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H<sub>2</sub>–SCR NO<sub>x</sub> catalytic activity and N<sub>2</sub>-selectivity of Pd-exchanged perovskites

Mondragon Rodriguez, Guillermo Cesar and Saruhan Brings, Bilge (2008) H<sub>2</sub>–SCR NO<sub>x</sub> catalytic activity and N<sub>2</sub>-selectivity of Pd-exchanged perovskites. In: [2008 5th International Conference on Environmental Catalysis]. [5th ICEC], [2008-08-31 - 2008-09-04]], Belfast, UK.

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As demonstrated in the literature, palladium exchanged perovskites offers enhanced catalytic performance in TWC applications [1]. Concerning the elimination of nitrogen oxides under lean conditions over perovskite catalysts, the use of hydrogen as a reducing agent has been less studied [2]. Considering the stringency of the legislation for emission in engines, the use of hydrogen as a reducing agent to eliminate NO<sub>x</sub> under lean conditions and at relatively low temperatures may be a feasible solution in the forthcoming future. In this work we compare two palladium exchanged perovskite catalysts (La<sub>0.95</sub>Ce<sub>0.05</sub>Fe<sub>0.95</sub>Pd<sub>0.05</sub>O<sub>3</sub> and BaTi<sub>0.95</sub>Pd<sub>0.05</sub>O<sub>3</sub> both calcined at 900°C) in terms of their catalytic activity regarding the NO-reduction employing H<sub>2</sub> as reducing agent. The effect of H<sub>2</sub>O + CO<sub>2</sub> or CO to the catalytic activity is also reported paying special attention to the N<sub>2</sub>-selectivity of the catalysts. Results Both catalysts showed similar NO-conversion capability (70-75%) under a feedstock composition of 720 ppm NO, 5% O<sub>2</sub> and 1% H<sub>2</sub>. Under these conditions, the catalytic performance of the BaTi<sub>0.95</sub>Pd<sub>0.05</sub>O<sub>3</sub> catalyst was at low temperatures compared to the La<sub>0.95</sub>Ce<sub>0.05</sub>Fe<sub>0.95</sub>Pd<sub>0.05</sub>O<sub>3</sub> catalyst (150°C vs. 225°C). In the presence of H<sub>2</sub>O and CO<sub>2</sub> in the feedstock, the maximum NO-conversion achieved at 240°C with the La<sub>0.95</sub>Ce<sub>0.05</sub>Fe<sub>0.95</sub>Pd<sub>0.05</sub>O<sub>3</sub> was 55% whilst 70% with the BaTi<sub>0.95</sub>Pd<sub>0.05</sub>O<sub>3</sub> catalyst. Addition of 0.25% CO to the feedstock (without H<sub>2</sub>O and CO<sub>2</sub>) reduced the NO-conversion capability of both catalysts drastically (50% with BaTi<sub>0.95</sub>Pd<sub>0.05</sub>O<sub>3</sub> and 60% with La<sub>0.95</sub>Ce<sub>0.05</sub>Fe<sub>0.95</sub>Pd<sub>0.05</sub>O<sub>3</sub> catalyst). N<sub>2</sub>-selectivity was higher with BaTi<sub>0.95</sub>Pd<sub>0.05</sub>O<sub>3</sub> (over 80%) compared to La<sub>0.95</sub>Ce<sub>0.05</sub>Fe<sub>0.95</sub>Pd<sub>0.05</sub>O<sub>3</sub> (65-75%) at temperatures below 200°C under lean conditions, indicating a more selective character at low temperatures for single-site catalyst. N<sub>2</sub>-selectivity of both catalysts was very little influenced in the presence of H<sub>2</sub>O and CO<sub>2</sub> in the feedstock, whereas it was reduced down to 50-60% with the addition of CO. [1] R. Karita, H. Kusabe, K. Sasaki, Y. Teraoka, Catal. Today 119 (2007) 83-87. [2] I. Twagiraschema, M. Engelman-Pirez, M. Frere, L. Burylo, L. Gengembre, C. Dujardin, P. Granger, Catal. Today 119 (2007) 100-105.

Item URL in elib:https://elib.dlr.de/56330/
Document Type:Conference or Workshop Item (Poster)
Title:H<sub>2</sub>–SCR NO<sub>x</sub> catalytic activity and N<sub>2</sub>-selectivity of Pd-exchanged perovskites
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Mondragon Rodriguez, Guillermo CesarUNSPECIFIEDUNSPECIFIED
Date:1 October 2008
Journal or Publication Title:[2008 5th International Conference on Environmental Catalysis]
Refereed publication:No
Open Access:No
Gold Open Access:No
In ISI Web of Science:No
Keywords:[Adaptive Perovskite, NOx-reduction, lean-burn conditions]
Event Title:[5th ICEC]
Event Location:Belfast, UK
Event Type:international Conference
Event Dates:[2008-08-31 - 2008-09-04]]
Organizer:Queen's University
HGF - Research field:Aeronautics, Space and Transport (old)
HGF - Program:Aeronautics
HGF - Program Themes:Propulsion Systems (old)
DLR - Research area:Aeronautics
DLR - Program:L ER - Engine Research
DLR - Research theme (Project):E - Schadstoffe (old)
Location: Köln-Porz
Institutes and Institutions:Institute of Materials Research > High Temperature and Functional Coatings
Deposited By: Mondragon Rodriguez, Guillermo Cesar
Deposited On:27 Nov 2008
Last Modified:27 Apr 2009 15:31

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