Design strategies for shape-controlled nanocatalysts for efficient dehydrogenation of ammonia borane: A review

Ammonia borane (AB) is known to be one of the most promising hydrogen storage materials due to its high hydrogen storage content ( 19. 6%, mass fraction) and stability under standard storage conditions. Ammonia borane is not easy to release hydrogen at room temperature, thus the development of efficient catalysts towards accelerating the rate of hydrogen release are significant and urgent. Active species can be immobilized on the surface or inside pores using support to increase their durability and boost their catalytic activity through the interaction between active components and the support. The overall shape of the catalysts plays a vital role in catalytic activity depending largely on how the active species are scattered on the support and interact with it. This review categorizes the nano catalysts according to their apparent spatial dimension of overall morphology. This paper summarizes the morphological features of various supported catalysts, including 1D, 2D, 3D, and composite materials of their respective combinations. The catalytic effects of nanocatalysts are also compared and discussed in relation to their overall shape as well as the interaction between the active species and the supports with the different morphologies. Finally, the design strategies for shape-controlled nanocatalysts for efficient AB hydrolysis are summarized. This review is aimed to provide some guidance for the rational shape design of nano catalysts towards the efficient dehydrogenation of AB.