Co–B supported on waxberry-like hierarchical porous carbon microspheres: An efficient catalyst for hydrogen generation via sodium borohydride hydrolysis

Rapid release of hydrogen at ambient condition is highly favorable and is necessary for fuel cell power generation on-demand. Hydrolysis of hydrides offers such advantage with sodium borohydride (NaBH 4 ) as a representative exemplar. Despite with exceptionally high hydrogen content, the hydrolysis kinetics of NaBH 4 is sluggish in the absence of catalyst. Co–B alloy has generally been employed as effective catalyst in the hydrolysis of borohydrides. However, Co–B particles are prone to agglomeration during the reaction, reducing the activity and durability of the catalyst. In this work, waxberry-like hierarchical porous carbon microspheres (HPCMs) were successfully prepared and were used as carriers to support Co–B particles to form the Co–B/HPCMs catalyst. The effects of HPCMs with different nitrogen contents in Co–B/HPCMs on the catalytic dehydrogenation rate of NaBH 4 hydrolysis were systematically investigated. The experimental results showed that Co–B/HPCM-2 exhibited excellent catalytic activity in the hydrolysis of NaBH 4 at 298 K, with a low activation energy of 43.3 kJ ·mol −1 and a high hydrogen generation rate of 3083.1 ml H2 ·min −1 ·g −1 . Moreover, after five consecutive cycles, its catalytic activity maintained at 91.7 % of the initial catalytic activity, displaying satisfactory cycling performance. The findings obtained from this study are expected to expand a novel path for the development of efficient Co-based catalysts in heterogeneous catalytic reactions .