Heterojunction synergistic catalysis of MXene-supported PrF₃ nanosheets for the efficient hydrogen storage of AlH₃

Aluminum hydride is a promising chemical hydrogen storage material that can achieve dehydrogenation under mild conditions as well as high hydrogen storage capacity. However, designing an efficient and cost-effective catalyst, especially a synergistic catalyst, for realizing low-temperature and high-efficiency hydrogen supply remains challenging. In this study, the heterojunction synergistic catalyst of Ti₃C₂ supported PrF₃ nanosheets considerably improved the dehydrogenation kinetics of AlH₃ at low temperatures and maintained a high hydrogen storage capacity. In the synergistic catalyst, Pr produced a synergistic coupling interaction through its unique electronic structure. The sandwich structure with close contact between the two phases enhanced the interaction between species and the synergistic effect. The initial dehydrogenation temperature of the composite is reduced to 70.2 °C, and the dehydrogenation capacity is 8.6 wt.% at 120 °C in 90 min under the kinetic test, which reached 93% of the theoretical hydrogen storage capacity. The catalyst considerably reduced the activation energy of the dehydrogenation reaction. Furthermore, the multielectron pairs on the surface of the catalyst promoted electron transfer and accelerated the reaction.