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 & sdot; mol - 1 and a high hydrogen generation rate of 3083.1 ml H2 & sdot; min - 1 & sdot; 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.