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MoO3/SiO2–Al2O3 catalysts are prepared via flame spray pyrolysis and evaluated in the self-metathesis of propene to ethene and butene. Their specific surface area ranges between 100 and 170 m2 g−1 depending on the MoO3 loading (1–15 wt.%, corresponding to Mo surface density between 0.3 and 6.1 Mo atoms per nm2). The catalysts were characterized by N2-physisorption, X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and time of flight secondary ion mass spectroscopy (ToF-SIMS). The silica–alumina matrix condenses first in the flame and forms non-porous spherical particles of 5–20 nm, followed by the dispersion of Mo oxide at their surface. Depending on the MoO3 loading, different MoOx species are stabilized: dispersed and amorphous molybdates (mono- and oligomeric) at low loadings ( |
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