Adsorption properties of SO 2 on ultrafine precious metal particles studied using density functional calculation

Nobumoto Ohashi, Kentaro Yoshizawa, Akira Endou, Seiichi Takami, Momoji Kubo, Akira Miyamoto

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)180-188
Number of pages9
JournalApplied Surface Science
Volume177
Issue number3
DOIs
Publication statusPublished - 2001 Jun 8

Keywords

  • Adsorption energy
  • Density functional calculations
  • Metal cluster
  • Molecular adsorption
  • Pd
  • Pt
  • SO

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Physics and Astronomy(all)
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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