Tailoring of the structure of Fe-cationic species in Fe-ZSM-5 by distribution of Al atoms in the framework for N2O decomposition and NH3-SCR-NOx

Sazama, Petr; Wichterlová, Blanka; Tábor, Edyta; Stastny, Petr; Sathu, Naveen K.; Sobalı́k, Zdenĕk; Dědeček, Jiřı́; Sklenák, Štěpán; Klein, Petr; Vondrová, Alena

doi:10.1016/j.jcat.2014.01.019

Cited by 108 publications

(117 citation statements)

References 94 publications

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“…[18][19][20][21] However, the role of the Brønsted sites in an ionexchanged zeolite is not well understood at present. For Cu-MFI and Cu-CHA zeolites it was found that the SCR activity at 200 • C is not dependent on the amount of Brønsted sites in these materials.…”

Section: Mechanistic Aspects Of the Scr Reactionmentioning

confidence: 99%

A Consistent Reaction Scheme for the Selective Catalytic Reduction of Nitrogen Oxides with Ammonia

et al. 2015

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For the first time, the standard and fast selective catalytic reduction (SCR) of NO by NH3 are described in a complete catalytic cycle that is able to produce the correct stoichiometry while allowing adsorption and desorption of stable molecules only. The standard SCR reaction is a coupling of the activation of NO by O2 with the fast SCR reaction, enabled by the release of NO2. According to the scheme, the SCR reaction can be divided into an oxidation of the catalyst by NO + O2 and a reduction by NO + NH3; these steps together constitute a complete catalytic cycle. Furthermore, both NO and NH3 are required in the reduction, and finally, oxidation by NO + O2 or NO2 leads to the same state of the catalyst. These points are shown experimentally for a Cu-CHA catalyst by combining in situ X-ray absorption spectroscopy (XAS), electron paramagnetic resonance (EPR), and Fourier transform infrared spectroscopy (FTIR). A consequence of the reaction scheme is that all intermediates in fast SCR are also part of the standard SCR cycle. The activation energy calculated by density functional theory (DFT) indicates that the oxidation of an NO molecule by O2 to a bidentate nitrate ligand is rate-determining for standard SCR. Finally, the role of a nitrate/nitrite equilibrium and the possible influence of Cu dimers and Brønsted sites are discussed, and an explanation is offered as to how a catalyst can be effective for SCR while being a poor catalyst for NO oxidation to NO2.

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Section: Mechanistic Aspects Of the Scr Reactionmentioning

confidence: 99%

A Consistent Reaction Scheme for the Selective Catalytic Reduction of Nitrogen Oxides with Ammonia

et al. 2015

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“…[1][2][3] Among the recent decades, such methods as the selective catalytic reduction (SCR) of NO x with NH 3 , catalytic decomposition, and plasma catalysis have been applied in eliminating NO x . [4][5][6] Nowadays, the NH 3 SCR technology is widely employed in the de-NO x applications, and the commercial V 2 O 5 -WO 3 (MoO 3 )/TiO 2 catalysts have been widely used for stationary source applications. [7][8][9][10] However, there are still some issues which need be solved, such as the high operation temperature as well as the biology toxicity of vanadium.…”

Section: Introductionmentioning

confidence: 99%

“…al found that WO 3 supported on TiO 2 achieved a preferable NO conversion with NH 3 at higher temperature ranging from 350-600 8C. [23] The newly formed surface O=WO 4 sites have been demonstrated to enhance the NH 3 SCR activity of WO 3 /TiO 2 catalyst. [24] Shan et.…”

Section: Introductionmentioning

confidence: 99%

Investigations on the Antimony Promotional Effect on CeO₂–WO₃/TiO₂ for Selective Catalytic Reduction of NO_x with NH₃

Liang

Liu

et al. 2016

ChemCatChem

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Antimony‐doped CeO2–WO3/TiO2 catalysts were prepared by a conventional ultrasonic‐assisted impregnation method and employed for selective catalytic reduction of NOx with NH3 at low temperature. Both experimental work and theoretical studies were employed to elucidate the effect of the antimony on promoting the CeO2–WO3/TiO2 catalyst. The catalytic activity of CeO2–WO3/TiO2 was largely improved after the addition of antimony oxide. It was found that antimony doping reduced the crystal size and strengthened the synergistic effect between the metal cations, which resulted in a favorable catalyst surface status with abundant active surface oxygen, Brønsted acid sites, and effective electron transfer. Both in situ diffuse reflectance infrared Fourier transform analysis and DFT calculation results revealed that the ammonia and NOx desorption behavior over the catalyst surface were considerably different. For the ammonia species, rather large amounts of the active NH4+ and NH3 species anchored on the surface of the Sb‐doped CeO2–WO3/TiO2. In view of the NOx species, the amount of nonactive bidentate nitrate species was largely reduced and the amount of active gaseous NO2 species was clearly enhanced, which lowered the activation energy of the catalytic process and gave rise to the elevated low‐temperature NH3 selective catalytic reduction activity. All these preferable properties resulted in the elevated de‐NOx activity of the Sb‐doped CeO2–WO3/TiO2 catalyst.

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“…In the present study, the role of sub-VIII elements in the division of N 2 O is more prominent. Sazama et al [10] obtained Fe / ZSM-5 catalyst by ion exchange method. The ferrous iron element obtained by UV-vis and TPD was favorable for the catalytic decomposition of N 2 O.…”

Section: The Catalytic Cracking Technologymentioning

confidence: 99%

Research Progress on Catalytic Reduction of NOx in Chemical Engineering

Cai¹

2017

dteees

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Abstract. With the increasingly serious environmental problems, catalytic denitrification technology of coal-fired flue gas has been developed rapidly. Aiming at the widely used selective catalytic reduction and denitrification technology, this paper summarizes the ammonia selective catalytic denitrification technology and non-ammonia catalytic denitrification technology at the low temperature from the mechanism of catalytic denitrification technology. The reaction mechanism and reaction process of metal oxide catalysts, molecular sieve catalysts and carbon-based catalysts were summarized among ammonia selective catalytic denitrification technology in the low-temperature. For the non-ammonia catalytic denitrification technology at low temperature, the catalytic cracking technology, HC-SCR technology, NO x adsorption-reduction technology and CO catalytic denitrification technology were summarized as well. On the basis of this, this paper figures out the future research direction of low temperature catalytic denitrification, which is to improve the denitrification process to improve the catalytic denitrification process, vigorously develop nitrogen oxide adsorption reduction technology.

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Tailoring of the structure of Fe-cationic species in Fe-ZSM-5 by distribution of Al atoms in the framework for N2O decomposition and NH3-SCR-NOx

Cited by 108 publications

References 94 publications

A Consistent Reaction Scheme for the Selective Catalytic Reduction of Nitrogen Oxides with Ammonia

A Consistent Reaction Scheme for the Selective Catalytic Reduction of Nitrogen Oxides with Ammonia

Investigations on the Antimony Promotional Effect on CeO₂–WO₃/TiO₂ for Selective Catalytic Reduction of NO_x with NH₃

Research Progress on Catalytic Reduction of NOx in Chemical Engineering

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Tailoring of the structure of Fe-cationic species in Fe-ZSM-5 by distribution of Al atoms in the framework for N2O decomposition and NH3-SCR-NOx

Cited by 108 publications

References 94 publications

A Consistent Reaction Scheme for the Selective Catalytic Reduction of Nitrogen Oxides with Ammonia

A Consistent Reaction Scheme for the Selective Catalytic Reduction of Nitrogen Oxides with Ammonia

Investigations on the Antimony Promotional Effect on CeO2–WO3/TiO2 for Selective Catalytic Reduction of NOx with NH3

Research Progress on Catalytic Reduction of NOx in Chemical Engineering

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Investigations on the Antimony Promotional Effect on CeO₂–WO₃/TiO₂ for Selective Catalytic Reduction of NO_x with NH₃