Combined “Gateway” and “Spillover” effects originated from a CeNi₅ alloy catalyst for hydrogen storage of MgH₂

Efficient catalysts enable MgH₂ with superior hydrogen storage performance. Herein, we successfully synthesized a catalyst composed of Ce and Ni (i.e. CeNi₅ alloy) with splendid catalytic action for boosting the hydrogen storage property of magnesium hydride (MgH₂). The MgH₂–5wt%CeNi₅ composite’s initial hydrogen release temperature was reduced to 174°C and approximately 6.4wt% H₂ was released at 275°C within 10 min. Besides, the dehydrogenation enthalpy of MgH₂ was slightly decreased by adding CeNi₅. For hydrogenation, the fully dehydrogenated sample absorbed 4.8wt% H₂ at a low temperature of 175°C. The hydrogenation apparent activation energy was decreased from (73.60 ± 1.79) to (46.12 ± 7.33) kJ/mol. Microstructure analysis revealed that Mg₂Ni/Mg₂NiH₄ and CeH_2.73 were formed during the process of hydrogen absorption and desorption, exerted combined “Gateway” and “Spillover” effects to reduce the operating temperature and improve the hydrogen storage kinetics of MgH₂. Our work provides an example of merging “Gateway” and “Spillover” effects in one catalyst and may shed light on designing novel highly-effective catalysts for MgH₂ in near future.