ausblenden:
Schlagwörter:
C–H activation; Oxygen; Nitrous oxide; Cellulose templating; Deactivation
Zusammenfassung:
The synthesis of selected state-of-the-art catalysts providing high performances in the oxidative coupling
of methane (OCM) with O2 was reproduced according to the respective recipes reported in literature. A
reference material with identical stoichiometric composition was further synthesized by applying the
cellulose templating method. This method increases the surface area and affects the phase composition
and crystallite size of the catalysts as determined by N2-physisoprtion, X-ray diffraction and scanning
electron microscopy. This, however, is in most cases detrimental to the catalytic OCM performance due
to enhanced global activity resulting in hot spots in the catalyst bed. Catalysts were tested in the OCM
under variation of temperature (973–1073 K), GHSV (3600–100,000 h−1) and oxidizing agent (O2 and
N2O). In general, conversions of CH4 when using N2O are lower than in the presence of O2, however, the
selectivities to C2 products ethane and ethylene are higher even at a similar level of CH4 conversion. This
confirms the presence of different oxygen species formed by activation of these oxidizing agents.
