STUDY OF RHCO BIMETAL CATALYSTS .4. FORMS AND PROPERTIES OF ADSORPTION SITES ON RH2CO2 AL2O3/

The forms and properties of adsorption sites on Rh-2/Co-2/Al2O3 have b een studied in detail by using CO and NO as double probes. The results indicate that there are Rh-I sites and bridged sites on Rh and linear sites on Co over Rh-4/Al2O3. The chemisorption properties of Rh-I sit es and bridged sites on Rh over Rh2Co2/Al2O3 for CO and NO are similar to that over Rh-4/Al2O3. While the chemisorption properties of the li near sites on Co over Rh2Co2/Al2O3 art which preadsorbed CO can be rep laced by NO and preadsorbed NO can not be replaced by CO are different from that of linear sites on Rh-4/Al2O3 and that of Co sites on Co-2/ Al2O3 and Rh + Co/Al2O3. To relate above results with the structure of original Rh2Co2(CO)(12), it indicate that Rh2CO2(CO)(12) impregnated on Al2O3 retain its structure after reduction with H-2 at 400 degrees C. The interaction between Rh and Co is strong.