TY - JOUR
T1 - Adsorption properties of SO 2 on ultrafine precious metal particles studied using density functional calculation
AU - Ohashi, Nobumoto
AU - Yoshizawa, Kentaro
AU - Endou, Akira
AU - Takami, Seiichi
AU - Kubo, Momoji
AU - Miyamoto, Akira
PY - 2001/6/8
Y1 - 2001/6/8
N2 - The microscopic adsorption properties of molecules including SO 2 on ultrafine precious metal particles such as Pd and Pt were investigated using density functional quantum chemical calculations. The precious metal particles which are used as the activation sites in a three-way catalyst (TWC) were modeled by Pd 3 and Pt 3 clusters. The adsorption energies (E ads ) of the molecules on the metal clusters were calculated. Different possible adsorption sites of SO 2 on the Pd 3 and Pt 3 clusters were considered. It was found that the SO 2 adsorption states on the Pd 3 cluster are energetically more stable than those on the Pt 3 cluster when SO 2 molecule was initially located perpendicular to the cluster plane. There were only small differences in the values of E ads for the SO 2 adsorption on each adsorption site of the Pd 3 clusters. However, in the case of the Pt 3 cluster, the values of E ads for SO 2 adsorption depended on the adsorption sites. Moreover, when SO 2 molecule and the cluster were on the same plane, the SO 2 adsorption state on the Pd 3 cluster was energetically less stable than that on the Pt 3 cluster. These results indicate that the adsorption stabilities of SO 2 on the Pd 3 cluster strongly depend on the adsorption geometries. The difference in the adsorption stabilities of SO 2 on the Pd 3 cluster can be explained by the difference in the orbital interaction near the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energy levels.
AB - The microscopic adsorption properties of molecules including SO 2 on ultrafine precious metal particles such as Pd and Pt were investigated using density functional quantum chemical calculations. The precious metal particles which are used as the activation sites in a three-way catalyst (TWC) were modeled by Pd 3 and Pt 3 clusters. The adsorption energies (E ads ) of the molecules on the metal clusters were calculated. Different possible adsorption sites of SO 2 on the Pd 3 and Pt 3 clusters were considered. It was found that the SO 2 adsorption states on the Pd 3 cluster are energetically more stable than those on the Pt 3 cluster when SO 2 molecule was initially located perpendicular to the cluster plane. There were only small differences in the values of E ads for the SO 2 adsorption on each adsorption site of the Pd 3 clusters. However, in the case of the Pt 3 cluster, the values of E ads for SO 2 adsorption depended on the adsorption sites. Moreover, when SO 2 molecule and the cluster were on the same plane, the SO 2 adsorption state on the Pd 3 cluster was energetically less stable than that on the Pt 3 cluster. These results indicate that the adsorption stabilities of SO 2 on the Pd 3 cluster strongly depend on the adsorption geometries. The difference in the adsorption stabilities of SO 2 on the Pd 3 cluster can be explained by the difference in the orbital interaction near the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energy levels.
KW - Adsorption energy
KW - Density functional calculations
KW - Metal cluster
KW - Molecular adsorption
KW - Pd
KW - Pt
KW - SO
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U2 - 10.1016/S0169-4332(01)00198-2
DO - 10.1016/S0169-4332(01)00198-2
M3 - Article
AN - SCOPUS:0035827424
SN - 0169-4332
VL - 177
SP - 180
EP - 188
JO - Applied Surface Science
JF - Applied Surface Science
IS - 3
ER -