Hysteretic characteristics of 1/λ^4 scattering of light during adsorption and desorption of water in porous Vycor glass with nanopores

2013 ◽  
Vol 30 (10) ◽  
pp. 2079 ◽  
Author(s):  
Shigeo Ogawa ◽  
Jiro Nakamura
Keyword(s):  
Adsorption And Desorption ◽  
Vycor Glass ◽  
Scattering Of Light ◽  
Porous Vycor Glass ◽  
Hysteretic Characteristics

scholarly journals Thermal properties of metal-metal bonded Pd(I) complexes supported onto porous Vycor glass

2008 ◽  
Vol 80 (2) ◽  
pp. 263-269
Author(s):  
Iara F. Gimenez ◽  
Oswaldo L. Alves
Keyword(s):  
Solid State ◽  
Thermal Stabilization ◽  
Decomposition Products ◽  
Vycor Glass ◽  
X Ray ◽  
Porous Vycor Glass ◽  
Metal Metal ◽  
Condensed Phosphates ◽  
Diffuse Reflectance Infrared ◽  
Immobilized Complexes

Thermal behavior of the complexes Pd2(dppm)2Cl2, Pd2(dppm)2(SnCl3)Cl and Pd2(dppm)2(SnCl3)2 (dppm = bis[diphenylphosphino(methane)], ((C6H5)2PCH2P(C6H5)2) in the solid state and immobilized onto porous Vycor glass was studied. Similar decomposition mechanisms were observed for the solid and immobilized complexes, with a small thermal stabilization upon immobilization. The decomposition products were characterized by X-ray diffractometry, Raman and diffuse reflectance infrared spectroscopy, which indicated the presence of a mixture of metallic palladium and oxidized species such as PdO,condensed phosphates, SnO2 and SnP2O7. According to X-ray diffractometry, the decomposition products of the immobilized complexes presented higher amounts of PdO than the solid-state residues, probably as an effect of interactions with silanol groups present in the glass surface.

Freezing of molecular hydrogen and its isotopes in porous vycor glass

1996 ◽  
Vol 105 (1-2) ◽  
pp. 113-131 ◽  
Author(s):  
G. Beaudoin ◽  
P. Haljan ◽  
M. Paetkau ◽  
J. R. Beamish
Keyword(s):  
Molecular Hydrogen ◽  
Vycor Glass ◽  
Porous Vycor Glass

PHASE TRANSITIONS OF WATER AND XENON ADSORBED IN POROUS VYCOR GLASS

1963 ◽  
Vol 41 (12) ◽  
pp. 3095-3107 ◽  
Author(s):  
G. Litvan ◽  
R. McIntosh
Keyword(s):  
Phase Transition ◽  
Capillary Condensation ◽  
Adsorbed Water ◽  
Surface Concentration ◽  
Adsorptive Capacity ◽  
Temperature Cycle ◽  
Length Variation ◽  
Vycor Glass ◽  
Porous Vycor Glass ◽  
Lower Temperature

Measurements of the expansion of porous Vycor glass containing fixed quantities of adsorbed water indicate that in every instance a phase transition starts below −50 °C, with the main change occurring below −160 °C. Two other anomalies of the length variation were observed near −22 °C and −7 °C when the amount of adsorbed water exceeded the value equivalent to two monolayers. The length of the adsorbent after completion of a temperature cycle was different from the initial length. This is thought to be due to damage suffered by the glass and to the fact that the length of the adsorbent is different for adsorption and desorption although the quantity adsorbed may be the same.The phase transition of adsorbed xenon takes place below the normal triple point and is a function of surface concentration as shown by length variations and equilibrium pressures for fixed quantities adsorbed. All transitions are gradual and hysteresis is exhibited by the isosteres. The adsorption isotherms for xenon – Vycor glass show a decreasing adsorptive capacity and a contraction of the hysteresis loop with lower temperature. The inadequacy of the capillary condensation theory of adsorption in relation to these results is discussed.

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