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| Format: | Recurso digital |
| Language: | English |
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2026
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| Online Access: | https://doi.org/10.5281/zenodo.20097352 |
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| author | YOUNES, Rassim ALYMOV, Mikhael |
| author_facet | YOUNES, Rassim ALYMOV, Mikhael |
| contents | <p class="ds-markdown-paragraph"><span>The precise control over microstructure and phase composition is essential for optimizing chromium oxide (Cr₂O₃) powders for advanced applications. This study investigates the influence of low-level alumina (Al₂O₃) doping on the microstructure, phase evolution, and optical properties of Cr₂O₃ powders synthesized via an aqueous sol–gel route. Pure and Al₂O₃-doped (using Al(NO₃)₃·9H₂O) powders were prepared with citric acid as a complexing agent, followed by gelation, drying, and calcination at 1100 °C.</span></p> <p class="ds-markdown-paragraph"><span>Results demonstrate that Al₂O₃ incorporation significantly refines the microstructure, reducing the average grain size from approximately 28 µm (pure Cr₂O₃) to 24 µm after heat treatment. <em><span>In-situ</span></em> pH monitoring revealed that Al₂O₃ doping modifies gelation kinetics, leading to a more controlled and linear pH evolution compared to the fluctuating profile of the pure system. X-ray diffraction (XRD) confirmed the formation of crystalline Cr₂O₃ (hexagonal, R-3c) as the primary phase in both materials, with the successful integration of </span><span>α</span><span>-Al₂O₃ in the doped powder, indicating effective chemical incorporation without phase segregation.</span></p> <p><span>Fourier-transform infrared (FTIR) spectroscopy showed that Al₂O₃ promotes more complete polycondensation and dehydration, evidenced by a reduced intensity of O–H stretching bands (~3500 cm⁻¹), suggesting a denser, less porous oxide network. Ultraviolet–visible (UV–Vis) spectroscopy revealed a substantial blue shift in the absorption maximum from 366 nm (pure Cr₂O₃) to 248 nm (Al₂O₃-doped), indicating a widening of the effective optical band gap due to electronic interactions between Cr³⁺ and the Al₂O₃ matrix</span></p> |
| format | Recurso digital |
| id | zenodo_https___doi_org_10_5281_zenodo_20097352 |
| institution | Zenodo |
| language | eng |
| publishDate | 2026 |
| publisher | Zenodo |
| record_format | zenodo |
| spellingShingle | Influence of Low Al2O3 Doping on the Microstructure and Phase Evolution of Sol–Gel Derived Chromium Oxide Powders. YOUNES, Rassim ALYMOV, Mikhael Chromium oxide Alumina doping Sol–gel synthesis XRD <p class="ds-markdown-paragraph"><span>The precise control over microstructure and phase composition is essential for optimizing chromium oxide (Cr₂O₃) powders for advanced applications. This study investigates the influence of low-level alumina (Al₂O₃) doping on the microstructure, phase evolution, and optical properties of Cr₂O₃ powders synthesized via an aqueous sol–gel route. Pure and Al₂O₃-doped (using Al(NO₃)₃·9H₂O) powders were prepared with citric acid as a complexing agent, followed by gelation, drying, and calcination at 1100 °C.</span></p> <p class="ds-markdown-paragraph"><span>Results demonstrate that Al₂O₃ incorporation significantly refines the microstructure, reducing the average grain size from approximately 28 µm (pure Cr₂O₃) to 24 µm after heat treatment. <em><span>In-situ</span></em> pH monitoring revealed that Al₂O₃ doping modifies gelation kinetics, leading to a more controlled and linear pH evolution compared to the fluctuating profile of the pure system. X-ray diffraction (XRD) confirmed the formation of crystalline Cr₂O₃ (hexagonal, R-3c) as the primary phase in both materials, with the successful integration of </span><span>α</span><span>-Al₂O₃ in the doped powder, indicating effective chemical incorporation without phase segregation.</span></p> <p><span>Fourier-transform infrared (FTIR) spectroscopy showed that Al₂O₃ promotes more complete polycondensation and dehydration, evidenced by a reduced intensity of O–H stretching bands (~3500 cm⁻¹), suggesting a denser, less porous oxide network. Ultraviolet–visible (UV–Vis) spectroscopy revealed a substantial blue shift in the absorption maximum from 366 nm (pure Cr₂O₃) to 248 nm (Al₂O₃-doped), indicating a widening of the effective optical band gap due to electronic interactions between Cr³⁺ and the Al₂O₃ matrix</span></p> |
| title | Influence of Low Al2O3 Doping on the Microstructure and Phase Evolution of Sol–Gel Derived Chromium Oxide Powders. |
| topic | Chromium oxide Alumina doping Sol–gel synthesis XRD |
| url | https://doi.org/10.5281/zenodo.20097352 |