Construction and performance of an aluminum-water system for real-time hydrogen production in a severe cold environment

Abstract

To achieve real-time hydrogen delivery in a severe cold environment with temperatures between 253.15 K and 233.15 K, a unique aluminum-water system composed of Al-Ga-In-SnCl2 (AGISc)/NaBH4/g-C3N4 composite and CoCl2 methanol solution are logically designed and constructed in this study. The final hydrogen generation from AGISc/NaBH4/1g-g-C3N4 composite in a 0.04 M CoCl2 methanol aqueous solution is 1185 mL·gAl−1, and the conversion efficiency is 85.6% at 253.15 K. Even at 233.15 K, a 0.06 M CoCl2 methanol aqueous solution may generate 1133 mL·gAl−1 of total hydrogen. With a maximum hydrogen generation rate (HGR) of 14 mL·gAl−1·s−1 and a conversion efficiency of 81.8%, real-time hydrogen production under extremely cold conditions is effectively possible. The microstructure and phase characterization of samples reveal that g-C3N4 can facilitate mechanical alloying in the preparing process, while NaBH4 can release a large amount of heat and create a mildly alkaline environment during hydrolysis, both of which enhance the hydrolysis activity. Moreover, CoCl2 solvents in solution acting as the catalysts is essential to the reaction system by forming micro-cells of Al–Co or Al–Co2B.