CO adsorption on W(100) during temperature-programmed desorption: A combined density functional theory and kinetic Monte Carlo study
Issue Date
2-2017
Abstract
Using a combined density functional theory (DFT) and kinetic Monte Carlo (KMC) simulations, we study the adsorption at 800 K and subsequent desorption of CO on W(100) at higher temperatures. The resulting TPD profiles are known experimentally to exhibit three desorption peaks β 1 , β 2 , and β 3 at 930 K, 1070 K, and 1375 K, respectively. Unlike more recent theoretical studies that propose that all three aforementioned peaks are molecularly rather than associatively desorbed, our KMC analyses are in support of the latter, since at 800 K dissociation is facile and that CO exists as dissociation fragments C and O. We show that these peaks arise from desorption from the same adsorption site but whose binding energy varies depending on local environment, that is, the presence of CO as well as dissociation fragments C and O nearby. Furthermore we show that several key parameters, such as desorption, dissociation and recombination barriers all play a key role in the TPD spectra—these parameter effectively controls not only the location of the TPD peaks but the shape and width of the desorption peaks as well. Moreover, our KMC simulations reveal that varying the heating rate shifts the peaks but leaves their shape intact.
Source or Periodical Title
Applied Surface Science
ISSN
0169-4332
Volume
396
Page
1282-1288
Document Type
Article
Physical Description
illustrations, tables, graphs
Language
English
Subject
Density functional theory, Desorption, Kinetic Monte Carlo simulation, Temperature-programmed desorption, Tungsten
Recommended Citation
Albao, M.A., Padama, A.A.B. (2017). CO adsorption on W(100) during temperature-programmed desorption: A combined density functional theory and kinetic Monte Carlo study. Applied Surface Science, 396, 1282-1288.
Identifier
https://doi.org/10.1016/j.apsusc.2016.11.144
Digital Copy
yes
