Preferential Oxygen Transport in Nanophase Mesoporous Ceramic Ion Conducting Membranes

2002 ◽  
Vol 752 ◽  
Author(s):  
C. Guizard ◽  
C. Levy ◽  
L. Dalmazio ◽  
A. Julbe
Keyword(s):  
Oxygen Transport ◽  
Sol Gel ◽  
Synergetic Effect ◽  
Pt Nanoparticles ◽  
Noble Metal Nanoparticles ◽  
Triple Phase Boundary ◽  
Activated Oxygen ◽  
Sol Gel Process ◽  
Ion Conducting ◽  
Conducting Membranes

ABSTRACTRecent data from the literature dealing with the influence on oxygen transport of porous nanophase ion conducting ceramics are reviewed, and then transposed to the design of mesoporous nanophase ceria-based membranes. Mesoporous CeO2/Al2O3 and Gd doped CeO2 membranes containing Pd and Pt nanoparticles were prepared using the sol-gel process. Permeation of N2 and O2 single gases was studied in a temperature range 20–500°C. Permeation measurements indicate an activated oxygen transport in agreement with the literature data. A synergetic effect of the noble metal nanoparticles on oxygen transport has been evidenced, in relation with the triple phase boundary concept. However, these membranes do not perform totally the preferential oxygen transport predicted by the theory. Several directions are proposed for membrane improvement, in particular concerning pore and grain optimal sizes.

Assembled Behavior of Noble Metal Nanoparticles Related to Capping Agents in Sol–Gel Process

2017 ◽  
Vol 17 (2) ◽  
pp. 1367-1372
Author(s):  
Simin Lu ◽  
Feifei Zhang ◽  
Meng Li ◽  
Debao Liu ◽  
Yuntao Yang ◽  
...  
Keyword(s):  
Metal Nanoparticles ◽  
Noble Metal ◽  
Sol Gel ◽  
Noble Metal Nanoparticles ◽  
Capping Agents ◽  
Sol Gel Process

Organic-Inorganic Hybrid Protonic Polymeric Electrolytes Grafted by Sulfonic Acid / Sulfonamide Moieties

1999 ◽  
Vol 575 ◽  
Author(s):  
Laurent Depre ◽  
Christiane Poinsignon ◽  
Michael Popall
Keyword(s):  
Relative Humidity ◽  
Polymer Electrolyte ◽  
Functional Groups ◽  
Sulfonic Acid ◽  
Sol Gel ◽  
Inorganic Hybrid ◽  
Conduction Mechanisms ◽  
Sol Gel Process ◽  
Polymeric Electrolytes ◽  
Conducting Membranes

ABSTRACTThin proton conducting membranes of an organic-inorganic polymer electrolyte bearing sulphonamide and sulfonic groups are prepared by sol-gel process. Polycondensation of alkoxysilanes provides the inorganic silicate backbone whereas the organic network is formed from reactive functional groups R'((-CH2)3-SO3H) and [(-CH2)3-SO2 NH2] of alkoxysilanes of R'Si[OR3] type. Proton conductivity measured in the dry and wet state under controlled Temperature and Relative Humidity increases from 10 -4 S.cm-1 under vacuum to 6 10-2S.cm-1 at 70°C and 96% RH. Conductivity dependence on temperature and associated conduction mechanisms are discussed in both states.

Preparation of Pt Nanoparticles Dispersed in Mesoporous Silica

2009 ◽  
Vol 1217 ◽  
Author(s):  
Yukitoshi Chiba ◽  
Hirobumi Shibata ◽  
Daichi Nagata ◽  
Takahiro Gunji ◽  
Ryuji Tamura ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Platinum Nanoparticles ◽  
Triblock Copolymer ◽  
Sol Gel ◽  
Pt Nanoparticles ◽  
Chelating Agent ◽  
Pluronic P123 ◽  
Amphiphilic Triblock Copolymer ◽  
Sol Gel Process ◽  
Phenanthroline Complex

AbstractPlatinum nanoparticles were dispersed in mesopores of mesoporous silica using a sol-gel process with a composite template consisting of an amphiphilic triblock copolymer (Pluronic P123 or F127) and a Pt-organic complex, which was prepared with K2Pt(II)Cl4 as a Pt source and 1,10-phenanthroline as a chelating agent. The obtained Pt-1,10-phenanthroline complex did not dissolve in any of several solvents, e.g., hexane, benzene, toluene, THF, H2O, CH3OH, and C2H5OH. However, when the Pt-1,10-phenanthroline complex was reacted with ethylenediamine it dissolved in many solvents. Platinum nanoparticles dispersed in mesoporous silica were obtained using a sol-gel process with a complex template consisting of Pt-1,10-phenanthroline-ethylenediamine, and an amphiphilic triblock copolymer (Pluronic P123 or F127). A sample dried at 353 K was bright yellow. When it was subsequently heat-treated at 823 K, it turned light gray. This change indicates that Pt nanoparticles can be obtained by heat-treatment at high temperature, because, to generate Pt nanoparticles, the organics chelated to Pt ions must be removed. Measurements from small-angle x-ray scattering show that mesoporous silica obtained using a complex template has a much more highly ordered pore structure than that obtained using only an amphiphilic triblock copolymer. It has both large pores (above 8 nm) and a large surface area (about 290 m2/g). Furthermore, results of a TEM investigation showed that Pt nanoparticles were generated only in mesopores of mesoporous silica.

Synergetic effect dependence on activated oxygen in the interface of NiOx modified Pt nanoparticles for CO oxidation from first-principles

2021 ◽  
Author(s):  
Zihang Yao ◽  
Jiaqiang Yang ◽  
Zhang Liu ◽  
Bin Shan ◽  
Rong Chen ◽  
...  
Keyword(s):  
Co Oxidation ◽  
First Principles ◽  
Co Adsorption ◽  
Synergetic Effect ◽  
Pt Nanoparticles ◽  
Binding Energies ◽  
First Principles Calculations ◽  
Activated Oxygen

CO oxidation on NiOx-modified Pt nanoparticles (NPs) is investigated by first-principles calculations and microkinetic methods. The binding energies of O2 and CO on NiOx/Pt suggest that CO adsorption is dominated...

The crystallization of thin-film ceramics

1992 ◽  
Vol 50 (1) ◽  
pp. 338-339
Author(s):  
J.M. Schwartz ◽  
L.F. Francis ◽  
L.D. Schmidt ◽  
P.S. Schabes-Retchkiman
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Sol Gel ◽  
Processing Route ◽  
Small Areas ◽  
Ceramic Thin Films ◽  
Complex Shapes ◽  
Sol Gel Process ◽  
Ceramic Precursors ◽  
Crystalline Ceramic

Ceramic thin films and coatings are of interest for electrical, optical, magnetic and thermal barrier applications. Critical for improved properties in thin films is the development of specific microstructures during processing. To this end, the sol-gel method is advantageous as a versatile processing route. The sol-gel process involves depositing a solution containing metalorganic or colloidal ceramic precursors onto a substrate and heating the deposited layer to form a crystalline or non-crystalline ceramic coating. This route has several advantages, including the ability to create tailored microstructures and properties, to coat large or small areas, simple or complex shapes, and to more easily prepare multicomponent ceramics. Sol-gel derived coatings are amorphous in the as-deposited state and develop their crystalline structure and microstructure during heat-treatment. We are particularly interested in studying the amorphous to crystalline transformation, because many key features of the microstructure such as grain size and grain size distribution may be linked to this transformation.

Epitaxial Growth of Sr0.3Ba0.7Nb2O6 Thin Films Prepared by Sol-Gel Process

1999 ◽  
Vol 606 ◽  
Author(s):  
Keishi Nishio ◽  
Jirawat Thongrueng ◽  
Yuichi Watanabe ◽  
Toshio Tsuchiya
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Epitaxial Growth ◽  
Raw Materials ◽  
Substrate Surface ◽  
Sol Gel ◽  
Tungsten Bronze ◽  
Monomethyl Ether ◽  
Tetragonal Tungsten Bronze ◽  
Sol Gel Process

AbstructWe succeeded in the preparation of strontium-barium niobate (Sr0.3Ba0.7Nb2O6 : SBN30)that have a tetragonal tungsten bronze type structure thin films on SrTiO3 (100), STO, or La doped SrTiO3 (100), LSTO, single crystal substrates by a spin coating process. LSTO substrate can be used for electrode. A homogeneous coating solution was prepared with Sr and Ba acetates and Nb(OEt)5 as raw materials, and acetic acid and diethylene glycol monomethyl ether as solvents. The coating thin films were sintered at temperature from 700 to 1000°C for 10 min in air. It was confirmed that the thin films on STO substrate sintered above 700°C were in the epitaxial growth because the 16 diffraction spots were observed on the pole figure using (121) reflection. The <130> and <310> direction of the thin film on STO were oriented with the c-axis in parallel to the substrate surface. However, the diffraction spots of thin film on LSTO substrate sintered at 700°C were corresponds to the expected pattern for (110).

UV Curable Organic-Inorganic Hybrid Materials

2000 ◽  
Vol 628 ◽  
Author(s):  
Guang-Way Jang ◽  
Ren-Jye Wu ◽  
Yuung-Ching Sheen ◽  
Ya-Hui Lin ◽  
Chi-Jung Chang
Keyword(s):  
Hybrid Materials ◽  
Colloidal Silica ◽  
Sol Gel ◽  
Solution Ph ◽  
Uv Curable ◽  
Inorganic Hybrid ◽  
Degradation Temperature ◽  
Sol Gel Process ◽  
The Stability ◽  
Thermal Degradation Temperature

This work successfully prepared an UV curable organic-inorganic hybrid material consisting of organic modified colloidal silica. Applications of UV curable organic-inorganic hybrid materials include abrasion resistant coatings, photo-patternable thin films and waveguides. Colloidal silica containing reactive functional groups were also prepared by reacting organic silane and tetraethyl orthosilicate (TEOS) using sol-gel process. In addition, the efficiency of grafting organic moiety onto silica nanoparticles was investigated by applying TGA and FTIR techniques. Experimental results indicated a strong interdependence between surface modification efficiency and solution pH. Acrylate-SiO2 hybrid formation could result in a shifting of thermal degradation temperature of organic component from about 200°C to near 400°C. In addition, the stability of organic modified colloidal silica in UV curable formula and the physical properties of resulting coatings were discussed. Furthermore, the morphology of organic modified colloidal silica was investigated by performing TEM and SEM studies‥

Halogenation of ORMOSIL: A Promising Rout for Tailoring Optical Absorptions

2003 ◽  
Vol 771 ◽  
Author(s):  
Amir Fardad ◽  
Wei Liang ◽  
Yadong Zhang ◽  
Bryson Case ◽  
Shibin Jiang ◽  
...  
Keyword(s):  
Process Parameters ◽  
Sol Gel ◽  
Fiber Amplifiers ◽  
Grignard Reaction ◽  
Coupling Loss ◽  
Beam Splitters ◽  
Silicon Technology ◽  
Sol Gel Process ◽  
Propagation Losses ◽  
Signal Intensities

AbstractFluorinated and photo-imageable precursors are synthesized through a Barbier-Grignard reaction for 1550-nm window. The precursors are used for the sol-gel process of integrated optic components for silica-on-silicon technology. Material compositions and process parameters are optimized to achieve internal absorptions >0.1 dB/cm and propagation losses of about 0.5 dB/cm at 1550 nm. Compact 1×16 Beam splitters are designed and fabricated which exhibit >0.3 dB power uniformity, >0.1 dB PDL and 1.5 dB coupling loss. By hybrid integration of the passive splitters and in-house fiber amplifiers, amplifying splitters are demonstrated at various signal intensities.

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