Gdo@C Composite Catalyst for Enhanced Hydrogen Storage Performance of Mg-La-Ni Alloy

Abstract

GdO@C composite catalyst synthesis was achieved through a novel chemical blowing carbonization method. Nano-sized GdO uniformly distributed throughout a high-surface-area, defect-laden carbon matrix translates to catalytic performance. To elucidate the influence of GdO@C doping on hydrogen storage, Mg96La3Ni-GdO@C alloys were prepared by ball milling, and the hydrogen storage performance was evaluated. Adding GdO@C can refine the alloy particles, which boosts the surface area and the number of active sites available for the hydrogenation reaction. GdO@C greatly enhanced the de/hydriding kinetics of the alloys, with 1 wt.% GdO@C exhibiting the optimal effect. At 360 °C, this material could quickly absorb a large amount of hydrogen (84.4 wt.% of its maximum capacity) in just 2 minutes, but it only took 1.6 minutes to release a small amount (3 wt.%). Doping the alloys with GdO@C reduced the activation energy barrier for dehydrogenation (to 106.3 kJ/mol) and shifted the endothermic peak to a lower temperature (334 °C). Nevertheless, there was no improvement observed in the thermodynamic properties of the composites, as the enthalpy change remained constant at 77.1 kJ/mol.

Keywords: Mg-based alloys, Hydrogen storage performance, GdO@C, composite catalyst, Kinetics.