Research on the modification of magnesium hydride by two-dimensional layered Mo2Ti2C3 MXene

One of the most important technologies for the sustainable development of energy in the future is solid-state hydrogen storage. This study employed etching methods to fabricate two-dimensional layered catalyst Mo 2 Ti 2 C 3 MXene, which was compared with unetched MAX phases Mo 2 Ti 2 AlC 3 and Ti 3 C 2 , as well as Mo 2 C. Through mechanical ball milling, these materials were mixed with MgH 2 to prepare composite materials, including MgH 2  + Ti 2 C 3 , MgH 2  + Mo 2 C, MgH 2  + Mo 2 Ti 2 AlC 3 , and MgH 2  + Mo 2 Ti 2 C 3 . According to the study, Mo 2 Ti 2 C 3 demonstrates the synergistic catalytic actions of Ti and Mo in contrast to Ti 2 C 3 and Mo 2 C. The composite material MgH 2  + Mo 2 Ti 2 C 3 lowers the initial dehydrogenation temperature of MgH 2 to 180 °C, which is 165 °C lower than pure MgH 2 . After 30 min at 250 °C, the dehydrogenation amount is approximately 5.85 wt%. Hydrogen absorption begins at 40 °C and reaches approximately 5.75 wt% at 150 °C. Additionally, it maintains a reversible hydrogen storage capacity of up to 96 % even after 20th cycles at 300 °C. This is because Mo 2 Ti 2 C 3 has one less layer of Al than Mo 2 Ti 2 AlC 3 , which results in a wider interlayer spacing, more active sites for MgH 2 , and facilitates hydrogen molecule dissociation and recombination.