Two-components catalysts Rh-ReO
x/SiO
2, Rh-MoO
x/SiO
2 and Ir-ReO
x/SiO
2 were active in the C-O hydrogenolysis of glycerol, 1,2-propanediol and tetrahydrofurfuryl alcohol. The activities were much higher than those of monometallic catalysts. The selectivities to terminal alcohols decreased in the following order: Ir-ReO
x/SiO
2 > Rh-ReO
x/SiO
2 > Rh-MoO
x/SiO
2 » Rh/SiO
2. Characterization with XRD, TEM, CO adsorption, temperature-programmed reduction (TPR), XANES and EXAFS revealed that noble-metal particles were partially covered with ReO
x or MoO
x species. The MoO
x species in Rh-MoO
x/SiO
2 formed a monomeric structure. The ReO
x species in Rh-ReO
x/SiO
2 and Ir-ReO
x/SiO
2 formed monolayer clusters and multilayer clusters, respectively. A reaction mechanism was proposed where the alkoxide species formed on ReO
x (or MoO
x) was attacked by the active hydrogen species on Rh (or Ir) atoms bonded with the Re (or Mo) atom. The difference of the size of the modifier may affect the selectivity.
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