The adsorption of Ar, H-2 O-2, N-2 and CO on (H,Na)-Y zeolite (Si/Al 2.9, H+/Na+ approximate to 5) has been studied at variable-temperature (90-20 K) and sub-atmospheric pressure (0-40 mbar) by FTIR spectroscopy. Unprecedented filling conditions of the zeolite cavities were attained, which allowed the investigation of very weakly adsorbed species and of condensed, liquid-like or solid-like, phases. Two pressure regimes were singled out, characterized by: (i) specific interaction at low pressure of the probe molecules (P) with the internal Bronsted and Lewis sites, and (ii) multilayer adsorption at higher pressure. In the case of CO the perturbation of the protonic sites located inside the socialite cages was also observed. As the molecule is too large to penetrate the sodalite cage, the perturbation is thought to involve a proton jump tunneling mechanism. The adsorption energy for the (HF)(OHP)-P-... (P = Ar, H-2, O-2, N-2 and CO) specific interaction involving the high frequency Bronsted acid sites exposed in the supercages was derived following the VTIR (variable temperature infrared spectroscopy) method described by E. Garrone and C. Otero Arean.

Vibrational and thermodynamic properties of Ar, N-2, O-2, H-2 and CO adsorbed and condensed into (H,Na)-Y zeolite cages as studied by variable temperature IR spectroscopy

SPOTO, Giuseppe;BORDIGA, Silvia;RICCHIARDI, Gabriele;ZECCHINA, Adriano
2006-01-01

Abstract

The adsorption of Ar, H-2 O-2, N-2 and CO on (H,Na)-Y zeolite (Si/Al 2.9, H+/Na+ approximate to 5) has been studied at variable-temperature (90-20 K) and sub-atmospheric pressure (0-40 mbar) by FTIR spectroscopy. Unprecedented filling conditions of the zeolite cavities were attained, which allowed the investigation of very weakly adsorbed species and of condensed, liquid-like or solid-like, phases. Two pressure regimes were singled out, characterized by: (i) specific interaction at low pressure of the probe molecules (P) with the internal Bronsted and Lewis sites, and (ii) multilayer adsorption at higher pressure. In the case of CO the perturbation of the protonic sites located inside the socialite cages was also observed. As the molecule is too large to penetrate the sodalite cage, the perturbation is thought to involve a proton jump tunneling mechanism. The adsorption energy for the (HF)(OHP)-P-... (P = Ar, H-2, O-2, N-2 and CO) specific interaction involving the high frequency Bronsted acid sites exposed in the supercages was derived following the VTIR (variable temperature infrared spectroscopy) method described by E. Garrone and C. Otero Arean.
2006
8
1186
1196
http://www.rsc.org/publishing/journals/CP/article.asp?doi=b513367j
H-Y zeolite; simple molecular probes; carbon-monoxide; hydroxyl-groups; NAA zeolite; OH groups; FT-IR; adsorption-isotherms; hydrogen complexes; calorimetric heats
E.N. GRIBOV; D. COCINA; G. SPOTO; S. BORDIGA; G. RICCHIARDI; A. ZECCHINA
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/42840
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 44
  • ???jsp.display-item.citation.isi??? 42
social impact