Catalysis by oxide-supported clusters of iridium and rhodium: Hydrogenation of ethene, propene, and toluene

被引:51
作者
Argo, AM [1 ]
Odzak, JF [1 ]
Goellner, JF [1 ]
Lai, FS [1 ]
Xiao, FS [1 ]
Gates, BC [1 ]
机构
[1] Univ Calif Davis, Dept Chem Engn & Mat Sci, Davis, CA 95616 USA
关键词
D O I
10.1021/jp0548523
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The hydrogenation reactions of ethenc, propene, and toluene were used as probes of the catalytic properties of small clusters of rhodium (Rh-6) and of iridium (Ir-4 and Ir-6) (as well as of larger aggregates of these metals) on oxide supports (gamma-Al2O3, MgO, and La2O3). The catalysts were characterized in the working state by extended-X-ray absorption fine structure (EXAFS) spectroscopy, providing evidence of the cluster structures and cluster-support interactions; by infrared spectroscopy, providing evidence of hydrocarbon adsorbates and possible reaction intermediates on the clusters; and by kinetics of the hydrogenation reactions. The EXAFS data indicate that the metal clusters, while remaining intact and maintaining their bonding to the support during catalysis, under-went slight rearrangements to accommodate reactive intermediates. As the concentrations of reactive intermediates such as pi-bonded alkenes and alkyls on the clusters increased, the cluster frames swelled, and the clusters flexed away from the support. The data indicate self-inhibition of reaction by adsorbed hydrocarbons and differences between ethene hydrogenation and propene hydrogenation that may arise primarily from different adsorbate-adsorbate interactions.
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页码:1775 / 1786
页数:12
相关论文
共 42 条
  • [11] BEEK O, 1950, DISCUSS FARADAY SOC, P118
  • [12] CRYSTAL-STRUCTURE OF TETRAIRIDIUM DODECACARBONYL, IR4(CO)12 - UNPLEASANT CASE OF DISORDER
    CHURCHILL, MR
    HUTCHINSON, JP
    [J]. INORGANIC CHEMISTRY, 1978, 17 (12) : 3528 - 3535
  • [13] CRYSTAL STRUCTURE OF RH2O3
    COEY, JMD
    [J]. ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL CRYSTALLOGRAPHY AND CRYSTAL CHEMISTRY, 1970, B 26 (NOV15): : 1876 - &
  • [14] KINETIC-STUDY OF ETHYLENE HYDROGENATION
    CORTRIGHT, RD
    GODDARD, SA
    REKOSKE, JE
    DUMESIC, JA
    [J]. JOURNAL OF CATALYSIS, 1991, 127 (01) : 342 - 353
  • [15] Ethylene hydrogenation on Pt(111) monitored in situ at high pressures using sum frequency generation
    Cremer, PS
    Su, XC
    Shen, YR
    Somorjai, GA
    [J]. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1996, 118 (12) : 2942 - 2949
  • [16] The first measurement of an absolute surface concentration of reaction intermediates in ethylene hydrogenation
    Cremer, PS
    Su, XC
    Shen, YR
    Somorjai, GA
    [J]. CATALYSIS LETTERS, 1996, 40 (3-4) : 143 - 145
  • [17] DONNAY JDH, 1973, CRYSTAL DATA DETERMI, V2, pC4
  • [18] DEUTERIUM TRACING STUDIES AND MICROKINETIC ANALYSIS OF ETHYLENE HYDROGENATION OVER PLATINUM
    GODDARD, SA
    CORTRIGHT, RD
    DUMESIC, JA
    [J]. JOURNAL OF CATALYSIS, 1992, 137 (01) : 186 - 198
  • [19] GOELLNER JF, 2000, THESIS U CALIFORNIA
  • [20] Horiuti J., 1968, Hydrogenation of Ethylene on Metallic Catalysts