TPD Study of Mordenite-Type Zeolites for Selective Catalytic Reduction of NO by NH3

Choi, Eun‐Young; Nam, In−Sik; Kim, Young Gul

doi:10.1006/jcat.1996.0222

Cited by 119 publications

(68 citation statements)

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“…[1][2][3] It has been found that pentasil zeolites (ZSM-5, ferrierite and mordenite) loaded with transition metal ions may display high activities towards the decomposition and reduction of NO. [4][5][6] Despite the large amount of available experimental and theoretical studies, the exact nature of the active site and the reaction mechanism are still under debate. Detailed knowledge of the location and coordination of the transition metal ions in these zeolites is an important first step to a better understanding of these materials.…”

Section: Introductionmentioning

confidence: 99%

The siting of Cu(II) in mordenite: a theoretical spectroscopic study

Delabie

Pierloot

Groothaert

et al. 2001

Phys. Chem. Chem. Phys.

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The siting of Cu(II) in mordenite has been studied by ab initio calculations on large cluster models, representing the cation exchange sites in mordenite. Partial geometry optimizations, based on density functional theory (DFT), were performed to obtain the structure of the coordination environment of Cu(II) at the different sites. The ligand field spectra and EPR g-tensors of these clusters were then calculated by means of multiconfigurational perturbation theory (CASPT2). The calculated results were compared with experimental information, obtained by diffuse reflectance spectroscopy (DRS) and EPR. The calculations indicate that at low exchange levels Cu(II) is coordinated to oxygen six-rings in the main channel of mordenite, in the presence of two aluminiums. At higher loadings, six-or five-rings containing only one aluminium also become occupied, where Cu(II) is coordinated as a single ion, not as (Cu-OH) þ . The calculations indicate also that in fully dehydrated mordenite, the twisted eight-ring (site A) is not occupied by Cu(II).

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Section: Introductionmentioning

confidence: 99%

The siting of Cu(II) in mordenite: a theoretical spectroscopic study

Delabie

Pierloot

Groothaert

et al. 2001

Phys. Chem. Chem. Phys.

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show abstract

“…However, the role and the influence of protons should be considered, since the H-forms of zeolites are active, [10] and a dual site mechanism on H and Fe n sites was proposed for the SCR of NO by NH 3 on partially exchanged Fe-ZSM-5. [11] On highly loaded Cu-FAU catalysts, the presence of remaining protons has only a small effect, and the SCR is mainly regulated by the Cu /Cu 2 redox cycle.…”

Section: Introductionmentioning

confidence: 99%

Selective Catalytic Reduction of NO by NH3 on Cu-Faujasite Catalysts: An Experimental and Quantum Chemical Approach

et al. 2002

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“…The Barrett-Joyner-Halenda (BJH) average pore size of the resulting SBA-15 was 200 Å . 3 , Aldrich) solution. The catalyst was dried at 100°C overnight and calcined at 400°C for 6 h in air.…”

Section: Methodsmentioning

confidence: 99%

“…However, some problems remain in the application of NH 3 -SCR & Ralph T. Yang yang@umich.edu technology, such as ammonia slip, SO 2 oxidation (by vanadia catalysts), and air heater and equipment fouling by the formation of a ''white powder'' (i.e., ammonium compounds such as bisulfate, sulfate and nitrate….) as well as SO 3 .…”

Section: Introductionmentioning

confidence: 98%

“…The selective catalytic reduction (SCR) of NO x is one of the most effective methods. The commercial removal of NO x in power plants is SCR using ammonia as the reducing agent [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. However, some problems remain in the application of NH 3 -SCR & Ralph T. Yang yang@umich.edu technology, such as ammonia slip, SO 2 oxidation (by vanadia catalysts), and air heater and equipment fouling by the formation of a ''white powder'' (i.e., ammonium compounds such as bisulfate, sulfate and nitrate….)…”

Section: Introductionmentioning

confidence: 99%

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SCR of Nitric Oxide by Hydrogen over Pd and Ir Based Catalysts with Different Supports

et al. 2015

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Selective catalytic reduction of NO x with hydrogen (H 2 -SCR) in excess oxygen over Pd and Ir based catalysts with various silica supports was studied. The Pd/ V 2 O 5 /TiO 2 /SBA-15 and Ir/SBA-15 catalysts showed the highest activities. The effects of noble metal, various silica supports, CO and SO 2 on H 2 -SCR over these catalysts were also studied and compared, and possible underlying mechanisms discussed. A comparison of 1 % Ir-doped on silicas with a wide range of pore sizes showed that the peak temperature (where the NO conversion maximum was located) was directly related to the pore size: larger pores of the support resulted in higher peak temperatures. This result indicates that pore diffusion limitation played a role in determining the peak temperature. In addition, a nonnoble metal catalyst, Nb 2 O 5 /SiO 2 , was found to have considerable activity.Graphical Abstract Larger pores of the support resulted in higher peak temperatures, which indicated that pore diffusion limitation played a direct role.

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TPD Study of Mordenite-Type Zeolites for Selective Catalytic Reduction of NO by NH3

Cited by 119 publications

References 0 publications

The siting of Cu(II) in mordenite: a theoretical spectroscopic study

The siting of Cu(II) in mordenite: a theoretical spectroscopic study

Selective Catalytic Reduction of NO by NH3 on Cu-Faujasite Catalysts: An Experimental and Quantum Chemical Approach

SCR of Nitric Oxide by Hydrogen over Pd and Ir Based Catalysts with Different Supports

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