La. Boot et al., PREPARATION, CHARACTERIZATION AND TESTING OF TITANIA-SUPPORTED IRON-OXIDE BASED DEHYDROGENATION CATALYSTS, Recueil des travaux chimiques des Pays-Bas, 115(11-12), 1996, pp. 525
Iron oxide-based catalysts supported on titania and zirconia have been
investigated as alternatives for the currently used bulk iron oxide d
ehydrogenation catalysts. The present study focuses on titania-support
ed catalysts. Catalyst samples were prepared by pore-volume impregnati
on of commercially available pre-shaped support bodies with solutions
of various iron precursor compounds, Transmission electron microscopy
(TEM) and temperature-programmed reduction (TPR) revealed that the bes
t microscopic distribution is achieved with ammonium iron citrate. X-r
ay diffraction (XRD) showed a difference between the investigated supp
orts: on rutile TiO2, iron was present as hematite (Fe2O3), whereas on
anatase, pseudobrookite (Fe2TiO5) was formed. When testing the cataly
tic activity in but-1-ene dehydrogenation, rapid deactivation was obse
rved which could not be prevented by using a catalyst containing potas
sium. Without potassium, deactivation is attributed to the formation o
f ilmenite, FeTiO3. With potassium, the iron oxide phase reacts with b
oth potassium and TiO2, which diminishes the activity which initially
was present in catalysts without potassium. When a more inert support
is used, viz. ZrO2, no solid state reaction is observed, and a stable
catalyst is obtained.