Studies of Ni-Mg catalyst for stable high efficiency hydrogen storage

Doping engineering is an effective strategy to improve the hydrogen storage capacity of magnesium-based materials. Here, we report a magnesium composite containing trace amounts of nickel catalyst (Ni-Mg), in which Ni and Mg layers form a new structural phase. The test shows that Ni-Mg composite has a hydrogen storage capacity of 7.5 wt%, with rapid absorption/desorption kinetics and stable reversible absorption/desorption performance on cycling. Ni-Mg exhibits a superior hydrogen storage performance as compared to the MgNi alloys and Mg-based materials previously reported in the literature. We conclude that a new MgNi phase and MgNi 2 intermetallic compound are formed during the H 2 adsorption process . Based on the theoretical calculations, we show that Ni facilitates hydrogenation by accelerating the dissociation of H 2 molecules into the H atoms, while the MgNi phase formed during the hydrogenation is conducive to the subsequent dehydrogenation, promoting H atoms diffusion between the subsurface and the surface. This work provides a guidance for the development of the efficient hydrogen storage materials .