Remarkable catalytic effect of Ni and ZrO2 nanoparticles on the hydrogen sorption properties of MgH2

Abstract

In the present study, the catalytic effect of Ni and ZrO2 nanoparticles on the hydrogen absorption and desorption properties of MgH2 has been investigated. The MgH2 nanocomposites were prepared by high-energy ball-milling. The morphology, phase structure, thermal behavior, and hydrogen storage properties of the materials were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), temperature-programmed desorption (TPD), differential scanning calorimetry (DSC), and the pressure-composition temperature (PCT) methods. ZrO2 and Ni nanoparticles were homogenously dispersed into the MgH2 matrix. The calculated apparent activation energy for dehydrogenation was 63.4 kJ/mol, which was decreased by 80.1 kJ/mol compared to that of as-milled MgH2. As a result, MgH2+5 wt.%Ni+5 wt.%ZrO2 demonstrated improved dehydrogenation and hydrogenation kinetics at 310 °C. The MgH2+5 wt.%Ni+5 wt.%ZrO2 sample released about 6.83 wt.% and absorbed about 6.10 wt.% in less than 30 min. Therefore, the co-catalysis of Ni and ZrO2 significantly enhances the hydrogenation and dehydrogenation properties of MgH2.