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Quantitative approach to the understanding of catalytic effect of metal oxides on the desorption reaction of MgH 2
Author(s) -
Hirate H.,
Saito Y.,
Nakaya I.,
Sawai H.,
Shinzato Y.,
Yukawa H.,
Morinaga M.,
Baba T.,
Nakai H.
Publication year - 2009
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.22075
Subject(s) - catalysis , oxide , desorption , metal , hydrogen , magnesium hydride , hydride , chemistry , inorganic chemistry , magnesium , activation energy , analytical chemistry (journal) , adsorption , organic chemistry
The hydrogen desorption reaction of magnesium hydride (MgH 2 ), MgH 2 →Mg+H 2 , is accelerated by mixing catalytic metal oxides (e.g., Nb 2 O 5 ). This catalytic effect of metal oxides, M x O y , is theoretically estimated in a quantitative way using atomization energy concept. The atomization energies, Δ E M for metal ion and Δ E O for oxide ion in various metal oxides are evaluated using the energy density analysis of the total energy. It is shown that the hydrogen desorption rate increases monotonously with increasing y ×Δ E O values of metal oxides. This indicates that the oxide ion in M x O y interacts mainly with hydrogen atoms in MgH 2 . The y × Δ E O value is a measure of the magnitude of the OH interaction operating between M x O y and MgH 2 , and hence, it is indeed a good parameter to show the catalytic activities of metal oxides. This approach is useful for the analysis of other catalyst and catalytic reactions. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009