EXCHANGE AND OXIDATION OF (CO)-O-16 ON O-18-PREDOSED RH-AL2O3 AND RH-CEO2 CATALYSTS

Exchange and oxidation of (CO)-O-16 were investigated at 450 degrees C on O-18-predosed Ph and Pt catalysts supported on Al2O3, CeO2 and CeO 2-Al2O3. In all cases, a rapid exchange of (CO)-O-16 With the surface can be observed. CO oxidation leads to (CO2)-O-16, (COO)-O-16-O-18 and (CO2)-O-18. Significant formation of (CO2)-O-16 is due to the relativ ely high O-16 coverage in reaction resulting O-18 surface species and O-16 internal atoms. Hydrogen is also from the (CO)-O-16 exchange and from an exchange between formed via a water-gas shift reaction (CO + s urface OH) in higher proportion on CeO2-containing catalysts than on A l2O3. Chlorine inhibits all the reactions (exchange, oxidation and WGS ) and particularly the internal exchange.