Graphene oxide supported oxygen vacancy-rich Co3O4 and Ni nanoparticle for boosting the hydrogen storage properties of MgH2

Developing efficient catalysts is pivotal for advancing MgH 2 -based hydrogen storage systems. In this study, a novel catalyst, graphene oxide-supported oxygen vacancy-rich Co 3 O 4 and Ni nanoparticles (Ni-O V -C@GO), was synthesized to enhance the hydrogen storage performance of MgH 2 . The catalyst dramatically improved the kinetics of MgH 2 , lowering the initial hydrogen desorption temperature of Ni-O V -C@GO-MgH 2 –7 to 438 K, which is 386 K lower than that of as-milled MgH 2 . The composite achieved 5.0 wt% hydrogen absorption at 423 K within 600 s and retained 97.3 % capacity after 30 cycles. Notably, the activation energy for H 2 desorption was reduced to 40.78 kJ/mol, an 80 % decrease compared to pristine MgH 2 . The in-situ formation of CoMg 2 /CoMg 2 H 5 and Mg 2 Ni/Mg 2 NiH 4 acted as “hydrogen pumps”, facilitating multiple hydrogen transfer pathways. Additionally, oxygen vacancies elongated Mg-H bonds, enhancing dehydrogenation kinetics through catalytic effects. These findings provide valuable insights into improving hydrogen adsorption and desorption kinetics in MgH 2 -based systems.