The mechanism of emerging catalytic activity of gold nano-clusters on rutile TiO 2(110) in CO oxidation reaction

K. Mitsuhara, M. Tagami, T. Matsuda, A. Visikovskiy, M. Takizawa, Y. Kido

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11 Citations (Scopus)

Abstract

This paper reveals the fact that the O adatoms (O ad) adsorbed on the 5-fold Ti rows of rutile TiO 2(110) react with CO to form CO 2 at room temperature and the oxidation reaction is pronouncedly enhanced by Au nano-clusters deposited on the above O-rich TiO 2(110) surfaces. The optimum activity is obtained for 2D clusters with a lateral size of ∼1.5 nm and two-atomic layer height corresponding to ∼50 Au atomscluster. This strong activity emerging is attributed to an electronic charge transfer from Au clusters to O-rich TiO 2(110) supports observed clearly by work function measurement, which results in an interface dipole. The interface dipoles lower the potential barrier for dissociative O 2 adsorption on the surface and also enhance the reaction of CO with the O ad atoms to form CO 2 owing to the electric field of the interface dipoles, which generate an attractive force upon polar CO molecules and thus prolong the duration time on the Au nano-clusters. This electric field is screened by the valence electrons of Au clusters except near the perimeter interfaces, thereby the activity is diminished for three-dimensional clusters with a larger size.

Original languageEnglish
Article number124303
JournalJournal of Chemical Physics
Volume136
Issue number12
DOIs
Publication statusPublished - Mar 28 2012
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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