Preparation of Ni/Ti3O5@graphene oxide double heterojunction for enhancing hydrogen storage in MgH2

Magnesium hydride serves as a promising solid-state hydrogen storage material owing to its high potential. However, its practical applications are constrained by the high enthalpy of hydrogen absorption and slow kinetics. In this study, we prepared a Ni/Ti 3 O 5 @graphene oxide (GO) dual-heterojunction composite material via solvent heating, electrostatic adsorption, and calcination to improve the hydrogen storage capabilities of MgH 2 . Adding Ni/Ti 3 O 5 @GO to MgH 2 lowered the initial dehydrogenation temperature of MgH 2 to 183 °C; at a dehydrogenation temperature of 275 °C, 6.4 wt.% of H 2 escaped from the MgH 2 bulk. In addition, the hydrogen storage material absorbed 1.8 wt.% H 2 at 30 °C for 30 min. The calculated activation energy of dehydrogenation was 48.221 ± 0.141 kJ·mol −1 , which was significantly lower than that of the ball-milled MgH 2 (112.63 ± 1.44 kJ·mol −1 ). Mechanistic analysis results revealed that the heterojunction constructed from the multiphase compound system provided a large number of active sites and hydrogen diffusion routes, resulting in a synergistic catalytic effect that enhanced the hydrogen storage capacity of MgH 2 . In this work, we clarified the compositions of fuzzy interfaces in heterostructured materials by conducting ultraviolet photoelectron spectroscopy tests and identified key composite materials for the formation of heterojunctions.