Abstract: Magnesium is one of the most promising candidates of light metal materials for hydrogen production by hydrolysis due to its efficient and economical properties. Various modification methods have been investigated to improve the hydrolytic properties of Mg. However, the direction of the design of efficient catalysts is unclear and needs to be guided by a richer catalytic mechanism of hydrolysis. In this work, a simple approach was used to synthesize Few Layer Graphene (FLG)-loaded ultra-fine highly dispersed Ni/Sc₂O₃ nanocatalyst, which achieves impressive catalytic hydrolysis results. Here, the addition of 4 wt% Ni/Sc₂O₃@FLG catalyst allows Mg to produce 833 mL g^-1 of H₂ in 20 s at 30 °C. There is an initial hydrogen release rate as high as 5942 mL g^-1 min^-1, a final hydrogen yield of 859 mL g^-1 (99.13%), and almost complete conversion of Mg to Mg(OH)₂. Furthermore, surprisingly, even with only 0.2 wt% catalysts added, Mg still has an initial hydrogen generation rate of 3627 mL g^-1 min^-1, which is over 20 times faster than that of Mg. It also produces 690 mL g^-1 of H₂ in 30 s at 30 °C. Hydrolysis kinetic curves and microscopic morphology tests show that FLG could shape and hold Mg into thin sheets, giving them an ultra-high hydrolysis rate and conversion rate. The formation of micro-galvanic cells between Ni and Mg accelerates the electrochemical corrosion of Mg and greatly enhances electron transfer during hydrolysis. This work provides a new strategy for the preparation of efficient nanocatalysts, which is expected to make “Mg-efficient catalyst” the most ideal light metal-based material for hydrogen production by hydrolysis.

Key words: Mg-based materials, Hydrolysis, Catalyst, Hydrogen generation