Interfacial ensemble effect of copper nanoparticles and nickel metal-organic framework on promoting hydrogen generation

Abstract

Ammonia borane is a promising chemical hydrogen storage material to the hydrogen economy in the future. However, efficient and inexpensive catalyst for realizing this process remains challenging. Herein, the interfaces of copper nanoparticles (NPs) and nickel metal-organic framework (MOF) with different Cu/Ni ratios (Cu@Nix-MOF) have been constructed by Cu NPs in situ growth in Ni-MOF via a facile one-step solvothermal method. The Cu@Nix-MOF composites show much higher catalytic activity than their monometal counterparts and the optimized Cu@Ni6-MOF catalyst achieves a turnover frequency of 69.1 min−1 for ammonia borane hydrolysis, superior to most reported Ni-based catalysts. Density functional theory simulation and in situ Raman spectroscopy analysis propose that this remarkable enhanced activity of Ni-based catalysts is induced by a synergetic effect of Cu–Ni2+ dual active sites at their interfaces. This study shows that the strategy of dual active sites hold great promise to achieve efficient non-noble metal catalysts toward heterogeneous catalysis.