Effect of additive distribution in H2 absorption and desorption kinetics in MgH2 milled with NbH0.9 or NbF5
| Autor: | Bruno Coco, Guillermina Urretavizcaya, H. E. Troiani, Santiago Alberto Pighin, F.J. Castro |
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| Rok vydání: | 2018 |
| Předmět: |
Materials science
Hydrogen Kinetics NIOBIUM HYDRIDE Energy Engineering and Power Technology chemistry.chemical_element INGENIERÍAS Y TECNOLOGÍAS 02 engineering and technology NIOBIUM FLUORIDE 010402 general chemistry 01 natural sciences chemistry.chemical_compound Hydrogen storage Ingeniería de los Materiales Desorption Phase (matter) BALL MILLING MAGNESIUM HYDRIDE Renewable Energy Sustainability and the Environment Magnesium hydride HYDROGEN STORAGE 021001 nanoscience & nanotechnology Condensed Matter Physics 0104 chemical sciences Fuel Technology chemistry Chemical engineering Absorption (chemistry) HYDRIDING/DEHYDRIDING KINETICS 0210 nano-technology Solid solution |
| Zdroj: | International Journal of Hydrogen Energy. 43:7430-7439 |
| ISSN: | 0360-3199 |
| DOI: | 10.1016/j.ijhydene.2018.02.151 |
| Popis: | This paper presents a comparative study of H2 absorption and desorption in MgH2 milled with NbF5 or NbH0.9. The addition of NbF5 or NbH0.9 greatly improves hydriding and dehydriding kinetics. After 80 h of milling the mixture of MgH2 with 7 mol.% of NbF5 absorbs 60% of its hydrogen capacity at 250 °C in 30 s, whereas the mixture with 7 mol.% of NbH0.9 takes up 48%, and MgH2 milled without additive only absorbs 2%. At the same temperature, hydrogen desorption in the mixture with NbF5 finishes in 10 min, whereas the mixture with NbH0.9 only desorbs 50% of its hydrogen content, and MgH2 without additive practically does not releases hydrogen. The kinetic improvement is attributed to NbH0.9, a phase observed in the hydrogen cycled MgH2 + NbF5 and MgH2 + NbH0.9 materials, either hydrided or dehydrided. The better kinetic performance of the NbF5-added material is attributed to the combination of smaller size and enhanced distribution of NbH0.9 with more favorable microstructural characteristics. The addition of NbF5 also produces the formation of Mg(HxF1-x)2 solid solutions that limit the practically achievable hydrogen storage capacity of the material. These undesired effects are discussed. Fil: Pighin, Santiago Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche; Argentina Fil: Coco, Bruno. Universidad Nacional de Cuyo; Argentina Fil: Troiani, Horacio Esteban. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina Fil: Castro, Facundo. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina Fil: Urretavizcaya, Guillermina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina |
| Databáze: | OpenAIRE |
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