A Solid-System Strategy for Controlled Hydrolytic Release of Hydrogen by Encapsulation of Ammonia Borane in Cobalt Decorated Halloysite Aerogel

Exploring the "on–off" control of hydrogen release remains a critical issue for efficiently on-demand utilization of hydrogen energy. In this work, a new hydrogen storage strategy of loading ammonia borane (AB) solid and metal catalyst Co in a halloysite nanotube aerogel (AB@Co/HNTA) is proposed for controlled hydrogen release from AB hydrolysis by controlling the added water. The results show that Co nanoparticles with a size of 3.07 nm are uniformly distributed on halloysite and HNTA surface, and AB can be packaged into HNTA to form a bulk solid composite. Controlled hydrogen generation is achieved in the AB@Co/HNTA solid system, which can be turned on and off by controlling the amount of water added to the aerogel. Further, the Co decorated HNTA (Co/HNTA) can be reused to encapsulate AB for the next run after AB complete hydrolysis. This work provides a new approach to control the release of hydrogen for application in the field of "on-board" device, and this solid-system strategy of controlled hydrolytic hydrogen release can be extended to any other porous material loaded with catalysts.