Enhancement of the low temperature activity in NO reduction in lean conditions by SMSI effect in Pt/CeO2-ZrO2 on alumina catalyst

A treatment with H-2 at 800 degreesC followed by mild reoxidation (<300<deg rees>C) increases the low temperature (<200<degrees>C) steady-state activit y in the reduction of NO by propene in the presence Of O-2 of a Pt(1.5%)/(Z rO2-CeO2 on Al2O3) catalyst. The effect is not present for a lower temperat ure treatment with H-2 or for reoxidation above 300 degreesC. Transient rea ctivity tests together with characterization data (H-2-TPR, O-2 uptake, H-2 chemisorption) indicate that the high temperature reduction modifies the c haracteristics of ceria-zirconia and induced metal-support interaction effe cts, both responsible of the enhanced catalytic activity at low temperature .