Interactions of CO with Pt/ceria catalysts

摘要

The interaction between CO and Pt/ceria catalysts was investigated by oxygen storage capacity measurements, CO and CO_2 isotope exchange and FT-IR measurements. A Pt/alumina sample was also investigated for comparison. The capacity to store and release oxygen as a function of ceria surface-area and Pt-ceria contact was estimated. The presence of chlorine from the Pt pre-cursor was found not to decrease the oxygen storage capacity. However, FT-IR measurements showed that chlorine hindered the carbonate formation during CO exposure, which was found to be the main form of carbon storage on the pre-oxidized sample. On a strongly reduced sample, CO disproportionation was found to occur to an increasing extent with increasing degree of reduction. CO and CO_2 isotope exchange showed that these molecules exchange their oxygen with Pt/ceria and ceria quite easily at 400 deg C. CO uptake on ceria was strongly suppressed, especially on the Cl-free sample, but not completely hindered.