Multicomponent Ni–Y₂O₃–Al₂O₃ Nanospheres as Highly Efficient Catalysts for the Ammonia Decomposition Reaction

Ammonia is a promising hydrogen storage medium, and the catalytic decomposition of ammonia offers a route to clean hydrogen generation. Constructing efficient multicomponent catalysts with an appropriate choice of components is a feasible strategy to enhance the catalytic performance in ammonia decomposition. In this work, a series of multicomponent Ni–Y 2 O 3 –Al 2 O 3 catalysts with a unique internal hollow spherical structure were synthesized by a facile aerosol-assisted self-assembly approach. Compared with the Ni–Y 2 O 3 and Ni–Al 2 O 3 catalysts, the Ni–Y 2 O 3 –Al 2 O 3 catalysts exhibited a significant advantage in the catalytic performance of ammonia decomposition, and their activity remained stable during tests up to 100 h under very harsh reaction conditions (550 °C and space velocity of 60,000 mL·g cat –1 ·h –1 ), outperforming almost all Ni-based catalysts reported so far. Systematic characterizations demonstrated that Y 2 O 3 effectively dispersed Ni nanoparticles, alleviated the poisoning effect of H 2 on the catalysts, and provided sufficient basic sites to improve the catalytic activity. In addition, the introduction of Al 2 O 3 further inhibited the aggregation of Ni and Y 2 O 3 nanoparticles and maintained their high dispersion in the reaction. This work elucidates the contribution of different compositions in multicomponent catalysts and provides a strategy for the construction of efficient Ni-based ammonia decomposition catalysts.