Efficient and Full‐Spectrum Photothermal Dehydrogenation of Ammonia Borane for Low‐Temperature Release of Hydrogen

Abstract Efficient hydrogen release from ammonia borane (AB) with a striking hydrogen content (19.6 wt%) via thermolysis provides a promising pathway for on‐board applications utilizing hydrogen energy. However, the sluggish kinetics at low temperatures and high energy consumption of thermal dehydrogenation are major obstacles for hydrogen release from AB. Herein, a novel solar‐driven strategy for hydrogen production from AB at low temperature is proposed, in which Ti 2 O 3 is utilized as a full‐spectrum light absorber for photothermal‐activating solid‐state AB reactants to produce hydrogen. Through a reduction transformation method, nanoscale Ti 2 O 3 particles with high chemical stability and narrow band gap are prepared, realizing a rapid production of 2.0 equivalents of hydrogen from AB at ambient temperature, with an excellent recyclable and full‐spectrum‐responsive photothermal dehydrogenation. Importantly, a record high photothermal activation efficiency of 35% is achieved with nanoscale Ti 2 O 3 particles due to an enhanced local photothermal effect contributed by improved light absorption and decreased thermal conduction. Moreover, assisted with CuCl 2 promoter, a release of 2.0 equivalents of hydrogen under 1.0 solar irradiation at 70 °C is successfully achieved, revealing its potential applications in practical vehicles based on proton exchange membrane fuel cells.