PREPARATION, CHARACTERIZATION, AND CATALYTIC BEHAVIOR OF MORH2O6 SUPPORTED ON SIO2

Rh double-oxide compound (MoRh2O6) supported on SiO2 was prepared by air calcination treatment of a molybdenum oxide-promoted Rh/SiO2 catalyst at 700-degrees-C, and the chemisorptive and catalytic properties of the compound, as well as the changes in those behaviors by H-2 reduction, have been studied. The MoRh2O6/SiO2 catalyst exhibited almost no ability of H-2 and CO chemisorption, but a high activity for CO oxidation reaction. After H-2 treatment at 200-degrees-C, X-ray diffraction showed that the MoRh2O6 compound was reduced to a MoRh alloy, and this catalyst now exhibited a significant activity for the hydrogenolysis of cyclohexane. A drastic decrease in the activity was, however, observed after H-2 treatment at 500-degrees-C.