Hydrolysis behaviour of magnides and aluminides and its application to the synthesis of nanoparticles

The hydrolysis behaviour of magnides and aluminides and the thermodynamic analysis of the hydrolysis have been systematically investigated. Two compounds in the Mg–Ni binary system (Mg2Ni and MgNi2) both exhibit hydrolysis behaviour at room temperature. Ni nanoparticles are the product of the hydrolysis of these two compounds. The size of the Ni nanoparticles synthesized by the hydrolysis of MgNi2 had a mean diameter of 16.1 nm, which was slightly coarser than that for the Ni nanoparticles prepared by hydrolysis of Mg2Ni (mean diameter of 11.7 nm). Using MgNi2 to produce the Ni nanoparticles is more efficient and economical than using Mg2Ni. The hydrolysis of magnides can be used to produce a range of transition metal nanoparticles such as Cu, Co, Au, Ag, and Pd. Al3Ni amongst the Ni aluminides only exhibited spontaneous hydrolysis behaviour in water at room temperature. However, Ni nanoparticles were difficult to obtain because of Ni dissolution during removal of Al(OH)3 by an acid. The hydrolysis of the Al-richest compounds has the potential to produce chemically inert transition metal nanoparticles such as Ag and Au.