Epsilon‐Fe₂O₃ Nanocrystals inside Mesoporous Silicas with Tailored Morphologies of Rod, Platelet and Donut

Abstract The ϵ‐Fe₂O₃ polymorph of iron oxide, which has outstanding physical properties, is successfully stabilized inside mesoporous silica particles with tailored shapes. Using mesoporous silica particles with three different morphologies of rod, platelet and donut, we obtain ϵ‐Fe₂O₃/mesoporous silica nanocomposites. Iron oxide is loaded inside the porosity using a two steps impregnation cycle: solvent‐free impregnation followed by oxidation under 1000 °C. The amount of loaded iron oxide can be enhanced using two successive impregnation cycles. We fully characterise these nanocomposite particles with a wide panel of techniques to establish the exact amount of loaded iron inside the porosity, the nature of the iron oxide phase and the size of the nanocrystals. As a result, we conclude that ϵ‐Fe₂O₃ nanocrystals can be confined and stabilized in all types of morphologies, even inside the donut morphology which possesses closed mesopores.