Co-Based Nanoparticles Fabricated on Ni Foams for Efficient Hydrogen Generation from Ammonia Borane
Sehrish Mehdi, Yanyan Liu, Huijuan Wei, Hao Wen, Ruofan Shen, Zhikun Peng, Huanhuan Zhang, Xianli Wu, Chengming Wang, Shuyan Guan, Tao Liu, Baojun Li
Abstract
Zeolitic imidazole framework (ZIF-67)-derived Co metal catalysts have gained attention as competitive catalysts due to their high metal loading and superior metal dispersion. However, the problems of Co cluster aggregation during use and difficulty in collection of the powder catalyst from the reaction system need to be solved. In this work, Co-based nanoparticles (NPs) are fabricated on a Ni foam. The monolithic catalyst, Co–NC/NF, has been prepared by the pyrolysis of the ZIF-67/NF precursor using manual coating. The characterization confirms the embedding and uniform distribution of Co NPs (10–20 nm) in the N-doped C matrix. The optimized Co–NC/NF600 reveals satisfactory catalytic activity upon hydrolysis of ammonia borane with a hydrogen evolution (rB = 1176 mL min–1 g–1Co), a turn over frequency (TOF = 180 h–1), and an apparent activation energy (Ea = 64 kJ mol–1). The catalytic activity of Co–NC/NF600 with Co and CoOx as active sites has the best rank among the previously reported Co monolithic catalysts. The superior stability and reusability of the catalyst with ∼ 90% retention after five uses are demonstrated under mild NH3BH3 hydrolysis conditions, originating from the high antiaggregation ability of the active sites and the easy recollection of the catalyst. The adopted novel strategy has the potential to synthesize monolithic catalysts applicable in other fields of heterogeneous catalysis in industrial applications such as energy storage and conversion.