Nanoscale magnesium as a hydrogen storage material

This work investigates the structural and hydrogenation properties of nanoscale magnesium in various forms (powders and thin films). A structure consisting of Mg and Ti multilayered thin films is also proposed and studied. The Mg and Mg/Ti thin film samples were fabricated using a magnetron sputtering system. SEM and XRD allowed the study of the structures and composition of the Mg and Mg/Ti thin film samples. XRD confirmed a (002) preferential orientation of the films in agreement with literature. Differences in the sputtering conditions of the Mg/Ti samples also showed differences in their XRD patterns. Furthermore, the XRD results also showed the existence of intrinsic stresses within the films. Hydrogenation properties were studied mainly using thermo-volumetric and gravimetric analysis. The hydrogenation of the samples was confirmed using XRD. Sorption enthalpies of the films were calculated through van’t Hoff plots and were found to be quite high. However, the 40 layer Mg/Ti sample displayed the lowest enthalpy of all (due to the cooperative phenomena). Studies on sorption kinetics showed the fastest absorption kinetics for the 40 layer Mg/Ti sample while the 20 layered sample exhibited the fastest desorption. Finally, TPD results showed a possible presence of the metastable γ-MgH₂ phase.

Name dc:type.qualificationname

m_rs

Level dc:type.qualificationlevel

m_rs

Grantor dc:publisher.institution

University of Birmingham

Year dc:date.issued

2010

Author dc:creator

• Paloumpi, Athanasia

• TP Chemical technology
• TN Mining engineering. Metallurgy