Light‐Driven Reversible Hydrogen Storage in Light‐Weight Metal Hydrides Enabled by Photothermal Effect

Requiring high temperature for hydrogen storage is the main feature impeding practical application of light metal hydrides. Herein, to lift the restrictions associated with traditional electric heating, light is used as an alternative energy input, and a light-mediated catalytic strategy coupling photothermal and catalytic effects is proposed. With NaAlH4 as the initial target material, TiO2 nanoparticles uniformly distribute on carbon nanosheets (TiO2 @C), which couples the catalytic effect of TiO2 and photothermal property of C, is constructed to drive reversible hydrogen storage in NaAlH4 under light irradiation. Under the catalysis of TiO2 @C, complete hydrogen release from NaAlH4 is achieved within 7 min under a light intensity of 10 sun. Furthermore, owing to the stable catalytic and photothermal effect of TiO2 @C, NaAlH4 delivers a reversible capacity of 4 wt% after 10 cycles with a capacity retention of 85% under light irradiation only. The proposed strategy is also applicable to other light metal hydrides such as LiAlH4 and MgH2 , validating its universality. The concept of light-driven hydrogen storage provides an alternative approach to electric heating, and the light-mediated catalytic strategy proposed herein paves the way to the design of reversible high-density hydrogen storage systems that do not rely on artificial energy.