The influence of xMnyCe/γ-Al2O3 on NOx catalysts on the properties of NOx storage and reduction over Pt-Ce-Ba/γ-Al2O3 catalysts

- The oxidation activity of all xMnyCe/γ-Al2O3 samples present in different order.
- NOx storage speed and periodic storage capability of NSR increased by NO2 generation.
- H2 reacted with O2 to form H2O over DOC will accelerate the NOx desorption process.

The aim of the study was to investigate the influence of Diesel Oxidation Catalysts (DOC) xMnyCe/γ-Al2O3catalysts on the properties of NOx storage and reduction (NSR) under the treatment of Pt-Ce-Ba/γ-Al2O3 catalysts. The physicochemical properties of DOC and NSR were determined with XRD, TEM and XPS. The results showed that Pt-CeO2 interaction had a great impact on the dispersion of the NSR catalyst. Furthermore, the performance of NO oxidation by DOC and NOx desorption by DOC/NSR combined system were evaluated based on the simulation experiments. Moreover, optimal operation of the single NSR catalyst and the DOC/NSR combined system were attained at 400 °C, while the durations of the lean and rich periods were tL = 240 s and tR = 30 s/45 s/60 s, respectively. The single NSR catalyst showed that the highest NOx conversion and maximum NOx adsorption conversion were 58.0% and 74.8%. The DOC/NSR combined system allowed Pt10Ce15Ba/γ-Al2O3 catalyst storing the NO2 oxidized on the 6Mn10Ce/γ-Al2O3 catalyst, favoring the NOx storage process during the lean phase. And it also allowed the stored NOx species of NSR catalysts desorbing due to H2 oxidation by the 6Mn10Ce/γ-Al2O3 catalyst, favoring the NOx desorption process during the rich phase.

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