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Title: Carbon dioxide as oxidant for the conversion of methane to ethane and ethylene using modified CeO{sub 2} catalysts

Abstract

CaO-CeO{sub 2} is the most effective catalyst for the conversion at 850 C of CH{sub 4} to C{sub 2}H{sub 6} and C{sub 2}H{sub 4} by CO{sub 2} among a series of CeO{sub 2} catalysts modified with alkali and alkaline earth metal oxides. When the CaO-CeO{sub 2} catalyst is prepared in the range of Ca/Ce ratio 0.1--0.5 by impregnation method, there exist synergistic effects between the two components for the formation of C{sub 2} hydrocarbons, and the catalyst forms solid solution. It is thus suggested that the formation of solid solution is responsible for synergistic effects. The lattice oxygen of the CaO-CeO{sub 2} catalyst converts CH{sub 4} mainly to H{sub 2} and CO, and the presence of CO{sub 2} is indispensable for C{sub 2} formation. Both C{sub 2} selectivity and C{sub 2} yield increase remarkably with increasing partial pressure of CO{sub 2}, these values at 850 C reaching 75 and 4% at 70 kPa, respectively. Correlation of the results of kinetic analyses and CO{sub 2} TPD measurements indicates that the existence of the pool of the CO{sub 2} chemisorbed on the CaO-CeO{sub 2} catalyst accounts for high C{sub 2} selectivity and yield. The characterization of the binary catalyst show that bulkmore » carbonates are not detectable during reaction and Ce{sup 3+} sites are formed at the outermost layer. It is speculated that these sites activate the chemisorbed CO{sub 2} to generate active oxygen species, which work for the conversion of CH{sub 4} to C{sub 2} hydrocarbons.« less

Authors:
; ;  [1]
  1. Tohoku Univ., Sendai (Japan)
Publication Date:
OSTI Identifier:
687732
Resource Type:
Journal Article
Journal Name:
Journal of Catalysis
Additional Journal Information:
Journal Volume: 186; Journal Issue: 1; Other Information: PBD: 15 Aug 1999
Country of Publication:
United States
Language:
English
Subject:
03 NATURAL GAS; 10 SYNTHETIC FUELS; METHANE; REFORMER PROCESSES; CALCIUM OXIDES; CERIUM OXIDES; CATALYTIC EFFECTS; ETHYLENE; SYNTHESIS; CARBON DIOXIDE; OXIDIZERS

Citation Formats

Wang, Y., Takahashi, Yoshimoto, and Ohtsuka, Yasuo. Carbon dioxide as oxidant for the conversion of methane to ethane and ethylene using modified CeO{sub 2} catalysts. United States: N. p., 1999. Web. doi:10.1006/jcat.1999.2538.
Wang, Y., Takahashi, Yoshimoto, & Ohtsuka, Yasuo. Carbon dioxide as oxidant for the conversion of methane to ethane and ethylene using modified CeO{sub 2} catalysts. United States. doi:10.1006/jcat.1999.2538.
Wang, Y., Takahashi, Yoshimoto, and Ohtsuka, Yasuo. Sun . "Carbon dioxide as oxidant for the conversion of methane to ethane and ethylene using modified CeO{sub 2} catalysts". United States. doi:10.1006/jcat.1999.2538.
@article{osti_687732,
title = {Carbon dioxide as oxidant for the conversion of methane to ethane and ethylene using modified CeO{sub 2} catalysts},
author = {Wang, Y. and Takahashi, Yoshimoto and Ohtsuka, Yasuo},
abstractNote = {CaO-CeO{sub 2} is the most effective catalyst for the conversion at 850 C of CH{sub 4} to C{sub 2}H{sub 6} and C{sub 2}H{sub 4} by CO{sub 2} among a series of CeO{sub 2} catalysts modified with alkali and alkaline earth metal oxides. When the CaO-CeO{sub 2} catalyst is prepared in the range of Ca/Ce ratio 0.1--0.5 by impregnation method, there exist synergistic effects between the two components for the formation of C{sub 2} hydrocarbons, and the catalyst forms solid solution. It is thus suggested that the formation of solid solution is responsible for synergistic effects. The lattice oxygen of the CaO-CeO{sub 2} catalyst converts CH{sub 4} mainly to H{sub 2} and CO, and the presence of CO{sub 2} is indispensable for C{sub 2} formation. Both C{sub 2} selectivity and C{sub 2} yield increase remarkably with increasing partial pressure of CO{sub 2}, these values at 850 C reaching 75 and 4% at 70 kPa, respectively. Correlation of the results of kinetic analyses and CO{sub 2} TPD measurements indicates that the existence of the pool of the CO{sub 2} chemisorbed on the CaO-CeO{sub 2} catalyst accounts for high C{sub 2} selectivity and yield. The characterization of the binary catalyst show that bulk carbonates are not detectable during reaction and Ce{sup 3+} sites are formed at the outermost layer. It is speculated that these sites activate the chemisorbed CO{sub 2} to generate active oxygen species, which work for the conversion of CH{sub 4} to C{sub 2} hydrocarbons.},
doi = {10.1006/jcat.1999.2538},
journal = {Journal of Catalysis},
number = 1,
volume = 186,
place = {United States},
year = {1999},
month = {8}
}