Mechanism of silica dissolution and state of silicic acid in hydrothermal solutions

Mitsyuk, B. M.

doi:10.1007/bf00526030

Cited by 8 publications

(7 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In contrast to exposure to acid, dissolution continues at longer exposure times, albeit with reduced rate, and the intensity of the O Ru O 1s signal remains constant throughout the Scheme 3 Possible reaction mechanism leading to hydroxylation of the silica surface involving a cyclic transition state as proposed in Ref. [38] (upper line) and subsequent steps that lead to oxygen exchange between the film and adsorbed water (lower line) series. The equal relative signal intensity losses of Si and O peaks observed with time of exposure ( Fig.…”

Section: Dissolution Of Sio 2 /Ru In Liquid Environmentsmentioning

confidence: 99%

“…In the presence of additional water molecules, the initial hydroxide attack may also act to activate Si-O bonds in the siloxane bridges to result in water dissociation via a process like the one shown below in Scheme 3. Note that this scheme incorporates a cyclic transition state as proposed by Mitsyuk [38] and added reaction steps (protonation of the :Si-Osite and siloxane bridge reformation) that provide a means of accounting for the 16 O- 18 O isotope exchange between the film and molecular water reported above.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Insights into Silica Bilayer Hydroxylation and Dissolution

et al. 2016

View full text Add to dashboard Cite

Hydroxylation and dissolution of well-structured silica bilayer films grown on a ruthenium single-crystal support (SiO₂/Ru(0001)) was studied by temperature programmed desorption and X-ray photoelectron spectroscopy (XPS). Water desorption signals from SiO₂/Ru(0001) hydroxylated by electron-bombardment of adsorbed ice at 100 K were found to be comparable to those of hydroxylated bulk silica samples and attributed to adsorbed molecular water and silanol groups (vicinal and terminal). Isotopic exchange between ¹⁸O-labeled SiO₂ and ¹⁶O-labeled water suggests the occurrence of dynamic siloxane bond cleavage and re-formation during electron bombardment. Together with the observed strong dependence of hydroxylation activity on ice coverage, which is found to increase with increasing thickness of the ice layer, a hydroxylation mechanism based on the activation of siloxane bonds by water radiolysis products (e.g. hydroxyls) and subsequent water dissociation is proposed. Dissolution rates obtained from the attenuation of Si 2p and O1s XPS signal intensities upon exposure of bilayer SiO₂/ Ru(0001) to alkaline conditions at various temperatures are in agreement with the proposed rate model for bulk silica dissolution by OH^- attack and provide further corroboration of the proposed hydroxylation mechanism

show abstract

Section: Dissolution Of Sio 2 /Ru In Liquid Environmentsmentioning

confidence: 99%

mentioning

confidence: 99%

Insights into Silica Bilayer Hydroxylation and Dissolution

et al. 2016

View full text Add to dashboard Cite

show abstract

“…That these SiO 2 nanoparticle morphologies appear earlier in the presence of HOAc is consistent with the literature: geochemical studies have shown that, e.g., quartz can dissolve in H 2 O in small quantities, 48 and that such dissolution is up to one order of magnitude faster in the presence of (organic) acids. [49][50][51] (iii) Fig. 5C (T r ¼ 250 Cjno HOAc): (1) no thin bers are found at any t r , pointing at HTP being much more rapid at 250 C, which is expected.…”

Section: The Micromorphological Evolution Of Pi(tapb-pma) As a Function Of The Htp The Reaction Parametersmentioning

confidence: 87%

Hydrothermal polymerization of porous aromatic polyimide networks and machine learning-assisted computational morphology evolution interpretation

et al. 2021

View full text Add to dashboard Cite

show abstract

“…It is well known that siloxane bonds are easily cleaved by HF. 42 The reference GPC chromatogram above was prepared using MONC resin to identify peaks in the HFderived tether GPC chromatogram.…”

Section: Characterizationmentioning

confidence: 99%

Network structure–property relationship in UV-cured organic/inorganic hybrid nanocomposites

2011

View full text Add to dashboard Cite

The UV-induced cross-linked network structures of methacryl-oligosiloxane nanoclusters (MONCs) were analyzed with a hydrofluoric acid dissolution derived gel permeation chromatography technique (HF-GPC) to study their network structure-property relationships. With this method the oligosiloxane cores were dissolved in HF and the remaining organic tethers underwent GPC analysis to observe the tether species and characterize the original cross-linked network structures. It was found that the MONC nanocomposites have a highly cross-linked structure, resulting in oligosiloxane cores which are completely isolated by short methacryl chain segments (two-or three-armed methacryl tethers). This structural analysis was found to be consistent with the macroscale properties of MONC nanocomposites when characterized with thermal (TGA) and thermo-mechanical (DMA and TMA) analyses.

show abstract

Mechanism of silica dissolution and state of silicic acid in hydrothermal solutions

Cited by 8 publications

References 7 publications

Insights into Silica Bilayer Hydroxylation and Dissolution

Insights into Silica Bilayer Hydroxylation and Dissolution

Hydrothermal polymerization of porous aromatic polyimide networks and machine learning-assisted computational morphology evolution interpretation

Network structure–property relationship in UV-cured organic/inorganic hybrid nanocomposites

Contact Info

Product

Resources

About