Synergism in the reaction of CO with O2on bimetallic Rh[ndash ]Pd catalysts supported on silica

A study is made of the activity of Pd–Rh/SiO2 catalysts prepared by different impregnation methods on the reaction of CO with O2, with particular emphasis on the possible existence of a synergistic effect between the two metals in an oxidizing atmosphere. The results show a remarkable influence of the impregnation method on the catalysts' activity, confirming the existence of a synergistic effect in the catalysts prepared by sequential impregnation. This effect is strongly dependent on the previous treatment of the catalyst.