Insights into the Fe<sup>3+</sup> Doping Effects on the Structure and Electron Distribution of Cr<sub>2</sub>O<sub>3</sub> Nanoparticles
Herein, we carefully investigated the Fe<sup>3+</sup> doping effects on the structure and electron distribution of Cr<sub>2</sub>O<sub>3</sub> nanoparticles using X-ray diffraction analysis (XRD), maximum entropy method (MEM), and density functional theory (DFT) c...
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MDPI AG
2023-03-01
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| Series: | Nanomaterials |
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| Online Access: | https://www.mdpi.com/2079-4991/13/6/980 |
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| author | Cledson Santos John M. Attah-Baah Romualdo S. Silva Junior Marcelo A. Mâcedo Marcos V. S. Rezende Robert S. Matos Ştefan Ţălu Dung Nguyen Trong Simone P. A. da Paz Rômulo S. Angélica Nilson S. Ferreira |
| author_facet | Cledson Santos John M. Attah-Baah Romualdo S. Silva Junior Marcelo A. Mâcedo Marcos V. S. Rezende Robert S. Matos Ştefan Ţălu Dung Nguyen Trong Simone P. A. da Paz Rômulo S. Angélica Nilson S. Ferreira |
| author_sort | Cledson Santos |
| collection | DOAJ |
| description | Herein, we carefully investigated the Fe<sup>3+</sup> doping effects on the structure and electron distribution of Cr<sub>2</sub>O<sub>3</sub> nanoparticles using X-ray diffraction analysis (XRD), maximum entropy method (MEM), and density functional theory (DFT) calculations. We showed that increasing the Fe doping induces an enlargement in the axial ratio of <i>c</i>/<i>a</i>, which is associated with an anisotropic expansion of the unit cell. We found that as Fe<sup>3+</sup> replaces Cr in the Cr<sub>2</sub>O<sub>3</sub> lattice, it caused a higher interaction between the metal 3<i>d</i> states and the oxygen 2<i>p</i> states, which led to a slight increase in the Cr/Fe–O1 bond length followed by an opposite effect for the Cr/Fe–O2 bonds. Our results also suggest that the excitations characterize a well-localized bandgap region from occupied Cr <i>d</i> to unoccupied Fe <i>d</i> states. The Cr<sub>2</sub>O<sub>3</sub> and Fe-doped Cr<sub>2</sub>O<sub>3</sub> nanoparticles behave as Mott–Hubbard insulators due to their band gap being in the <i>d</i>−<i>d</i> gap, and Cr 3<i>d</i> orbitals dominate the conduction band. These findings suggest that the magnitude and the character of the electronic density near the O atom bonds in Cr<sub>2</sub>O<sub>3</sub> nanoparticles are modulated by the Cr–Cr distances until its stabilization at the induced quasi-equilibrium of the Cr<sub>2</sub>O<sub>3</sub> lattice when the Fe<sup>3+</sup> doping values reaches the saturation level range. |
| first_indexed | 2024-03-11T06:06:11Z |
| format | Article |
| id | doaj.art-6877194eed0e41628ea28ab6d3ceab5d |
| institution | Directory Open Access Journal |
| issn | 2079-4991 |
| language | English |
| last_indexed | 2024-03-11T06:06:11Z |
| publishDate | 2023-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Nanomaterials |
| spelling | doaj.art-6877194eed0e41628ea28ab6d3ceab5d2023-11-17T12:59:51ZengMDPI AGNanomaterials2079-49912023-03-0113698010.3390/nano13060980Insights into the Fe<sup>3+</sup> Doping Effects on the Structure and Electron Distribution of Cr<sub>2</sub>O<sub>3</sub> NanoparticlesCledson Santos0John M. Attah-Baah1Romualdo S. Silva Junior2Marcelo A. Mâcedo3Marcos V. S. Rezende4Robert S. Matos5Ştefan Ţălu6Dung Nguyen Trong7Simone P. A. da Paz8Rômulo S. Angélica9Nilson S. Ferreira10Department of Physics, Federal University of Sergipe, São Cristóvão 49100-000, SE, BrazilDepartment of Physics, Federal University of Sergipe, São Cristóvão 49100-000, SE, BrazilDepartment of Physics, Federal University of Sergipe, São Cristóvão 49100-000, SE, BrazilDepartment of Physics, Federal University of Sergipe, São Cristóvão 49100-000, SE, BrazilDepartment of Physics, Federal University of Sergipe, São Cristóvão 49100-000, SE, BrazilAmazonian Materials Group, Federal University of Amapá, Macapá 68902-280, AP, BrazilThe Directorate of Research, Development and Innovation Management (DMCDI), Technical University of Cluj-Napoca, 15 Constantin Daicoviciu St., 400020 Cluj-Napoca, RomaniaFaculty of Physics, Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, Hanoi 100000, VietnamInstitute of Geosciences, Federal University of Pará, Belém 66075-110, PA, BrazilInstitute of Geosciences, Federal University of Pará, Belém 66075-110, PA, BrazilDepartment of Physics, Federal University of Sergipe, São Cristóvão 49100-000, SE, BrazilHerein, we carefully investigated the Fe<sup>3+</sup> doping effects on the structure and electron distribution of Cr<sub>2</sub>O<sub>3</sub> nanoparticles using X-ray diffraction analysis (XRD), maximum entropy method (MEM), and density functional theory (DFT) calculations. We showed that increasing the Fe doping induces an enlargement in the axial ratio of <i>c</i>/<i>a</i>, which is associated with an anisotropic expansion of the unit cell. We found that as Fe<sup>3+</sup> replaces Cr in the Cr<sub>2</sub>O<sub>3</sub> lattice, it caused a higher interaction between the metal 3<i>d</i> states and the oxygen 2<i>p</i> states, which led to a slight increase in the Cr/Fe–O1 bond length followed by an opposite effect for the Cr/Fe–O2 bonds. Our results also suggest that the excitations characterize a well-localized bandgap region from occupied Cr <i>d</i> to unoccupied Fe <i>d</i> states. The Cr<sub>2</sub>O<sub>3</sub> and Fe-doped Cr<sub>2</sub>O<sub>3</sub> nanoparticles behave as Mott–Hubbard insulators due to their band gap being in the <i>d</i>−<i>d</i> gap, and Cr 3<i>d</i> orbitals dominate the conduction band. These findings suggest that the magnitude and the character of the electronic density near the O atom bonds in Cr<sub>2</sub>O<sub>3</sub> nanoparticles are modulated by the Cr–Cr distances until its stabilization at the induced quasi-equilibrium of the Cr<sub>2</sub>O<sub>3</sub> lattice when the Fe<sup>3+</sup> doping values reaches the saturation level range.https://www.mdpi.com/2079-4991/13/6/980chromium oxideCr<sub>2</sub>O<sub>3</sub>tapiocananoparticleselectron distribution |
| spellingShingle | Cledson Santos John M. Attah-Baah Romualdo S. Silva Junior Marcelo A. Mâcedo Marcos V. S. Rezende Robert S. Matos Ştefan Ţălu Dung Nguyen Trong Simone P. A. da Paz Rômulo S. Angélica Nilson S. Ferreira Insights into the Fe<sup>3+</sup> Doping Effects on the Structure and Electron Distribution of Cr<sub>2</sub>O<sub>3</sub> Nanoparticles Nanomaterials chromium oxide Cr<sub>2</sub>O<sub>3</sub> tapioca nanoparticles electron distribution |
| title | Insights into the Fe<sup>3+</sup> Doping Effects on the Structure and Electron Distribution of Cr<sub>2</sub>O<sub>3</sub> Nanoparticles |
| title_full | Insights into the Fe<sup>3+</sup> Doping Effects on the Structure and Electron Distribution of Cr<sub>2</sub>O<sub>3</sub> Nanoparticles |
| title_fullStr | Insights into the Fe<sup>3+</sup> Doping Effects on the Structure and Electron Distribution of Cr<sub>2</sub>O<sub>3</sub> Nanoparticles |
| title_full_unstemmed | Insights into the Fe<sup>3+</sup> Doping Effects on the Structure and Electron Distribution of Cr<sub>2</sub>O<sub>3</sub> Nanoparticles |
| title_short | Insights into the Fe<sup>3+</sup> Doping Effects on the Structure and Electron Distribution of Cr<sub>2</sub>O<sub>3</sub> Nanoparticles |
| title_sort | insights into the fe sup 3 sup doping effects on the structure and electron distribution of cr sub 2 sub o sub 3 sub nanoparticles |
| topic | chromium oxide Cr<sub>2</sub>O<sub>3</sub> tapioca nanoparticles electron distribution |
| url | https://www.mdpi.com/2079-4991/13/6/980 |
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