Abstract Both CaH2 and MgH2 are good candidate for the development of hydrogen storage materials because of their high hydrogen storage capacity. However, both the hydrides are quite stable thermodynamically and required high temperature for hydrogen sorption process. The MgH2–CaH2 composite could show the favourable hydrogen sorption reaction because of Ca–Mg intermetallic formation. The idea motivated to perform the experiments starting with these metal hydrides. It has been found that the hydrogen sorption reaction kinetics improved substantially. The dihydrogen product has shown a few intermetallic of magnesium and calcium. The hydrogen sorption temperature and pressure of the alloy was remarkably improved by the doping with ZrCl4 as a catalyst. The activation energy and the thermodynamic parameters of un-catalyzed and catalyzed alloy were studied. Present studied indicated that the CaH2–MgH2–ZrCl4 could be a potential candidate for the mobile hydrogen storage system.