On the mechanism of the SCR reaction on Fe/HBEA zeolite

Klukowski, D.; Balle, Peter; Geiger, Bastian; Wagloehner, Steffen; Kureti, Sven; Kimmerle, Bertram; Baiker, Alfons; Grunwaldt, Jan‐Dierk

doi:10.1016/j.apcatb.2009.09.028

Cited by 106 publications

(88 citation statements)

References 36 publications

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“…In addition, Brandenberger et al 111 concluded that the Brønsted acid sites might not be required directly in the SCR process for adsorbing or activating NH 3 , but they were necessary to bind and disperse the reactive Fe 3+ ions in the preparation process for Fe-based zeolite catalysts, similar to the results reported by Iwasaki et al 104 Furthermore, the zeolite support with Brønsted acidity could also play a role as an NH 3 reservoir, regardless of the form in which the NH 3 was stored, and in the NH 3 -SCR reaction the stored NH 3 could migrate to the active sites so as to undergo a reaction with NO. 111 A similar spill-over effect of NH 3 on the zeolite support to the active Fe 3+ sites in the NH 3 -SCR reaction was also reported by Klukowski et al 112 on their Fe-HBEA catalyst. Therefore, in brief summary, nowadays researchers basically agree that in the standard NH 3 -SCR reaction the oxidation function of Fe-based zeolite catalysts and the amount of active Fe species, but not the acidic properties of the zeolite supports, are the main factors controlling the deNO x efficiency.…”

Section: Nh 3 -Scr Of No X Over Zeolite Catalystssupporting

confidence: 72%

Environmentally-benign catalysts for the selective catalytic reduction of NO_xfrom diesel engines: structure–activity relationship and reaction mechanism aspects

2014

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Selective catalytic reduction of NO x using NH 3 or hydrocarbons (NH 3 -SCR or HC-SCR) in oxygen-rich exhaust from diesel engines remains a major challenge in environmental catalysis. The development of highly efficient, stable and environmentally-benign catalysts for SCR processes is very important for practical use. In this feature article, the structure-activity relationship of vanadium-free catalysts in the NH 3 -SCR reaction is discussed in detail, including Fe-, Ce-based oxide catalysts and Fe-, Cu-based zeolite catalysts, which is beneficial for catalyst redesign and activity improvement. Based on our research, a comprehensive mechanism contributing to the performance of Ag/Al 2 O 3 in HC-SCR is provided, giving a clue to the design of a catalytic system with high efficiency.

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Section: Nh 3 -Scr Of No X Over Zeolite Catalystssupporting

confidence: 72%

Environmentally-benign catalysts for the selective catalytic reduction of NO_xfrom diesel engines: structure–activity relationship and reaction mechanism aspects

2014

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“…Furthermore, the zeolite support with Brønsted acidity could play a role as NH 3 reservoir no matter what form of NH 3 was stored, and in the NH 3 -SCR reaction, the stored NH 3 could migrate to the active sites so as to undergo a reaction with NO [50]. A similar spillover effect of NH 3 on the zeolite support to the active Fe 3+ sites in the NH 3 -SCR reaction was also reported by Klukowski et al [51] on their Fe-HBEA catalyst.…”

Section: Acid Sites Of Fe-zeolite Catalysts In the Nh 3 -Scr Reactionsupporting

confidence: 56%

Emerging Applications of Environmentally Friendly Zeolites in the Selective Catalytic Reduction of Nitrogen Oxides

Xie

Shi

2016

Green Chemistry and Sustainable Technology

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The catalytic removal of nitrogen oxides (NO x ) from diesel exhaust under oxygen-rich conditions remains a major challenge in the field of environmental catalysis, and the selective catalytic reduction of NO x with NH 3 (NH 3 -SCR), especially over zeolite catalysts, is a well-proven technique for the catalytic deNO x process for diesel vehicles. The comprehensive understanding of the structure-activity relationship of zeolite catalysts in the NH 3 -SCR reaction and the elucidation of the detailed reaction mechanism are very important for the practical use of these catalytic materials. In this chapter, using the environmentally friendly Fe-and Cu-based zeolite catalysts (i.e. Fe-ZSM-5, Cu-ZSM-5, Cu-SSZ-13 and Cu-SAPO-34, etc.) as examples, the influence of preparation methods on NH 3 -SCR performance, the role of metal active sites/surface acid sites, the impact of NO 2 and co-existing pollutants, the hydrothermal stability and also the possible SCR reaction pathways over these materials are discussed in detail, which can provide theoretical and empirical guidance for the redesign and activity improvement of these catalysts in their practical applications.

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“…Recent in situ UV-vis and combined XAFS/XRD studies confirmed that such species remain intact during NH 3 -SCR and are thus responsible for the high catalytic activity [5,9]. A similar conclusion has recently been put forward for the high activity of Fe-BEA systems for the same reaction, the active species being proposed to be monomeric Fe 3+ species [10].…”

Section: Introductionmentioning

confidence: 77%

Changing active sites in Cu–CHA catalysts: deNOx selectivity as a function of the preparation method

Deka

Lezcano‐González

Warrender

et al. 2013

Microporous and Mesoporous Materials

135

119

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On the mechanism of the SCR reaction on Fe/HBEA zeolite

Cited by 106 publications

References 36 publications

Environmentally-benign catalysts for the selective catalytic reduction of NO_xfrom diesel engines: structure–activity relationship and reaction mechanism aspects

Environmentally-benign catalysts for the selective catalytic reduction of NO_xfrom diesel engines: structure–activity relationship and reaction mechanism aspects

Emerging Applications of Environmentally Friendly Zeolites in the Selective Catalytic Reduction of Nitrogen Oxides

Changing active sites in Cu–CHA catalysts: deNOx selectivity as a function of the preparation method

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On the mechanism of the SCR reaction on Fe/HBEA zeolite

Cited by 106 publications

References 36 publications

Environmentally-benign catalysts for the selective catalytic reduction of NOxfrom diesel engines: structure–activity relationship and reaction mechanism aspects

Environmentally-benign catalysts for the selective catalytic reduction of NOxfrom diesel engines: structure–activity relationship and reaction mechanism aspects

Emerging Applications of Environmentally Friendly Zeolites in the Selective Catalytic Reduction of Nitrogen Oxides

Changing active sites in Cu–CHA catalysts: deNOx selectivity as a function of the preparation method

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Environmentally-benign catalysts for the selective catalytic reduction of NO_xfrom diesel engines: structure–activity relationship and reaction mechanism aspects

Environmentally-benign catalysts for the selective catalytic reduction of NO_xfrom diesel engines: structure–activity relationship and reaction mechanism aspects