Ethylene Epoxidation on a Au Nanoparticle versus a Au(111) Surface: A DFT Study
Ethylene Epoxidation on a Au Nanoparticle versus a Au(111) Surface: A DFT Study
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DOI：
10.1021/jz900469f
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发表时间：
2010-02-18
影响因子：
5.7
通讯作者：
Chen, Hui-Lung
中科院分区：
文献类型：
--
作者：
Chen, Hsin-Tsung;Chang, Jee-Gong;Chen, Hui-Lung
烯烃的多相催化环氧化反应是一个实验性强、理论性强、技术性强的研究课题。最近的实验研究表明，负载在惰性材料上的小的金纳米粒子是有效的和鲁棒的催化剂，用于烯烃的选择性氧化。利用密度泛函理论研究了Au纳米粒子催化性能优异的原因，并与Au（111）表面进行了比较。纳米粒子本质上是多的。在环氧化反应中比表面更有选择性。其根本原因是环氧化物形成与乙醛形成的竞争途径的活化屏障的顺序颠倒。在纳米颗粒上，环氧化物形成的活性低于。乙醛在（111）表面上相反。这种行为与纳米颗粒上的环氧化的后期过渡态（即，类似产物），相比之下，在（111）表面上的环氧化的早期（类似反应物）过渡态。
The heterogeneously catalyzed epoxidation of alkenes is experiment, tally challenging, theoretically interesting, and technologically of vital importance. Recent experimental studies show that small gold nanoparticles supported on inert materials are efficient and robust catalysts for the selective oxidation of alkenes. The reasons for the outstanding catalyst of Au nanoparticles have been investigated and compared with the Au(111) surface by means of density functional theory. The nanoparticle is intrinsically much. more selective than the surface in the epoxidation. The fundamental cause is the inversion in the ordering Of activation-barriers for the competing pathways to epoxide formation versus acetaldehyde formation. On the nanoparticle, epoxide formation is less activated than. acetaldehyde. formation, whereas the opposite is true on the (111) surface. This behavior is associated with a late transition state to epoxidation on the nanoparticle (i.e., product-like) compared to an early (reactant-like) transition state to epoxidation on the (111) surface.