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

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 Ti2O3 is utilized as a full-spectrum light absorber for photothermal-activating solid-state AB reactants to produce hydrogen. Through a reduction transformation method, nanoscale Ti2O3 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 Ti2O3 particles due to an enhanced local photothermal effect contributed by improved light absorption and decreased thermal conduction. Moreover, assisted with CuCl2 promoter, a release of 2.0 equivalents of hydrogen under 1.0 solar irradiation at 70 degrees C is successfully achieved, revealing its potential applications in practical vehicles based on proton exchange membrane fuel cells.