TiVC MXene mediated enhancement in hydrogen storage performance of NaAlH4 and the related mechanisms

Developing efficient hydrogen storage technologies remains a critical challenge for advancing clean hydrogen energy applications. This study addresses the challenges of high dehydrogenation temperature and sluggish dehydrogenation kinetics in NaAlH 4 through the development of TiVC MXene-enhanced composite systems . In this paper, TiVC MXene was prepared by etching TiVAlC with HCl/LiF, and TiVC/NaAlH 4 composite systems were made via milling. The unit cell of NaAlH 4 expanded during milling due to M (M = Ti, V) point defects . The optimal 8 wt% TiVC-doped sample demonstrated remarkable performance: onset dehydrogenation temperature reduced to 90 °C and activation energy decreased by 41% in the 2 nd dehydrogenation step. Notably, the dehydrogenated product achieved 4.1 wt% hydrogenation capacity within 30 min at 120 °C. Structural and mechanistic analyses showed that TiVC decomposed, and its reaction products, such as M defects, Ti–Al alloy and Ti/V oxides , were the real catalysts. They enhanced NaAlH 4 's hydrogen-storage performance by offering active H and smaller Al particles . This work demonstrates the potential of MXene-derived multiphase catalysts for metal hydride storage systems.