Phase transition and bandgap modulation in TiO2 nanostructures for enhanced visible-light activity and environmental applications
Abstract Due to its wide-ranging applications in the climate and energy fields, enhancing the visible-light photoactivity of TiO2 nanoparticles remains a crucial challenge in photocatalysis. Interestingly, this work examined the phase transition, structural, optical, and photocatalytic characteristi...
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Nature Portfolio
2025-06-01
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| Online Access: | https://doi.org/10.1038/s41598-025-07000-x |
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| author | Rajwali Khan Nasir Rahman Adhimoorthy Prasannan Khayriniso Ganiyeva Sabyasachi Chakrabortty Sambasivam Sangaraju |
| author_facet | Rajwali Khan Nasir Rahman Adhimoorthy Prasannan Khayriniso Ganiyeva Sabyasachi Chakrabortty Sambasivam Sangaraju |
| author_sort | Rajwali Khan |
| collection | DOAJ |
| description | Abstract Due to its wide-ranging applications in the climate and energy fields, enhancing the visible-light photoactivity of TiO2 nanoparticles remains a crucial challenge in photocatalysis. Interestingly, this work examined the phase transition, structural, optical, and photocatalytic characteristics of TiO2 nanoparticles doped with Al3⁺/Al2⁺ and S⁶⁺ ions. It was observed that the anatase phase (AP) dominates in pure TiO2 (100%) nanoparticles, whereas the rutile phase (RP) content increases in doped samples, reaching 20 ± 2.1% for X1 (Al = 2%, S = 2%) and falling to 12 ± 1.2% in X4 (Al = 2%, S = 8%). The introduction of Al3⁺/Al2⁺ and S⁶⁺ induces oxygen vacancies (Ovs) and alters the phase stability, as evidenced by the reduction of transformation energy to − 0.033 eV, facilitating the AP to RP transition. The effective integration of dopants indicates that a redshift and intensity in the Photoluminescence spectrum reduced by X-series nanoparticles is due to band gap reductions (from 3.23 eV for pure TiO2 to 1.98 eV for X4) and distortions in the lattice generated by Al/S doping. Raman spectroscopy results show peak broadening and shifts due to lattice strain from dopants, which validates dopant incorporation via peak shifts in Fourier-transform infrared spectroscopy. ESR study reveals paramagnetic centers in Ti3⁺-Ovs complexes, indicating defect-induced magnetic characteristics. When methylene blue (MB) dye is photocatalyzed under visible light exhibits increased activity and degradation efficiencies that are higher than pure TiO2. The pseudo-first-order kinetic results show that co-doping effectively improves photocatalytic activity. Rate constants of 0.017 min⁻1 for X4 are found to be much higher than 7.28 × 10⁻4 min⁻1 for pure TiO2 nanoparticles. Finally, anatase X-series samples degraded MB at a maximum rate of 96.4% in 150 min, outperforming undoped TiO2 (15%) and rutile-TiO2 nanoparticles (65% degradation). The fundamental mechanism explains that the photocatalytic characteristics of TiO2 are modulated by co-doping, which is why these compounds are potential candidates for environmental remediation applications. |
| format | Article |
| id | doaj-art-2700efe7c1034c6e800d2040b136dd1d |
| institution | Kabale University |
| issn | 2045-2322 |
| language | English |
| publishDate | 2025-06-01 |
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| spelling | doaj-art-2700efe7c1034c6e800d2040b136dd1d2025-08-20T03:27:09ZengNature PortfolioScientific Reports2045-23222025-06-0115111710.1038/s41598-025-07000-xPhase transition and bandgap modulation in TiO2 nanostructures for enhanced visible-light activity and environmental applicationsRajwali Khan0Nasir Rahman1Adhimoorthy Prasannan2Khayriniso Ganiyeva3Sabyasachi Chakrabortty4Sambasivam Sangaraju5National Water and Energy Center, United Arab Emirates UniversityDepartment of Physics, University of Lakki MarwatDepartment of Materials Science and Engineering, National Taiwan University of Science and TechnologyForeign Language Department in Pre-School and Primary Education, Jizzakh State Pedagogical UniversityDepartment of Chemistry, SRM University Amravati-APNational Water and Energy Center, United Arab Emirates UniversityAbstract Due to its wide-ranging applications in the climate and energy fields, enhancing the visible-light photoactivity of TiO2 nanoparticles remains a crucial challenge in photocatalysis. Interestingly, this work examined the phase transition, structural, optical, and photocatalytic characteristics of TiO2 nanoparticles doped with Al3⁺/Al2⁺ and S⁶⁺ ions. It was observed that the anatase phase (AP) dominates in pure TiO2 (100%) nanoparticles, whereas the rutile phase (RP) content increases in doped samples, reaching 20 ± 2.1% for X1 (Al = 2%, S = 2%) and falling to 12 ± 1.2% in X4 (Al = 2%, S = 8%). The introduction of Al3⁺/Al2⁺ and S⁶⁺ induces oxygen vacancies (Ovs) and alters the phase stability, as evidenced by the reduction of transformation energy to − 0.033 eV, facilitating the AP to RP transition. The effective integration of dopants indicates that a redshift and intensity in the Photoluminescence spectrum reduced by X-series nanoparticles is due to band gap reductions (from 3.23 eV for pure TiO2 to 1.98 eV for X4) and distortions in the lattice generated by Al/S doping. Raman spectroscopy results show peak broadening and shifts due to lattice strain from dopants, which validates dopant incorporation via peak shifts in Fourier-transform infrared spectroscopy. ESR study reveals paramagnetic centers in Ti3⁺-Ovs complexes, indicating defect-induced magnetic characteristics. When methylene blue (MB) dye is photocatalyzed under visible light exhibits increased activity and degradation efficiencies that are higher than pure TiO2. The pseudo-first-order kinetic results show that co-doping effectively improves photocatalytic activity. Rate constants of 0.017 min⁻1 for X4 are found to be much higher than 7.28 × 10⁻4 min⁻1 for pure TiO2 nanoparticles. Finally, anatase X-series samples degraded MB at a maximum rate of 96.4% in 150 min, outperforming undoped TiO2 (15%) and rutile-TiO2 nanoparticles (65% degradation). The fundamental mechanism explains that the photocatalytic characteristics of TiO2 are modulated by co-doping, which is why these compounds are potential candidates for environmental remediation applications.https://doi.org/10.1038/s41598-025-07000-xAnatase phaseRutile phaseNanoparticlesBand gapNanomaterialsPhotodegradation |
| spellingShingle | Rajwali Khan Nasir Rahman Adhimoorthy Prasannan Khayriniso Ganiyeva Sabyasachi Chakrabortty Sambasivam Sangaraju Phase transition and bandgap modulation in TiO2 nanostructures for enhanced visible-light activity and environmental applications Scientific Reports Anatase phase Rutile phase Nanoparticles Band gap Nanomaterials Photodegradation |
| title | Phase transition and bandgap modulation in TiO2 nanostructures for enhanced visible-light activity and environmental applications |
| title_full | Phase transition and bandgap modulation in TiO2 nanostructures for enhanced visible-light activity and environmental applications |
| title_fullStr | Phase transition and bandgap modulation in TiO2 nanostructures for enhanced visible-light activity and environmental applications |
| title_full_unstemmed | Phase transition and bandgap modulation in TiO2 nanostructures for enhanced visible-light activity and environmental applications |
| title_short | Phase transition and bandgap modulation in TiO2 nanostructures for enhanced visible-light activity and environmental applications |
| title_sort | phase transition and bandgap modulation in tio2 nanostructures for enhanced visible light activity and environmental applications |
| topic | Anatase phase Rutile phase Nanoparticles Band gap Nanomaterials Photodegradation |
| url | https://doi.org/10.1038/s41598-025-07000-x |
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