Thermally-assisted milling and hydrogenolysis for synthesizing ultrafine MgH₂with destabilized thermodynamics

A novel process has been developed to synthesize MgH₂nanoparticles by combining ball milling and thermal hydrogenolysis of di-n-butylmagnesium (C₄H₉)₂Mg, denoted as MgBu₂. With the aid of mechanical impact, the hydrogenolysis temperature of MgBu₂in heptane and cyclohexane solution was considerably lowered down to 100 °C, and the MgH₂nanoparticles with an average particle size ofca.8.9 nm were obtained without scaffolds. The nano-size effect of the MgH₂nanoparticles causes a notable decrease in the onset dehydrogenation temperature of 225 °C and enthalpy of 69.78 kJ mol^-1 · H₂. This thermally-assisted milling and hydrogenolysis process may also be extended for synthesizing other nanomaterials.