Ammonia Decomposition over Nickel Catalysts Supported on Rare-Earth Oxides for the On-Site Generation of Hydrogen

Ammonia decomposition has attracted the interest of many researchers as a promising process for the on-site generation of H-2. In this study, Ni catalysts supported on various rare-earth oxides were prepared by the impregnation method and employed for ammonia decomposition. The Ni/Y2O3 catalyst exhibited the best performance among the samples investigated. The reaction kinetics study indicated that most of rare-earth oxide supports were effective for the alleviation of the hydrogen inhibition phenomenon in the decomposition reaction. The desorption behavior of hydrogen has revealed that the amount of hydrogen atoms adsorbed strongly on the Ni surface up to high temperatures was relatively small in the case of Ni/Y2O3. Furthermore, for Ni/Y2O3 the optimal Ni loading was 40 wt% in terms of the catalytic activity because of the appropriate Ni dispersion.