Undoped and Fe-Doped Anatase/Brookite TiO<sub>2</sub> Mixed Phases, Obtained by a Simple Template-Free Synthesis Method: Physico-Chemical Characterization and Photocatalytic Activity towards Simazine Degradation
For the first time, Fe-doping (0.05, 1.0, and 2.5 wt.% Fe) was performed on a high-surface-area anatase/brookite TiO<sub>2</sub> by adopting a simple template-free sol-gel synthesis followed by calcination at a mild temperature. The powders’ textural and surface properties were character...
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MDPI AG
2023-03-01
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| Online Access: | https://www.mdpi.com/2073-4344/13/4/667 |
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| author | Stefano Gervasi Nicola Blangetti Francesca S. Freyria Salvatore Guastella Barbara Bonelli |
| author_facet | Stefano Gervasi Nicola Blangetti Francesca S. Freyria Salvatore Guastella Barbara Bonelli |
| author_sort | Stefano Gervasi |
| collection | DOAJ |
| description | For the first time, Fe-doping (0.05, 1.0, and 2.5 wt.% Fe) was performed on a high-surface-area anatase/brookite TiO<sub>2</sub> by adopting a simple template-free sol-gel synthesis followed by calcination at a mild temperature. The powders’ textural and surface properties were characterized by following a multi-technique approach. XRD analysis showed that the anatase/brookite ratio slightly varied in the Fe-doped TiO<sub>2</sub> (from 76.9/23.1 to 79.3/22.7); Fe doping noticeably affected the cell volume of the brookite phase, which decreased, likely due to Fe<sup>3+</sup> ions occupying interstitial positions, and retarded the crystallite growth. N<sub>2</sub> sorption at −196 °C showed the occurrence of samples with disordered interparticle mesopores, with an increase in the specific surface area from 236 m<sup>2</sup> g<sup>−1</sup> (undoped TiO<sub>2</sub>) to 263 m<sup>2</sup> g<sup>−1</sup> (2.5 wt.% Fe). Diffuse Reflectance UV-Vis spectroscopy showed a progressive decrease in the bandgap energy from 3.10 eV (undoped TiO<sub>2</sub>) to 2.85 eV (2.5 wt.% Fe). XPS analysis showed the presence of some surface Fe species only at 2.5 wt.% Fe, and accordingly, the ζ-potential measurements showed small changes in the pH at the isoelectric point. The photocatalytic degradation of simazine (a persistent water contaminant) both under UV and simulated solar light was performed as a probe reaction. Under UV light, Fe-doping improved simazine degradation in the sample at 0.05 wt.% Fe, capable of degrading ca. 77% simazine. Interestingly, the undoped TiO<sub>2</sub> was also active both under UV and 1 SUN. This is likely due to the occurrence of anatase/brookite heterojunctions, which help stabilize the photogenerated electrons/holes. |
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| spelling | doaj.art-55932380c6884bb7bc5ca81a3d62a33b2023-11-17T18:40:53ZengMDPI AGCatalysts2073-43442023-03-0113466710.3390/catal13040667Undoped and Fe-Doped Anatase/Brookite TiO<sub>2</sub> Mixed Phases, Obtained by a Simple Template-Free Synthesis Method: Physico-Chemical Characterization and Photocatalytic Activity towards Simazine DegradationStefano Gervasi0Nicola Blangetti1Francesca S. Freyria2Salvatore Guastella3Barbara Bonelli4Department of Applied Science and Technology and INSTM Unit of Torino-Politecnico, Corso Duca degli Abruzzi 24, I-10129 Torino, ItalyDepartment of Applied Science and Technology and INSTM Unit of Torino-Politecnico, Corso Duca degli Abruzzi 24, I-10129 Torino, ItalyDepartment of Applied Science and Technology and INSTM Unit of Torino-Politecnico, Corso Duca degli Abruzzi 24, I-10129 Torino, ItalyDepartment of Applied Science and Technology and INSTM Unit of Torino-Politecnico, Corso Duca degli Abruzzi 24, I-10129 Torino, ItalyDepartment of Applied Science and Technology and INSTM Unit of Torino-Politecnico, Corso Duca degli Abruzzi 24, I-10129 Torino, ItalyFor the first time, Fe-doping (0.05, 1.0, and 2.5 wt.% Fe) was performed on a high-surface-area anatase/brookite TiO<sub>2</sub> by adopting a simple template-free sol-gel synthesis followed by calcination at a mild temperature. The powders’ textural and surface properties were characterized by following a multi-technique approach. XRD analysis showed that the anatase/brookite ratio slightly varied in the Fe-doped TiO<sub>2</sub> (from 76.9/23.1 to 79.3/22.7); Fe doping noticeably affected the cell volume of the brookite phase, which decreased, likely due to Fe<sup>3+</sup> ions occupying interstitial positions, and retarded the crystallite growth. N<sub>2</sub> sorption at −196 °C showed the occurrence of samples with disordered interparticle mesopores, with an increase in the specific surface area from 236 m<sup>2</sup> g<sup>−1</sup> (undoped TiO<sub>2</sub>) to 263 m<sup>2</sup> g<sup>−1</sup> (2.5 wt.% Fe). Diffuse Reflectance UV-Vis spectroscopy showed a progressive decrease in the bandgap energy from 3.10 eV (undoped TiO<sub>2</sub>) to 2.85 eV (2.5 wt.% Fe). XPS analysis showed the presence of some surface Fe species only at 2.5 wt.% Fe, and accordingly, the ζ-potential measurements showed small changes in the pH at the isoelectric point. The photocatalytic degradation of simazine (a persistent water contaminant) both under UV and simulated solar light was performed as a probe reaction. Under UV light, Fe-doping improved simazine degradation in the sample at 0.05 wt.% Fe, capable of degrading ca. 77% simazine. Interestingly, the undoped TiO<sub>2</sub> was also active both under UV and 1 SUN. This is likely due to the occurrence of anatase/brookite heterojunctions, which help stabilize the photogenerated electrons/holes.https://www.mdpi.com/2073-4344/13/4/667TiO<sub>2</sub> polymorphsanatase/brookite heterojunctionsFe-doped TiO<sub>2</sub>simazine degradationdetoxification |
| spellingShingle | Stefano Gervasi Nicola Blangetti Francesca S. Freyria Salvatore Guastella Barbara Bonelli Undoped and Fe-Doped Anatase/Brookite TiO<sub>2</sub> Mixed Phases, Obtained by a Simple Template-Free Synthesis Method: Physico-Chemical Characterization and Photocatalytic Activity towards Simazine Degradation Catalysts TiO<sub>2</sub> polymorphs anatase/brookite heterojunctions Fe-doped TiO<sub>2</sub> simazine degradation detoxification |
| title | Undoped and Fe-Doped Anatase/Brookite TiO<sub>2</sub> Mixed Phases, Obtained by a Simple Template-Free Synthesis Method: Physico-Chemical Characterization and Photocatalytic Activity towards Simazine Degradation |
| title_full | Undoped and Fe-Doped Anatase/Brookite TiO<sub>2</sub> Mixed Phases, Obtained by a Simple Template-Free Synthesis Method: Physico-Chemical Characterization and Photocatalytic Activity towards Simazine Degradation |
| title_fullStr | Undoped and Fe-Doped Anatase/Brookite TiO<sub>2</sub> Mixed Phases, Obtained by a Simple Template-Free Synthesis Method: Physico-Chemical Characterization and Photocatalytic Activity towards Simazine Degradation |
| title_full_unstemmed | Undoped and Fe-Doped Anatase/Brookite TiO<sub>2</sub> Mixed Phases, Obtained by a Simple Template-Free Synthesis Method: Physico-Chemical Characterization and Photocatalytic Activity towards Simazine Degradation |
| title_short | Undoped and Fe-Doped Anatase/Brookite TiO<sub>2</sub> Mixed Phases, Obtained by a Simple Template-Free Synthesis Method: Physico-Chemical Characterization and Photocatalytic Activity towards Simazine Degradation |
| title_sort | undoped and fe doped anatase brookite tio sub 2 sub mixed phases obtained by a simple template free synthesis method physico chemical characterization and photocatalytic activity towards simazine degradation |
| topic | TiO<sub>2</sub> polymorphs anatase/brookite heterojunctions Fe-doped TiO<sub>2</sub> simazine degradation detoxification |
| url | https://www.mdpi.com/2073-4344/13/4/667 |
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