Vicky Mann

MgH2 → Mg phase transformation driven by a high-energy electron beam: An in situ transmission electron microscopy study

The dynamics of a phase change have been studied using the electron beam in a transmission electron microscope to transform MgH2 into Mg. The study involved selected-area diffraction and electron-energy-loss spectroscopy (EELS). The orientation relation ( and ), obtained from the electron diffraction study, has been used to propose a model for the movements of magnesium atoms during the phase change. The in situ EELS results have been compared with the existing H-desorption model. The study aims to describe the sorption dynamics of hydrogen in MgH2, which is a base material for a number of promising hydrogen storage systems.

Hydrogen storage properties of nanostructured graphite-based materials

Ball milling is an effective way of producing defective and nanostructured graphite. In this work, graphite was milled under 3 bar hydrogen in a tungsten carbide milling pot, and the effect of milling conditions on the microstructure and hydrogen storage properties was investigated by TGA-Mass Spectrometry, XRD, SEM and Raman spectroscopy. After milling for 10 hours, 5.5 wt% hydrogen was released upon heating under argon to 990°C. After milling for 40 hours, the graphite became significantly more disordered, and the amount of hydrogen desorbed upon heating decreased.