Hydrogen generation: Via hydrolysis of magnesium with seawater using Mo, MoO₂, MoO₃ and MoS₂ as catalysts

Hydrogen generation is one of the enabling technologies for realization of hydrogen economy. In this study, we developed a high-performance hydrogen generation system using the transition metal Mo and its compounds (MoS₂, MoO₂, and MoO₃) for catalyzing the hydrolysis of Mg composites in seawater. These Mg-based composites for the hydrolysis process were synthesized through a simple planetary ball mill technique. The results demonstrate that small amounts of added MoS₂ could significantly accelerate and enhance the hydrolysis reaction of Mg in seawater. In particular, the Mg-10 wt% MoS₂ composite releases 838 mL g^-1 hydrogen in 10 min (about 89.8% of the theoretical hydrogen generation yield), and the recycled catalysts exhibit high cycle stability, which is the most significant achievement in this study. In addition, Mo, MoO₂, and MoO₃ also showed similar enhancement in the hydrolysis reaction of Mg. The activation energies for the hydrolysis of Mg decreased from 63.9 kJ mol^-1 to 27.6 kJ mol^-1, 20.4 kJ mol^-1, 14.3 kJ mol^-1, and 12.1 kJ mol^-1 on introducing Mo, MoS₂, MoO₂, and MoO₃, respectively. The attractive hydrolysis performance of the composites of Mg milled with Mo and its compounds in seawater may shed light on future developments of hydrogen generation technologies.