The forms and properties of adsorption sites on Rh2Co2/Al2O3 have been 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 Rh4/Al2O3. The chemisorption properties of Rh^I sites and briged sites on Rh over Rh2Co2/Al2O3 for CO and NO are similar to that over Rh4Al2O3. While the chemisorption propertties of the linear sites on Co over Rh2Co2/Al2O3 on which preadsorbed CO can be replaced by NO and preadsorbed NO can not be replaced by CO are different from that of linear sites on Rh4/Al2O3 and that of Co sites on Co2/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 H2 at 400℃. The interaction between Rh and Co is strong.

Key words: COBALT, INFRARED SPECTROPHOTOMETRY, CATALYST, ALUMINIUM OXIDE, CARBON MONOXIDE, ADSORPTION, RHODIUM, NITROGEN MONOXIDE