A molecular dynamics framework to explore the structure and dynamics of layered double hydroxides
authors Perez-Sanchez, G; Galvao, TLP; Tedim, J; Gomes, JRB
nationality International
journal APPLIED CLAY SCIENCE
author keywords Density functional theory; Molecular dynamics; Force field; CLAYFF; LDH
keywords HYDROTALCITE-LIKE COMPOUNDS; TOTAL-ENERGY CALCULATIONS; X-RAY-DIFFRACTION; WAVE BASIS-SET; AB-INITIO; INTERLAYER ANIONS; CRYSTAL-CHEMISTRY; FORCE-FIELD; INTERCALATION; SIMULATIONS
abstract It is presented a straightforward procedure based on the CLAYFF force field to perform molecular dynamics (MD) computer simulations with the GROMACS open source package of layered double hydroxide (LDH) materials with different intercalated anions. This procedure enables running very long simulations of systems where all atomic positions are allowed to move freely, while maintaining the integrity of the LDH structure intact. Therefore, it has the potential to model different important applications of LDH involving ion-exchange and interlayer equilibrium processes in diverse areas as drug delivery, water purification, and corrosion protection. The magnesium-aluminium based LDH with a metallic ratio 2:1 (Mg2Al) was chosen to validate our computer simulation framework, because of the comprehensive experimental and computational studies reported in the literature devoted to the understanding of the structure of Mg2Al LDH. Potential parameters from the literature were used to model the Mg2Al LDH with different intercalated anions using a new set of atomic point charges calculated with the DDEC6 formalism. Once the model was validated through careful comparisons of the simulated and experimental structures, the procedure was adapted to the Zn2Al LDH materials. Lennard-Jones parameters had to be developed for zinc (II) cations and calibrated using the experimental structural data found in the literature for Zn2Al LDH and the height of the galleries determined experimentally in this work for Zn2Al with intercalated nitrate anions. The consistency of the model is proved by carrying out MD simulations to reproduce in the computer the typical experimental conditions in which the Zn2Al LDH is immersed in a sodium chloride water solution to act as a nanotrap for aggressive anions in corrosion protection applications. The LDH structure is maintained in the MD simulation in which the LDH is free to move alongside the solution and allowing a natural anion exchange between the LDH and the solution as well as dehydration/hydration of the basal space.
publisher ELSEVIER SCIENCE BV
issn 0169-1317
year published 2018
volume 163
beginning page 164
ending page 177
digital object identifier (doi) 10.1016/j.clay.2018.06.037
web of science category Chemistry, Physical; Materials Science, Multidisciplinary; Mineralogy
subject category Chemistry; Materials Science; Mineralogy
unique article identifier WOS:000442067900018
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journal analysis (jcr 2017):
journal impact factor 3.641
5 year journal impact factor 3.616
category normalized journal impact factor percentile 75.255
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