Dirba, Imants ; Schwöbel, C. A. ; Zintler, Alexander ; Komissinskiy, Philipp ; Molina-Luna, Leopoldo ; Gutfleisch, Oliver (2020)
Production of Fe nanoparticles from γ-Fe2O3 by high-pressure hydrogen reduction.
In: Nanoscale Advances, 2 (10)
doi: 10.1039/D0NA00635A
Article, Bibliographie
Abstract
In this work, the reduction of iron oxide γ-Fe2O3 nanoparticles by hydrogen at high pressures is studied. Increasing the hydrogen pressure enables reduction of γ-Fe2O3 to α-Fe at significantly lower temperatures. At low pressures, a temperature of 390 °C is necessary whereas at 530 bar complete reduction can be realized at temperatures as low as 210 °C. This leads to significant improvement in the final particle morphology, maintaining high surface-to-volume ratio of the nanoparticles with an average size of 47 ± 5 nm which is close to that of the precursor γ-Fe2O3. Neck formation, coalescence and growth during reduction can be significantly suppressed. Investigations of magnetic properties show that saturation magnetization of the reduced α-Fe nanoparticles decreases with particle size from 209 A m2 kg−1 at 390 °C reduction temperature to 204 A m2 kg−1 at 210 °C. Coercivity for the fine iron particles reaches 0.076 T which exceeds the theoretical anisotropy field. This is attributed to nano-scale surface effects.
| Item Type: | Article |
|---|---|
| Erschienen: | 2020 |
| Creators: | Dirba, Imants ; Schwöbel, C. A. ; Zintler, Alexander ; Komissinskiy, Philipp ; Molina-Luna, Leopoldo ; Gutfleisch, Oliver |
| Type of entry: | Bibliographie |
| Title: | Production of Fe nanoparticles from γ-Fe2O3 by high-pressure hydrogen reduction |
| Language: | English |
| Date: | 26 August 2020 |
| Publisher: | Royal Society of Chemistry |
| Journal or Publication Title: | Nanoscale Advances |
| Volume of the journal: | 2 |
| Issue Number: | 10 |
| DOI: | 10.1039/D0NA00635A |
| Abstract: | In this work, the reduction of iron oxide γ-Fe2O3 nanoparticles by hydrogen at high pressures is studied. Increasing the hydrogen pressure enables reduction of γ-Fe2O3 to α-Fe at significantly lower temperatures. At low pressures, a temperature of 390 °C is necessary whereas at 530 bar complete reduction can be realized at temperatures as low as 210 °C. This leads to significant improvement in the final particle morphology, maintaining high surface-to-volume ratio of the nanoparticles with an average size of 47 ± 5 nm which is close to that of the precursor γ-Fe2O3. Neck formation, coalescence and growth during reduction can be significantly suppressed. Investigations of magnetic properties show that saturation magnetization of the reduced α-Fe nanoparticles decreases with particle size from 209 A m2 kg−1 at 390 °C reduction temperature to 204 A m2 kg−1 at 210 °C. Coercivity for the fine iron particles reaches 0.076 T which exceeds the theoretical anisotropy field. This is attributed to nano-scale surface effects. |
| Divisions: | 11 Department of Materials and Earth Sciences 11 Department of Materials and Earth Sciences > Material Science 11 Department of Materials and Earth Sciences > Material Science > Advanced Electron Microscopy (aem) 11 Department of Materials and Earth Sciences > Material Science > Advanced Thin Film Technology 11 Department of Materials and Earth Sciences > Material Science > Functional Materials |
| Date Deposited: | 09 Sep 2020 05:52 |
| Last Modified: | 20 Nov 2020 09:00 |
| PPN: | |
| Projects: | This work was supported by the German Federal Ministry of Education and Research (BMBF) within the project 03X3582., This work was also supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation), Project ID No. 405553726, TRR 270. |
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