Iron(III)-containing mesoporous silica (MCM-41) with Fe contents up to 1.8 wt% have been prepared by direct hydrothermal synthesis
(DHT) and template ion exchange (TIE) methods. Characterizations of these catalysts have been done by XRD, XPS, diffuse reflectance
UV–vis, ESR, Mossbauer, and XAFS spectroscopies. Fe species in MCM-41 materials are tetrahedrally coordinated for the DHT method ¨
with Fe contents up to 1.1 wt% while those are mainly octahedrally coordinated for the TIE method. Among these catalysts, ferrisilicate and
Fe2O3/Cab-O-Sil as references, Fe-MCM-41-DHT exhibited the highest catalytic activity for Baeyer–Villiger (B–V) oxidation of ketones using
molecular oxygen and benzaldehyde. The prominent performance of the Fe-MCM-41-DHT could be ascribed to both tetrahedrally coordinated
Fe3+ incorporated inside the framework of MCM-41 and its uniform nano-order mesopores allowing the access of bulky compounds to the
active sites. Furthermore, this heterogeneous Fe catalyst was reusable without any appreciable loss in activity and selectivity. It has been
confirmed by IR spectroscopy that the Fe-MCM-41-DHT-catalyzed B–V reaction proceeded via coordination of carbonyl groups of ketone
to Fe3+.