نتایج جستجو برای: xerogel matrix

تعداد نتایج: 365035  

The silica xerogel is prepared using copper source; 0.02 mol of Cu(NO3)2.3H2O that has been added to 1 mol TEOS (tetraethyl orthosilicate). The Copper ions are doped to silica matrix by the sol gel method and determination of total molar ratio of components with a reported molar ratio of H2O /TEOS(R) = 6.2. In this method, the acidity the of reaction (pH) depends on the catalyst type in the hyd...

Journal: :Langmuir : the ACS journal of surfaces and colloids 2004
Ronald C Hedden Hae-Jeong Lee Barry J Bauer

Small-angle neutron scattering contrast variation is applied to characterization of nanoporous low-dielectric constant (low-k) thin films. Films are exposed to saturated solvent vapor in air, whereby the pores fill with liquid by capillary condensation. The pores are filled with mixtures of hydrogen- and deuterium-containing solvents to vary the neutron contrast with the matrix (wall). The comp...

2010
Katarzyna Czarnobaj

Silica, silica/polydimethylsiloxane and silica/polydimethylsiloxane/ calcium xerogels were examined as polymeric carriers for the controlled release of drug—Metronidazole. Characterization assays comprised analysis of the matrix by Fourier transform infrared spectroscopy (FTIR), determining the specific surface area of solids (BET) and scanning electron microscope (SEM) techniques and further m...

Journal: :Chemical science 2015
Harshitha Barike Aiyappa Subhadeep Saha Pritish Wadge Rahul Banerjee Sreekumar Kurungot

A proton conducting metallogel [FNPA; ferric nitrate (FN)-phytic acid (PA)] is synthesized by immobilizing a protogenic ligand (phytic acid) using iron(iii) nitrate in DMF. The xerogel shows high proton conductivity of 2.4 × 10-2 S cm-1 at 120 °C, the best value known among all metal organic materials (MOMs). Marking the first such attempt in MOMs, an electrode made using the xerogel showed a p...

2003
R. Cerc Korošec P. Bukovec B. Pihlar J. Padežnik Gomilšek

Nickel oxide thin films have been widely studied as an optical active layer in electrochromic devices. It is well known for these films that thermal treatment is the key factor which determines the electrochromic effect during potential cycling. Therefore, it is extremely important to perform thermal analysis on the thin films rather than on the corresponding xerogels. In this article, the ther...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 2013
vahidah homaunmir sayed hossein tohidi garnik grigoryan,

one distinct concentration of copper ions was embedded into the silica matrix to xerogel form using copper source cu(no3)2∙3h2o. the xerogel samples were prepared with using hydrolysis and condensation reactions of tetraethyl ortho-silicate (teos) by the sol-gel method. in this investigation, new molar ratio of h2o/teos was determined to be 11.7. also, the necessary amount of tri-hydrated coppe...

2015
Cinthia Alegre María Elena Gálvez Rafael Moliner

Platinum catalysts supported on carbon xerogel and carbon black (Vulcan) were synthesized with the aim of investigating the influence of the characteristics of the support on the electrochemical performance of the catalysts. Three synthesis methods were compared: an impregnation method with two different reducing agents, sodium borohydride and formic acid, and a microemulsion method, in order t...

Journal: :Journal of the American Chemical Society 2002
Valeri Petkov Pantelis N Trikalitis Emil S Bozin Simon J L Billinge Thomas Vogt Mercouri G Kanatzidis

A long-standing issue regarding the local and long-range structure of V(2)O(5)*nH(2)O xerogel has been successfully addressed. The full three-dimensional structure of the lamellar turbostratic V(2)O(5)*nH(2)O xerogel was determined by the atomic pair distribution function technique. We show that on the atomic scale the slabs of the xerogel can be described well as almost perfect pairs (i.e., bi...

Journal: :journal of nanostructures 2015
f. b. sarand s. hassani m. fazli k. haghbeen

classical xerogels are robust, inexpensive and nontoxic materials with low-ordered nanoporous structures. in water streams where the ph is higher than the point of zero charge, the surface of classical xerogels such as tetraethoxy orthosilan (teos) xerogel is negatively charged. it was assumed that a xerogel can work as a strong adsorbent for metal ions without further modification. therefore, ...

Farhood Ziaie Garnik Grigoryan Sayed Hossein Tohidi, Verzhine Sarkeziyan

Various concentrations of copper are embedded into silica matrix to xerogel form using copper source - Cu(NO3)2∙3H2O. The xerogel samples are prepared by hydrolysis and condensation of tetraethyl orthosilicate (TEOS) by the sol-gel method  and with determination of new molar ratio of components H2O/TEOS to be 6.2. In this investigation, the necess...

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