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Title: Mechanistic cause of hydrocarbon specificity over Cu/ZSM-5 and Co/ZSM-5 catalysts in the selective catalytic reduction of NO{sub x}

Abstract

The nature of adsorbed nitrogen oxide complexes (NO{sub y}) has been identified by FTIR spectroscopy. Nitrito groups are most prominent on Co/ZSM-5. These complexes are stable at 150{degrees}C in He but are reduced upon exposure to either C{sub 3}H{sub 8} or CH{sub 4} leading to the formation of N{sub 2}. Conversely, Cu/ZSM-5 forms nitro and nitrate groups which are stable at 200{degrees}C. At this temperature these complexes are chemically reduced to N{sub 2} upon exposure to CA yet remain inert to CH{sub 4}. At higher temperatures, thermal decomposition yields NO/NO{sub 2}, O{sub 2}, and H{sub 2}O. The specific rate of NO reduction over Cu/ZSM-5 decreases with Cu loading indicating that isolated Cu{sup 2+}{center_dot}NO{sub 2} complexes pay a significant role in the mechanism. The hydrocarbon specificity of these complexes thus matches the known catalytic specificity of NO, reduction over Cu/ZSM-5 and Co/ZSM-5. The mechanistic cause for the catalytic specificity of the ZSM-5 hosted metals in NO, reduction thus is traced back to the structure and reactivity of the specific NO{sub y} adsorption complexes which these metals produce upon interacting with NO + O{sub 2}. The consumption of CH{sub 4} when feeds containing NO, CH{sub 4} and O{sub 2} are exposed tomore » Cu/ZSM-5 can be attributed to nonselective combustion with adsorbed oxygen and not to reactions with NO{sub y}. 26 refs., 8 figs., 3 tabs.« less

Authors:
; ;  [1]
  1. Northwestern Univ., Evanston, IL (United States) [and others
Publication Date:
OSTI Identifier:
223993
Resource Type:
Journal Article
Journal Name:
Journal of Catalysis
Additional Journal Information:
Journal Volume: 158; Journal Issue: 1; Other Information: PBD: Jan 1996
Country of Publication:
United States
Language:
English
Subject:
33 ADVANCED PROPULSION SYSTEMS; 20 FOSSIL-FUELED POWER PLANTS; 40 CHEMISTRY; COPPER; CATALYTIC EFFECTS; COBALT; NITROGEN OXIDES; SELECTIVE CATALYTIC REDUCTION; ZEOLITES; PROPANE; OXIDATION; CHEMICAL REACTION KINETICS; CATALYSTS; CATALYST SUPPORTS; ABSORPTION SPECTROSCOPY

Citation Formats

Adelman, B.J., Beutel, T., and Lei, G.D. Mechanistic cause of hydrocarbon specificity over Cu/ZSM-5 and Co/ZSM-5 catalysts in the selective catalytic reduction of NO{sub x}. United States: N. p., 1996. Web. doi:10.1006/jcat.1996.0031.
Adelman, B.J., Beutel, T., & Lei, G.D. Mechanistic cause of hydrocarbon specificity over Cu/ZSM-5 and Co/ZSM-5 catalysts in the selective catalytic reduction of NO{sub x}. United States. doi:10.1006/jcat.1996.0031.
Adelman, B.J., Beutel, T., and Lei, G.D. Mon . "Mechanistic cause of hydrocarbon specificity over Cu/ZSM-5 and Co/ZSM-5 catalysts in the selective catalytic reduction of NO{sub x}". United States. doi:10.1006/jcat.1996.0031.
@article{osti_223993,
title = {Mechanistic cause of hydrocarbon specificity over Cu/ZSM-5 and Co/ZSM-5 catalysts in the selective catalytic reduction of NO{sub x}},
author = {Adelman, B.J. and Beutel, T. and Lei, G.D.},
abstractNote = {The nature of adsorbed nitrogen oxide complexes (NO{sub y}) has been identified by FTIR spectroscopy. Nitrito groups are most prominent on Co/ZSM-5. These complexes are stable at 150{degrees}C in He but are reduced upon exposure to either C{sub 3}H{sub 8} or CH{sub 4} leading to the formation of N{sub 2}. Conversely, Cu/ZSM-5 forms nitro and nitrate groups which are stable at 200{degrees}C. At this temperature these complexes are chemically reduced to N{sub 2} upon exposure to CA yet remain inert to CH{sub 4}. At higher temperatures, thermal decomposition yields NO/NO{sub 2}, O{sub 2}, and H{sub 2}O. The specific rate of NO reduction over Cu/ZSM-5 decreases with Cu loading indicating that isolated Cu{sup 2+}{center_dot}NO{sub 2} complexes pay a significant role in the mechanism. The hydrocarbon specificity of these complexes thus matches the known catalytic specificity of NO, reduction over Cu/ZSM-5 and Co/ZSM-5. The mechanistic cause for the catalytic specificity of the ZSM-5 hosted metals in NO, reduction thus is traced back to the structure and reactivity of the specific NO{sub y} adsorption complexes which these metals produce upon interacting with NO + O{sub 2}. The consumption of CH{sub 4} when feeds containing NO, CH{sub 4} and O{sub 2} are exposed to Cu/ZSM-5 can be attributed to nonselective combustion with adsorbed oxygen and not to reactions with NO{sub y}. 26 refs., 8 figs., 3 tabs.},
doi = {10.1006/jcat.1996.0031},
journal = {Journal of Catalysis},
number = 1,
volume = 158,
place = {United States},
year = {1996},
month = {1}
}