Interfacial catalysis and electronic modulation enable near-room-temperature and ultrafast dehydrogenation of α-AlH3 by 2D V4C3 MXene

α -phase AlH 3 , as a high-capacity hydrogen storage material (10.01 wt%), is often used in the hydrogen fuel cell industry. However, its high dehydrogenation temperature remains difficult to match with the operating temperature of proton exchange membranes. Designing efficient catalysts can effectively improve the dehydrogenation performance of AlH 3 , enabling low-temperature dehydrogenation by destabilizing it. In this work, a two-dimensional transition metal carbide V 4 C 3 with a layered structure was designed. Using V 4 AlC 3 as a precursor, two-dimensional V 4 C 3 was prepared via hydrofluoric acid etching. The AlH 3 –V 4 C 3 composite material was constructed by combining V 4 C 3 with AlH 3 through mild ball milling, which significantly enhanced the dehydrogenation performance of AlH 3 . With an optimal additive ratio (+3 wt% V 4 C 3 ), AlH 3 began to release hydrogen at temperatures as low as 47°C, exhibited a dehydrogenation peak temperature of only 110.2°C, and achieved a final hydrogen release capacity of 8.37 wt%. In isothermal dehydrogenation kinetic tests, the dehydrogenation capacity of V 4 C 3 -modified AlH 3 within 60 min at 120°C was significantly increased from 2.11 wt% to 7.50 wt%, and the activation energy for dehydrogenation was reduced from 88.5 kJ/mol to 35.7 kJ/mol, demonstrating remarkable improvement in isothermal dehydrogenation performance. The mechanism behind the improved dehydrogenation of AlH 3 by V 4 C 3 was investigated through a combination of characterization techniques and density functional theory (DFT) calculations. The results indicate that V 4 C 3 effectively weakens the Al-H bonds in AlH 3 , facilitates hydrogen dissociation, and alters the nucleation and growth mechanism of AlH 3 during dehydrogenation. Throughout the entire dehydrogenation process, V 4 C 3 remains chemically stable and enhances the dehydrogenation kinetics of AlH 3 via interfacial catalysis. The aforementioned approach effectively improves the overall dehydrogenation performance of AlH 3 , providing a novel paradigm for enhancing light-metal high-capacity hydrides.