Comparison of magnetic-nanometer titanium dioxide/ferriferous oxide (TiO₂/Fe₃O₄) composite photocatalyst prepared by acid–sol and homogeneous precipitation methods

Novel magnetic-nanometer titanium dioxide/ferriferous oxide (TiO₂/Fe₃O₄) composite photocatalyst was prepared using acid–sol and homogenous precipitation methods. The photocatalyst particle was made of a Fe₃O₄ core covered with nanocrystal anatase TiO₂, without a high-temperature heat-treatment step. The catalyst has been characterized by X-ray diffraction, transmission electron microscopy, differential thermal analysis measurements, and ultraviolet spectrum. The results suggested that titania was mainly presented as anatase and Fe₃O₄ did not appear on the surface of the composite particles when the molar ratio of TiO₂/Fe₃O₄ increased to 20:1 in the acid–sol method, but 5:1 in the homogeneous precipitin method. The size of the crystal was ranged from 2.4 to 3.6 nm prepared by both methods. In the catalytic test, the composite particles, which were prepared by acid–sol, had higher catalytic activity than that prepared by homogenous precipitation method due to the size difference of the composite particles.