Excellent hydrolysis performances of Mg3RE hydrides

Hydrogenated Mg3Mm (where Mm denotes La-rich and Ce-rich misch metal) has been identified as an excellent hydrolysis material for the first time. Hydrolysis of the as-hydrogenated Mg3Mm produced 695 mL g−1 hydrogen in 5 min, 828 mL g−1 hydrogen in 15 min, and the highest hydrogen yield reached 9.79 wt.% at 298 K. Compared to hydrogenated Mg3La, Mg3Ce, Mg3Pr, and Mg3Nd, hydrogenated Mg3Mm displayed the fastest hydrolysis rate due to mutual catalysis of LaH3, CeH3, PrH3, and Nd2H5. The hydrolysis mechanisms of hydrogenated Mg3RE are also discussed herein.

► The fully hydrogenated Mg3Mm yields 9.79 wt.% hydrogen at 298 K.
► H–Mg3Mm is a cheap and efficient hydrolysis material compared with pure H–Mg3RE.
► The in situ formed rare earth hydrides could accelerate the hydrolysis rate of MgH2.
► The hydrolysis property could be optimized by adjusting the ratio of MgH2 to REH3.
► The hydrolysis mechanisms for H–Mg3RE hydrides are revealed.