open access

https://hdl.handle.net/2115/52060

CO oxidation on h-BN supported Au atom

英語

surface chemistry

2013-01-21

American Institute of Physics

Journal of Chemical Physics

138(3)

034701

The mechanism of CO oxidation by O2 on Au atoms supported on the pristine and defected hexagonal boron nitride (h-BN) surface has been studied theoretically using density functional theory. It is found that O2 binds stronger than CO on an Au atom supported on the defect free h-BN surface and h-BN surface with nitrogen vacancy (V_[N]@h-BN), but weaker than CO on a free Au atom or Au trapped by a boron vacancy (V_[B]@h-BN). The excess of the positive or negative charge on Au can considerably change its catalytic properties and enhance activation of the adsorbed O2. Coadsorption of CO and O2 on Au, Au/V_[N]@h-BN, and Au/V_[B]@h-BN results in additional charge transfer to O2. Various pathways of the CO oxidation reaction by molecular oxygen are studied. We found two different pathways for CO oxidation: a two-step pathway where two CO2 molecules are formed independently, and a self-promotion pathway where oxidation of the first CO molecule is promoted by the second CO molecule. Interaction of Au with the defect-free and defected h-BN surface considerably affects the CO oxidation reaction pathways and barriers. Therefore, Au supported on the h-BN surface (pristine or defected) cannot be considered as pseudo-free atom and support effects have to be taken into account, even when the interaction of Au with the support is weak.

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Copyright 2013 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in J. Chem. Phys. 138, 034701 (2013) and may be found at https://dx.doi.org/10.1063/1.4774216

0021-9606