Characteristics and optical properties of iron ion (Fe3+)-doped titanium oxide thin films prepared by a sol–gel spin coating

Characterization and Photocatalytic Evaluation (UV-Visible) of Fe-doped TiO2 Systems Calcined at Different Temperatures

“…The shift to the visible spectrum is attributed to charge transitions (or excitation) between the 3d electrons of the Fe 3+ ion and the TiO 2 conduction band (25,27,(38)(39). We estimated the indirect band gap for the samples, as shown in Table 2.…”

“…Specimens containing up to 1% Fe are substitutional solid solutions in which Fe 3+ is dispersed in the lattice of TiO 2 , specimens with higher iron contents to accommodate any excess of iron as minute particles or small aggregates of iron oxides (hematite) and or mixed oxides at the surface of the solid solution particles (26). The brookite phase could not be observed by XRD; this phase has been reported in acidic conditions with a pH between 1.8 and 3.6 (27). In addition, it is possible that the main (101) diffraction peak of anatase at 2θ = 25.28° overlaps with the (120) and (111) peaks of brookite at 2θ = 25.34° and 25.69°, respectively (28).…”

“…We can see that the sintering process caused an increase in the crystal size and therefore a decrease in the surface area. Additionally, we observed an effect caused by the amount of dopant; greater amounts of iron added to the synthesis led to smaller crystal sizes (27,(30)(31). This effect was minor compared to the increase in the calcination temperature.…”

Synthesis, Optical and Photocatalytic Properties of Mesoporous Iron Doped Titania Films

“…However, the presence of iron ions in titania led to the narrowing of band gap of the semiconductor forcing to the possibility to absorb quantum of visible light as indicated herein [16]. The band gap energy values of Fe-TiO 2 films varied from 3.3 to 2.8 eV with iron content increase from 0 to 25 %, respectively [17]. Influence of iron doping on the electronic and structural properties of TiO 2 by density functional theory (DFT) showed that the increase in Fe 3+ /TiO 2 photoactivity occurred due to the formation of additional electronic levels in the band gap of titania [18].…”

“…The high photocatalytic activity under visible light as well under UV was rarely reported [9,15]. It is known [5][6][7][8][9][10][11][12][13][14][15][16][17][18] that the physico-chemical properties of iron-doped titania nanostructures are strongly dependent on the synthesis route and its conditions as well as on the doping agent content. Therefore, the properties of materials obtained by different method significantly vary, such as the valence of the elements, electronic structure, morphology of the surface, iron ions distribution, structural properties (the formation of iron titanate or separated oxide phases) and, in turn, photocatalytic activity.…”