Catalysis of the Silica Sol−Gel Process by Divalent Transition Metal Bis(acetylacetonate) Complexes

2000 ◽  
Vol 39 (5) ◽  
pp. 899-905 ◽  
Author(s):  
Elizabeth I. Mayo ◽  
Duke D. Pooré ◽  
A. E. Stiegman
Keyword(s):  
Transition Metal ◽  
Sol Gel ◽  
Silica Sol ◽  
Sol Gel Process

Introduction of Organic Moieties into Transition-Metal Oxide Matrices via Phosphonate Groups

1998 ◽  
Vol 519 ◽  
Author(s):  
P.H. Mutin ◽  
C. Delenne ◽  
D. Medoukali ◽  
R. Corriu ◽  
A. Vioux
Keyword(s):  
Transition Metal ◽  
Metal Oxide ◽  
Phosphonic Acid ◽  
Sol Gel ◽  
Transition Metal Oxide ◽  
Metal Alkoxide ◽  
Hydrolytic Condensation ◽  
Metal Phosphonates ◽  
Or Groups ◽  
Sol Gel Process

AbstractTransition metal oxide / phenylphosphonate hybrids with M/P ratios ranging from 1 to 5, (M= Ti, Zr) and metal phosphonates (M/P = 0.5) have been prepared by a sol-gel process involving in a first step the non-hydrolytic condensation between metal alkoxide and phosphonic acid leading to M-O-P bonds, followed by the hydrolysis-condensation of the remaining M-OR groups. The composition, texture and structure of the materials were investigated using EDX, TGA, XRD, IR and 31P NMR.

scholarly journals Tuning the structure and the mechanical properties of epoxy–silica sol–gel hybrid materials

RSC Advances ◽  
2016 ◽  
Vol 6 (13) ◽  
pp. 10736-10742 ◽  
Author(s):  
Berta Domènech ◽  
Ignasi Mata ◽  
Elies Molins
Keyword(s):  
Mechanical Properties ◽  
Porous Material ◽  
Hybrid Materials ◽  
Sol Gel ◽  
Silica Sol ◽  
One Pot ◽  
Sol Gel Process

A new epoxy–silica porous material prepared via one-pot sol–gel process. Mechanical properties can be continuously tuned by modifying reactant proportions.

Study on Preparation and Hydrophobicity of MTES Derived Silica Sol and Gel

2012 ◽  
Vol 535-537 ◽  
pp. 2563-2566 ◽  
Author(s):  
Yu Ma ◽  
Hye Ryeon Lee ◽  
Toshinori Tsuru
Keyword(s):  
Reaction Rate ◽  
Sol Gel ◽  
Phase Segregation ◽  
Silica Sol ◽  
Molar Ratio ◽  
Modified Silica ◽  
Sol Gel Process ◽  
One Step ◽  
Inorganic Precursors

The synthesis of hydrophobic sol by one-step sol-gel process ammonia catalyzed was investigated. The water molar ratio and catalyst molar ratio were discussed to prevent phase segregation during the hydrolysis and co-condensation of the organic and inorganic precursors. The reactant system with water molar ratio 70 could make the reaction rate of MTES slightly less than that of TEOS, so that the hydrolysis - condensation – gelling reaction with MTES and TEOS as co-precursors could be synchronously. With the increase of the MTES/TEOS molar ratio, the reaction rate of the silica sol preparation decreased, the hydrophobicity of the sol and gel increased as the molar ratio MTES/TEOS change from 0.5~4. But the hydrophobicity of the methyl-modified silica sol and gel prepared with pure MTES in the sol-gel process were slightly lower than that of the methyl-modified silica sol and gel prepared with MTES and TEOS as co-precursors.

Rietveld refinement of transition metal doped ZnO

2008 ◽  
Vol 23 (S1) ◽  
pp. S36-S41 ◽  
Author(s):  
D. A. A. Santos ◽  
A. D. P. Rocha ◽  
M. A. Macêdo
Keyword(s):  
Transition Metal ◽  
Rietveld Refinement ◽  
Sol Gel ◽  
Hexagonal Wurtzite Structure ◽  
X Ray Diffraction ◽  
Ionic Radii ◽  
X Ray ◽  
Sol Gel Process ◽  
Doped Zno ◽  
Metal Doped

Nanocrystals of Zn1−xMxO (M=Mn, Co, or Ni) were grown using proteic sol-gel process, and the crystalline phases were identified by X-ray diffraction and Rietveld refinement. The nanocrystals have hexagonal wurtzite structure, with space group P63mc. The insertion of Mn2+ in the place of Zn2+ provoked an increase in the size of the nanocrystals, and the insertion of Co2+ or Ni2+ caused a reduction in the sizes of the nanocrystals, as compared to pure ZnO. This occurred because these three transition metals have very different ionic radii (Co2+=0.58 A˚, Mn2+=0.66 A˚, Ni2+=0.55 A˚, and Zn2+=0.60 A˚).

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