A Simulation Study of Effect of Mn-Ce/γ-Al2O3on NOxStorage and Reduction over Pt-Ce-Ba/γ-Al2O3Catalysts

Abstract

A series of Pt-Ce-Ba/γ-Al2O3and Mn-Ce/γ-Al2O3catalysts were synthesized by a sol-gel method and the samples were characterized by XRD, SEM, and EDS. The effect of Mn-Ce/γ-Al2O3on the storage and reduction of NOxover Pt-Ce-Ba/γ-Al2O3catalysts was studied in a fix-bed reactor with simulation gases NO, O2, and N2. The results indicated that NO oxidation to NO2was reduced with the increase of inlet NO concentration, which was up to 83% when the concentration of NO was 500 ppm but reduced to 76% with the concentration of NO increasing to 1000 ppm. Comparing with the Pt-Ce-Ba/γ-Al2O3catalysts, the rate of NOxstorage and reduction was remarkably increased over Pt-Ce-Ba/γ-Al2O3combined with Mn-Ce/γ-Al2O3catalysts. However, the reductant used for NOxreduction reaction over Pt-Ce-Ba/γ-Al2O3catalysts was consumed under the treatment of Mn-Ce/γ-Al2O3catalyst, which caused the NOxconversion to obviously drop, but the rate of NOxabsorption declined slightly.