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Title: Selective reduction of NO{sub x} by methane on Co-ferrierites. II. Catalyst characterization

Abstract

Co-ferrierite, active for the selective NO reduction by CH{sub 4}, was characterized by X-ray photon spectroscopy and magnetic susceptibility measurements. The adsorption of NO and NO{sub 2} was studied by diffuse-reflectance FTIR spectroscopy to discover which intermediates participate in the NO{sub x} reduction. The valence state of cobalt in Co-ferrierite and other Co-zeolite catalysts was found to be 2+. The dominant NO species adsorbed on Co-Y, Co-ZSM-5, and Co-ferrierite is in a dinitrosyl form appearing at 1810 and 1897 cm{sup -1} for Co-Y and 1810 and 1890 cm{sup -1} for Co-ZSM-5 and Co-ferrierite. The mononitrosyl form of the adsorbed NO is a minor species appearing at 1930-1935 cm{sup -1} on all three samples. The mononitrosyl species on all samples is extremely weakly adsorbed. The dinitrosyl species adsorbed on Co-ferrierite is strongly adsorbed and needs to be heated above 300{degrees}C to desorb. Interestingly, the weakly adsorbed mononitrosyl species is enhanced in an O{sub 2} environment (100 Torr of O{sub 2}) and is now stable to 200{degrees}C. However, in an oxygen environment, the dinitrosyl species is less stable, desorbing at {approximately}200{degrees}C. All adsorbed NO species disappear at >200{degrees}C in 100 Torr O{sub 2}, and adsorbed NO{sub 2} species were observed. NO{sub 2}more » adsorbed on Co-ferrierite shows a weakly adsorbed, covalent N{sub 2}O{sub 5} in addition to stable species, such as nitro, nitrito, and nitrato species. Together with earlier kinetic and reaction studies, the authors suggest a mechanism for the selective reduction of NO{sub x} by CH{sub 4}. 44 refs., 9 figs., 4 tabs.« less

Authors:
; ;  [1]
  1. Air Products and Cheimicals, Inc., Allentown, PA (United States)
Publication Date:
OSTI Identifier:
47983
Resource Type:
Journal Article
Journal Name:
Journal of Catalysis
Additional Journal Information:
Journal Volume: 150; Journal Issue: 2; Other Information: PBD: Dec 1994
Country of Publication:
United States
Language:
English
Subject:
40 CHEMISTRY; 20 FOSSIL-FUELED POWER PLANTS; ZEOLITES; CATALYTIC EFFECTS; NITROGEN OXIDES; SELECTIVE CATALYTIC REDUCTION; COBALT OXIDES; REACTION INTERMEDIATES; METHANE; ACTIVATION ENERGY; COMBUSTION; CHEMICAL REACTION KINETICS; X-RAY SPECTROSCOPY; MAGNETIC SUSCEPTIBILITY; SORPTIVE PROPERTIES; ABSORPTION SPECTROSCOPY

Citation Formats

Li, Yuejin, Slager, T L, and Armor, J N. Selective reduction of NO{sub x} by methane on Co-ferrierites. II. Catalyst characterization. United States: N. p., 1994. Web. doi:10.1006/jcat.1994.1357.
Li, Yuejin, Slager, T L, & Armor, J N. Selective reduction of NO{sub x} by methane on Co-ferrierites. II. Catalyst characterization. United States. https://doi.org/10.1006/jcat.1994.1357
Li, Yuejin, Slager, T L, and Armor, J N. Thu . "Selective reduction of NO{sub x} by methane on Co-ferrierites. II. Catalyst characterization". United States. https://doi.org/10.1006/jcat.1994.1357.
@article{osti_47983,
title = {Selective reduction of NO{sub x} by methane on Co-ferrierites. II. Catalyst characterization},
author = {Li, Yuejin and Slager, T L and Armor, J N},
abstractNote = {Co-ferrierite, active for the selective NO reduction by CH{sub 4}, was characterized by X-ray photon spectroscopy and magnetic susceptibility measurements. The adsorption of NO and NO{sub 2} was studied by diffuse-reflectance FTIR spectroscopy to discover which intermediates participate in the NO{sub x} reduction. The valence state of cobalt in Co-ferrierite and other Co-zeolite catalysts was found to be 2+. The dominant NO species adsorbed on Co-Y, Co-ZSM-5, and Co-ferrierite is in a dinitrosyl form appearing at 1810 and 1897 cm{sup -1} for Co-Y and 1810 and 1890 cm{sup -1} for Co-ZSM-5 and Co-ferrierite. The mononitrosyl form of the adsorbed NO is a minor species appearing at 1930-1935 cm{sup -1} on all three samples. The mononitrosyl species on all samples is extremely weakly adsorbed. The dinitrosyl species adsorbed on Co-ferrierite is strongly adsorbed and needs to be heated above 300{degrees}C to desorb. Interestingly, the weakly adsorbed mononitrosyl species is enhanced in an O{sub 2} environment (100 Torr of O{sub 2}) and is now stable to 200{degrees}C. However, in an oxygen environment, the dinitrosyl species is less stable, desorbing at {approximately}200{degrees}C. All adsorbed NO species disappear at >200{degrees}C in 100 Torr O{sub 2}, and adsorbed NO{sub 2} species were observed. NO{sub 2} adsorbed on Co-ferrierite shows a weakly adsorbed, covalent N{sub 2}O{sub 5} in addition to stable species, such as nitro, nitrito, and nitrato species. Together with earlier kinetic and reaction studies, the authors suggest a mechanism for the selective reduction of NO{sub x} by CH{sub 4}. 44 refs., 9 figs., 4 tabs.},
doi = {10.1006/jcat.1994.1357},
url = {https://www.osti.gov/biblio/47983}, journal = {Journal of Catalysis},
number = 2,
volume = 150,
place = {United States},
year = {1994},
month = {12}
}