Dissociative chemisorption of water onto silica surfaces and formation of hydronium ions

T. S. Mahadevan, Steve Garofalini

Research output: Contribution to journalArticle

107 Citations (Scopus)

Abstract

Molecular dynamics (MD) computer simulation of the adsorption of water molecules onto the vitreous silica surface was performed using a new dissociative water potential.58 The simulations showed dissociative chemisorption of water molecules onto the silica surface, forming silanol (SiOH) groups at a concentration consistent with experimental data. Water penetration and silanol formation ∼7-8 Å below the outermost oxygen are observed. Because of the dissociative nature of the water potential, formation of hydronium ions is allowed, and, whereas seldom observed in the simulations of bulk water, hydronium ions are formed during the reactions causing the formation of the silanols. The formation of hydronium ions has also been observed in ab initio calculations of water adsorption onto silica surfaces. The time evolution of the reactions involving hydronium ions in our MD simulations is similar to that observed in first-principles MD calculations. Hydronium ions offer a mechanism by which initially singly coordinated terminal oxygen (Si-O -) receives a H+ ion from a relatively distant chemisorbed H2O molecule via multiple H+ ion transfer, creating two SiOH sites.

Original languageEnglish
Pages (from-to)1507-1515
Number of pages9
JournalJournal of Physical Chemistry C
Volume112
Issue number5
DOIs
Publication statusPublished - Feb 7 2008

Fingerprint

hydronium ions
Chemisorption
Silicon Dioxide
chemisorption
Silica
silicon dioxide
Water
Ions
water
Molecular dynamics
molecular dynamics
Molecules
Oxygen
Adsorption
molecules
adsorption
simulation
Computer simulation
oxygen
Fused silica

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Electronic, Optical and Magnetic Materials
  • Surfaces, Coatings and Films
  • Energy(all)

Cite this

Dissociative chemisorption of water onto silica surfaces and formation of hydronium ions. / Mahadevan, T. S.; Garofalini, Steve.

In: Journal of Physical Chemistry C, Vol. 112, No. 5, 07.02.2008, p. 1507-1515.

Research output: Contribution to journalArticle

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