Mössbauer spectroscopy on superparamagnetic nanoparticles used as catalyst supports for the production of fine chemicals

Abstract

Temperature and field dependent Mössbauer spectroscopy has been used to characterize silica coated iron oxide nanoparticles with a core size of ~ 10 nm. Covalent attachment of oxodiperoxo molybdenum complexes to the silica surface of these particles yields an organic-inorganic hybrid nanocatalyst which is an active, magnetically separable epoxidation catalyst. Mössbauer spectroscopy identifies superparamagnetic γ-Fe2O3 particles, whereas the presence of significant amounts of Fe3O4 (≥ 5 %) can be excluded.