Activation of O2 on Cu, Ag, and Au surfaces for the epoxidation of ethylene

Dipped adcluster model study

Hiroshi Nakatsuji, Zhen Ming Hu, Hiromi Nakai, Keiji Ikeda

    Research output: Contribution to journalArticle

    64 Citations (Scopus)

    Abstract

    Aiming to clarify why only silver is an effective catalyst for the partial oxidation of ethylene, we studied theoretically the reactivity and the stability of oxygen species on Cu, Ag, and Au surfaces. We used the dipped adcluster model (DAM), since electron transfer from metal to oxygen is important, and the SAC/SAC-CI method, since several electronic states are involved. We found that if Superoxide species exists on the surface, both Cu and Au surfaces show a reactivity similar to Ag surface, leading smoothly to ethylene oxide, and the barriers leading to complete oxidations should be very high. Therefore, the point is the relative stability of the various oxygen species and, in particular, the stability of the Superoxide species on the metal surface. On Cu, Superoxide is much less stable than peroxide, which again is less stable than the dissociated species, and no barrier exists for the conversion from Superoxide to peroxide. On Au, our DAM calculations show that the electron flow from the bulk metal into the adcluster does not occur, so that the molecularly adsorbed oxygen species, as well as the dissociative ones, find it difficult to exist stably on the clean surface. On Ag, Superoxide should certainly have some life time to react with ethylene to give ethylene oxide, which is considered to be the origin of the unique catalytic activity of silver for the epoxidation of ethylene. This is related to the ability of electron transfer and to the geometry of the Ag surface. We have proposed a basic idea for a new catalytic design of the epoxidation reaction.

    Original languageEnglish
    Pages (from-to)328-341
    Number of pages14
    JournalSurface Science
    Volume387
    Issue number1-3
    Publication statusPublished - 1997 Oct 8

    Fingerprint

    epoxidation
    Epoxidation
    inorganic peroxides
    Ethylene
    ethylene
    Chemical activation
    activation
    Superoxides
    Oxygen
    Ethylene Oxide
    peroxides
    oxygen
    ethylene oxide
    Metals
    Peroxides
    Silver
    electron transfer
    reactivity
    Electrons
    silver

    Keywords

    • Copper
    • Dipped adcluster model (DAM)
    • Epoxidation of ethylene
    • Gold
    • Oxygen chemisorption
    • Peroxide
    • Reactivity
    • SAC/SAC-CI method
    • Silver
    • Stability
    • Superoxide

    ASJC Scopus subject areas

    • Physical and Theoretical Chemistry
    • Condensed Matter Physics
    • Surfaces and Interfaces

    Cite this

    Activation of O2 on Cu, Ag, and Au surfaces for the epoxidation of ethylene : Dipped adcluster model study. / Nakatsuji, Hiroshi; Hu, Zhen Ming; Nakai, Hiromi; Ikeda, Keiji.

    In: Surface Science, Vol. 387, No. 1-3, 08.10.1997, p. 328-341.

    Research output: Contribution to journalArticle

    Nakatsuji, Hiroshi ; Hu, Zhen Ming ; Nakai, Hiromi ; Ikeda, Keiji. / Activation of O2 on Cu, Ag, and Au surfaces for the epoxidation of ethylene : Dipped adcluster model study. In: Surface Science. 1997 ; Vol. 387, No. 1-3. pp. 328-341.
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