Hydrolysis enhancing mechanisms of Mg-based alloys/hydrides from perspectives: Electrochemical corrosion, active sites, mass transfer, and kinetics

Hydrogen energy is considered to be an ideal new energy carrier in the 21st century due to its clean, environmentally friendly, renewable characteristics and high energy density. The generation of hydrogen by hydrolysis of Mg-based alloys/hydrides has attracted extensive attention attributed to the high hydrogen yield, environmentally-benign by-products, high crust abundance, and well-developed industrial production of Mg. However, in the hydrolysis process of Mg or MgH2 to generate hydrogen, the formed Mg(OH)2 passivation layer attaches to the surface of the active materials to prevent the reaction from continuing. To improve the hydrolysis performance, a series of methods have been put forward. In this paper, focusing on the mechanisms of hydrogen generation by hydrolysis of Mg-based alloys/hydrides, we summarize the recent research progress from four different perspectives: electrochemical corrosion promotion by constructing galvanic cells, active sites increment by refining the particles, mass transfer enhancement by breaking Mg(OH)2 and corresponding kinetic improvement.