Hydrogen desorption from hydride matrix is still an open field of research. Extensive, density functional theory based, ab-initio molecular dynamics simulations of MgH2-Mg interface catches the atomic level structural mechanism leading to hydrogen desorption. The numerical model estimates the desorption temperature for an interface with Fe catalyst in excellent agreement with experimental results. Formation energies and the analysis of the structural data reveal the role played by the catalysts to lower the desorption temperature. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.