A novel fractional crystallization route to porous TiO2–Fe2O3 composites: large scale preparation and high performances as a photocatalyst and Li-ion battery anode

Abstract

Meso/macroporous TiO₂–Fe₂O₃ composite particles are prepared using naturally abundant ilmenite via a novel heat treatment induced fractional crystallization strategy in a fluidized bed. Fluid-bed roasting in oxidizing and reducing environments is carried out in order to realize the fractional crystallization of ilmenite. Subsequently, acid leaching is employed to remove most of the ferrous phase and form porous TiO₂–Fe₂O₃ composites. The influences of the reaction parameters on the composition, structure and properties of the products are studied. It is found that the pore structure and composition of the porous TiO₂–Fe₂O₃ composite particles can be controlled simply by controlling some parameters, such as the roasting time, temperature, precursor particle size, and post-roasting treatment. Photocatalytic and electrochemical cycling measurements show that the synergism of porous structures and the controlled doping of α-Fe₂O₃ endow the as-obtained products with excellent visible light photocatalytic activity and provide enhanced performance in lithium ion batteries. The composite porous particles thus obtained may have some promising applications in the fields of photocatalysts, electrode materials, absorbers, pigments etc. This work opens a new avenue for reasonable combination of cost-effective raw materials, a large scale fabricating process and fine control over the structure and composition in the design and preparation of functional materials.