Hydrogen desorption performance of high-energy ball milled Mg₂NiH₄ catalyzed by multi-walled carbon nanotubes coupling with TiF₃

The Mg₂NiH₄ complex hydrides were synthesized by high-energy ball milling (HEBM) MgH2 Ni mixtures. Multi-walled carbon nanotubes (MWCNTs) or TiF3 as catalysts were added and the catalytic-dehydrogenation behaviors were investigated. All prepared samples are characterized by X-ray diffraction (XRD) spectroscopy, scanning electron microscope (SEM) and differential scanning calorimetry (DSC) to acquire information of microstructure, phase compositions, surface and dehydrogenation properties. The results indicate that the method of adding catalysts by HEBM is reasonable and the hydrogen desorption property of Mg₂NiH₄ is improved by catalysts. It is worth noting that the dehydrogenation temperature (TD) and the activation energy (Ea) of Mg₂NiH₄ catalyzed by MWCNTs coupling with TiF3 are reduced to 230 °C (243.6 °C of Mg₂NiH₄) and 53.24 kJ/mol (90.13 kJ/mol of Mg₂NiH₄), respectively. The addition of proper catalysts is proved to be an effective strategy to decrease TD and Ea of Mg₂NiH₄ hydrides.