This study establishes an in situ synchrotron approach to directly link molten-salt chemistry, redox-buffer speciation, and alloy corrosion in chloride melts. Using a first-of-its-kind corrosion cell coupled to simultaneous X-ray absorption spectroscopy (XAS) and X-ray fluorescence (XRF), we monitor europium redox-buffer speciation and chromium dissolution during corrosion of Ni-20Cr in molten LiCl-KCl and KCl-MgCl2 salts. To build a mechanistic framework, we combine UV-vis optical basicity measurements, in situ electrochemistry, and molecular dynamics simulations to quantify how salt chlorobasicity reshapes europium solvation and shifts the Eu(III)/Eu(II) apparent potential. Increasing MgCl2 content drives the apparent potential of the Eu(III)/Eu(II) couple +0.49 V relative to LiCl-KCl and stabilizes Eu(II)-compatible solvation environments. In situ, time-resolved Eu L3-edge XANES reveals progressive Eu(III) reduction in KCl-MgCl2 melts, while Eu(III) remains predominantly stable in LiCl-KCl. This behavior is consistent with a chlorobasicity-activated reaction with boron nitride (BN) cell components. In less chlorobasic melts, salt redox chemistry enables BN chlorination, allowing BN to act as a sacrificial reductant and chlorinating agent that promotes Eu(III) to Eu(II) conversion, whereas this pathway is not thermodynamically favored in LiCl-KCl. During active corrosion of Ni-20Cr, coupled Eu XANES and Cr XRF measurements show concurrent Eu(III) to Eu(II) conversion and Cr dissolution, confirming that Eu(III) is the oxidizing species driving chromium oxidation. Together, these results demonstrate that chlorobasicity is a central control variable for redox-buffer speciation and corrosion thermodynamics, and more broadly that chlorobasicity can enable or suppress reactive pathways with structural materials in high-temperature molten salts.
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BibTeX
@article{buttice2026redox,
title = {{Redox Buffering and Corrosion in Molten Chloride Salts Dictated by Chlorobasicity.}},
author = {Kailee Buttice and Bonita Goh and Matthew S Emerson and Ellie Kim and Yuxiang Peng and Bobby Layne and Isabelle Baggenstoss and Shea McCarthy and George Vukovic and Changkyu Kim and Jagadeesh Sure and Sheng Dai and Céline Cannes and Sylvie Delpech and James F Wishart and Santanu Roy and Yu-Chen Karen Chen-Wiegart and Adrien Couet},
journal = {Journal of the American Chemical Society},
year = {2026},
month = oct,
doi = {10.1021/jacs.6c11331},
url = {https://europepmc.org/article/MED/42954569},
note = {CC BY},
}
RIS
TY - JOUR
TI - Redox Buffering and Corrosion in Molten Chloride Salts Dictated by Chlorobasicity.
AU - Kailee Buttice
AU - Bonita Goh
AU - Matthew S Emerson
AU - Ellie Kim
AU - Yuxiang Peng
AU - Bobby Layne
AU - Isabelle Baggenstoss
AU - Shea McCarthy
AU - George Vukovic
AU - Changkyu Kim
AU - Jagadeesh Sure
AU - Sheng Dai
AU - Céline Cannes
AU - Sylvie Delpech
AU - James F Wishart
AU - Santanu Roy
AU - Yu-Chen Karen Chen-Wiegart
AU - Adrien Couet
PY - 2026
DA - 2026/10/01
JO - Journal of the American Chemical Society
DO - 10.1021/jacs.6c11331
UR - https://europepmc.org/article/MED/42954569
AB - This study establishes an in situ synchrotron approach to directly link molten-salt chemistry, redox-buffer speciation, and alloy corrosion in chloride melts. Using a first-of-its-kind corrosion cell coupled to simultaneous X-ray absorption spectroscopy (XAS) and X-ray fluorescence (XRF), we monitor europium redox-buffer speciation and chromium dissolution during corrosion of Ni-20Cr in molten LiCl-KCl and KCl-MgCl2 salts. To build a mechanistic framework, we combine UV-vis optical basicity measurements, in situ electrochemistry, and molecular dynamics simulations to quantify how salt chlorobasicity reshapes europium solvation and shifts the Eu(III)/Eu(II) apparent potential. Increasing MgCl2 content drives the apparent potential of the Eu(III)/Eu(II) couple +0.49 V relative to LiCl-KCl and stabilizes Eu(II)-compatible solvation environments. In situ, time-resolved Eu L3-edge XANES reveals progressive Eu(III) reduction in KCl-MgCl2 melts, while Eu(III) remains predominantly stable in LiCl-KCl. This behavior is consistent with a chlorobasicity-activated reaction with boron nitride (BN) cell components. In less chlorobasic melts, salt redox chemistry enables BN chlorination, allowing BN to act as a sacrificial reductant and chlorinating agent that promotes Eu(III) to Eu(II) conversion, whereas this pathway is not thermodynamically favored in LiCl-KCl. During active corrosion of Ni-20Cr, coupled Eu XANES and Cr XRF measurements show concurrent Eu(III) to Eu(II) conversion and Cr dissolution, confirming that Eu(III) is the oxidizing species driving chromium oxidation. Together, these results demonstrate that chlorobasicity is a central control variable for redox-buffer speciation and corrosion thermodynamics, and more broadly that chlorobasicity can enable or suppress reactive pathways with structural materials in high-temperature molten salts.
SN - 0002-7863
SN - 1520-5126
ER -