The reaction of ethylene on a model automotive emissions control catalyst

The reaction of ethylene on a model automotive emissions control catalyst c onsisting of Rh particles on an epitaxial ceria film grown on the (100) sur face of an yttria-stabilized zirconia single crystal was studied using TPD. The TPD results showed that ethylene undergoes dehydrogenation on the mode l catalyst at temperatures below 500 K depositing carbon on the Rh particle s. Surface carbon formed in this manner was oxidized to CO upon heating to above 550 K using oxygen supplied by the ceria lattice. Heating to 900 K wa s found to induce reduction of the ceria film resulting in a marked decreas e in oxidation activity.