Nmr Characterization of the Chemical Homogeneity in Sol-Gel Derived Siloxane-Silica Materials

1996 ◽  
Vol 435 ◽  
Author(s):  
Florence Babonneau ◽  
Virginie Gualandris ◽  
Monique Pauthe
Keyword(s):  
Sol Gel ◽  
Chemical Homogeneity ◽  
Nmr Characterization ◽  
Silica Materials

scholarly journals Sol-Gel Synthesis and Characterization of Cubic Bismuth Zinc Niobium Oxide Nanopowders

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Ganchimeg Perenlei ◽  
Peter C. Talbot ◽  
Wayde N. Martens
Keyword(s):  
Niobium Oxide ◽  
Sol Gel ◽  
Atomic Ratio ◽  
X Ray Diffraction ◽  
Metal Acetate ◽  
Chemical Homogeneity ◽  
Liquid Suspension ◽  
Crystallite Sizes ◽  
Sol Gel Synthesis

Bismuth zinc niobium oxide (BZN) was successfully synthesized by a diol-based sol-gel reaction utilizing metal acetate and alkoxide precursors. Thermal analysis of a liquid suspension of precursors suggests that the majority of organic precursors decompose at temperatures up to 150°C, and organic free powders form above 350°C. The experimental results indicate that a homogeneous gel is obtained at about 200°C and then converts to a mixture of intermediate oxides at 350–400°C. Finally, single-phased BZN powders are obtained between 500 and 900°C. The degree of chemical homogeneity as determined by X-ray diffraction and EDS mapping is consistent throughout the samples. Elemental analysis indicates that the atomic ratio of metals closely matches a Bi1.5ZnNb1.5O7composition. Crystallite sizes of the BZN powders calculated from the Scherrer equation are about 33–98 nm for the samples prepared at 500–700°C, respectively. The particle and crystallite sizes increase with increased sintering temperature. The estimated band gap of the BZN nanopowders from optical analysis is about 2.60–2.75 eV at 500-600°C. The observed phase formations and measured results in this study were compared with those of previous reports.

Solid-State NMR Characterization of Phenylbenzimidazolesulfonic Acid Coencapsulated with Cetyltrimethylammonium in Mesoporous Silica Materials

2009 ◽  
Vol 114 (2) ◽  
pp. 752-759 ◽  
Author(s):  
Raphaël Bongur ◽  
Nicolas Marx ◽  
Claire Marichal ◽  
Bénédicte Lebeau ◽  
Philippe Guarilloff
Keyword(s):  
Solid State ◽  
Mesoporous Silica ◽  
Solid State Nmr ◽  
Nmr Characterization ◽  
Silica Materials ◽  
Mesoporous Silica Materials

Characterization of Boria−Alumina Mixed Oxides Prepared by a Sol−Gel Method. 1. NMR Characterization of the Xerogels

2005 ◽  
Vol 17 (9) ◽  
pp. 2361-2368 ◽  
Author(s):  
Franck Dumeignil ◽  
Monique Rigole ◽  
Michel Guelton ◽  
Jean Grimblot
Keyword(s):  
Mixed Oxides ◽  
Sol Gel ◽  
Gel Method ◽  
Sol Gel Method ◽  
Nmr Characterization

29Si, 17O Liquid NMR and 29Si CP-MAS NMR Characterization of Siloxane-Oxide Materials, [(CH3)2SiO/TiO2, (CH3)2SiO/ZrO2]

1994 ◽  
Vol 346 ◽  
Author(s):  
Florence Babonneau
Keyword(s):  
Sol Gel ◽  
Mas Nmr ◽  
Model Systems ◽  
Oxide Materials ◽  
Whole Process ◽  
New Family ◽  
Nmr Characterization ◽  
Potential Applications ◽  
Suitable Technique

ABSTRACTSol-gel derived siloxane oxide materials are an entirely new family of hybrid systems at the frontier between silicones and glasses or ceramics, with a large variety of potential applications. Better control of the chemistry involved in their preparation should lead to an improvement in their properties, and this requires an investigation of the whole process, from the solution to the final materials. Nuclear Magnetic Resonance is a very suitable technique for this purpose, and this paper will give some illustrations on model systems (CH3)2SiO/TiO2, (CH3)2SiO/ZrO2, prepared from dimethyldiethoxysilane and titanium or zirconium alkoxides. It will be focused mainly on the use of 170 solution NMR which clearly shows the formation of Si-O-Ti or Si-O-Zr bonds, but also their disappearance during the aging process. 29Si MAS-NMR spectra of dried gels confirm that the difunctional units are mainly in polydimethylsiloxane chains, and that the system is phase separated. However, the use of cross-polarization techniques involving lK and 29Si nuclei will allow the detection of small number of units in a more constrained environment, certainly close to oxide-based particles.

NMR characterization of the role of silane precursors on the catalytic activity of sol–gel encapsulated lipase

2006 ◽  
Vol 352 (32-35) ◽  
pp. 3469-3477 ◽  
Author(s):  
Cleide M.F. Soares ◽  
Onélia A.A. dos Santos ◽  
Heizir F. de Castro ◽  
Juliana E. Itako ◽  
Flavio F. de Moraes ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Sol Gel ◽  
Nmr Characterization

X-Ray Diffraction, FTIR, and NMR Characterization of Sol–Gel Alumina Doped with Lanthanum and Cerium

1997 ◽  
Vol 128 (2) ◽  
pp. 161-168 ◽  
Author(s):  
A. Vázquez ◽  
T. López ◽  
R. Gómez ◽  
Bokhimi ◽  
A. Morales ◽  
...  
Keyword(s):  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nmr Characterization
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