PdZn Intermetallic Nanostructure with Pd-Zn-Pd Ensembles for Highly Active and Chemoselective Semi-Hydrogenation of Acetylene
PdZn Intermetallic Nanostructure with Pd-Zn-Pd Ensembles for Highly Active and Chemoselective Semi-Hydrogenation of Acetylene
复制标题
具有 Pd-Zn-Pd 整体的 PdZn 金属间纳米结构用于乙炔的高活性和化学选择性半氢化
DOI：
10.1021/acscatal.5b01933
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发表时间：
2016-02-01
期刊：
影响因子：
12.9
通讯作者：
Zhang, Tao
中科院分区：
文献类型：
--
作者：
Zhou, Huiran;Yang, Xiaofeng;Zhang, Tao
一种活性金属与另一种惰性金属的金属间合金化不仅提供了活性中心的改善的分散，而且还提供了活性位点的独特且均匀的整体，从而在各种反应中提供了新的机会。在此，我们报告了具有Pd-Zn-Pd系综的PdZn金属间纳米结构对于乙炔半氢化为乙烯具有高活性和选择性，这通常是由于顺序氢化为乙烷而无法实现的。微量热测量和密度泛函理论计算表明，在PdZn合金的Pd-Zn-Pd系综中，Pd位的适当空间排列导致乙炔与两个相邻Pd位的中等σ-键合模式，而乙烯在单个Pd位上的弱π-键合模式有利于乙炔的化学吸附并促进乙烯从催化剂表面的脱附.结果表明，该反应有利于选择性转化。
Intermetallic alloying of one active metal to another inert metal provides not only the improved dispersion of active centers but also a unique and homogeneous ensemble of active sites, thus offering new opportunities in a variety of reactions. Herein, we report that PdZn intermetallic nanostructure with Pd–Zn–Pd ensembles are both highly active and selective for the semihydrogenation of acetylene to ethylene, which is usually inaccessible due to the sequential hydrogenation to ethane. Microcalorimetric measurements and density functional theory calculations demonstrate that the appropriate spatial arrangement of Pd sites in the Pd–Zn–Pd ensembles of the PdZn alloy leads to the moderate σ-bonding mode for acetylene with two neighboring Pd sites while the weak π-bonding pattern of ethylene adsorption on the single Pd site, which facilitates the chemisorption toward acetylene and promotes the desorption of ethylene from the catalyst surface. As a result, it leads to the kinetic favor of the selective conver...