A novel approach for low-temperature synthesis of nanostructured rutile-like Ti_1- Fe O₂ solid solutions

We present a straightforward method for synthesizing rutile-like Ti_1- Fe O₂ solid solutions at 90 °C, with x = 0.02, 0.04, 0.06, and 0.08. Additionally, for reference, we synthesized Fe-free rutile under identical conditions. All samples were characterized using XRPD, Rietveld refinement, elemental analysis, and specific surface area. Further characterization of the pure rutile and the solid solution with x = 0.04 was conducted using HRTEM, SEM-EDS, Raman spectroscopy, UV-vis DRS, and Mössbauer spectroscopy. The results indicated that Fe atoms incorporated into the crystalline structure of rutile, replacing Ti atoms. All phases exhibited a tetragonal crystalline structure with lattice parameters that increased with Fe content. Rietveld refinement and the electron microscopy revealed that the crystallites had a morphology elongated along the c-axis. Experimental evidence showed that the incorporation of iron into the crystalline structure altered the optical properties, as corroborated through DFT calculations on a Fe-free rutile cluster and one doped with Fe. These calculations also suggest enhancement of the stability of the solid solutions.