Insights into an Amorphous NiCoB Nanoparticle-Catalyzed MgH<sub>2</sub> System for Hydrogen Storage
Liuting Zhang, Yan Zhang, Fuying Wu, Yiqun Jiang, Yijing Wang
Abstract
In the paper, we synthesized amorphous NiCoB nanoparticles by a simple chemical reduction method and employed them as high-activity catalysts to considerably improve the hydrogen storage properties of MgH 2 . The MgH 2 –NiCoB composite quickly absorbed 3.6 wt % H 2 at a low temperature of 85 °C and released 5.5 wt % H 2 below 270 °C within 600 s. It is worth noting that the hydrogenation activation energy was reduced to 33.0 kJ·mol –1 . Detailed microstructure analysis reveals that MgB 2, Mg 2 Ni/Mg 2 NiH 4, and Mg 2 Co/Mg 2 CoH 5 were in situ generated during the first de/absorption cycle and dispersed at the surface of NiCoB. These active ingredients created lots of boundary interfaces to facilitate the hydrogen diffusion and destabilize the Mg–H bonds, thus decreasing the kinetic barriers. This work provides support for a promising catalytic effect of amorphous NiCoB on de/absorption reactions of MgH 2, showing new ways for designing Mg-based hydrogen storage systems toward practical application.