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Adsorption of O2, SO2, and SO3, on nickel oxide - Mechanism for sulfate formationCalculations based on the atom superposition and electron delocalization molecular orbital technique suggest that O2 will adsorb preferentially end-on at an angle 45 deg from normal on a nickel cation site on the (100) surface of NiO. SO2 adsorption is also stronger on the nickel site; SO2 bonds through the sulfur atom in a plane perpendicular to the surface. Adsorption energies for SO3 on the nickel and oxygen sites are comparable in the preferred orientation in which the SO3 plane is parallel to the surface. The calculations suggest that the strength of adsorption varies as O2 greater than SO2 greater than SO3. On activation, SO3 adsorbed to an O(2-) site forms a trigonal pyramidal SO4 species which yields, with a low barrier, a tetrahedral sulfate anion. Subsequently the anion reorients on the surface. Alternative mechanisms which require the formation of Ni(3+) or O(-) are discussed. NiSO4 thus formed may play a passivating role for the corrosion of Ni at low temperatures in the SO2 + O2 + SO3 atmospheres and an active role at high temperatures, as discussed in the experimental literature.
Document ID
19860049500
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Mehandru, S. P.
(Case Western Reserve Univ. Cleveland, OH, United States)
Anderson, A. B.
(Case Western Reserve University Cleveland, OH, United States)
Date Acquired
August 12, 2013
Publication Date
April 1, 1986
Publication Information
Publication: Electrochemical Society, Journal
Volume: 133
ISSN: 0013-4651
Subject Category
Inorganic And Physical Chemistry
Accession Number
86A34238
Funding Number(s)
CONTRACT_GRANT: NAG3-341
Distribution Limits
Public
Copyright
Other

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