Cu0.6Ni0.4Co2O4 nanowires,a novel noble-metal-free catalyst with ultrahigh catalytic activity towards the hydrolysis of ammonia borane for hydrogen production

In this work, we have prepared a series of Cu_xNi_1-xCo₂O₄ (x = 0, 0.2, 0.4, 0.5, 0.6, 0.8, and 1) nanowires with a diameter of approximately 30 nm, which were characterized by X-ray powder diffractometry, scanning and transmission electron microscopy, and X-ray photoelectron spectrometry. For the first time, the catalytic activity of these Cu_xNi_1-xCo₂O₄ nanowires in ammonia borane (AB) hydrolysis was investigated, and it was found that a significant synergistic effect exists between NiCo₂O₄ and CuCo₂O₄ in the hydrolytic reaction. Among these Cu_xNi_1-xCo₂O₄ samples, the Cu_0.6Ni_0.4Co₂O₄ nanowires showed the highest turnover frequency (TOF) of 119.5 mol_hydrogen min^?1 mol_cat^?1. This value is 1.66 times as high as that for CoP nanoparticles, which is the most active noble-metal-free catalyst towards AB hydrolysis ever reported in the literature. Because of the low cost and high catalytic performance, the Cu_0.6Ni_0.4Co₂O₄ nanowires can be a robust catalyst towards AB hydrolysis in practical applications.