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-MgH2have 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 °C for the un-doped sample (prepared and tested for comparison) to 235 °C for the VNbO5-doped sample. Furthermore, more than 5 wt% of hydrogen can be absorbed in 5 minutes at 160 °C 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 °C and 50 cycles at 300 °C. 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.

Remarkable hydrogen storage properties of MgH2doped with VNbO5 / Valentoni, Antonio; Mulas, Gabriele; Enzo, Stefano; Garroni, Sebastiano. - In: PHYSICAL CHEMISTRY CHEMICAL PHYSICS. - ISSN 1463-9076. - 20:6(2018), pp. 4100-4108. [10.1039/c7cp07157d]

Remarkable hydrogen storage properties of MgH2doped with VNbO5

Valentoni, Antonio;Mulas, Gabriele;Enzo, Stefano;Garroni, Sebastiano
2018

Abstract

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-MgH2have 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 °C for the un-doped sample (prepared and tested for comparison) to 235 °C for the VNbO5-doped sample. Furthermore, more than 5 wt% of hydrogen can be absorbed in 5 minutes at 160 °C 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 °C and 50 cycles at 300 °C. 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.
Remarkable hydrogen storage properties of MgH2doped with VNbO5 / Valentoni, Antonio; Mulas, Gabriele; Enzo, Stefano; Garroni, Sebastiano. - In: PHYSICAL CHEMISTRY CHEMICAL PHYSICS. - ISSN 1463-9076. - 20:6(2018), pp. 4100-4108. [10.1039/c7cp07157d]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11388/202860
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