Influence of Nanosized CoTiO(3) Synthesized via a Solid-State Method on the Hydrogen Storage Behavior of MgH(2)

Magnesium hydride (MgH(2)) has received outstanding attention as a safe and efficient material to store hydrogen because of its 7.6 wt.% hydrogen content and excellent reversibility. Nevertheless, the application of MgH(2) is obstructed by its unfavorable thermodynamic stability and sluggish sorption kinetic. To overcome these drawbacks, ball milling MgH(2) is vital in reducing the particle size that contribute to the reduction of the decomposition temperature. However, the milling process would become inefficient in reducing particle sizes when equilibrium between cold-welding and fracturing is achieved. Therefore, to further ameliorate the performance of MgH(2), nanosized cobalt titanate (CoTiO(3)) has been synthesized using a solid-state method and was introduced to the MgH(2) system. The different weight percentages of CoTiO(3) were doped to the MgH(2) system, and their catalytic function on the performance of MgH(2) was scrutinized in this study. The MgH(2) + 10 wt.% CoTiO(3) composite presents the most outstanding performance, where the initial decomposition temperature of MgH(2) can be downshifted to 275 °C. Moreover, the MgH(2) + 10 wt.% CoTiO(3) absorbed 6.4 wt.% H(2) at low temperature (200 °C) in only 10 min and rapidly releases 2.3 wt.% H(2) in the first 10 min, demonstrating a 23-times-faster desorption rate than as-milled MgH(2) at 300 °C. The desorption activation energy of the 10 wt.% CoTiO(3)-doped MgH(2) sample was dramatically lowered by 30.4 kJ/mol compared to undoped MgH(2). The enhanced performance of the MgH(2)–CoTiO(3) system is believed to be due to the in situ formation of MgTiO(3), CoMg(2), CoTi(2), and MgO during the heating process, which offer a notable impact on the behavior of MgH(2).