Synergistic Effects in Bimetallic Palladium–Copper Catalysts Improve Selectivity in Oxygenate Coupling Reactions

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• 作者：Konstantinos A. Goulas ; Sanil Sreekumar ; Yuying Song ; Purnima Kharidehal ; Gorkem Gunbas ; Paul J. Dietrich ; Gregory R. Johnson ; Y. C. Wang ; Adam M. Grippo ; Lars C. Grabow ; Amit A. Gokhale ; F. Dean Toste
• 刊名：Journal of the American Chemical Society
• 出版年：2016
• 出版时间：June 1, 2016
• 年：2016
• 卷：138
• 期：21
• 页码：6805-6812
• 全文大小：584K
• 年卷期：0
• ISSN：1520-5126

文摘

Condensation reactions such as Guerbet and aldol are important since they allow for C–C bond formation and give higher molecular weight oxygenates. An initial study identified Pd-supported on hydrotalcite as an active catalyst for the transformation, although this catalyst showed extensive undesirable decarbonylation. A catalyst containing Pd and Cu in a 3:1 ratio dramatically decreased decarbonylation, while preserving the high catalytic rates seen with Pd-based catalysts. A combination of XRD, EXAFS, TEM, and CO chemisorption and TPD revealed the formation of CuPd bimetallic nanoparticles with a Cu-enriched surface. Finally, density functional theory studies suggest that the surface segregation of Cu atoms in the bimetallic alloy catalyst produces Cu sites with increased reactivity, while the Pd sites responsible for unselective decarbonylation pathways are selectively poisoned by CO.