From the powder to the honeycomb. A comparative study of the NSRefficiency and selectivity over Pt–CeZr based active phaseReport as inadecuate




From the powder to the honeycomb. A comparative study of the NSRefficiency and selectivity over Pt–CeZr based active phase - Download this document for free, or read online. Document in PDF available to download.

* Corresponding author 1 Du site actif au matériau catalytique E3 IC2MP - Institut de Chimie des Milieux et Matériaux de Poitiers 2 Ceramiques Techniques et Industrielles CTI 3 IFPEN - IFP Energies nouvelles

Abstract : From the powder to the honeycomb. A comparative study of the NSR efficiency and selectivity over Pt-CeZr based active phase. Abstract The efficiency and the selectivity of a model platinum based catalyst supported on a modified ceria-zirconia oxide was evaluated in the NOx storage-reduction NSR process at four catalytic scales: powder, 0.5-x1.5- flow-through monolith FTM system, small size 1-x2- and full size 5.66-x10- catalysed Diesel Particulate Filter DPF. The washcoating of the active phase over FTM affects both the NOx storage properties and the NOx reduction step. The reduction step efficiency is especially decreased at low temperatures. It is associated with an incomplete regeneration of the storage sites and with a strong NOx desorption peak during the rich pulses of the NSR process for the FTM supported system. The NOx reduction selectivity is also strongly affected by the upscale, with an important N2O selectivity detected over FTM. The recorded NOx profiles during NSR cycles indicate a probable diffusion limitation. However, same trends were observed for both powder and FTM systems concerning the effect of the reductant mixture, for both NSR efficiency and N-compounds selectivity. After incorporation of the active phase in the porosity of the DPF, a sharp drop in NOx storage properties and subsequently in NSR efficiency are observed. Supplementary tests suggest that the diffusion from the platinum oxidizing sites to the storage sites is again very affected by the upscale. Finally, the engine bench tests confirm the low DeNOx activity of the DPF system.

Keywords : NSR catalyst LNT NOx Honeycomb Washcoat DPF





Author: L Masdrag - X Courtois - F Can - B Cartoixa - Stéphane Raux - Aranud Frobert - D Duprez -

Source: https://hal.archives-ouvertes.fr/



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