Heterostructured Ni/NiO Nanoparticles on 1D Porous MoO_x for Hydrolysis of Ammonia Borane

The hydrolysis of AB has been regarded as a kind of secure and efficient method for hydrogen generation. However, the development of economical and stable catalysts with high catalytic activities remains a bottleneck for realizing further industrial application of AB. Herein, high-loading heterostructured Ni/NiO nanoparticles with different Ni/NiO weight ratios anchored on one-dimensional porous MoOx nanorods (denoted as Ni/NiO@MoOx) have been synthesized and introduced into the hydrolysis of AB for the first time. The Ni/NiO@MoOx-50H catalyst (synthesized under the reduction atmosphere of 50% H2/50% Ar) with an optimal Ni/NiO weight ratio (73.96/26.04) exhibits an excellent catalytic activity for the hydrolysis of AB with the turnover frequency (TOF) value reaching 86.29 molH2 molNi–1 min–1 at 298 K, which is one of the highest TOF values among the reported non-noble metal catalysts. In addition, on account of high Ni loading weight (29.15 wt %), the hydrogen generation rate of Ni/NiO@MoOx-50H achieves 10,478 mL·min–1 g–1 (35,947 mL·min–1 gNi–1), overtaking most values both in noble and non-noble metal catalysts for the hydrolysis of AB. The bridging effect of NiO steadily connects the Ni and MoOx carrier and promotes great durability of Ni/NiO@MoOx-50H, of which the catalytic activity exhibits not significant degradation in the fifth cycle. The catalysis originated from the metal/metal oxide (Ni/NiO@MoOx) provides a novel insight into the catalyst design, preparation, and application for chemical hydrogen storage systems.