Size dependence in solvent-free aerobic oxidation of alcohols catalyzed by zeolite-supported palladium nanoparticles
Size dependence in solvent-free aerobic oxidation of alcohols catalyzed by zeolite-supported palladium nanoparticles
复制标题
沸石负载钯纳米粒子催化醇无溶剂有氧氧化的尺寸依赖性
DOI：
10.1016/j.apcata.2007.10.008
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发表时间：
2008-01-01
影响因子：
5.5
通讯作者：
Wang, Ye
中科院分区：
文献类型：
--
作者：
Li, Feng;Zhang, Qinghong;Wang, Ye
研究了钯纳米粒子催化无溶剂醇类有氧氧化反应的尺寸依赖性。以NaX分子筛为载体，采用离子交换法制备了平均粒径在2.0- 10.5nm范围内可调的钯纳米粒子。发现煅烧温度是决定Pd纳米颗粒平均尺寸的关键因素。合适Pd平均粒径的Pd/NaX催化剂可以催化各种醇的无溶剂有氧氧化，尤其是对苯环上没有取代基的苄醇的催化氧化效果最好。采用不同平均粒径的Pd/NaX催化剂对苯甲醇的无溶剂氧化反应进行了详细的研究，结果表明，苯甲醇的无溶剂氧化反应具有结构敏感性，在中等平均粒径的Pd（2.8 nm）处，苯甲醇的本征转换频率（TOF）达到最大值.另一方面，对于没有离域π环的香叶醇或2-辛醇的氧化，反应是结构不敏感的，并且本征TOF不随Pd颗粒的平均尺寸显著变化。(c)2007 Elsevier B. V.保留所有权利。
The size dependence in the palladium nanoparticle-catalyzed solvent-free aerobic oxidation of alcohols was studied. Palladium nanoparticles with tunable mean sizes in a range of 2.0-10.5 nm were prepared over NaX zeolite by ion exchange of Na+ with an ionic Pd precursor followed by calcination and H-2 reduction. The calcination temperature was found to be a crucial factor in determining the mean size of Pd nanoparticles. Pd/NaX catalysts with proper mean sizes of Pd could catalyze the solvent-free aerobic oxidation of various alcohols, and were particularly efficient for the oxidation of benzylic alcohols without substituents in benzene ring. Detailed studies using the Pd/NaX catalysts with different mean sizes of Pd revealed that the solvent-free aerobic oxidation of benzyl alcohol was structure-sensitive, and the intrinsic turnover frequency (TOF) reached a maximum at a medium mean size of Pd (2.8 nm). On the other hand, for the oxidation of geraniol or 2-octanol without delocalized pi-ring, the reaction was structure-insensitive, and the intrinsic TOF did not change significantly with the mean size of Pd particles. (c) 2007 Elsevier B.V. All rights reserved.