Abstract
The oxidation of methanol has been studied over chromium-containing corundum and spinel phase solid solutions. The corundum phase catalysts (α-Al 2 − x Cr x O 3) were less active but very much more selective to formaldehyde than the spinel catalysts (MgAl 2 − x Cr x O 4). At chromium contents below about 10% there were dramatic fluctuations in activity and selectivity as a function of the chromium content for both catalyst systems. Above 10% chromium the activity behavior became relatively constant as [Cr] increased. The reaction selectivity over corundum catalysts settled at 0.7 at 670 K whereas it was zero over spinel catalysts at 470 K. The activity behavior at low Cr contents is discussed in terms of the localized sites which are formed and how these affect the basic activity of the host matrix in generating active oxygen, and in adsorbing methanol. At higher Cr contents electron delocalization between the active sites is thought to be the reason for the stabilization of behavior, though at a very different level for the two catalyst systems.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call