Towards enhanced photocatalysis: Iron-doped TiO2 nanostructures

Abstract

Nanostructured Titania (TiO2), a wide band gap semiconducting oxide, has found a wide range of applications such as photocatalysis and sensing. It is known that doping titania with ferromagnetic transition metals such as Fe can enhance its surface activity and catalytic response mainly through band gap engineering that is in part fostered by structural defects in the titania lattice. Further, iron incorporation may foster multifunctionality by integrating magnetic, semiconducting and catalytic characteristics. ææIn this study, Fe cations are incorporated into the growing titania nanoparticles at a concentration of ~3 at% via a modified sol-gel process.? Morphological, electronic and crystal structure as well as magnetic properties of pure and Fe-incorporated titania nanoparticles are investigated in their as-made and calcined states (three-hour calcination in air at 400 ÁC). æResults indicate that Fe incorporation leads to a decrease in the band gap energy and an expansion of the anatase unit cell volume. In addition, higher magnetic moment and an enhanced metallic-like behavior were observed in the calcined Fe-incorporated nanoparticles. The observed changes in the band gap, crystal structure, magnetic moment and density of states in the Fe-incorporated nanoparticles may be associated with the tailoring of electronic structure of titania and thus providing insight into the enhancement of the photocatalytic activity of these nanostructures. Acknowledgments: The authors would like to thank D. Reid, S. Seal and R. Draper from the University of Central Florida for providing the samples. This material is based upon work supported by the National Science Foundation under Grant No. DMR-0906608.