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

Abstract

In this work, we have prepared a series of CuxNi1-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 CuxNi1-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 CuxNi1-xCo2O4 samples, the Cu0.6Ni0.4Co2O4 nanowires showed the highest turnover frequency (TOF) of 119.5 molhydrogen min−1 molcat−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 Cu0.6Ni0.4Co2O4 nanowires can be a robust catalyst towards AB hydrolysis in practical applications.