scholarly journals Incorporation of Organic Compound into Silica Matrix by a Sol-Gel Process for NLO Applications

1993 ◽  
Vol 101 (1169) ◽  
pp. 76-77 ◽  
Author(s):  
Yong-Gun SHUL ◽  
Dong-Jo LEE ◽  
Jae-Suk LEE ◽  
Tatsuo WADA
Keyword(s):  
Organic Compound ◽  
Sol Gel ◽  
Silica Matrix ◽  
Sol Gel Process

Leaching Behavior of Edta In A Silica Sol-Gel Matrix

1994 ◽  
Vol 346 ◽  
Author(s):  
Kris S. Oka ◽  
J.D. Mackenzie
Keyword(s):  
Pore Volume ◽  
Sol Gel ◽  
Silica Matrix ◽  
Silica Gels ◽  
Volume Distribution ◽  
Leaching Behavior ◽  
Sol Gel Process ◽  
The Matrix ◽  
Physical Changes ◽  
Hydrolysis Of

ABSTRACTEthylene diamine tetra-acetic acid (EDTA) doped silica gels were made by the sol-gel process for the potential application as a filter for heavy metal ions in wastewater. The behavior of the organic molecule in the matrix was studied by investigating the percentage of EDTA leached out with a variation in the timing of addition of the EDTA molecule into the starting silica gel solution. Leach tests using water as the medium were performed for 2, 12 and 24 hours in order to determine the amount of EDTA trapped in the pores or in the matrix. A minimum amount of EDTA leached from the gels was detected in the samples to which EDTA was added 4 hours after initial hydrolysis of TEOS. This result was correlated to having a greater percentage of pore volume in the range of 15–20 Å, which was further substantiated with density measurements. The physical changes in the silica matrix altering the pore volume distribution were attributed to the addition of the water into which the EDTA molecule was initially dissolved.

Synthesis of tin oxide nanosized crystals embedded in silica matrix through sol–gel process using alkoxide precursors

2009 ◽  
Vol 355 (16-17) ◽  
pp. 951-959 ◽  
Author(s):  
Y.C. Wu ◽  
W. Hamd ◽  
E. Thune ◽  
A. Boulle ◽  
C. Rochas ◽  
...  
Keyword(s):  
Tin Oxide ◽  
Sol Gel ◽  
Silica Matrix ◽  
Sol Gel Process ◽  
Alkoxide Precursors ◽  
Nanosized Crystals

Cobalt ferrite dispersed in a silica matrix prepared by sol–gel process

2004 ◽  
Vol 272-276 ◽  
pp. E1851-E1853 ◽  
Author(s):  
J.B. Silva ◽  
C.F. Diniz ◽  
J.D. Ardinson ◽  
A.I.C. Persiano ◽  
N.D.S. Mohallem
Keyword(s):  
Cobalt Ferrite ◽  
Sol Gel ◽  
Silica Matrix ◽  
Sol Gel Process

Structure and chemistry of Ag‒Cu nanoclusters in a silica matrix by the sol-gel process

1997 ◽  
Vol 76 (4) ◽  
pp. 621-628 ◽  
Author(s):  
M. Catalano ◽  
E. Carlino ◽  
G. De ◽  
L. Tapfer ◽  
F. Gonella ◽  
...  
Keyword(s):  
Sol Gel ◽  
Silica Matrix ◽  
Sol Gel Process ◽  
Cu Nanoclusters

Synthesis and Characterization of Silicon Oxycarbide Derived Nanocomposites Obtained through Ceramic Processing of TEOS/PDMS Preceramic Materials

2011 ◽  
Vol 14 ◽  
pp. 27-38 ◽  
Author(s):  
J.L. Oteo ◽  
M. Alejandra Mazo ◽  
Cristina Palencia ◽  
F. Rubio ◽  
Juan Rubio
Keyword(s):  
Silicon Carbide ◽  
Sol Gel ◽  
Silica Matrix ◽  
Silicon Oxycarbide ◽  
Glassy Matrix ◽  
Ceramic Processing ◽  
Carbon Phase ◽  
Graphite Phase ◽  
Sol Gel Process ◽  
Silicon Oxycarbide Glasses

Bulk silicon oxycarbide derived ceramic nanocomposites have been prepared by the application of the conventional ceramic processing to preceramic materials. Tetraethylortosilicate/ polydimethylsiloxane preceramic materials obtained by sol-gel process were thermally treated and attrition milled to 4 micrometers. Subsequently, the preceramic powders were pyrolized at 1100 °C to obtain silicon oxycarbide powders that were pressed and sintered at 1550 °C up to 16 hours. Silicon oxycarbide glasses obtained at 1100 °C from pyrolysis of preceramic materials consist of a Si-O-C network and a carbon like graphite phase well dispersed. At annealing temperatures higher than 1100°C silicon oxycarbide glasses undergo a rearrangement which involves a phase separation to silica and silicon carbide and a segregation of carbon like graphite phase. At these temperatures the material can be considered as a glassy matrix nanocomposite. At temperatures higher than 1500 °C the carbothermal reduction occurs with the consumption of both silica and free carbon phase. However, the nanocomposite structure is maintained but with different constituents. The silicon oxycarbide glasses obtained at 1100 °C are amorphous. However, as a result of all involving processes taken place during the ceramic process, the nanocomposites formed at 1550 °C comprise a silica matrix and nanodomains of carbon like graphite and silicon carbide both of them displaying an incipient crystallization. Structure and crystalline size evolution, from preceramic materials to silicon oxycarbide derived nanocomposites, have been determined by FT-IR and Raman spectroscopies, XRD and 29Si-MASNMR.

scholarly journals CO2 Hydrogenation to Methanol with Ga- and Zn-Doped Mesoporous Cu/SiO2 Catalysts Prepared by the Aerosol-Assisted Sol-Gel Process

2020 ◽  
Author(s):  
Charlie Paris ◽  
Alejandro Karelovic ◽  
Raydel Manrique ◽  
Solène Le Bras ◽  
François Devred ◽  
...  
Keyword(s):  
Heterogeneous Catalysts ◽  
Continuous Production ◽  
Sol Gel ◽  
Active Phase ◽  
High Specific Surface Area ◽  
Silica Matrix ◽  
Promoting Effect ◽  
Process Step ◽  
Sol Gel Process ◽  
One Step

The preparation of copper-based heterogeneous catalysts dedicated to the hydrogenation of CO2 to methanol typically relies on multi-step procedures carried out in batch. These steps are precisely tailored to introduce the active phase (Cu) and the promoters (e.g. zinc, gallium) onto a preformed support, to maximize catalyst performance. However, each process step – often carried out in batch – can be associated with the formation of waste and with the consumption of energy, thereby negatively impacting the environmental performance of the overall catalyst preparation procedure. Here, we propose a direct and continuous production process for the synthesis of efficient catalysts for the CO2 to methanol reaction. Gallium- and zinc-promoted mesoporous Cu-SiO2 catalysts are prepared in one step by the aerosol-assisted sol-gel process. The catalysts consist of spherical microparticles and feature high specific surface area and pore volume, with interconnected pores of about 6 nm. A strong promoting effect of Ga and Zn is highlighted, boosting the selectivity for methanol at the expense of CO. Upon calcination, we show that Cu species – initially trapped in the silica matrix – undergo a migration towards the catalyst surface and a progressive sintering. After optimization, the catalysts obtained via such direct route compete with the best catalysts reported in the literature and obtained via multi-step approaches. <br>

Single-Layer Silica Anti-Reflective Films Modified with Polytetramethylene Glycol

2010 ◽  
Vol 663-665 ◽  
pp. 969-973
Author(s):  
Hong Tian ◽  
Dong Jiang Yang ◽  
Yao Xu
Keyword(s):  
Colloidal Silica ◽  
Sol Gel ◽  
Single Layer ◽  
Damage Threshold ◽  
Silica Matrix ◽  
Hybrid Films ◽  
Sio2 Coating ◽  
Silica Films ◽  
Sol Gel Process ◽  
Pure Sio2

Single-layer silica films modified with polytetramethylene glycol (PTMEG) were prepared via sol-gel process in the presence of NH4OH as catalyst. Compared with the pure SiO2 coating, the hybrid films possessed higher lased-induced damage threshold (LDT). The characterization results from AFM and TEM indicated that the introduction of PTMEG molecules changes the structure of the colloidal silica matrix, which directly resulted in the improvement of the transparency and LDT.

scholarly journals Nanostructured Nickel on Porous Carbon-Silica Matrix as an Efficient Electrocatalytic Material for a Non-Enzymatic Glucose Sensor

Chemosensors ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 54 ◽  
Author(s):  
Nassim Zahmouli ◽  
Silvia Marini ◽  
Mouna Guediri ◽  
Nabil Ben Mansour ◽  
Mokhtar Hjiri ◽  
...  
Keyword(s):  
Porous Carbon ◽  
Glucose Sensor ◽  
Sol Gel ◽  
Silica Matrix ◽  
Electrochemical Activation ◽  
X Ray Diffraction ◽  
Amperometric Determination ◽  
X Ray ◽  
Sol Gel Process ◽  
Electrochemical Monitoring

Nanostructured nickel on porous carbon-silica matrix (N-CS) has been synthesized using a sol gel process and subsequent pyrolysis treatment at a temperature of 650 °C. The morphology and microstructure of the N-CS sample has been investigated using XRD (X-ray Diffraction), SEM-EDS (Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy), and BET (Brunauer-Emmett-Teller) analysis. The synthesized nanocomposite has been used for developing NCS-modified screen-printed electrodes (NCS-SPCEs) and was applied in the electrochemical monitoring of glucose. After electrochemical activation, via cycling the modified electrode in a potential window from 0 to 0.8 V in 0.1 M KOH solution, the fabricated NCS-SPCEs electrodes were evaluated for the voltammetric and amperometric determination of glucose. The developed sensors showed good sensing performance towards glucose, displaying a sensitivity of 585 µA/mM cm−1 in the linear range from 0.05 to 1.5 mM, a detection limit lower than 30 µM with excellent selectivity.

Characterization of lanthanum salicylate complex nanoparticles in situ synthesized in silica matrix by a sol–gel process

2004 ◽  
Vol 58 (5) ◽  
pp. 757-761 ◽  
Author(s):  
Xiaofei Yang ◽  
Qizhuang He ◽  
Xianghong He ◽  
Liang Huang
Keyword(s):  
Sol Gel ◽  
Silica Matrix ◽  
Sol Gel Process
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