Use of nitriles as probe molecules for the accessibility of the active sites and the detection of complex interactions in zeolites through IR spectroscopy

2006 ◽  
Vol 307 (1) ◽  
pp. 21-29 ◽  
Author(s):  
Tania Montanari ◽  
Maria Bevilacqua ◽  
Guido Busca
Keyword(s):  
Ir Spectroscopy ◽  
Active Sites ◽  
Probe Molecules ◽  
Complex Interactions

scholarly journals The Properties of Cu Ions in Zeolites CuY Studied by IR Spectroscopy

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4686
Author(s):  
Jerzy Podobiński ◽  
Mariusz Gackowski ◽  
Grzegorz Mordarski ◽  
Katarzyna Samson ◽  
Michał Śliwa ◽  
...  
Keyword(s):  
Ir Spectroscopy ◽  
Positive Charge ◽  
Co Adsorption ◽  
The Other ◽  
Probe Molecules ◽  
Adsorption And Desorption ◽  
Other Hand ◽  
Close Proximity ◽  
No And Co Adsorption ◽  
Cu Ions

The properties of both Cu2+ and Cu+ ions in zeolite CuY were followed with NO and CO as probe molecules. Cu2+ was found to be located in SII, SII*, and SIII sites, whereas Cu+ was found in SII and SII* sites. The fine analysis of the spectra of Cu2+-NO and Cu+-CO adducts suggests that both in SII and in SII* sites two kinds of Cu cations exist. They differ in the positive charge, which may be related to the varying numbers of AlO4− in close proximity. The experiments of NO and CO adsorption and desorption evidenced that both Cu2+ and Cu+ sites of highest positive charge bind probe molecules most strongly but activate them to a lesser extent than the Cu sites of lowest positive charge. The experiments of reduction with hydrogen evidenced that the Cu ions of higher positive charge are first reduced by hydrogen. On the other hand, Cu sites of the lowest positive charge are first oxidized by oxygen. The experiments with CuNaY zeolites of various Cu contents suggest that the first introduced Cu (at low Cu contents) created Cu+, which was the most neutralized by framework oxygens. Such Cu cations are the most stabilized by framework oxygens.

Modelling active sites for the Beckmann rearrangement reaction in boron-containing zeolites and their interaction with probe molecules

2010 ◽  
Vol 12 (24) ◽  
pp. 6396 ◽  
Author(s):  
Inés Lezcano-González ◽  
Alejandro Vidal-Moya ◽  
Mercedes Boronat ◽  
Teresa Blasco ◽  
Avelino Corma
Keyword(s):  
Active Sites ◽  
Beckmann Rearrangement ◽  
Probe Molecules ◽  
Rearrangement Reaction

Study of the active sites of alkaline-earth Y-type zeolites by IR spectroscopy

1978 ◽  
Vol 13 (5) ◽  
pp. 541-544
Author(s):  
L. V. Levshin ◽  
L. A. Ignat'eva ◽  
L. V. Efimenko ◽  
G. D. Chukin ◽  
M. A. Piontkovskaya ◽  
...  
Keyword(s):  
Ir Spectroscopy ◽  
Active Sites ◽  
Alkaline Earth

scholarly journals Comparative study of the active sites in zeolites by different probe molecules

2005 ◽  
Vol 70 (3) ◽  
pp. 457-474 ◽  
Author(s):  
Vera Dondur ◽  
Vesna Rakic ◽  
Ljiljana Damjanovic ◽  
Aline Auroux
Keyword(s):  
Comparative Study ◽  
Active Sites ◽  
Temperature Programmed Desorption ◽  
Acid Sites ◽  
Probe Molecules ◽  
Adsorption Calorimetry ◽  
Temperature Programmed ◽  
First Time

This review summarizes some of the recently published results concerning the acid sites in the zeolites ZSM-5 and Y studied by temperature-programmed desorption (TPD) and adsorption calorimetry using different probe molecules NH3, CO, N2O and n-hexane. For the first time it has been shown that the acid sites in hydrated zeolites are accessible for n-hexane adsorption.

Determination of the Acidity of High Surface AlF3by IR Spectroscopy of Adsorbed CO Probe Molecules

2007 ◽  
Vol 111 (49) ◽  
pp. 18317-18325 ◽  
Author(s):  
Thoralf Krahl ◽  
Alexandre Vimont ◽  
Gehan Eltanany ◽  
Marco Daturi ◽  
Erhard Kemnitz
Keyword(s):  
Ir Spectroscopy ◽  
High Surface ◽  
Probe Molecules ◽  
Co Probe ◽  
Adsorbed Co

scholarly journals Reduction and Oxidation of Cu Species in Cu-Faujasites Studied by IR Spectroscopy

Molecules ◽  
2020 ◽  
Vol 25 (20) ◽  
pp. 4765
Author(s):  
Łukasz Kuterasiński ◽  
Jerzy Podobiński ◽  
Ewa Madej ◽  
Małgorzata Smoliło-Utrata ◽  
Dorota Rutkowska-Zbik ◽  
...  
Keyword(s):  
Ir Spectroscopy ◽  
Room Temperature ◽  
Probe Molecules ◽  
First Order ◽  
Reduction And Oxidation

The process of reduction (by hydrogen and ethanol) and oxidation (by oxygen and NO) of Cu sites in dealuminated faujasite-type zeolites (of Si/Al = 31) was studied by infrared (IR) spectroscopy with CO (for Cu+) and NO (for Cu2+) as probe molecules. Two zeolites were studied: one of them contained mostly Cu+exch., whereas another one contained mostly Cu2+ and Cu+ox. The susceptibility of various forms of Cu for reduction were investigated. IR experiments of CO sorption evidenced that Cu+ox. was more prone for the reduction than Cu+exch. According to NO sorption studies, Cu2+exch. was reduced in the first order before Cu2+ox. Ethanol reduced mostly Cu2+ and, also, some amounts of Cu+. The treatment with oxygen caused the oxidation of Cu+ (both Cu+exch. and Cu+ox.) to Cu2+. The adsorption of NO at 190K produced Cu+(NO)2 dinitrosyls, but heating to room temperature transformed dinitrosyls to mononitrosyls and increased the Cu2+ content.

Sign in / Sign up

Export Citation Format

Share Document