Mesoporous Silica and Titania by Glycol-Modified Precursors

2007 ◽  
Vol 1007 ◽  
Author(s):  
Jasmin Geserick ◽  
Nicola Hüsing ◽  
Renate Roßmanith ◽  
Clemens K. Weiss ◽  
Katharina Landfester ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Low Temperature ◽  
Sol Gel ◽  
Oxidation Reactions ◽  
Low Temperature Co Oxidation ◽  
Catalytic Applications ◽  
Aqueous Conditions ◽  
Gel Processing ◽  
Silica And Titania

ABSTRACTEthylene glycol modified precursors, such as tetrakis(2-hydroxyethyl)orthosilicate (EGMS) or bis(2-hydroxyethyl)titanate (EGMT), have distinct advantages in the synthesis of mesoporous materials by sol-gel processing compared to the commercially available tetraalkoxide precursors. The glycols released upon hydrolysis have proven to be compatible with lyotropic surfactant mesophases and in addition, these precursors allow for processing in purely aqueous conditions. Besides the standard characterization of the resulting titania and silica-based materials by XRD, electron microscopy, and nitrogen sorption, the potential of the titania-based materials for catalytic applications was tested using Au/TiO2 catalysts in low temperature CO oxidation reactions.

Synthesis and characterization of BaMgAl10O17:Eu phosphors derived by sol–gel processing

2002 ◽  
Vol 126 (2) ◽  
pp. 161-165 ◽  
Author(s):  
Junying Zhang ◽  
Zhongtai Zhang ◽  
Zilong Tang ◽  
Zishan Zheng ◽  
Yuanhua Lin
Keyword(s):  
Sol Gel ◽  
Synthesis And Characterization ◽  
Gel Processing

Grain growth and sintering in Bi–(Pb)—Sr—Ca—Cu—O superconductors made by sol-gel

1994 ◽  
Vol 9 (2) ◽  
pp. 286-291 ◽  
Author(s):  
Kunsong Ma ◽  
Alain C. Pierre
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Citric Acid ◽  
Grain Growth ◽  
Sol Gel ◽  
Gel Processing ◽  
Scanning Electron

Bi—(Pb)—Sr—Ca—Cu—O superconductors were synthesized by sol-gel processing from nitrates by complexation with citric acid. Their grain growth and sintering above 800 °C were studied by Scanning Electron Microscopy (SEM) and Brunauer, Emmett, Teller (BET) porosimetry. The sintering was limited by anisotropic grain growth, and microcracks in 2212 phase grains were created due to the formation of 2223 phase.

Fabrication and Characterization of Sol-Gel Derived PZT/WO3 Ceramics

2008 ◽  
Vol 55-57 ◽  
pp. 369-372 ◽  
Author(s):  
T. Sreesattabud ◽  
Anucha Watcharapasorn ◽  
Sukanda Jiansirisomboon
Keyword(s):  
Lead Zirconate Titanate ◽  
Sol Gel ◽  
Rhombohedral Phase ◽  
Lead Zirconate ◽  
X Ray Diffraction ◽  
Calcination Process ◽  
Materials Used ◽  
Phase Characterization ◽  
Gel Processing

Lead zirconate titanate/tungsten oxide (PZT/WO3) ceramics were prepared from the powders synthesized by a modified triol sol-gel processing method. In this study, the starting materials used for synthesis of PZT-sol were zirconium (IV) propoxide, titanium (IV) isopropxide, lead (II) acetate trihydrate and 1,1,1,- tris (hydroxymethyl) ethane. To prepare PZT/xWO3 powders (where x = 0, 0.5, 1 and 3 wt%), nano-sized WO3 was ultrasonically dispersed and mixed with the PZT sol, dried and calcined at 600°C for 4 h. X-ray diffraction results indicated that fully crystallized powders were obtained. Phase characterization suggested that at high WO3 concentration, the reaction between PZT and WO3 occurred during the calcination process. To prepare PZT/xWO3 ceramics, the powders were pressed and sintered at 1100°C for 6 h. Phase characterization by XRD indicated that the content of WO3 significantly affected tetragonal-to-rhombohedral phase transition. Microstructure of thermally etched samples showed that increasing the content of WO3 decreased grain size of the ceramics.

One Pot Synthesis and Characterization of Ultra Fine CeO2 and Cu/CeO2 Nanoparticles. Application for Low Temperature CO Oxidation

2011 ◽  
Vol 11 (10) ◽  
pp. 8593-8598 ◽  
Author(s):  
Apostolos Fotopoulos ◽  
Jiannis Arvanitidis ◽  
Dimitris Christofilos ◽  
Konstantinos Papaggelis ◽  
M. Kalyva ◽  
...  
Keyword(s):  
Low Temperature ◽  
Co Oxidation ◽  
Synthesis And Characterization ◽  
One Pot ◽  
One Pot Synthesis ◽  
Low Temperature Co Oxidation

scholarly journals Preparation and Characterization of Ta-substituted Li7La3Zr2-xO12 Garnet Solid Electrolyte by Sol-Gel Processing

2017 ◽  
Vol 54 (4) ◽  
pp. 278-284 ◽  
Author(s):  
Sang A Yoon ◽  
Nu Ri Oh ◽  
Ae Ri Yoo ◽  
Hee Gyun Lee ◽  
Hee Chul Lee
Keyword(s):  
Solid Electrolyte ◽  
Sol Gel ◽  
Gel Processing

scholarly journals Characterization of Gaas/Si/GaAs Heterointerfaces

1989 ◽  
Vol 148 ◽  
Author(s):  
Zuzanna Liliental-Weber ◽  
Raymond P. Mariella
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Low Temperature ◽  
Defect Density ◽  
Si Substrate ◽  
Reverse Polarity ◽  
Si Substrates ◽  
Transmission Electron ◽  
Metal Semiconductor Metal

ABSTRACTTransmission electron microscopy of GaAs grown on Si for metal-semiconductor-metal photodetectors is presented in this paper. Two kinds of samples are compared: GaAs grown on a 15 Å Si epilayer grown on GaAs, and GaAs grown at low temperature (300°C) on Si substrates. It is shown that the GaAs epitaxial layer grown on thin Si layer has reverse polarity to the substrate (antiphase relation). Higher defect density is observed for GaAs grown on Si substrate. This higher defect density correlates with an increased device speed, but with reduced sensitivity.

Preparation and Characterization of Carbon Xerogel Based Composites for Electrochemical Sensing and Photocatalytic Degradation

2021 ◽  
Vol 21 (4) ◽  
pp. 2323-2333
Author(s):  
Carmen I. Fort ◽  
Mihai M. Rusu ◽  
Lucian C. Pop ◽  
Liviu C. Cotet ◽  
Adriana Vulpoi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Degradation ◽  
Electrochemical Sensors ◽  
Sol Gel ◽  
Nanocomposite Material ◽  
Electrochemical Sensing ◽  
Ambient Conditions ◽  
Carbon Xerogel ◽  
Voltammetric Detection

In order to obtain a multifunctional nanocomposite material-for electrochemical sensors and photocatalytic applications, structures based on Bi, Fe and TiO2 were grown inside carbon xerogel supports (BiFeCX and BiFeCX-TiO2). First, a wet polymer containing Bi and Fe salts was obtained by following a modified resorcinol-formaldehyde based sol–gel route, followed by drying in ambient conditions, and pyrolysis under inert atmosphere. Then, through TiCl4 hydrolysis, TiO2 nanoparticles were deposited on the BiFeCX xerogel leading to BiFeCX-TiO2. The morphological and structural characterization of the investigated nanocomposites consisted in X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy and N2 adsorption measurements, revealing porous carbon structures with embedded nanoparticles and the particularities driven by the pyrolysis and TiCl4 treatment. The new modified electrodes based on BiFeCX or BiFeCX-TiO2 nanocomposite materials, kept in a chitosan matrix (Chi) and deposited on a glassy carbon (GC) electrode surface (GC/Chi-BiFeCX or GC/Chi-BiFeCX-TiO2), were obtained and investigated for Pb(II) voltammetric detection and H2O2 amperometric detection. Moreover, the BiFeCX-TiO2 nanocomposite was tested for the photocatalytic degradation of methyl orange. The great potential of BiFeCX nanocomposite material for developing electrochemical sensors, or BiFeCX-TiO2 for sensors application and photocatalytic application was demonstrated.

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