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On Adsorption of Hydrogen on (100) Titanium Hydride Surface

Gryciuk M., Górecki J.

Polish Journal of Chemistry

2008

Vol. 82, nr 10

1981-1990

We apply quantum density functional theory methods to calculate the reaction path linking a free hydrogen molecule placed over TiH2 (100) surface with a pair of hyrogen atoms ad sorbed on it. The considered path is composed of highly symmetrical orientations of H2 molecule; in the process of dissociative adsorption the line linking hydrogen atoms is al ways parallel to the surface and located on the symmetry plane of the supercell. The results indicate that adsorption is characterized by the energetic barrier (1.18 eV/molecule) and the reaction heat (0.26 eV/ atom).

Quantum chemical description of catalytic activation of the C-H bond

Bracławik E.

Polish Journal of Chemistry

1998

Vol. 72, nr 7S

1551-1564

Density functional theory is presented from the point of view of its applicability in modelling catalytic reaction. Reaction path for C-H bond scission in methane interacting with metal oxide/transiton metal catalytic sites for gallium oxide in zeolitic lattice and palladium or rhodium based supported catalysts are analysed. On the basis of interdependence between the elektronic structure and activity of the bond two mechanisms for activation of the C-H bond are described: via electrons withdrawal from bonding states (on oxide catalysts) and via electron insertion to antibonding orbitals (on metals).