Defect of HY as catalyst for selective catalytic reduction of NO in comparison with the pentasil zeolites

Ma, Xiaofei; Wang, Xinping; Bi, Ran; Zhao, Zhen; He, Hong

doi:10.1016/j.molcata.2009.01.005

Cited by 8 publications

(3 citation statements)

References 35 publications

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“…Coming to the second group of bands, it is composed of a broad absorption, with a maximum at 2139 cm −1 and a shoulder at 2070 cm −1 , with a very broad band centered at 1975 cm −1 , which are not present on the reduced sample. Similar bands have been assigned by different authors to NO + [48][49][50], formed by the reaction of NO with adsorbed oxygen atoms, and with the formation of NO 2 , which then reacts with protons to give NO + and water [51]. Similarly, Rivallan et al proposed that NO 2 is transformed into physisorbed HNO 3 , which mediates the formation of NO + ions that exchange zeolite protons [44].…”

Section: Zp Samplesupporting

confidence: 62%

Fe Speciation in Iron Modified Natural Zeolites as Sustainable Environmental Catalysts

et al. 2019

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Natural purified mordenite from Palmarito de Cauto (ZP) deposit, Cuba, was subjected to a hydrothermal ion exchange process in acid medium with Fe2+ or Fe3+ salts (Fe2+ZP and Fe3+ZP). The set of samples was characterized regarding their textural properties, morphology, and crystallinity, and tested in the NO reduction with CO/C3H6. Infrared spectroscopy coupled with NO as a probe molecule was used to give a qualitative description of the Fe species’ nature and distribution. The exchange process caused an increase in the iron loading of the samples and a redistribution, resulting in more dispersed Fe2+ and Fe3+ species. When contacted with the NO probe, Fe2+ZP showed the highest intensity of nitrosyl bands, assigned to NO adducts on isolated/highly dispersed Fe2+/Fe3+ extra-framework sites and FexOy clusters. This sample is also characterized by the highest NO sorption capacity and activity in NO reduction. Fe3+ZP showed a higher intensity of nitrosonium (NO+) species, without a correlation to NO storage and conversion, pointing to the reactivity of small FexOy aggregates in providing oxygen atoms for the NO to NO+ reaction. The same sites are proposed to be responsible for the higher production of CO2 observed on this sample, and thus to be detrimental to the activity in NO SCR.

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Section: Zp Samplesupporting

confidence: 62%

Fe Speciation in Iron Modified Natural Zeolites as Sustainable Environmental Catalysts

et al. 2019

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show abstract

“…Coming to the second group of bands, it is composed of a broad absorption, with a maximum at 2139 cm −1 and a shoulder at 2070 cm −1 , with a very broad band centered at 1975 cm −1 , which are not present on the reduced sample. Similar bands have been assigned by different authors to NO + [49][50][51], formed by the www.videleaf.com reaction of NO with adsorbed oxygen atoms, and with the formation of NO 2 , which then reacts with protons to give NO + and water [52]. Similarly, Rivallan et al proposed that NO 2 is transformed into physisorbed HNO 3 , which mediates the formation of NO + ions that exchange zeolite protons [45].…”

Section: Zp Samplesupporting

confidence: 59%

Iron Modified Natural Zeolite as Sustainable Environmental Catalysts: Correlation between Iron Speciation and Catalytic Activity in NO-Reduction

Petranovskii¹,

Concepción-Rosabal²,

Ferro³

et al. 2020

Prime Archives in Chemistry

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Natural purified mordenite from Palmarito de Cauto (ZP) deposit, Cuba, was subjected to a hydrothermal ion exchange process in acid medium with Fe 2+ or Fe 3+ salts (Fe 2+ ZP and Fe 3+ ZP). The set of samples was characterized regarding their textural properties, morphology, and crystallinity, and tested in the NO reduction with CO/C 3 H 6 . Infrared spectroscopy coupled Prime Archives in Chemistry 3 www.videleaf.com with NO as a probe molecule was used to give a qualitative description of the Fe species' nature and distribution. The exchange process caused an increase in the iron loading of the samples and a redistribution, resulting in more dispersed Fe 2+ and Fe 3+ species. When contacted with the NO probe, Fe 2+ ZP showed the highest intensity of nitrosyl bands, assigned to NO adducts on isolated/highly dispersed Fe 2+ /Fe 3+ extra-framework sites and Fe x O y clusters. This sample is also characterized by the highest NO sorption capacity and activity in NO reduction. Fe 3+ ZP showed a higher intensity of nitrosonium (NO + ) species, without a correlation to NO storage and conversion, pointing to the reactivity of small Fe x O y aggregates, and providing oxygen atoms for the NO to NO + reaction. The same sites are proposed to be responsible for the higher production of CO 2 observed on this sample, and thus to be detrimental to the activity in NO SCR.

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“…The small concentration of strong Bronsted acid sites in HY were blamed for the inferior catalytic ability of the zeolite as are required for HC-SCR, and accordingly a low activity in the reduction of NO. 137…”

Section: Gases Adsorbed In Zeolitesmentioning

confidence: 99%

Spectroscopic characterisation of molecules adsorbed at zeolite surfaces

Rhodes¹

2010

Annu. Rep. Prog. Chem., Sect. C: Phys. Chem.

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Defect of HY as catalyst for selective catalytic reduction of NO in comparison with the pentasil zeolites

Cited by 8 publications

References 35 publications

Fe Speciation in Iron Modified Natural Zeolites as Sustainable Environmental Catalysts

Fe Speciation in Iron Modified Natural Zeolites as Sustainable Environmental Catalysts

Iron Modified Natural Zeolite as Sustainable Environmental Catalysts: Correlation between Iron Speciation and Catalytic Activity in NO-Reduction

Spectroscopic characterisation of molecules adsorbed at zeolite surfaces

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