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 °C, and the chemisorptive and catalytic properties of the compound, as well as the changes in those behaviors by H₂ reduction, have been studied.The MoRh₂O₆/SiO₂ catalyst exhibited almost no ability of H₂ and CO chemisorption, but a high activity for CO oxidation reaction. After H₂ treatment at 200 °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 H₂ treatment at 500 °C.