Temperature programmed oxidative coupling of methane over a Li-Ni-Co-O catalyst monitoredin-situ by a.c. electrical parameters coupled to multiple-ion monitoring of the product species
| Autor: | A. Ovenston, D. Qin, J. R. Walls |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
chemistry.chemical_classification
Materials science Mechanical Engineering Inorganic chemistry chemistry.chemical_element Heterogeneous catalysis Oxygen Methane Catalysis chemistry.chemical_compound Hydrocarbon chemistry Mechanics of Materials Chemisorption General Materials Science Oxidative coupling of methane Quadrupole mass analyzer |
| Zdroj: | Journal of Materials Science. 31:5849-5858 |
| ISSN: | 1573-4803 0022-2461 |
| DOI: | 10.1007/bf01152132 |
| Popis: | By using the multiple ion-monitoring facility of a quadrupole mass spectrometer, the on-line analysis of species has been studied for temperature programmed methane coupling over a non-stoichiometric mixed oxide Li0.9Ni0.5Co0.5O2−δ catalyst between 400–800°C. The effects of water vapour, methane and oxygen were also separately studied. The a.c. electrical characteristics of the catalyst pellet between 100 Hz and 1 MHz were simultaneously monitoredin-situ. Catalytic changes are immediately reflected in changes in the a.c. characteristics. Frequency dependent a.c. losses due to surface dipole effects dominate during phases of strong chemisorption and reaction, whilst reversion to thermally activated behaviour occurs during regions of reduced chemical activity. Lattice oxygen is able to act as a source of oxygen and react with methane. The oxidative coupling of methane showed stable behaviour for 3h at 750°C. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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