Abstract
The adsorption of CO onto the hydroxylated α-Al2O 3(0001) surface was studied using density functional theory (DFT). Dissociated adsorption of water was found to be stable, with an adsorption energy (Ea) of 1.62 eV at θwater = 0.75. The most stable hydroxylation form on the clean surface was found to be in the 1-2 dissociation configuration, where the OH group binds to a surface Al ion and the H ion binds to one of the three equivalent surface O ions. The adsorption energy of CO was found to be dependent on the degree of pre-hydroxylation of the surface as well as on the CO coverage. The highest adsorption energy of CO was found when θCO = 0.25 on a pre-hydroxylated surface with θwater = 0.25; Ea = 0.57 eV. The adsorption energy of CO decreased upon increasing the degree of pre-hydroxylation. The vibrational frequency of νCO was also computed and in all cases it was blue shifted with respect to gas-phase CO. The shift, Δν, decreased with increasing CO coverage but increased with increasing surface hydroxylation. A comparison with available experimental work is discussed.
Original language | English |
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Pages (from-to) | 14287-14297 |
Number of pages | 11 |
Journal | Physical Chemistry Chemical Physics |
Volume | 16 |
Issue number | 27 |
Early online date | 19 May 2014 |
DOIs | |
Publication status | Published - 21 Jul 2014 |