Morphology-Dependent\nNi/Al<sub>0.1</sub>Ce<sub>0.9</sub>O<sub><i>x</i></sub> Catalysts\nfor Efficient Hydrogen Production\nfrom Ammonia Decomposition

The conventional Ni/Al<sub>2</sub>O<sub>3</sub> catalyst\nwith certain\nactivity has attracted great attention for NH<sub>3</sub> decomposition,\nbut designing and optimizing the morphology of the catalyst to achieve\nhigh activity and stability remain a challenge. Herein, three Ni/Al<sub>0.1</sub>Ce<sub>0.9</sub>O<sub><i>x</i></sub> catalysts\nwith different morphologies were skillfully prepared by adding a high\ncontent of reducible CeO<sub>2</sub> to Al<sub>2</sub>O<sub>3</sub>. Based on a series of fundamental and synchrotron radiation characterizations,\nit was found that Ni/Al<sub>0.1</sub>Ce<sub>0.9</sub>O<sub><i>x</i></sub>-S exhibited significantly improved activity and\nstability for NH<sub>3</sub> decomposition. The strong electronic\nmetal–support interaction between CeO<sub>2</sub>(111) and\nNi promoted the dispersion of Ni species and generated a large number\nof Ni–O–Ce interface sites, which are both critical\nfor the enhanced catalytic activity of Ni/Al<sub>0.1</sub>Ce<sub>0.9</sub>O<sub><i>x</i></sub>-S. Additionally, such an interaction\nfacilitated the formation of abundant oxygen vacancies, which are\nbeneficial for NH<sub>3</sub> adsorption and activation. This study\npresents a new strategy to design high-efficiency composite-supported\nNi catalysts by morphology-dependent synthesis for NH<sub>3</sub> decomposition.