Enhanced dehydrogenation properties and mechanism analysis of MgH2 solid solution containing Fe nano-catalyst

Magnesium hydride (MgH2) has been proposed as a promising hydrogen storage material due to its high hydrogen capacity. However, its application is hindered by sluggish kinetics and high dehydrogenation temperature. Herein, we report the successful preparation of the Fe containing MgH2 solid solution by milling method, and systematically investigate the dehydrogenation properties and mechanism of the composite through experiments and first principle calculations. The results show that the serious lattice distortion and charge transfer caused by Fe atoms lead to the instability of MgH2, significantly improving the dehydrogenation kinetics of MgH2. As a result, the dehydrogenation activation energy of MgH2–Fe composite was successfully reduced by 44.5%. Notably, the initial dehydrogenation temperature of the composites is nearly 200 °C lower than that of pure MgH2, and 4.5 wt% of H2 can be released at 230 °C for 30 min. These findings provide novel insights for designing simple, low-cost catalysts for MgH2 synthesis.