Highly Porous (TiO2−SiO2−TeO2)/Al2O3/TiO2Composite Nanostructures on Glass with Enhanced Photocatalysis Fabricated by Anodization and Sol−Gel Process

2003 ◽  
Vol 107 (27) ◽  
pp. 6586-6589 ◽  
Author(s):  
Song-Zhu Chu ◽  
Satoru Inoue ◽  
Kenji Wada ◽  
Di Li ◽  
Hajime Haneda ◽  
...  
Keyword(s):  
Sol Gel ◽  
Porous Tio2 ◽  
Sol Gel Process ◽  
Highly Porous

Porous Silica: A Potential Material for Low Dielectric Constant Applications

1998 ◽  
Vol 511 ◽  
Author(s):  
Edward D. Birdsell ◽  
Rosario A. Gerhardt
Keyword(s):  
Spin Coating ◽  
Colloidal Silica ◽  
Sol Gel ◽  
Gelation Time ◽  
Porous Silica ◽  
Low Dielectric Constant ◽  
Low Dielectric ◽  
Sol Gel Process ◽  
Gel Composition ◽  
Highly Porous

ABSTRACTHighly porous (15% dense) silica thin films with k < 2.2 have been produced using a colloidal sol-gel process. This process uses relatively inexpensive, commercially available colloidal silica and potassium silicate. These films were deposited by spin coating. The parameters for spin coating (spin speed, gelation time, gel composition, etc.) have been optimized and coherent films with thicknesses ranging from 0.7–2.0 μm can be reproducibly fabricated. Preliminary work shows that the porosity of these films ranges from a few rn to < 1 μm. The dielectric properties were examined for frequencies up to 1 MHz. Compatibility of the films with IC processing was also investigated.

Adsorption Property and Photocatalytic Activity of Sol-Gel Prepared Porous TiO2 Using PEG1000 as Template

2011 ◽  
Vol 48-49 ◽  
pp. 153-156 ◽  
Author(s):  
Chun Ling Liu ◽  
Ru Yuan Li ◽  
Wen Jie Zhang
Keyword(s):  
Methyl Orange ◽  
Calcination Temperature ◽  
Adsorption Property ◽  
Sol Gel ◽  
Time Range ◽  
Porous Tio2 ◽  
Calcination Temperatures ◽  
Sol Gel Process ◽  
Degradation Activity ◽  
Content Range

PEG1000 was used as a template to prepare porous TiO2 photocatalyst through sol-gel process. The amount of PEG1000 and calcination temperature and time were studied with respect to porous TiO2 activity. At the optimum adding amount of PEG1000, 30.0% of the initial methyl orange was degraded. Methyl orange adsorption on the porous TiO2 maintained less than 2% during the whole template content range. During the calcination temperature range from 400 oC to 600 oC and time range from 2 h to 5 h, the optimum degradation activity appeared to the sample calcinated at 500 oC for 4 h. Adsorption of the materials had no variation at different calcination temperatures and times, and was quite weak compared with degradation efficiencies. 96.2% of the initial methyl orange was degraded after 100 min of irradiation.

Catalytic activity of porous TiO2 obtained by sol–gel process in the degradation of phenol

2004 ◽  
Vol 348 ◽  
pp. 185-189 ◽  
Author(s):  
Alysson A.C. Magalhães ◽  
Diego Luiz Nunes ◽  
Patricia A. Robles-Dutenhefner ◽  
Edésia M.B. de Sousa
Keyword(s):  
Catalytic Activity ◽  
Sol Gel ◽  
Porous Tio2 ◽  
Sol Gel Process

scholarly journals A Photocatalytic Active Adsorbent for Gas Cleaning in a Fixed Bed Reactor

2008 ◽  
Vol 2008 ◽  
pp. 1-7 ◽  
Author(s):  
Peter Pucher ◽  
Rabah Azouani ◽  
Andrei Kanaev ◽  
Gernot Krammer
Keyword(s):  
Sol Gel ◽  
Fixed Bed ◽  
Porous Silica ◽  
Active Surface ◽  
Fixed Bed Reactor ◽  
Total Oxidation ◽  
Gas Cleaning ◽  
Silica Substrate ◽  
Sol Gel Process ◽  
Highly Porous

Efficient photocatalysis for gas cleaning purposes requires a large accessible, illuminated active surface in a simple and compact reactor. Conventional concepts use powdered catalysts, which are nontransparent. Hence a uniform distribution of light is difficult to be attained. Our approach is based on a coarse granular, UV-A light transparent, and highly porous adsorbent that can be used in a simple fixed bed reactor. A novel sol-gel process with rapid micro mixing is used to coat a porous silica substrate withTiO2-based nanoparticles. The resulting material posses a high adsorption capacity and a photocatalytic activity under UV-A illumination (PCAA = photocatalytic active adsorbent). Its photocatalytic performance was studied on the oxidation of trichloroethylene (TCE) in a fixed bed reactor setup in continuous and discontinuous operation modes. Continuous operation resulted in a higher conversion rate due to less slip while discontinuous operation is superior for a total oxidation toCO2due to a user-defined longer residence time.

Partially Hydrolyzed Alkoxysilanes as Precursors for Silica Aerogels

1988 ◽  
Vol 121 ◽  
Author(s):  
T. M. Tillotson ◽  
L. W. Hrubesh ◽  
I. M. Thomas
Keyword(s):  
Sol Gel ◽  
Silica Aerogels ◽  
Low Density ◽  
Density Range ◽  
Moist Air ◽  
Wide Range ◽  
Sol Gel Process ◽  
Hydrolysis Of ◽  
Highly Porous ◽  
Controlled Hydrolysis

ABSTRACTThe classical sol-gel process for synthesizing SiO2 aerogels involves the hydrolysis/condensation of tetraethyoxysilane (TEOS) and/or teramethyoxysilane (TMOS) to produce a gel which can then be super-critically extracted to a low density, highly porous aerogel glass. Controlled hydrolysis of TEOS and TMOS leads to partially hydrolyzed compounds that can be subsequently water processed to form silica aerogels in the density range from .020 to .500 gms/cc. The partially hydrolyzed compounds are stable when sealed from moist air and can be stored for future use.We discuss the controlled conditions used to obtain these compounds and present data that characterize their structure. We detail the procedures for preparing the wide range of aerogel densities. We also report on their use as an adhesive.

scholarly journals Aerogels in Aerospace: An Overview

2013 ◽  
Vol 2013 ◽  
pp. 1-18 ◽  
Author(s):  
Nadiir Bheekhun ◽  
Abd. Rahim Abu Talib ◽  
Mohd Roshdi Hassan
Keyword(s):  
Silica Aerogel ◽  
Outer Space ◽  
Sol Gel ◽  
Supercritical Drying ◽  
Research Trend ◽  
Sound Waves ◽  
Space Applications ◽  
Sol Gel Process ◽  
Drying Technology ◽  
Highly Porous

Aerogels are highly porous structures prepared via a sol-gel process and supercritical drying technology. Among the classes of aerogels, silica aerogel exhibits the most remarkable physical properties, possessing lower density, thermal conductivity, refractive index, and dielectric constant than any solids. Its acoustical property is such that it can absorb the sound waves reducing speed to 100 m/s compared to 332 m/s for air. However, when it comes to commercialization, the result is not as expected. It seems that mass production, particularly in the aerospace industry, has dawdled behind. This paper highlights the evolution of aerogels in general and discusses the functions and significances of silica aerogel in previous astronautical applications. Future outer-space applications have been proposed as per the current research trend. Finally, the implementation of conventional silica aerogel in aeronautics is argued with an alternative known as Maerogel.

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