Abstract
The adsorptions of CO on Ni(110) surface at different coverages have been investigated by first-principle calculations. The results show that CO will be bonded at short bridge site preferentially. And CO preferentially absorbs upright at short bridge sites and top sites at 1/6 monolayer coverage. With increasing coverage to 0.5 ML, the enhanced steric repulsion leads to the slope of CO. For 1/6 and 1/2 monolayer coverage, CO is mainly bonded at short bridge site and atop site simultaneously at a certain ratio. When CO coverage is 1 monolayer, CO absorbs at short bridge site and forms p2mg configuration. As the coverage of CO is increased to finally form the p2mg structure, there is a continuous frequency shift up to the value 1962.27 cm-1. The vibration frequencies we calculated are consistent with relative experimental results. DOS of CO molecules and Ni atoms are discussed too.
Highlights
The adsorption of gas on catalyst surface is an important step in catalytic process
The absorption of CO on Ni(110) has been investigated in the temperature range 110-320 K using high resolution infrared spectroscopy together with LEED and TDS [11]; the results showed that atop and bridged sites are occupied for coverages below 0.8 monolayers; atop absorption is dominant, while bridged absorption is dominant, at full monolayer coverage, p2mg configuration formed
With increasing CO coverage, the disordered absorption gradually turned to ordered absorption, until CO coverage reaches a certain value, at which p2mg configurations will be formed
Summary
The adsorption of gas on catalyst surface is an important step in catalytic process. Understanding the adsorption structure and postadsorption dynamic behavior can provide theoretical basis for effectively controlling the reaction process CO molecular adsorption on surface of nickel has received considerable attention from experimental and theoretical workers [1,2,3,4,5,6,7]. The structural model proposed by Hannaman et al [8] for the full coverage CO on Ni(110) system is one in which the CO is bonded as a molecule to the short bridge. CO absorption on Ni(110) was studied by infrared ellipsometric spectroscopy [9]; the interpretation of the spectra obtained at 197 K indicated several structures probably occurs with increasing CO coverage. [10] believed that CO molecule was adsorbed at the short bridge site. Studies [3] showed that CO was adsorbed at the bridged site and atop site for low CO coverage. CO coverage is a key factor affecting CO absorption on Ni(110) surface. These investigations are mainly carried out experimentally. Density functional theory (DFT) was used to study the adsorption of CO on Ni(110) surface at different coverages
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