Low-temperature solid-state hydrogen storage via efficiently catalyzed MgH2

The urgent development of safe, high-density hydrogen transport and storage technologies is crucial for renewable hydrogen energy. In the present work, a highly efficient N, Nb-doped TiO2 catalyst was synthesized using an NH3 plasma process to catalyze reversible hydrogen sorption of the high-density hydride MgH2. The catalyzed MgH2 exhibits rapid hydrogen uptake even at room temperature and dehydrogenation at a greatly decreased temperature of 175 degrees C. The onset dehydrogenation temperature of the catalyzed MgH2 is reduced to 155 degrees C with an activation energy of 57.33 kJ/mol. Theoretical calculations suggest that the modified TiO2 significantly reduces the dissociation energy barrier and the H2 dissociation energy, accelerating the combination of hydrogen atoms with Mg. The presence of N atoms could also weaken the Mg-H bonds, facilitating the decomposition of MgH2. This work demonstrates the potential of high-density solid-state hydrogen storage via catalyzed MgH2 under moderate conditions.