FT-IR study of the adsorption of carbon monoxide and of some nitriles on Na-faujasites: Additional insight on the formation of complex interactions

Kozyra, Paweł; Salla, Isabel; Montanari, Tania; Dátka, Jerzy; Salagre, Pilar; Busca, Guido

doi:10.1016/j.cattod.2006.01.005

Cited by 19 publications

(19 citation statements)

References 44 publications

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“…This band is assigned to the formation of the wellidentified Na + (CO) carbonyl through a C-end bond with Na + in the S II position. [7][8][9][10][11] The small red-shift (i.e. 4 cm À1 ) from the 2175 cm À1 position to 2171 cm À1 can be attributed to a static effect which increases with CO coverage as already reported in the case of HY zeolites with low Si/Al ratio.…”

Section: Resultssupporting

confidence: 67%

Evidencing the three cationic coordination vacancies of SII Na+ in NaY zeolite: additional insights from IR surface species

Cairon

2010

Phys. Chem. Chem. Phys.

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The unresolved issue of the maximum number of adsorbed ligands binding to S(II) Na(+) cations contained in a Y zeolite has been investigated and explained using a new experimental approach, specially designed for the specific problem. The formation of Na(+)(CO)(2) di-carbonyls has been identified for the first time for high CO coverage using a survey of IR spectra of the adsorbed CO. Also, the formation of Na(+)(CO)(3) tri-carbonyls is confirmed and the conditions of its formation are thoroughly discussed. Moreover, the adsorption of the CO probe in the large NaY cavities is expressed in terms of four coexisting reactions reflecting the formation of the three Na-carbonyl species which involves the vacant coordination of sodium cations. This study refines the IR vibration bands of the three as-formed carbonyls of interest and provides new information towards the understanding at the molecular scale of how the three free coordination vacancies of Na(+) sites sitting in S(II) positions can be investigated by means of CO binding.

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Section: Resultssupporting

confidence: 67%

Evidencing the three cationic coordination vacancies of SII Na+ in NaY zeolite: additional insights from IR surface species

Cairon

2010

Phys. Chem. Chem. Phys.

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“…For instance CO used as a probe by means of IR spectroscopy has been extensively reported as a model for characterizing adsorption properties of many classes of zeolites containing various cations. [2][3][4][5][6][7][8][9][10] Its employment is based on the simple statement that IR bands of carbonyl adsorbed species recorded after CO introduction are relevant of specific CO/alkali metal interactions. However both interpretation and attribution of each IR band in connection to these adsorbed species is far from being always so obvious.…”

Section: Introductionmentioning

confidence: 99%

“…4 This latter concept-also called 'dual site' or (n : 1) interaction-is claimed to successfully describe the CO capture on vast amount of cationic zeolites investigated by both IR experiments and DFT approaches. [4][5][6][7] In contrast, despite its common use in a wide range of separation and purification processes based on physical adsorption, 1 NaY faujasites were never investigated by means of such combined approach. This can be easily explained by the lack of exploitable IR experimental data.…”

Section: Introductionmentioning

confidence: 99%

How does CO capture process on microporous NaY zeolites? A FTIR and DFT combined study

Cairon

Guesmi

2011

Phys. Chem. Chem. Phys.

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Reliable experimental IR and theoretical approaches, both investigating CO adsorption on NaY faujasites, are supporting that CO capture occurs through the completion of the vacant coordination of Na(+) cations located in the accessible S(II) sites. As a result, carbonyl adsorbed species are formed by the capture of one, two or three CO molecules and are experimentally discernable by their respective IR positions that are down-shifted by an average 11-12 cm(-1) value for each captured CO molecule. DFT analysis is proposed for comparison and reproduces well the observed experimental shift of the ν(CO) positions of the different polycarbonyls of interest. In addition, the effect of Si or Al composition surrounding the SII Na(+) cation is investigated and results suggest that polycarbonyls that are formed might be in connection with the acidic strength of the cationic sites. This combined study completes and improves the understanding of the complex issue of CO adsorption at 80 K widely used as a model to explain how physical adsorption takes place in NaY faujasites working as an efficient industrial adsorbent in gas separation or gas purification processes.

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“…Complex interactions, where more than one cationic site and oxygen atoms cooperate in adsorption have been found. 37 Mostly in the form of powder packed beds, alkali and alkali earth metal faujasite zeolites are largely used industrially: 25 Na-X faujasite (denoted commercially as 13X molecular sieve, according to the diameter of the supercage, 13 Å ) is a highly selective adsorbent designed for the elimination of trace contaminants from air and other gases. 38 It can also be used for the desulfurization (sweetening) of natural gas and other fluids, especially for the removal of mercaptanes, and for drying of gases and liquids.…”

Section: Alkali and Alkali Earth Exchanged Faujasites As Adsorbentsmentioning

confidence: 99%

Zeolites and Other Structurally Microporous Solids as Acid–Base Materials

Busca¹

2014

Heterogeneous Catalytic Materials

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FT-IR study of the adsorption of carbon monoxide and of some nitriles on Na-faujasites: Additional insight on the formation of complex interactions

Cited by 19 publications

References 44 publications

Evidencing the three cationic coordination vacancies of SII Na+ in NaY zeolite: additional insights from IR surface species

Evidencing the three cationic coordination vacancies of SII Na+ in NaY zeolite: additional insights from IR surface species

How does CO capture process on microporous NaY zeolites? A FTIR and DFT combined study

Zeolites and Other Structurally Microporous Solids as Acid–Base Materials

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