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Titolo:
FTIR study of low-temperature CO and N-15(2) adsorption on a CaNaY zeolite: formation of site-specified Ca2+(CO)(3) and Ca2+(N-15(2))(3) complexes
Autore:
Hadjiivanov, K; Knozinger, H; Ivanova, E; Dimitrov, L;
Indirizzi:
Bulgarian Acad Sci, Inst Gen & Inorgan Chem, BU-1113 Sofia, Bulgaria Bulgarian Acad Sci Sofia Bulgaria BU-1113 Chem, BU-1113 Sofia, Bulgaria Univ Munich, Dept Chem, D-81377 Munich, Germany Univ Munich Munich Germany D-81377 h, Dept Chem, D-81377 Munich, Germany Bulgarian Acad Sci, Inst Catalysis, BU-1113 Sofia, Bulgaria Bulgarian AcadSci Sofia Bulgaria BU-1113 lysis, BU-1113 Sofia, Bulgaria
Titolo Testata:
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
fascicolo: 12, volume: 3, anno: 2001,
pagine: 2531 - 2536
SICI:
1463-9076(2001)3:12<2531:FSOLCA>2.0.ZU;2-X
Fonte:
ISI
Lingua:
ENG
Soggetto:
ALKALI-EXCHANGED ZEOLITES; VIBRATIONAL SPECTROSCOPY; CARBON-DIOXIDE; N-2; IR; NA-ZSM-5; COADSORPTION; DINITROGEN; AG-ZSM-5; PROBE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
26
Recensione:
Indirizzi per estratti:
Indirizzo: Hadjiivanov, K Bulgarian Acad Sci, Inst Gen & Inorgan Chem, BU-1113 Sofia,Bulgaria Bulgarian Acad Sci Sofia Bulgaria BU-1113 Sofia, Bulgaria
Citazione:
K. Hadjiivanov et al., "FTIR study of low-temperature CO and N-15(2) adsorption on a CaNaY zeolite: formation of site-specified Ca2+(CO)(3) and Ca2+(N-15(2))(3) complexes", PHYS CHEM P, 3(12), 2001, pp. 2531-2536

Abstract

Adsorption of CO at room temperature on a CaNaY zeolite results in formation of several species: Ca2+(CO) (2198 cm(-1)); Ca2+(CO)(2) (2188 cm(-1)), Ca2+(OC) (2094 cm(-1)), Na+(CO) (2172 cm(-1)) and Na+(OC) (2119 cm(-1)). At 85 K no O-bonded CO is observable but, in addition to the C-bonded complexes found at room temperature, two additional species have been detected: Ca2(CO)(3) (2185 cm(-1)) and Na+(CO)(2) (2167 cm(-1)). At high CO coverages (equilibrium CO pressures above ca. 100 Pa), the Ca2+(CO)(3) and Na+(CO)(2) species are predominant. The Ca2+(CO)(3) complexes are decarbonylated stepwise and first converted into Ca2+(CO)(2) and then into Ca2+(CO) species with decreasing coverage. The latter are quite stable at 85 K. The Na+(CO)(2) species stepwise lose the two CO ligands. Adsorption of a (CO)-C-12-(CO)-C-13 mixture reveals that the CO ligands in the di- and tri-carbonyls behave as independent oscillators. Low temperature N-15(2) adsorption can also be explained in terms of formation of Ca2+(N-15(2))(n)(n = 1-3) and Na+(N-15(2))(m) (m = 1-2) species. A theoretical model of the process is proposed andadsorption isotherms well describing the experimental results are derived.

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Documento generato il 12/08/20 alle ore 21:01:33