Efficient Co-Nanocrystal-Based Catalyst for Hydrogen Generation from Borohydride

• Published in: Journal of physical chemistry. C Vol. 121; no. 23; pp. 12610 - 12616
• Main Authors: Liu, Bingrui, Rose, Alyssa, Zhang, Ning, Hu, Yan-Yan, Ma, Mingming
• Format: Journal Article
• Language: English
• Published: American Chemical Society 15.06.2017
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/acs.jpcc.7b03094

Sodium borohydride (NaBH4) has been proposed as a potential hydrogen storage material for fuel cells, and the development of highly active and robust catalysts for hydrolyzing NaBH4 is the key for the practical usage of NaBH4 for fuel cells. Herein we report Co-nanocrystal assembled hollow nanoparticles (Co-HNP) as an active and robust catalyst for the hydrolysis of NaBH4. A hydrogen generation rate of 10.8 L·min–1·g–1 at 25 °C was achieved by using the Co-HNP catalyst with a low activation energy of 23.7 kJ·mol–1, which is among the best performance of reported noble and non-noble catalysts for hydrolyzing NaBH4. Co-HNP also showed good stability in the long term cycling tests. The mechanism of the catalytic hydrolysis of NaBH4 on Co-HNP was studied by using 1H and 11B solid-state NMR, which provided unambiguous experimental evidence of the Co–H formation. The systematically designed NMR experiments unveiled the key role of Co-HNP in the activation of borohydride and the subsequent transfer of H– to water for generating H2 gas and helped to distinguish various hypotheses proposed for catalytic H2 generation reactions. The porous hollow nanostructure of the Co-HNP catalyst provides large surface area and facilitates mass transfer. The facile preparation and outstanding performance of Co-HNP enables it as a very competitive catalyst for hydrogen production.