Promoted Multimetal Oxide Catalysts for the Generation of Hydrogen via Ammonia Decomposition

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• 作者：Han Yan ; Yue-Jiao Xu ; Ying-Qiu Gu ; Hao Li ; Xu Wang ; Zhao Jin ; Shuo Shi ; Rui Si ; Chun-Jiang Jia ; Chun-Hua Yan
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：April 14, 2016
• 年：2016
• 卷：120
• 期：14
• 页码：7685-7696
• 全文大小：767K
• 年卷期：0
• ISSN：1932-7455

文摘

Mesoporous multimetal oxide microspheres (Ni–Ce–Al–O) with tuned and uniformly distributed composition are prepared through an aerosol-assisted self-assembly approach and further used as catalysts for ammonia decomposition. The as-prepared and spent materials are characterized by various techniques including ex situ/in situ X-ray diffraction (XRD), X-ray absorption fine structure (XAFS), scanning electron microscope (SEM)/transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and N₂-adsorption. The tricomponent Ni–Ce–Al–O catalysts show great superiority over pure NiO or bicomponent catalysts (Ni–Ce–O and Ni–Al–O) in both catalytic activity and durability. By using H₂-TPR combined with in situ XRD, we have identified metallic Ni⁰ as the active crystalline phase and further confirmed the strong interaction between alumina and other components. This strong interaction helps suppress the growth of both metallic Ni⁰ as active site and ceria as promoter under the harsh catalytic conditions (high temperature and reducing atmosphere) and thus improves the activity and stability simultaneously.