TY - JOUR
T1 - Evidence of Formation of Monolayer Hydrated Salts in Nanopores
AU - Zhao, Wenhui
AU - Xu, Wen Wu
AU - Jiang, Jian
AU - Zhao, Xiaorong
AU - Duan, Xiangmei
AU - Sun, Yunxiang
AU - Francisco, Joseph S.
AU - Zeng, Xiao Cheng
N1 - Funding Information:
W.Z. was supported by the National Natural Science Foundation of China (NSFC, Grant no. 21503205) and Zhejiang Provincial Natural Science Foundation of China (LY18B030003); Y.S. was supported by the NSFC (11904189), W.W.X. by the NFSC (11974195), and X.D. by the NFSC (11874033). W.Z., W.W.X., and Y.S. acknowledge the Supercomputer Center of NBU. J.J. and X.C.Z. acknowledge the computational supporting from University of Nebraska Holland Computing Center. X.C.Z. also acknowledges the support by Hong Kong Global STEM Professorship Scheme.
Publisher Copyright:
© 2022 American Chemical Society. All rights reserved.
PY - 2022/10/19
Y1 - 2022/10/19
N2 - Despite much effort being devoted to the study of ionic aqueous solutions at the nanoscale, our fundamental understanding of the microscopic kinetic and thermodynamic behaviors in these systems remains largely incomplete. Herein, we reported the first 10 μs molecular dynamics simulation, providing evidence of the spontaneous formation of monolayer hexagonal honeycomb hydrated salts of XCl2·6H2O (X = Ba, Sr, Ca, and Mg) from electrolyte aqueous solutions confined in an angstrom-scale slit under ambient conditions. By using both the classical molecular dynamics simulations and the first-principles Born-Oppenheimer molecular dynamics simulations, we further demonstrated that the hydrated salts were stable not only at ambient temperature but also at elevated temperatures. This phenomenon of formation of hydrated salt in water is contrary to the conventional view. The free energy calculations and dehydration analyses indicated that the spontaneous formation of hydrated salts can be attributed to the interplay between ion hydration and Coulombic attractions in the highly confined water. In addition to providing molecular-level insights into the novel behavior of ionic aqueous solutions at the nanoscale, our findings may have implications for the future exploration of potential existence of water molecules in the saline deposits on hot planets.
AB - Despite much effort being devoted to the study of ionic aqueous solutions at the nanoscale, our fundamental understanding of the microscopic kinetic and thermodynamic behaviors in these systems remains largely incomplete. Herein, we reported the first 10 μs molecular dynamics simulation, providing evidence of the spontaneous formation of monolayer hexagonal honeycomb hydrated salts of XCl2·6H2O (X = Ba, Sr, Ca, and Mg) from electrolyte aqueous solutions confined in an angstrom-scale slit under ambient conditions. By using both the classical molecular dynamics simulations and the first-principles Born-Oppenheimer molecular dynamics simulations, we further demonstrated that the hydrated salts were stable not only at ambient temperature but also at elevated temperatures. This phenomenon of formation of hydrated salt in water is contrary to the conventional view. The free energy calculations and dehydration analyses indicated that the spontaneous formation of hydrated salts can be attributed to the interplay between ion hydration and Coulombic attractions in the highly confined water. In addition to providing molecular-level insights into the novel behavior of ionic aqueous solutions at the nanoscale, our findings may have implications for the future exploration of potential existence of water molecules in the saline deposits on hot planets.
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U2 - 10.1021/jacs.2c07372
DO - 10.1021/jacs.2c07372
M3 - Article
C2 - 36197785
AN - SCOPUS:85139498869
SN - 0002-7863
VL - 144
SP - 18976
EP - 18985
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 41
ER -