Bonding, structural and thermodynamic analysis of dissociative adsorption of H3O+ ion onto calcite (101¯4) surface: CPMD and DFT calculations

We used density functional theory (DFT) and Car-Parrinello molecular dynamics (CPMD) simulation to investigate the adsorption and bond formation of hydronium ion (H 3 O + ) onto a ( 10 1 ¯ 4 ) calcite surface. For surface coverage of 25% to 100%, the nature of H 3 O + interaction was explored throug...

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Bibliographic Details
Published in:Journal of molecular modeling 2017-11, Vol.23 (12), p.1-14
Main Authors: Ghatee, Mohammad Hadi, Koleini, Mohammad Mehdi
Format: Article
Language:English
Subjects:
Adsorbates
Adsorption
Calcite
Characterization and Evaluation of Materials
Chemical bonds
Chemistry
Chemistry and Materials Science
Computer Appl. in Life Sciences
Computer Applications in Chemistry
Correlation analysis
Density functional theory
Electron density
Free energy
Molecular dynamics
Molecular Medicine
Original Paper
Protonation
Surface chemistry
Theoretical and Computational Chemistry
Water chemistry
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Summary:We used density functional theory (DFT) and Car-Parrinello molecular dynamics (CPMD) simulation to investigate the adsorption and bond formation of hydronium ion (H 3 O + ) onto a ( 10 1 ¯ 4 ) calcite surface. For surface coverage of 25% to 100%, the nature of H 3 O + interaction was explored through electron density and energetics in the context of bond critical points. The adsorbate–adsorbent structure was studied by simulation of pair correlation function. The results revealed that dissociation into water molecule(s) and proton(s) complements H 3 O + ion(s) adsorbtion. The H 2 O molecule adsorbs onto the surface via its O atom, and interacts with surface calcium in a closed-shell mode; the H + ion makes a covalent bond to the surface oxygen while maintaining H-bonding with water. Adsorption energies were diminished by 70–90 kJ mol −1 when O bridge -bonded H + ions transferred to the O terminal manually. While dissociative adsorption of H 3 O + ions is spontaneous at all surface coverages tested, the free energy was lowest at 75% coverage. Also, protonation of a completely pre-hydrated calcite surface leads to stronger interaction of water molecules with the surface. This unique outlook on hydrating calcite provides specific insights into biomineralization of this mineral, and helps depict further pH consequences in the field of biomaterial adsorption. Graphical abstract Dissociative adsorption of hydronium ion onto the surface of calcite
ISSN:1610-2940
0948-5023
DOI:10.1007/s00894-017-3499-1