Facile synthesis of titania-encapsulated magnetites with controlled magnetism and surface morphology

Titania-encapsulated magnetites (A-Fe3O4@TiO2) were facilely fabricated through the modified sol-gel reaction of APTMS-complexed Fe3O4 (A-Fe3O4) with tetraethyl orthotitanate (TEOT). The magnetism and surface morphology of A-Fe3O4@TiO2 were controlled by adjusting the thickness of titania capsule layer. A-Fe3O4@TiO2 exhibited the superparamagnetic characteristics of negligible remanence and coercity. Thermal analysis of A-Fe3O4@TiO2 showed that the amorphous titania was transformed into crystalline phase at around 440 °C. The core-shell magnetite-titanium nanocomposites can be an attractive candidate for recyclable photocatalysts with magnetite core and/or active Fe3O4 electrode materials with buffering TiO2 capsules.