Investigations on sol–gel process and structural characterization of SiO2-P2O5 powders

Sava, Bogdan Alexandru; Elisa, M.; Vasiliu, Ileana Cristina; Nastase, F.; Simon, S.

doi:10.1016/j.jnoncrysol.2012.07.016

Cited by 14 publications

(4 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Already upon addition of small amounts of P 2 O 5 the liquidus temperature of vitreous SiO 2 is lowered drastically, and similarly dramatic changes are observed for the viscosity and the glass transition temperatures . Structural studies of binary (SiO 2 ) 100‑ x (P 2 O 5 ) x (0 ≤ x ≤ 35) glasses, prepared from either melts − or sol–gel routes , or by chemical vapor deposition − have been conducted by Raman, EXAFS, and solid state NMR. Results have suggested that these glasses are fully polymerized, consisting of randomly interconnected P (3) and Si (4) units.…”

Section: Introductionmentioning

confidence: 99%

Structure of P₂O₅–SiO₂ Pure Network Former Glasses Studied by Solid State NMR Spectroscopy

2018

View full text Add to dashboard Cite

The structure of binary (SiO 2 ) 100-x −(P 2 O 5 ) x glasses has been investigated by Raman scattering, 29 Si and 31 P magic angle spinning (MAS) as well as static 31 P NMR spectroscopy. 29 Si chemical shift trends reflect the successive replacement of Si−O−Si by Si−O−P linkages as the compositional parameter x is increased. While 31 P MAS NMR does not resolve separate phosphate species, the static 31 P NMR lineshapes were successfully simulated by considering the effect of uncorrelated distribution functions of the chemical shift tensor components upon the line shape. On the basis of these simulations, which were also found to be consistent with the experimental 31 P MAS NMR spectra, two distinct sites can be resolved: a dominant site characterized by an axially symmetric chemical shift tensor, assigned to P (3) units, and (only in the case of the x = 25 and 30 glasses) a Gaussian component reflecting phosphate species interacting with fiveand six-coordinated silicon species. For 0 ≤ x < 25, the decrease in average coordination number may provide the structural explanation for the strong decrease in the glass transition and liquidus temperatures over this composition range, whereas the subsequent increase in T g at higher P 2 O 5 contents is correlated with the appearance of the higher-coordinated silicon species. While these higher-coordinated silicon species occur within separate microdomains, 31 P spin echo decay spectroscopy suggests that the majority of P atoms tend to be randomly distributed in space, consistent with a statistical P−O−P, Si−O−P, and Si−O−Si connectivity distribution.

show abstract

Section: Introductionmentioning

confidence: 99%

Structure of P₂O₅–SiO₂ Pure Network Former Glasses Studied by Solid State NMR Spectroscopy

2018

View full text Add to dashboard Cite

show abstract

“…In good agreement with these results, 11 B, 29 Si, and 29 Si{ 11 B} double resonance NMR studies have shown that the maximum number of Si−O−B linkages per Si (4) species is limited to two, suggesting a phase separation tendency at high B 2 O 3 contents. 12 Likewise, the structure of binary SiO 2 −P 2 O 5 glasses, prepared from either melts, 13−17 sol−gel routes, 18,19 or chemical vapor deposition, 20−22 has been studied in detail, suggesting the absence of phase separation and the formation of P−O−Si linkages in the silica-rich region.…”

Section: ■ Introductionmentioning

confidence: 99%

The Structure of Borophosphosilicate Pure Network Former Glasses Studied by Multinuclear NMR Spectroscopy

et al. 2017

View full text Add to dashboard Cite

New mixed network glasses along the composition line xB2O3–(30 – x)P2O5–70SiO2 have been prepared and characterized in terms of their chemical composition, viscosity, and characteristic temperatures. The physical properties have been correlated with structural information, obtained from Raman spectroscopy and advanced 11B, 29Si, and 31P single and double resonance solid state NMR studies. Both the macroscopic and structural properties show nonlinear changes as a function of composition, with maximal values of the viscometric glass transition temperature near 12–13 mol % B2O3. The structure of phosphorus-rich glasses is dominated by tetrahedral B(4) units linked to three to four phosphorus species and multiple phosphorus environments, including P(3) (branching phosphate) groups linked to silicon, and P(4) units forming B–O–P linkages as in boron phosphate, BPO4 (superscripts denote the number of bridging oxygen species). In the boron-rich region, the phosphorus species are exclusively present as P(4) groups and the boron atoms present in excess of a B/P ratio of unity are present in the form of three-coordinated B(3) units forming both B–O–B and B–O–Si linkages. While these results document a strong mutual affinity of the boron oxide and phosphorus oxide components, the species concentrations and numbers of B–O–P linkages fall consistently below those numbers expected from a clustering scenario maximizing the number of such connectivities, indicating the absence of macroscopic phase separation. Important differences relative to the previously studied system xAl2O3–(30 – x)P2O5–70SiO2 are discussed.

show abstract

“…For the PO 4 tetrahedra with bridging oxygen, the peak shifts to the high magnetic field side. 16) From these spectra, a peak at around 0 ppm still exists, which may be derived from isolated phosphate. That is, most of the phosphate did not form the bond.…”

Section: Preparation Of Mps-phosphate Hybridsmentioning

confidence: 94%

“…MCM-41 contains homogeneous pores of 210 nm in diameter and specific surface areas above 1000 m 2 /g. 5)7) MCM-41 can be synthesized by a solgel method using cetyltrimethylammonium bromide [CTAB, C 16 H 33 N(CH 3 ) 3 Br] as a template. The silica wall of MPS is amorphous at the atomic level, but it has a crystal structure at the meso scale.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of mesoporous silica-phosphate hybrids and their adsorption competency for rare earth metal cations

Okabe

Mochizuki

Takei

et al. 2017

J. Ceram. Soc. Japan

View full text Add to dashboard Cite

Mesoporous silica-phosphate hybrids were successfully prepared by three processes: hybridization post synthesis by H 3 PO 4 , hybridizations during synthesis by Na 2 HPO 4 and by PO(OC 2 H 5 ). X-ray diffraction patterns confirm that the hexagonal pore structure was maintained after the hybridization process. The maximum phosphate amount was 2.9 mol % in the sample prepared by hybridization during synthesis from Na 2 SiO 3 and PO(OC 2 H 5 ) 3 . The specific surface area showed a large value of approximately 1000 m 2 /g despite the hybridization. The SiOP bonds were confirmed by nuclear magnetic resonance and X-ray photoelectron spectroscopy. The maximum adsorption amount of rare earth metal cations into the hybrid was approximately 70% of the initial concentration (50 mg/L) for each rare earth metal cation in coexistence with 13 rare earth metal cations.

show abstract

Investigations on sol–gel process and structural characterization of SiO2-P2O5 powders

Cited by 14 publications

References 30 publications

Structure of P₂O₅–SiO₂ Pure Network Former Glasses Studied by Solid State NMR Spectroscopy

Structure of P₂O₅–SiO₂ Pure Network Former Glasses Studied by Solid State NMR Spectroscopy

The Structure of Borophosphosilicate Pure Network Former Glasses Studied by Multinuclear NMR Spectroscopy

Synthesis of mesoporous silica-phosphate hybrids and their adsorption competency for rare earth metal cations

Contact Info

Product

Resources

About

Investigations on sol–gel process and structural characterization of SiO2-P2O5 powders

Cited by 14 publications

References 30 publications

Structure of P2O5–SiO2 Pure Network Former Glasses Studied by Solid State NMR Spectroscopy

Structure of P2O5–SiO2 Pure Network Former Glasses Studied by Solid State NMR Spectroscopy

The Structure of Borophosphosilicate Pure Network Former Glasses Studied by Multinuclear NMR Spectroscopy

Synthesis of mesoporous silica-phosphate hybrids and their adsorption competency for rare earth metal cations

Contact Info

Product

Resources

About

Structure of P₂O₅–SiO₂ Pure Network Former Glasses Studied by Solid State NMR Spectroscopy

Structure of P₂O₅–SiO₂ Pure Network Former Glasses Studied by Solid State NMR Spectroscopy