Theoretical Calculation of the Interaction of Hydrogen with Models of Coordinatively Unsaturated Centers on Alumina

Autor:	Dan Farcasiu, Povilas Lukinskas
Rok vydání:	1999
Předmět:	Electronic correlation Hydrogen Chemistry Chemisorption Ab initio quantum chemistry methods Inorganic chemistry Cluster (physics) Molecule Physical chemistry chemistry.chemical_element Reactivity (chemistry) Physical and Theoretical Chemistry Endothermic process
Zdroj:	The Journal of Physical Chemistry A. 103:8483-8490
ISSN:	1520-5215 1089-5639
DOI:	10.1021/jp990939a
Popis:	Ab initio calculations with large basis sets and electron correlation were conducted on the reaction of hydrogen molecules with (HO)3Al(OH2)x clusters, where x = 0, 1, and 2. In this way, the reactivity of Al(III) species was studied as a function of their level of coordinative unsaturation. For the tricoordinated species, the geometry of the starting cluster was obtained by the optimization of the species (HO)3Al(OH 2)x+1 and removal of the extra water molecule, on the basis of idea that aluminum oxide surfaces are formed by calcination of hydrated forms. Two models, one assuming rigidity and the other allowing for flexibility of the tricoordinated aluminum center, were examined. The complexes with physisorbed and chemisorbed hydrogen were optimized in the same way. The reactions of tetra- and pentacoordinated aluminum clusters were studied without any constraints on the geometry. The calculations predicted the hydrogen chemisorption to be endothermic in all cases, the order being E(x = 0) < E(x = 1) < E...
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::60ea916ea109c903f1c2d40bf84768d4 https://doi.org/10.1021/jp990939a Zobrazit plný text záznamu