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oai:riubu.ubu.es:10259/57792024-07-25T07:26:31Zcom_10259_9476com_10259.4_106com_10259_2604col_10259_9477

2021-05-24T09:40:47Z urn:hdl:10259/5779 Remarkable hydrogen storage properties of MgH2 doped with VNbO5 Valentoni, Antonio Mulas, Gabriele Enzo, Stefano Garroni, Sebastiano The present work concerns the catalytic effect of VNbO5, a ternary oxide prepared via a solid-state route, on the sorption performance of MgH2. Three doped systems, namely 5, 10 and 15 wt% VNbO5– MgH2 have been prepared by ball milling and thoroughly characterized. Hydrogen sorption, evaluated by temperature programmed desorption experiments, revealed a significant reduction of the desorption temperature from 330 1C for the un-doped sample (prepared and tested for comparison) to 235 1C for the VNbO5-doped sample. Furthermore, more than 5 wt% of hydrogen can be absorbed in 5 minutes at 160 1C under 20 bar of hydrogen, which is remarkable compared to the 0.7 wt% achieved for the un-doped system. The sample doped with 15 wt% of additive, showed good reversibility: over 5 wt% of hydrogen with negligible degradation even after 70 consecutive cycles at 275 1C and 50 cycles at 300 1C. The kinetics analysis carried out by Kissinger’s method exhibited a considerable reduction of the activation energy for the desorption process. Finally, pressure-composition-isotherm experiments conducted at three different temperatures allowed estimating the thermodynamic stability of the system and shed light on the additive role of VNbO5. 2021-05-24T09:40:47Z 2021-05-24T09:40:47Z 2018-02 info:eu-repo/semantics/article 1463-9076 http://hdl.handle.net/10259/5779 10.1039/c7cp07157d 1463-9084 eng Physical Chemistry Chemical Physics. 2018, V. 20, n. 6, p. 4100-4108 https://doi.org/10.1039/C7CP07157D info:eu-repo/semantics/openAccess Royal Society of Chemistry