Oxidative Coupling of Methane by Adsorbed Oxygen Species on SrTi1-xMgxO3-δ Catalysts

Keiichi Tomishige, Xiao Hong Li, Kaoru Fujimoto

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

It was found that ethane was formed by the stoichiometric reaction between methane and an adsorbed oxygen species on SrTi1-xMgxO3-δ with high selectivity (> 80 %) at much lower temperatures (550-750 K) than those typically used for the catalytic reaction. The properties of the adsorbed oxygen species were investigated by means of temperature programmed desorption, and the role of Mg2+ was studied using XRD, BET, and the measurements of the exchange rate between lattice oxide ions and gas phase oxygen. The added Mg2+ ions seem to be located at the surface and bulk Ti4+ site of Sr-Ti mixed oxides, where oxide ion defects are formed because of differences in ion charges. Surface oxide ion defects play an important role in oxygen adsorption, while bulk defects promote the mobility of oxide ions. SrTi0.5Mg0.5O3-δ was initially active for oxidative coupling of methane at low temperature (873 K), but combustion of methane predominated under steady state conditions, due to a change in adsorbed oxygen species induced by the adsorption of COx.

Original languageEnglish
Pages (from-to)109-121
Number of pages13
JournalACS Symposium Series
Volume638
Publication statusPublished - 1996 Dec 1
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)

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