Mechanochemical Assisted Hydrogenation of Mg-Cnts-Ni ： Kinetics Modeling and Reaction Mechanism

MgH 2 as one of the most potential hydrogen storage materials has received considerable attention. However, its development has been plagued by its slow hydriding kinetics. Mechanochemical milling is an effective and convenient method for producing MgH 2 @CNTs-Ni through a solid-gas reaction between Mg-CNTs-Ni and H 2 . However, the hydriding kinetics and corresponding mechanism during the milling has not been mentioned. Thus, hydriding kinetics of Mg-CNTs-Ni were researched with the goal to gain insights about the reaction mechanism and to obtain best milling parameters. Also, phase transition during the milling were analyzed using XRD and TEM. It is apparent that Avrami-Erofeev (AE) model can be well described the mechanochemical process, which contains solid solution, phase transition and growth controlled regime. Kinetics of hydrogenation was limited by nucleation and growth of MgH 2 . By fitting with Arrhenius equation, average apparent activation energy for the hydrogenation of Mg-CNTs-Ni was estimated to be 47.8 kJ mol − 1