Results 181 to 190 of about 9,810 (226)

The Structure of Confined Oxygen in Silica Xerogels

Science, 1995
The microscopic structure of oxygen confined in silica xerogels has been studied as a function of temperature. In large pores, a crystalline solid forms with a structure consistent with that of the bulk. The size of the crystallites is much larger than the pore size, indicating that cooperative effects among pores are ...
B S, Schirato, M P, Fang, P E, Sokol, S, Komarneni   +3 more
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Carbon xerogels and ceria–carbon xerogel materials as catalysts in the ozonation of organic pollutants

Applied Catalysis B: Environmental, 2012
Abstract Carbon xerogels prepared at different pH and ceria–carbon xerogel materials with different compositions and synthesized by different procedures were evaluated as catalysts in the ozonation of oxalic acid and the textile dye CI Reactive Blue 5.
C.A. Orge, J.J.M. Órfão, M.F.R. Pereira   +2 more
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Structure of Hybrid Colloid−Polymer Xerogels

Langmuir, 2004
Crack-free monolithic gels were prepared from different mixtures of colloidal silica with a sol solution containing tetraethoxysilane, under powerful ultrasonic agitation (sonosol). Recently, information on the structure of these gels, inferred from N2 adsorption and mercury intrusion porosimetry, was presented.
Luis, Esquivias, Nicolás, de la Rosa-Fox, Mercedes, Bejarano, Maria J, Mosquera   +3 more
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Carbon Xerogels for Effluent Treatment

Journal of Chemical & Engineering Data, 2020
The adsorption process of carbonized xerogels in the form of porous microspheres or monoliths was found to be reversible.
Athulya Pillai, Balasubramanian Kandasubramanian   +1 more
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Aerogels and xerogels for catalytic applications

Journal of Non-Crystalline Solids, 1992
Abstract The aerogel method, consisting of preparation of solid catalysts by sol-gel processes of organometallic precursors and drying the wet gel under hypercritical conditions, is a particularly interesting way to obtain highly divided materials for catalytic applications. Special attention is given to PbO ZrO 2 and PbO Al 2 O 3 aerogel catalysts.
R. Tleimat-Manzalji, T. Manzalji, G.M. Pajonk   +2 more
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Antenna effect in an oxide xerogel

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 1998
Abstract Silica xerogel doped with [Eu⊂cryptand] 3+ was prepared by the sol-gel method from a hydrolyzed tetramethoxysilane solution containing [Eu⊂cryptand](CF 3 SO 3 ) 2 Br. UV-visible optical absorption spectra, fluorescence excitation and emission spectra, fluorescence lifetime as well as luminescence quantum yield were measured. Experiments were
K Czarnobaj, M Elbanowski, Z Hnatejko, A.M Klonkowski, S Lis, M Pietraszkiewicz   +5 more
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Elastic Properties of Silica Xerogels

Journal of the American Ceramic Society, 1990
To calculate elastic constants, longitudinal and tranverse acoustic wave velocities were measured for silica xerogels as a function of relative humidity (rh). The silica xerogels studied are microporous with open porosity of 53 vol%. The longitudinal wave velocity exhibits a minimum at about 35% rh.
Bennet Abramoff, Lisa C. Klein
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Carbon xerogels as catalyst supports: Study of mass transfer

AIChE Journal, 2006
AbstractHydrodechlorination of 1,2‐dichloroethane on Pd‐Ag alloys was used as a test reaction in order to study mass transfer in carbon xerogel supports. The selected supports were obtained from evaporative drying and pyrolysis of resorcinol‐formaldehyde aqueous gels. Since the pore texture of these materials can be tailored through the adequate choice
Job, Nathalie, Heinrichs, Benoît, Lambert, Stéphanie, Pirard, Jean-Paul, Colomer, Jean-François, Vertruyen, Bénédicte, Marien, José   +6 more
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Low-Energy Vibration Excess in Silica Xerogels

Physical Review Letters, 1997
Specific heat (1.5-25 K) and Raman scattering (below 100cm −1 in silica xerogels permit one to assess the frequency dependence of the coupling coefficient C(ω)and the low-energy density of states g(ω) Different network connectivity does not change the shape of the quasielastic scattering, but alters the spectral shape of C(ω)The results permit one to ...
FONTANA A, ROSSI F, CARINI, Giuseppe, D'ANGELO, Giovanna, TRIPODO, Gaspare, BARTOLOTTA A.   +5 more
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Xerogel film formation

Xerogels are solid, glass-like compounds formed through the sol-gel process. The sol-gel process is a route by which a colloidal solution is transformed into a solid gel through a series of hydrolysis and condensation reactions. The xerogel results from drying the gel via evaporation.
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