Cu/Ni-NiO_x Nanoparticles Distributed on Graphene as Catalysts for the Methanolysis of Ammonia Borane to Produce Hydrogen

Ultrasmall Cu/Ni-NiOx nanoparticles (NPs) had been successfully prepared by attaching and growing Ni-NiOx NPs on the surface of Cu NPs and then uniformly dispersed onto graphene (G) surface. High-angle annular dark-field–scanning transmission electron microscopy (HAADF-STEM) characterization confirmed that Ni-NiOx NPs were uniformly distributed on the surface of Cu NPs. The catalytic methanolysis of ammonia borane (AB) proved that Cu/Ni-NiOx NPs possessed high catalytic hydrogen (H2) evolution activity, and the highest turnover frequency (TOF) was 17.72 mol H2·mol–1 Cu·min–1. Comparative experiments revealed that the high catalytic activity originated from the abundant catalytic active sites of Cu/Ni-NiOx NPs. The attachment of Ni-NiOx on the surface of Cu NPs that dispersed on G (G-Cu/Ni-NiOx) can not only effectively improve the antioxidative performance of Cu NPs under ambient conditions but also promote the methanolysis of AB to produce H2.