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The Beneficial Effect of Hydrogen on CO Oxidation over Au Catalysts. A Computational Study
Physics Division, Pakistan Institute of Science and Technology (PINSTECH), P. O. Nilore, Islamabad 44000, Pakistan
Schuit Institute of Catalysis, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
* Author to whom correspondence should be addressed.
Received: 15 September 2011; in revised form: 30 October 2011 / Accepted: 3 November 2011 / Published: 16 November 2011
Abstract: Density functional theory calculations have been carried out to explore the effect of hydrogen on the oxidation of CO in relation to the preferential oxidation of CO in the presence of excess hydrogen (PROX). A range of gold surfaces have been selected including the (100), stepped (310) surfaces and diatomic rows on the (100) surface. These diatomic rows on Au(100) are very efficient in H-H bond scission. O2 hydrogenation strongly enhances the surface-oxygen interaction and assists in scission of the O–O bond. The activation energy required to make the reaction intermediate hydroperoxy (OOH) from O2 and H is small. However, we postulate its presence on our Au models as the result of diffusion from oxide supports to the gold surfaces. The OOH on Au in turn opens many low energy cost channels to produce H2O and CO2. CO is selectively oxidized in a H2 atmosphere due to the more favorable reaction barriers while the formation of adsorbed hydroperoxy enhances the reaction rate.
Keywords: PROX; DFT; gold; CO oxidation; adsorption
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Hussain, A.; Gracia, J.; Niemantsverdriet, J.W.; Nieuwenhuys, B.E. The Beneficial Effect of Hydrogen on CO Oxidation over Au Catalysts. A Computational Study. Molecules 2011, 16, 9582-9599.
Hussain A, Gracia J, Niemantsverdriet JW, Nieuwenhuys BE. The Beneficial Effect of Hydrogen on CO Oxidation over Au Catalysts. A Computational Study. Molecules. 2011; 16(11):9582-9599.
Hussain, Akhtar; Gracia, Jose; Niemantsverdriet, J. W.; Nieuwenhuys, B. E. 2011. "The Beneficial Effect of Hydrogen on CO Oxidation over Au Catalysts. A Computational Study." Molecules 16, no. 11: 9582-9599.