Preparation of Lanthanum Hexaaluminate Supported Nickel Catalysts for Hydrogen Production by Ammonia Decomposition

Lanthanum hexaaluminate (LHA) supported NiO catalysts (xNi/LHA) with varied mass loading of Ni (x = 15, 20, 25, 30 wt%) were prepared by impregnating NiO nanoparticles (NPs) on LHA support that synthesized through urea combustion method. The catalysts were characterized by high-resolution transmission electron microscope (HRTEM), temperature programmed reduction (TPR), temperature programmed desorption (TPD), etc. The results showed that NiO NPs were dispersed densely on the LHA surface. The 25Ni/LHA catalyst provided the optimal ammonia conversion of 85.75% with a space velocity of 30,000 ml g(cat)(-1) h(-1) at 600 degrees C, corresponding to the hydrogen production rate of 28.73 mmol H-2 g(cat)(-1) min(-1). The strong alkalinity of LHA could modify the interaction between the active sites and the nitrogen of ammonia, which was conducive to the ammonia decomposition reaction. The high performance of the catalyst represented a feasible approach towards the application of ammonia as hydrogen carrier to produce hydrogen. [GRAPHICS] .