Enhanced hydrogen generation via hydrolysis of Mg-Mg2NiH4 system

Producing hydrogen via hydrolysis of light weighted metal-based materials is a promising technology for exploiting portable hydrogen-air fuel cells. Various additives have been designed to catalyze the hydrolysis behavior of Mg-based materials. In most cases, however, the kinetic promotion is in the expense of the systematic hydrogen generation yield. In this work, Mg-Mg2NiH4 system with extraordinary hydrolysis property is explored for hydrogen generation in 3.5% NaC1 aqueous solution for the first time. The Mg-10 wt% Mg2NiH4 composite releases 845.1 mL g(-1) (yield of 94.7%) hydrogen in just 20 s, with a maximum hydrogen generation rate (mHGR) of 6391 mL g(-1) min(-1). Our results have experimentally shown the synergistic effect between Mg and Mg2NiH4 on hydrolysis reaction. The in-situ ultrafine Ni particles derived from the rapid hydrolysis of Mg2NiH4 form a large amount of micro-galvanic cells with Mg, accelerating the electrochemical corrosion of Mg efficiently. In turn, the hydrolysis reaction of Mg2NiH4 can be dramatically driven by the local solution heat due to the violent exothermic reaction of Mg. The cooperative effect provides fresh strategy designing high-property hydrolysis materials with no substantial loss of the hydrogen supply capacity.