Computational Insights into the Role of Metal and Acid Sites in Bifunctional Metal/Zeolite Catalysts: A Case Study of Acetone Hydrogenation to 2-Propanol and Subsequent Dehydration to Propene

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• 作者：Sai Sriharsha M. Konda ; Stavros Caratzoulas ; Dionisios G. Vlachos
• 刊名：ACS Catalysis
• 出版年：2016
• 出版时间：January 4, 2016
• 年：2016
• 卷：6
• 期：1
• 页码：123-133
• 全文大小：690K
• ISSN：2155-5435

文摘

We employ electronic structure calculations to elucidate the catalytic pathways on bifunctional metal/zeolite catalysts by modeling a HZSM-5-supported nickel tetramer cluster (Ni₄-ZSM-5). Hydrogenation of acetone to 2-propanol followed by dehydration to propene have been investigated as model reactions. In Ni₄-ZSM-5, we observe reverse hydrogen spillover, whereby the Br?nsted hydrogen migrates from the zeolite active site to the metal cluster. Consequently, the zeolite-supported metal cluster becomes electron-deficient, facilitating the hydrogenation reaction. In contrast, studies conducted on the dehydration reaction pathways indicate that the Br?nsted acid catalysis in HZSM-5 is preferred over the metal catalyzed pathway in the Ni₄-ZSM-5 system, again as a result of the electron-deficient nature of the metal species.