Rhodium Nanoparticle Anchoring on AlPO4 for Efficient Catalyst Sintering Suppression

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• 作者：Masato Machida ; Saki Minami ; Keita Ikeue ; Satoshi Hinokuma ; Yuki Nagao ; Takahiro Sato ; Yunosuke Nakahara
• 刊名：Chemistry of Materials
• 出版年：2014
• 出版时间：October 14, 2014
• 年：2014
• 卷：26
• 期：19
• 页码：5799-5805
• 全文大小：391K
• ISSN：1520-5002

文摘

Rhodium catalysts exhibited higher dispersion with tridymite-type AlPO₄ supports than with Al₂O₃ during thermal aging at 900 掳C under an oxidizing atmosphere. The local structural analysis via X-ray photoelectron spectroscopy, transmission electron microscopy, X-ray absorption fine structure, and infrared spectroscopy suggested that the sintering of AlPO₄-supported Rh nanoparticles was significantly suppressed because of anchoring via a Rh鈥揙鈥揚 linkage at the interface between the metal and support. Most of the AlPO₄ surface was terminated by phosphate P鈥揙H groups, which were converted into a Rh鈥揙鈥揚 linkage when Rh oxide (RhO_x) was loaded. This interaction enables the thin planar RhO_x nanoparticles to establish close and stable contact with the AlPO₄ surface. It differs from Rh鈥揙鈥揂l bonding in the oxide-supported catalyst Rh/Al₂O₃, which causes undesired solid reactions that yield deactivated phases. The Rh鈥揙鈥揚 interfacial linkage was preserved under oxidizing and reducing atmospheres, which contrasts with conventional metal oxide supports that only present the anchoring effect under an oxidizing atmosphere. These experimental results agree with a density functional theory optimized coherent interface RhO_x/AlPO₄ model.