Test and analysis methods of trace iron-doped titanium dioxide

This study presents a test and analysis method for trace iron-doped titanium dioxide (TiO2) using electron probe microanalysis (EPMA), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). EPMA with a detection limit of 0.001 wt%, accurately quantified the iron concentrations in five doped samples as 0.008 wt%, 0.072 wt%, 0.073 wt%, 0.175 wt% and 0.448 wt%, confirming successful iron incorporation at trace levels. XRD analysis reveals that all samples maintain the anatase phase, with the (101) diffraction peak shifting systematically toward lower angles as the doping content increases indicating lattice expansion due to Fe3+ substitution for Ti4+. FTIR spectra exhibit characteristic Ti–O–Fe vibrational bands in the 770–569 cm⁻¹ region, whose intensities correlate positively with iron concentration. Additionally, Ti–O stretching vibrations (1655 → 1639 cm⁻¹ , 1053 → 1037 cm⁻¹ and 922 → 885 cm⁻¹ ) further corroborate the successful incorporation of iron into the TiO2 lattice. The combined application of these three techniques provides complementary evidence for both elemental quantification and structural validation. Given the inherent challenges in characterizing trace-doped materials, this work offers an effective analytical approach for investigating trace-doped metal oxides.