New approach to enhance the NOx storage performance at high temperature using basic MgAl2O4 spinel support

Takahashi, Naoki; Matsunaga, Shigenori; Tanaka, Toŝhiyuki; Sobukawa, Hideo; Shinjoh, Hirofumi

doi:10.1016/j.apcatb.2007.07.007

Cited by 44 publications

(31 citation statements)

References 12 publications

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“…16 In Fig. 2, the thermal stability of the nitrates on the K sites of the CuO/K 2 CO 3 /MgAl 2 O 4 catalyst is higher compared with the CuO/K 2 CO 3 /Al 2 O 3 catalyst.…”

Section: Thermal Stability Of the Stored Nitratesmentioning

confidence: 98%

“…Under this condition, the activity of the traditional Pt/BaO/Al 2 O 3 NSR catalyst signicantly drops. 16,17 When the operating temperature exceeds 400 C, the solid-phase reaction between BaO and Al 2 O 3 to form BaAl 2 O 4 will lower the surface area and reduce the NO x storage sites. 18 Pt sintering also hampers the reduction of NO x from cycle to cycle.…”

Section: 7mentioning

confidence: 99%

“…16 MgAl 2 O 4 , as one of these mixed oxides, has been employed as support of high-temperature NSR catalysts. Through supported on MgAl 2 O 4 , the stability of nitrate species is strongly improved whether on potassium sites or barium sites, 16,18 and Pt sintering can also be effectively inhibited. 17 Additionally, the MgAl 2 O 4 support can provide extra storage sites for NO x .…”

Section: 7mentioning

confidence: 99%

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Enhanced activity of CuO/K₂CO₃/MgAl₂O₄catalyst for lean NO_xstorage and reduction at high temperatures

Liu

Guo

et al. 2017

RSC Adv.

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“…16 In Fig. 2, the thermal stability of the nitrates on the K sites of the CuO/K 2 CO 3 /MgAl 2 O 4 catalyst is higher compared with the CuO/K 2 CO 3 /Al 2 O 3 catalyst.…”

Section: Thermal Stability Of the Stored Nitratesmentioning

confidence: 98%

Section: 7mentioning

confidence: 99%

Section: 7mentioning

confidence: 99%

See 1 more Smart Citation

Enhanced activity of CuO/K₂CO₃/MgAl₂O₄catalyst for lean NO_xstorage and reduction at high temperatures

Liu

Guo

et al. 2017

RSC Adv.

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“…This research revealed that an alkaline earth ele ment added to Al2O3 yielded a mixed oxide with higher basicity than pure Al2O3 and effectively improved the storage material by stabilizing the nitrates formed, which thus enhanced the high-temperature NOx storage capacity. Details of this research are reported else where 26) . The NOx storage capacity at 523 K in Fig.…”

Section: U N D S D E T E C T E D I N T H E O U T L E T G a Smentioning

confidence: 99%

Improvement of Catalysts for NO<sub><i>x</i></sub> Storage and Reduction for Gasoline-fueled Automotive Exhaust

Takahashi

Imagawa

2009

J. Jpn. Petrol. Inst.

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Catalysts for nitrogen oxide (NOx) storage and reduction oxidize nitrogen monoxide (NO) emitted from auto motive lean-burn engines to nitrogen dioxide (NO2) that is then stored on doped NOx storage materials such as barium and/or potassium compounds as nitrate ions (NO3 -). In a reducing atmosphere provided by a suitable engine management system, the nitrates formed are subsequently reduced and decomposed into NOx via reactions between reducing agents in the exhaust gas such as hydrogen, carbon monoxide and hydrocarbons. The emitted NOx is finally reduced and detoxified to nitrogen. To meet stringent emission regulations for automotive exhaust pollutants, NOx storage and reduction catalysts must have excellent NOx removal activity and an extremely long lifetime. These catalysts can deteriorate not only due to thermal stress, but also to sulfur poisoning. Thermal stress causes a decrease in the number of active sites through sintering of precious metals, decreases the specific surface area of the support and leads to solid-phase reaction between the NOx storage material and the support. Sulfur is present in exhaust gas derived from gasoline fuel and it competes with NOx for storage and reacts with the doped NOx storage material to form sulfates. Once NOx storage materials are sulfated, they drastically lose their NOx storage capability. This report reviews the technologies used to overcome these issues and to improve the durability of NOx storage and reduction catalysts against both thermal damage and sulfur poisoning. An advanced novel catalyst system for NOx removal with synergistic NOx storage and reduction with ammonia (NH3) formation, storage and NOx selective reduction by NH3 functions is also described.

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“…Moreover, the results obtained over the Pt (1.0 wt%) / K (4.5 wt%) / Al 2 O 3 catalysts revealed that there are able to stored up to 0.797 mmol(NO)/g at 250 C within 1 h (Toops et al, 2005;Toops et al, 2006). The Pt(0.07-0.35 g)-K(1.0-3.3 g)/MgAl 2 O 4 catalysts, in which the spinel (MgAl 2 O 4 ) support enhanced the basicity of the K, were used as storage component (Takahashi et al, 2007a). The NO x storage capacity determined for the fresh and thermally aged K/Pt/MgAl 2 O 4 catalysts were apparently higher than those obtained for the K/Pt/Al 2 O 3 catalysts.…”

Section: Other Metal Oxide Supportsmentioning

confidence: 99%

A short review about NOx storage-reduction catalysts based on metal oxides and hydrotalcite-type anionic clays

Jabłońska¹,

Palomares

Węgrzyn³

et al. 2013

Acta Geodynamica Et Geomaterialia

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The increasing problem of atmospheric pollution by NO x has resulted in stricter regulations on their emissions. NO x storage/reduction (NSR) is considered as efficient catalytic technology to abate lean-burn NO x . A wide variety of catalysts have been extensively examined for this purpose. The use of metal oxides, hydrotalcites and their derivatives as NO x storage/reduction catalysts has been reviewed. Suitable combination particularly the catalytic redox component and the storage component can lead to improved activity in NO x decomposition and capturing under the lean-rich conditions. ARTICLE INFO

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New approach to enhance the NOx storage performance at high temperature using basic MgAl2O4 spinel support

Cited by 44 publications

References 12 publications

Enhanced activity of CuO/K₂CO₃/MgAl₂O₄catalyst for lean NO_xstorage and reduction at high temperatures

Enhanced activity of CuO/K₂CO₃/MgAl₂O₄catalyst for lean NO_xstorage and reduction at high temperatures

Improvement of Catalysts for NO<sub><i>x</i></sub> Storage and Reduction for Gasoline-fueled Automotive Exhaust

A short review about NOx storage-reduction catalysts based on metal oxides and hydrotalcite-type anionic clays

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New approach to enhance the NOx storage performance at high temperature using basic MgAl2O4 spinel support

Cited by 44 publications

References 12 publications

Enhanced activity of CuO/K2CO3/MgAl2O4catalyst for lean NOxstorage and reduction at high temperatures

Enhanced activity of CuO/K2CO3/MgAl2O4catalyst for lean NOxstorage and reduction at high temperatures

Improvement of Catalysts for NO<sub><i>x</i></sub> Storage and Reduction for Gasoline-fueled Automotive Exhaust

A short review about NOx storage-reduction catalysts based on metal oxides and hydrotalcite-type anionic clays

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Enhanced activity of CuO/K₂CO₃/MgAl₂O₄catalyst for lean NO_xstorage and reduction at high temperatures

Enhanced activity of CuO/K₂CO₃/MgAl₂O₄catalyst for lean NO_xstorage and reduction at high temperatures