Effects of SiC nanoparticles with and without Ni on the hydrogen storage properties of MgH_2

摘要

In this work, MgH_2-SiC-Ni was prepared by magneto-mechanical milling in hydrogen atmosphere. Scanning electron microscope mapping images showed a homogeneous dispersion of both Ni and SiC among MgH_2 particles. Based on the differential scanning calorimetry traces, the temperature of desorption is reduced by doping MgH_2 with SiC and Ni. Hydrogen absorption/desorption behaviour of the samples was investigated by Sievert's method at 300 ℃, and the results showed that both capacity and kinetics were improved by adding SiC and Ni. The hydrogen desorption kinetic investigation indicated that for pure MgH_2, the rate-determining step is surface controlled and recombination, while for the MgH_2-SiC-Ni sample it is controlled as described by the Johnson-Mehl-Avrami 3D model (JMA 3D).