Modification of silver surface with palladium and chlorine and its effect on the reaction of firmly adsorbed oxygen with ethene

Pulse chromatography revealed the reduced reactivity and enhanced selectivity of silver-chemisorbed oxygen in ethene oxidation in the presence of Pd0 and Cl-. The enhanced selectivity was found for both adsorbed and absorbed oxygen forms (OI and OII, respectively). The reduced reactivity is attributed to a high OI-Ag surface bond energy hindering the formation of an intermediate complex involved in partial and complete oxidation of ethene. The selectivity is enhanced because the centers adjacent to this complex are blocked by modifier species, thus preventing chemisorbed fragments from oxidizing into CO2 and water.