Improved hydrolysis properties of Mg3RE hydrides alloyed with Ni

•H-Mg3CeNi0.1 yielded 1088 mL g−1 (9.71 wt.%) of hydrogen at 298 K.•H-Mg3CeNi0.1 showed superior hydrolysis properties to those of H-Mg3RENi0.1.•Ni served to modify the hydrolysis mechanisms of H-Mg3RE (RE = La, Pr, Nd).•Ni promoted the direct hydrolysis of CeH3 to CeO2 to liberate more hydrogen.•Ni caused the stable Nd2H5 to react with water to increase the hydrogen yield.

Nickel has shown to be a good catalyst for improving the hydrolysis performances of hydrogenated Mg3RE (abbreviated as H-Mg3RE, RE = La, Ce, Pr, Nd) through investigating the hydrolysis kinetics and mechanisms of hydrogenated Mg3RENi0.1 (abbreviated as H-Mg3RENi0.1). A material with superior hydrolysis performance, namely H-Mg3CeNi0.1 has been identified, which can generate 276 mL g−1 min−1 hydrogen in the first 1.5 min and achieve a total yield of 1088 mL g−1. Ni served to modify the hydrolysis mechanisms of H-Mg3La, H-Mg3Pr, and H-Mg3Nd to improve their hydrolysis properties. Moreover, Ni has been found to promote the direct hydrolysis of CeH3 to CeO2 to liberate more hydrogen and to render the stable Nd2H5 reactive towards water. Therefore, the studied H-Mg3RE systems all show improved hydrolysis properties after the addition of Ni.