Anatase to rutile phase transformation of iron-doped titanium dioxide nanoparticles: The role of iron content

Control of the conditions that affect the formation of the anatase and rutile phases of TiO2 is of considerable interest. The aim of this work was to study the effect of Fe doping on the anatase to rutile transformation for the TiO2:Fe3+ samples not undergo annealing at high temperatures. In the hope of increasing photocatalysis efficiency, the decrease of TiO2 band-gap energy caused by Fe doping was studied. The Fe3+-doped TiO2 (TiO2:Fe3+) nanoparticles with dopant contents ranging from 0 to 14.54 at% have been synthesized by hydrothermal method. Different techniques such as transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, Raman scattering, diffuse reflection and photoluminescense spectroscopy were used to characterize the synthesized nanoparticles. The results showed that the increase of Fe3+ dopant content up to 9.29 at% leaded to the anatase to rutile phase transformation. The Fe-doping resulted in the shifting and broadening of the Raman modes, and the red shift of the absorption edge of the TiO2:Fe3+ nanoparticles as well. The band gap energy decreased from 3.57 to 3.06 eV for the direct and from 3.21 to 2.14 eV for indirect transitions with increasing Fe3+-doping concentration from 0 to 14.54 at%. In addition, the presence of Fe3+ dopant affected the photoluminescence spectra of the nanoparticles. © 2020 Elsevier B.V.