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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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Abstract
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/ | |||||||||
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| 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 | |||||||||
| Authors: |
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| 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 SCOPUS: | No | |||||||||
| In ISI Web of Science: | No | |||||||||
| Status: | Published | |||||||||
| 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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