Morphology-Dependent Ni/Al0.1Ce0.9Ox Catalysts for Efficient Hydrogen Production from Ammonia Decomposition

The conventional Ni/Al₂O₃ catalyst with certain activity has attracted great attention for NH₃ decomposition, but designing and optimizing the morphology of the catalyst to achieve high activity and stability remain a challenge. Herein, three Ni/Al_0.1Ce_0.9O_x catalysts with different morphologies were skillfully prepared by adding a high content of reducible CeO₂ to Al₂O₃. Based on a series of fundamental and synchrotron radiation characterizations, it was found that Ni/Al_0.1Ce_0.9O_x-S exhibited significantly improved activity and stability for NH₃ decomposition. The strong electronic metal–support interaction between CeO₂(111) and Ni promoted the dispersion of Ni species and generated a large number of Ni–O–Ce interface sites, which are both critical for the enhanced catalytic activity of Ni/Al_0.1Ce_0.9O_x-S. Additionally, such an interaction facilitated the formation of abundant oxygen vacancies, which are beneficial for NH₃ adsorption and activation. This study presents a new strategy to design high-efficiency composite-supported Ni catalysts by morphology-dependent synthesis for NH₃ decomposition.