Characterization of the Sol−Gel Formation of Iron(III) Oxide/Hydroxide Nanonetworks from Weak Base Molecules

2006 ◽  
Vol 18 (20) ◽  
pp. 4793-4801 ◽  
Author(s):  
Jeremy D. Walker ◽  
Rina Tannenbaum
Keyword(s):  
Sol Gel ◽  
Gel Formation ◽  
Weak Base ◽  
Oxide Hydroxide

Sol-Gel Synthesis of Nanocrystalline Ni-Ferrite and Co-Ferrite Redox Materials for Thermochemical Production of Solar Fuels

2014 ◽  
Vol 1675 ◽  
pp. 203-208 ◽  
Author(s):  
Rahul R. Bhosale ◽  
Ivo Alxneit ◽  
Leo L. P. van den Broeke ◽  
Anand Kumar ◽  
Mehak Jilani ◽  
...  
Keyword(s):  
Sol Gel ◽  
Solar Fuels ◽  
Bet Surface Area ◽  
Mixed Solution ◽  
Gel Formation ◽  
Thermochemical Cycles ◽  
X Ray ◽  
Thermogravimetric Analyzer ◽  
Sol Gel Synthesis

ABSTRACTIn this contribution, we report the synthesis and characterization of NixFe3-xO4 and CoxFe3-xO4 redox nanomaterials using sol-gel method. These materials will be used to produce solar fuels such as H2 or syngas from H2O and/or CO2 via solar thermochemical cycles (STCs). For the sol-gel synthesis of ferrites, the Ni, Co, Fe precursor salts were dissolved in ethanol and propylene oxide (PO) was added dropwise to the well mixed solution as a gelation agent to achieve gel formation. Freshly synthesized gels were aged, dried, and calcined by heating them to 600°C in air. The calcined powders were characterized by powder x-ray diffractometer (XRD), BET surface area, as well as scanning (SEM) and transmission (TEM) electron microscopy. Their suitability to be used in STCs for the production of solar fuels was assessed by performing several reduction/re-oxidation cycles using a thermogravimetric analyzer (TGA).

Preparation and Characterization of Doped Nanometer TiO2

2007 ◽  
Vol 26-28 ◽  
pp. 649-652 ◽  
Author(s):  
Lin Yun Song ◽  
Yu Cheng Wu ◽  
Xiang Fen Lu
Keyword(s):  
Degradation Rate ◽  
Sol Gel ◽  
Complexing Agent ◽  
Gel Formation ◽  
X Ray Diffraction ◽  
Nano Tio2 ◽  
Doped Tio2 ◽  
X Ray ◽  
Different Temperatures

With Ti(OBu)4 as precursor, and HAC as complexing agent, pure and Fe-doped TiO2 gelatins were prepared by sol-gel method. During the process of gel formation, metal ions were dispersed into the porous TiO2 matrix. Then, powders of pure nano-TiO2 and Fe-doped nano-TiO2 were prepared by drying, grinding and calcining at different temperatures. The grain size and phase structure of pure and Fe-doped TiO2 after calcined at different temperatures, were studied by X-ray diffraction (XRD) and Beckman Coulter Sorption Analysis. The results showed that, the Fe3+-TiO2 had better photocatalytic activity in degradation rate of methyl orange under sunlight. The degradation rate was up to 93% as the system was placed under sunlight for 5 h. The optimum calcination temperature for the best catalytic activity was determined to be 500°C, and the mechanism was discussed.

Characterization of iron(III) oxide/hydroxide nanostructured materials produced by sol–gel technology based on the Fe(NO3)3·9H2O–C2H5OH–CH3CHCH2O system

2011 ◽  
Vol 130 (1-2) ◽  
pp. 548-560 ◽  
Author(s):  
Luisa Durães ◽  
Ana Moutinho ◽  
Inês J. Seabra ◽  
Benilde F.O. Costa ◽  
Hermínio C. de Sousa ◽  
...  
Keyword(s):  
Nanostructured Materials ◽  
Sol Gel ◽  
Oxide Hydroxide

Characterization of New Ionically Conducting Peo-Based Networks by Diffusion, Elasticity Modulus and Ionic Conductivity Measurements

1992 ◽  
Vol 293 ◽  
Author(s):  
Herve Cheradame ◽  
F. Desbat ◽  
P. Mercier-Niddam ◽  
S. Boileau
Keyword(s):  
Diffusion Coefficient ◽  
Ionic Conductivity ◽  
Elasticity Modulus ◽  
Sol Gel ◽  
Cation Transport ◽  
Lithium Cation ◽  
Conductivity Measurements ◽  
Conducting Materials ◽  
Diffusion Studies

AbstractIonically conducting materials containing PEO were prepared from telechelic di(methyl-diethoxy-silane) PEO, synthesized by the hydrosilylation of telechelic diallyl-PEO with methyldiethoxysilane. The network is obtained by the usual sol-gel chemistry. Then, it is filled with LiClO4 by diffusion of the salt and further drying. A comparison is made with the same kind of materials crosslinked using urethane chemistry. Diffusion studies show that the diffusion coefficient of solvent is similar for both types of materials, whilst the ionic conductivity is higher for the networks crosslinked with siloxane bonds. An experiment of diffusion of LiClO4 without solvent showed that this salt has a diffusion coefficient of the order of 2.10-8 cm2.sec-1 at 34°C. The conductivity calculated from this determination is compatible with the mechanism of lithium cation transport by the diffusion of salt molecules. Elasticity modulus measurements show that the salt aggregates are essentially located within the crosslinks at low concentration, but also in the PEO chains for salt concentrations higher than 1 mol/l.

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