Enhancement of the hydrogen storage performance of MgH2 using CeO2@C with oxygen vacancy‑rich from Ce-MOF pyrolysis

MgH 2 exhibits significant potential as promising candidates for next-generation hydrogen storage solutions, owing to excellent hydrogen storage capacity. However, its high thermodynamic stability and kinetic barriers result in sluggish dehydrogenation kinetics and high dehydrogenation temperatures. Herein, oxygen vacancy (O V )-rich CeO 2 @C effectively weakens the Mg–H bond energy, which is manifested as the elongation of the Mg–H bond. Moreover, the O V -rich CeO 2 @C reacts with H 2 to form CeH 2.73 , which enhances hydrogen diffusion within the Mg/MgH 2 system. Meanwhile, the formation of CeH 2.73 promotes the formation of O V within the MgH 2 -CeO 2 @C, further facilitating the dehydrogenation of MgH 2 . Thereby, the synergistic effect of the O V -rich CeO 2 @C and CeH 2.73 lower the dehydrogenation temperature of MgH 2 and enhance kinetic performance. The MgH 2 -CeO 2 @C-3h behaves the most optimal dehydrogenation performance, achieving a release of 4.88   wt% H 2 within 10   min at 350 ℃. The initial dehydrogenation temperature of the MgH 2 -CeO 2 @C-3h is reduced to 274 ℃, and the dehydrogenation activation energy ( E a ) is lowered to 99.13   kJ   mol –1 , compared to 327 ℃ and 160.7   kJ   mol –1 for pristine MgH 2 . This work provides new insights into designing O V -rich metal oxide catalysts for MgH 2 .