Controlling Catalytic Properties of Pd Nanoclusters through Their Chemical Environment at the Atomic Level Using Isoreticular Metal–Organic Frameworks

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• 作者：Xinle Li ; Tian Wei Goh ; Lei Li ; Chaoxian Xiao ; Zhiyong Guo ; Xiao Cheng Zeng ; Wenyu Huang
• 刊名：ACS Catalysis
• 出版年：2016
• 出版时间：June 3, 2016
• 年：2016
• 卷：6
• 期：6
• 页码：3461-3468
• 全文大小：421K
• 年卷期：0
• ISSN：2155-5435

文摘

Control of heterogeneous catalytic sites through their surrounding chemical environment at an atomic level is crucial to catalyst design. We synthesize Pd nanoclusters (NCs) in an atomically tunable chemical environment using isoreticular metal–organic framework (MOF) supports (Pd@UiO-66-X, X = H, NH₂, OMe). In an aerobic reaction between benzaldehyde and ethylene glycol, these catalysts show product distributions that are completely altered from the acetal to the ester when we change the functional groups on the MOF linkers from −NH₂ to −H/–OMe. Diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) studies, along with density functional theory (DFT) calculations, show that the coordination of the −NH₂ groups to the Pd NCs could weaken their oxidation capability to a greater extent in comparison to that of the −OMe group. Moreover, the limited number of −NH₂ groups per cavity in the MOF change the electronic properties of the Pd NCs while still leaving open sites for catalysis.