How to increase the catalytic efficacy of platinum-based nanocatalysts for hydrogen generation from the hydrolysis of ammonia borane

It reports how to increase the overall catalytic performance of precious platinum nanocatalysts in hydrolytic dehydrogenation of ammonia borane which requires enhancement of both catalytic activity and reusability of the nanocatalysts as well as the fraction of active sites over the total platinum atoms. The following approaches are reported for increasing the utilization efficiency of platinum-based nanocatalysts: (i) The use of colloidal nanoparticles is an efficient way of increasing catalytic activity. However, colloidal platinum (0) nanoparticles are unstable against agglomeration and therefore not reusable. (ii) Supporting the platinum(0) nanoparticles on large surface area materials can increase their stability. Carbonaceous support materials provide moderate activity for platinum(0) nanoparticles but not stability because of the weak metal-support interaction. (iii) Selecting suitable oxide support can help in increasing the catalytic efficiency of platinum nanocatalysts. Particularly, using reducible oxides as support provides a favorable metal-support interaction leading to a notable increase in the catalytic activity and stability of platinum(0) nanoparticles. (iv) The utilization efficiency of the precious platinum nanocatalysts can be significantly enhanced by downsizing the nanoparticles and lowering the relative amount of platinum down to single-atom; that is, using the single-atom platinum nanocatalyst which, however, is limited by the amount of platinum as it cannot be increased because of unavoidable agglomeration. (v) The reusability of platinum(0) nanoparticles can be increased by using magnetic powder materials as support. Thus, the magnetically separable Pt-0/CoFe2O4 and Pt-0/Co3O4 nanoparticles possess superior catalytic activity plus outstanding reusability and hence, provide significant enhancement in catalytic performance or utilization efficiency of platinum(0) nanocatalysts in the evolution of H-2 from the hydrolysis of ammonia borane. Consequently, all these ultimately lower the cost of platinum nanocatalysts.