Measures to Reduce the N<sub>2</sub>O Formation at Perovskite-Based Lean NO<sub>x</sub> Trap Catalysts under Lean Conditions
The net oxidising atmosphere of lean burn engines requires a special after-treatment catalyst for NO<sub>x</sub> removal from the exhaust gas. Lean NO<sub>x</sub> traps (LNT) are such kind of catalysts. To increase the efficiency of LNTs at low temperatures platinised perovsk...
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MDPI AG
2021-07-01
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| author | Sabrina I. Ecker Jürgen Dornseiffer Stefan Baumann Olivier Guillon Henny J. M. Bouwmeester Wilhelm A. Meulenberg |
| author_facet | Sabrina I. Ecker Jürgen Dornseiffer Stefan Baumann Olivier Guillon Henny J. M. Bouwmeester Wilhelm A. Meulenberg |
| author_sort | Sabrina I. Ecker |
| collection | DOAJ |
| description | The net oxidising atmosphere of lean burn engines requires a special after-treatment catalyst for NO<sub>x</sub> removal from the exhaust gas. Lean NO<sub>x</sub> traps (LNT) are such kind of catalysts. To increase the efficiency of LNTs at low temperatures platinised perovskite-based infiltration composites La<sub>0.5</sub>Sr<sub>0.5</sub>Fe<sub>1-x</sub>M<sub>x</sub>O<sub>3-δ</sub>/Al<sub>2</sub>O<sub>3</sub> with M = Nb, Ti, Zr have been developed. In general, platinum based LNT catalysts show an undesired, hazardous formation of N<sub>2</sub>O in the lean operation mode due to a competing C<sub>3</sub>H<sub>6</sub>-selective catalytic reduction (SCR) at the platinum sites. To reduce N<sub>2</sub>O emissions an additional Rh-coating, obtained by incipient wetness impregnation, besides the Pt coating and a two-layered oxidation catalyst (2 wt.% Pd/20 wt.% CeO<sub>2</sub>/alumina)-LNT constitution, has been investigated. Though the combined Rh-Pt coating shows a slightly increased NO<sub>x</sub> storage capacity (NSC) at temperatures above 300 °C, it does not decrease N<sub>2</sub>O formation. The layered oxidation catalyst-LNT system shows a decrease in N<sub>2</sub>O formation of up to 60% at 200 °C, increasing the maximum NSC up to 176 µmol/g. Furthermore, the NSC temperature range is broadened compared to that of the pure LNT catalyst, now covering a range of 250–300 °C. |
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| last_indexed | 2024-03-10T08:56:21Z |
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| spelling | doaj.art-40dafb40383c498b9901640a163c73ae2023-11-22T07:06:41ZengMDPI AGCatalysts2073-43442021-07-0111891710.3390/catal11080917Measures to Reduce the N<sub>2</sub>O Formation at Perovskite-Based Lean NO<sub>x</sub> Trap Catalysts under Lean ConditionsSabrina I. Ecker0Jürgen Dornseiffer1Stefan Baumann2Olivier Guillon3Henny J. M. Bouwmeester4Wilhelm A. Meulenberg5Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research, IEK-1: Materials Synthesis and Processing, 52425 Jülich, GermanyForschungszentrum Jülich GmbH, Institute of Energy and Climate Research, IEK-1: Materials Synthesis and Processing, 52425 Jülich, GermanyForschungszentrum Jülich GmbH, Institute of Energy and Climate Research, IEK-1: Materials Synthesis and Processing, 52425 Jülich, GermanyForschungszentrum Jülich GmbH, Institute of Energy and Climate Research, IEK-1: Materials Synthesis and Processing, 52425 Jülich, GermanyForschungszentrum Jülich GmbH, Institute of Energy and Climate Research, IEK-1: Materials Synthesis and Processing, 52425 Jülich, GermanyForschungszentrum Jülich GmbH, Institute of Energy and Climate Research, IEK-1: Materials Synthesis and Processing, 52425 Jülich, GermanyThe net oxidising atmosphere of lean burn engines requires a special after-treatment catalyst for NO<sub>x</sub> removal from the exhaust gas. Lean NO<sub>x</sub> traps (LNT) are such kind of catalysts. To increase the efficiency of LNTs at low temperatures platinised perovskite-based infiltration composites La<sub>0.5</sub>Sr<sub>0.5</sub>Fe<sub>1-x</sub>M<sub>x</sub>O<sub>3-δ</sub>/Al<sub>2</sub>O<sub>3</sub> with M = Nb, Ti, Zr have been developed. In general, platinum based LNT catalysts show an undesired, hazardous formation of N<sub>2</sub>O in the lean operation mode due to a competing C<sub>3</sub>H<sub>6</sub>-selective catalytic reduction (SCR) at the platinum sites. To reduce N<sub>2</sub>O emissions an additional Rh-coating, obtained by incipient wetness impregnation, besides the Pt coating and a two-layered oxidation catalyst (2 wt.% Pd/20 wt.% CeO<sub>2</sub>/alumina)-LNT constitution, has been investigated. Though the combined Rh-Pt coating shows a slightly increased NO<sub>x</sub> storage capacity (NSC) at temperatures above 300 °C, it does not decrease N<sub>2</sub>O formation. The layered oxidation catalyst-LNT system shows a decrease in N<sub>2</sub>O formation of up to 60% at 200 °C, increasing the maximum NSC up to 176 µmol/g. Furthermore, the NSC temperature range is broadened compared to that of the pure LNT catalyst, now covering a range of 250–300 °C.https://www.mdpi.com/2073-4344/11/8/917Lean NO<sub>x</sub> trap (LNT)N<sub>2</sub>O formationC<sub>3</sub>H<sub>6</sub>-SCR (selective catalytic reduction)precious metal (Pt, Rh, Pd)layered catalyst constitution |
| spellingShingle | Sabrina I. Ecker Jürgen Dornseiffer Stefan Baumann Olivier Guillon Henny J. M. Bouwmeester Wilhelm A. Meulenberg Measures to Reduce the N<sub>2</sub>O Formation at Perovskite-Based Lean NO<sub>x</sub> Trap Catalysts under Lean Conditions Catalysts Lean NO<sub>x</sub> trap (LNT) N<sub>2</sub>O formation C<sub>3</sub>H<sub>6</sub>-SCR (selective catalytic reduction) precious metal (Pt, Rh, Pd) layered catalyst constitution |
| title | Measures to Reduce the N<sub>2</sub>O Formation at Perovskite-Based Lean NO<sub>x</sub> Trap Catalysts under Lean Conditions |
| title_full | Measures to Reduce the N<sub>2</sub>O Formation at Perovskite-Based Lean NO<sub>x</sub> Trap Catalysts under Lean Conditions |
| title_fullStr | Measures to Reduce the N<sub>2</sub>O Formation at Perovskite-Based Lean NO<sub>x</sub> Trap Catalysts under Lean Conditions |
| title_full_unstemmed | Measures to Reduce the N<sub>2</sub>O Formation at Perovskite-Based Lean NO<sub>x</sub> Trap Catalysts under Lean Conditions |
| title_short | Measures to Reduce the N<sub>2</sub>O Formation at Perovskite-Based Lean NO<sub>x</sub> Trap Catalysts under Lean Conditions |
| title_sort | measures to reduce the n sub 2 sub o formation at perovskite based lean no sub x sub trap catalysts under lean conditions |
| topic | Lean NO<sub>x</sub> trap (LNT) N<sub>2</sub>O formation C<sub>3</sub>H<sub>6</sub>-SCR (selective catalytic reduction) precious metal (Pt, Rh, Pd) layered catalyst constitution |
| url | https://www.mdpi.com/2073-4344/11/8/917 |
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