Co[sbnd]Mo[sbnd]B nanoparticles supported on foam Ni as efficient catalysts for hydrogen generation from hydrolysis of ammonia borane solution

Abstract

We report on CoMoB nanoparticles supported on foam Ni as catalysts for hydrogen generation from hydrolysis of ammonia borane (NH3BH3) solution. The CoMoB/foam Ni catalysts with different molar ratios of Co2+and MoO42− were synthesized via the electroless-deposition technique at ambient temperature. In order to analyze the phase composition, chemical composition, microstructure, and electron bonding structure of the as-prepared samples, powder X–ray diffraction (XRD), inductively coupled plasma-mass spectroscopy (ICP-MS), scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) were used. The results showed that CoMoB nanoparticles were variously dispersed on the surface of the foam Ni and the catalytic activity correlated with the molar ratio of Co2+ and MoO42−. The highest hydrogen generation rate was 5331.0 mL min−1 gcat−1 at 298 K, and the activation energy was calculated to be 45.5 kJ mol−1 toward the hydrolysis of NH3BH3 solution. The better catalytic activity was largely attributed to the smaller particle size, higher surface roughness and the novel three-dimensional cone-like architectures of the obtained samples. The kinetic results show that the hydrolysis of NH3BH3 is a first-order reaction in catalyst concentration. In addition, the reusability experiment exhibited that the catalytic activity was reduced after 5 cycles and the reason of the decay was also investigated.