Dual site multi-channel co-catalytically enhanced kinetic properties of high capacity MgH2–NiFe/CoFe composites

Magnesium-based solid hydrogen storage technology is anticipated to enhance the extensive utilization of hydrogen energy due to its secure and reversible hydrogen storage characteristics. Nonetheless, the intrinsic high Mg–H bond energy and surface dissociation energy of MgH 2 result in severe operating conditions and reduced efficiency. This work proposes a NiFe/CoFe nanocatalyst exhibiting a dual-site multichannel effect, which is incorporated into MgH 2 for surface catalysis using a brief high-energy ball milling technique. The surface-catalyzed composites can release over 90 % of the potential hydrogen storage capacity with a single activation. The MgH 2 -10 wt%NiFe/CoFe composite can absorb 4.88 wt% of H 2 at 150 °C. The release peak temperature of H 2 of MgH 2 -5wt.%NiFe/CoFe was markedly decreased to 281.01 °C, representing a reduction of 162.6 °C relative to ball milled state MgH 2 (BM-MgH 2 ). The Ea for dehydrogenation was markedly decreased to 71 kJ/mol, attributed to the dual-site adsorption of NiFe/CoFe catalysts and the multi-channel diffusion within the multiphase system. These factors facilitate the absorption and dissociation of H-atoms, thereby enhancing the kinetic properties of MgH 2 . This study provides valuable insights for designing multicomponent composite metal nano-catalysts and the advancement of MgH 2 hydrogen storage composites.