Two-dimensional molybdenum boride coordinating with ruthenium nanoparticles to boost hydrogen generation from hydrolytic dehydrogenation of ammonia borane

Abstract

The coordination between carrier and active metal is critical to the catalytic efficiency of ammonia borane (AB) hydrolysis reaction. In the present study, we report a new type of catalytic support based on molybdenum boride (MBene) MoAl1-xB and demonstrate that the effective combination of MoAl1-xB with Ru nanoparticles can realize the significantly enhanced performance for hydrogen generation. Owing to the efficient activation and dissociation of reactants, the optimal Ru/MoAl1-xB catalyst achieves the large turnover frequency of 494 molH2 molRu-1 min−1, high hydrogen generation rate of 119817 mL min−1 gRu-1 and favorable apparent activation energy of 39.2 kJ mol−1 for the catalytic hydrolysis of AB under alkaline-free condition. The isotopic test suggests the cleavage of OH bond in H2O is the rate-determining step for hydrolysis reaction, while the fracture of B–H bond in AB is also well revealed by attenuated total reflectance (ATR)-Fourier transform infrared (FTIR) spectroscopy. Significantly, the flexible on-demand hydrogen generation is achieved by using chemical switches for on–off AB hydrolysis. This study provides a new support platform based on two-dimensional MBene to exploit efficient catalysts to boost AB dehydrogenation.