Chapter 11
An Evaluation of Density Functional Theory
for CO Adsorption on Pt(111)
Yu-Wei Huang, Ren-Shiou Ke, Wei-Chang Hao, and Shyi-Long Lee
Abstract In this study, serveal different density functionals were applied to study
the CO adsorption on Pt(111) clusters. When adding more contribution of HF exchange energy, it can be found that the HOMO energy is decreased and LUMO
energy is increased, thus increasing the HOMO-LUMO energy gap. The accuracy
of S-T excitation energy can also be largely improved when increasing the ratio of
HF exchange energy. For CO adsorption at Pt 7–3 cluster, most functionals predict
that CO favors to adsorb at fcc site. Only when adding more than 40 % HF exchange energy, the M06HF, BMK, wB97 and M06-2X functionals can predict the
top-site preference. For CO adsorption at Pt 9–9–9 cluster, when adding more than
40 % HF exchange energy, the CO prefers to adsorb at top site than fcc site. Among
these functionals, the M06HF strongly predicts the top-site preference. The chemical bonding analysis shows that the effects of σ -repulsion are reduced as the CO S-T
excitation energy increasing, and the effect of reduction for CO at top site is more
remarkable than that for CO at fcc site. Therefore, CO would more favor to adsorb
at top site in those functionals which can give better CO S-T excitation energy. Although the opposite trend can be found for the π-attraction, the overall effect also
supports CO favoring to adsorb at top site.
11.1 Introduction
The CO adsorption on Pt surface has been studied extensively with great academic
and industrial interest because it is an important step of various CO catalytic reactions, such as CO oxidation, hydrogenation, Fischer-Tropsch reaction, and many
others [1, 2]. Due to its importance, the adsorption behaviors of CO on Pt have been
investigated not only experimentally but also theoretically [3–47]. Especially, CO
adsorption on Pt(111) has been long known as a puzzle and attracted much attention
in surface science [9]. Experimentally, low-energy electron diffraction (LEED) and
electron energy loss spectroscopy (EELS) indicates that the top site is favored for
S.-L. Lee (B)
Department of Chemistry and Biochemistry, National Chung-Cheng University, Chia-Yi 621,
Taiwan
e-mail: chesll@ccu.edu.tw
M. Hotokka et al. (eds.), Advances in Quantum Methods and Applications in
Chemistry, Physics, and Biology, Progress in Theoretical Chemistry and Physics 27,
DOI 10.1007/978-3-319-01529-3_11,
© Springer International Publishing Switzerland 2013
195
An Evaluation of Density Functional Theory
for CO Adsorption on Pt(111)
Yu-Wei Huang, Ren-Shiou Ke, Wei-Chang Hao, and Shyi-Long Lee
Abstract In this study, serveal different density functionals were applied to study
the CO adsorption on Pt(111) clusters. When adding more contribution of HF exchange energy, it can be found that the HOMO energy is decreased and LUMO
energy is increased, thus increasing the HOMO-LUMO energy gap. The accuracy
of S-T excitation energy can also be largely improved when increasing the ratio of
HF exchange energy. For CO adsorption at Pt 7–3 cluster, most functionals predict
that CO favors to adsorb at fcc site. Only when adding more than 40 % HF exchange energy, the M06HF, BMK, wB97 and M06-2X functionals can predict the
top-site preference. For CO adsorption at Pt 9–9–9 cluster, when adding more than
40 % HF exchange energy, the CO prefers to adsorb at top site than fcc site. Among
these functionals, the M06HF strongly predicts the top-site preference. The chemical bonding analysis shows that the effects of σ -repulsion are reduced as the CO S-T
excitation energy increasing, and the effect of reduction for CO at top site is more
remarkable than that for CO at fcc site. Therefore, CO would more favor to adsorb
at top site in those functionals which can give better CO S-T excitation energy. Although the opposite trend can be found for the π-attraction, the overall effect also
supports CO favoring to adsorb at top site.
11.1 Introduction
The CO adsorption on Pt surface has been studied extensively with great academic
and industrial interest because it is an important step of various CO catalytic reactions, such as CO oxidation, hydrogenation, Fischer-Tropsch reaction, and many
others [1, 2]. Due to its importance, the adsorption behaviors of CO on Pt have been
investigated not only experimentally but also theoretically [3–47]. Especially, CO
adsorption on Pt(111) has been long known as a puzzle and attracted much attention
in surface science [9]. Experimentally, low-energy electron diffraction (LEED) and
electron energy loss spectroscopy (EELS) indicates that the top site is favored for
S.-L. Lee (B)
Department of Chemistry and Biochemistry, National Chung-Cheng University, Chia-Yi 621,
Taiwan
e-mail: chesll@ccu.edu.tw
M. Hotokka et al. (eds.), Advances in Quantum Methods and Applications in
Chemistry, Physics, and Biology, Progress in Theoretical Chemistry and Physics 27,
DOI 10.1007/978-3-319-01529-3_11,
© Springer International Publishing Switzerland 2013
195