Changes in kinetic parameters of decomposition of MgH2 destabilized by irradiation with C2+ ions

Abstract

In attempt to improve desorption behaviour of MgH2, the influence of well-defined structural changes induced within a thin surface layer of MgH2 have been investigated. The defects were induced by 30 key C2+ ions irradiation using different fluencies ranging from 10(12)-10(16) ions/cm(2). The hydrogen desorption properties were investigated by thermal desorption spectroscopy analysis (TDS), while kinetics parameters were deduced using non-isothermal kinetic approach. The existence of multiple TDS peaks and different curve shapes indicate difference in desorption mechanism. To understand changes in the rate limiting step, shapes of all desorption peaks have been analyzed using different kinetic models. Regarding the irradiated sample, the function based on Avrami-Erofeev model with n = 4 gives the best fit over theta range from 0.3 to 0.8 while for untreated sample the best fit is obtained for Avrami-Erofeev model with n = 3. The change in mechanism can be attributed to the different way of nuclei growth. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.