Publikace detail

Energetic heterogeneity of Cu+-carbonyl complexes in Y zeolites: Kinetics of CO desorption studied by FTIR combined with CO adsorption microcalorimetry

Autoři: Frolich Karel | Bulánek Roman | Frýdová Eva

Rok: 2013

Druh publikace: článek v odborném periodiku

Název zdroje: Microporous and Mesoporous Materials

Název nakladatele: Elsevier Science BV

Místo vydání: Amsterdam

Strana od-do: 185-195

Tituly:

Jazyk	Název	Abstrakt	Klíčová slova
cze	Energetické heterogenity Cu+-karbonylových komplexů v Y zeolitech: Kinetika CO desorpce studovaná pomocí FTIR kombinované s CO dasorpční mikrokalorimetrií	Analyzovali jsme izotermní časově závislou CO desorpci na Cu+Me+H+-Y zeolitech (Me = Li, Na, K) za účelem výzkumu energetických heterogenit Cu+-CO částic. Po dekonvoluci spektra, integrální vazebná energie je vykreslena jako funkce času a fitována pomocí několika kinetických modelů.	FTIR; mikrokalorimetrie; Cu faujasit; stabilita karbonylu; desorpční kinetika
eng	Energetic heterogeneity of Cu+-carbonyl complexes in Y zeolites: Kinetics of CO desorption studied by FTIR combined with CO adsorption microcalorimetry	We analyzed IR spectra of the isothermal (RT) time-dependent CO desorption on Cu+Me+H+-Y zeolites (Me = Li, Na, K) in order to investigate the energetic heterogeneity of Cu+-CO species. After spectrum deconvolution, integral band area is plotted as a function of time and fitted by several kinetic models. The combination of three first-order kinetic processes has to be used for accurate description of CO desorption process for all tested IR bands. Under the band, carbonyl complexes are substantially differing in desorption rate contribution. The energy gap of complexes with similar geometry is ascribed to variable original Cu siting. Cu moves toward faujasite supercage where the adsorption proceeds: the higher the Cu interaction with framework the lower the stability of corresponding carbonyl complex. Stability of carbonyl IR band decreases with wavenumber. Lower frequency bands, due to Cu at II sites with 2 (or 3) Al at 6T ring, are characterized by significant population of low-stable carbonyls. IR stabilities are well correlated with CO heats of adsorption and changes on calorimetric curves justifying the kinetic evaluation. The influence of zeolite composition, namely Cu loading and kind of co-cation, on the character of IR spectrum and population of energetic components is discussed.	FTIR; microcalorimetry; copper faujasite; carbonyl stability; desorption kinetics

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