A Pt-Cluster-Based Heterogeneous Catalyst for Homogeneous Catalytic Reactions: X-ray Absorption Spectroscopy and Reaction Kinetic Studies of Their Activity and Stability against Leaching
A Pt-Cluster-Based Heterogeneous Catalyst for Homogeneous Catalytic Reactions: X-ray Absorption Spectroscopy and Reaction Kinetic Studies of Their Activity and Stability against Leaching
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DOI：
10.1021/ja204191t
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发表时间：
2011-08-31
影响因子：
15
通讯作者：
Somorjai, Gabor A.
中科院分区：
文献类型：
--
作者：
Li, Yimin;Liu, Jack Hung-Chang;Somorjai, Gabor A.
设计和开发在液相反应条件下具有高活性、高选择性和高稳定性的金属簇基多相催化剂将使其作为可循环催化剂在大规模精细化学品生产中得到应用。为了实现这些所需的催化性能，非均相催化剂必须含有高浓度的特定催化活性物质，并且活性物质必须在溶液相反应条件下稳定在固体催化剂载体上。这些要求对催化研究提出了很大的挑战，以设计金属簇基催化剂的液相催化过程。在这里，我们专注于二氧化硅负载的，聚合物封装的Pt催化剂的亲电氢烷氧基化反应在甲苯中，它表现出上级的选择性和稳定性，在温和的反应条件下对浸出。我们揭示了关键因素，导致观察到的上级催化性能相结合的X射线吸收光谱（XAS）和反应动力学研究。在这项工作中获得的机械的理解的基础上，我们还提供了有用的指导方针，为更广泛的反应在溶液相中的金属簇基催化剂的设计。
The design and development of metal-cluster-based heterogeneous catalysts wit l high activity, selectivity, and stability under solution-phase reaction conditions will enable their applications as recyclable catalysts in large-scale fine chemicals production. To achieve these required catalytic properties, a heterogeneous catalyst must contain specific catalytically active species in high concentration, and the active species must be stabilized on a solid catalyst support under solution-phase reaction conditions. These requirements pose a great challenge for catalysis research to design metal-cluster-based catalysts for solution-phase catalytic processes. Here, we focus on a silica-supported, polymer-encapsulated Pt catalyst for an electrophilic hydroalkoxylation reaction in toluene, which exhibits superior selectivity and stability against leaching under mild reaction conditions. We unveil the key factors leading to the observed superior catalytic performance by combining X-ray absorption spectroscopy (XAS) and reaction kinetic studies. On the basis of the mechanistic understandings obtained in this work, we also provide useful guidelines for designing metal-cluster-based catalyst for a broader range of reactions in the solution phase.