SILICA SUPPORTED RHODIUM-RUTHENIUM BIMETALLIC CATALYSTS IN CARBON-MONOXIDE HYDROGENATION .1. INFLUENCE OF THE METHOD OF PREPARATION AND METHANATION BEHAVIOR

Silica supported Rh-Ru bimetallic catalysts were prepared by impregnation, characterized by X-ray diffraction and hydrogen chemisorption and their methanation behavior studied over a wide temperature range. The influence of preparation method - specifically the drying step and the effect of preoxidation prior to reduction - was examined. The existence of mixed metal clusters was supported by the results of carbon monoxide methanation which was used as a probe reaction. The addition of rhodium to ruthenium gave catalysts which were more efficient for methanation of carbon monoxide at higher temperature. As the reaction temperature was raised, the methanation efficiency of ruthenium was lowered due to the competing water gas-shift reaction. Addition of rhodium helped methanation by suppressing the formation of carbon dioxide because of its better ability to convert carbon dioxide to methane.