Ammonia decomposition over Ni/La2O3 catalyst for on-site generation of hydrogen

Abstract

Ammonia decomposition is a promising process for on-site generation of hydrogen. In this study, various nickel catalysts supported on metal oxides were prepared and their catalytic activity for ammonia decomposition was investigated. Ni/Al2O3 catalyst achieved the highest ammonia conversion among catalysts investigated due to the high surface area of Al2O3 support (200m2g−1). Despite the low surface area of support material (4.7m2g−1), the catalytic activity of Ni/La2O3 was comparable to that of Ni/Al2O3. The basicity of support materials was not specifically related with the catalytic activity. For Ni/La2O3 catalyst, the small nickel particles were deposited over La2O3 from LaNiO3 during the reduction treatment. When the Ni loading amount was changed in the range of 10–70wt% for Ni/La2O3 catalyst, the sample with 40wt% Ni exhibited the highest conversion of 78.9% at 550°C. The catalytic performance of Ni/La2O3 was also affected by the preparation method and calcination temperature. The LaNiO3 formation was responsible for the high activity of Ni/La2O3 catalyst for the ammonia decomposition.