Room-Temperature Alane Dehydrogenation for Visible-Light-Driven Photocatalytic Hydrogen Supply System

Solar-driven hydrogen supply systems filled with high-density hydrides can overcome the traditional limitations of external heating and power sources. However, these systems commonly rely on photothermal effects to elevate the hydride surface temperature, significantly restricting their photon-to-chemical conversion efficiency. Therefore, exploring hydrogen supply systems driven by visible-light photocatalysis offers immense potential for achieving enhanced photon-to-chemical conversion. In this study, a non-thermodynamic regulation mechanism based on the dehydrogenation of alane and driven by the broadband-responsive photocatalysis of AlH₃-MOF is investigated. The dehydrogenation rate under visible-light irradiation reaches 30.8 µmol g^-1 min^-1, achieving a better than 20-fold improvement compared to room-temperature dark conditions. Moreover, a hydrogen release capacity of 4.7 wt.% is achieved at an ultra-low light intensity of 0.37 W cm^-2 without external heating. Experimental investigations confirm the in situ formation of a novel Al/MOF heterostructure during photocatalytic dehydrogenation. Al nanoparticles induce the injection of hot electrons into the MOF via localized surface plasmon resonance, significantly prolonging the photogenerated charge carrier lifetime. Density functional theory calculations reveal that AlH₃ chemisorption at Al/MOF interfaces induces interfacial charge redistribution and establishes a direct interfacial charge transfer channel. This study pioneers a non-thermodynamic photocatalytic regulation paradigm for solid-state high-energy hydrides, enabling portable application in abundant solar-irradiated regions.