Controlling surface ligand density and core size of alkanethiolate-capped Pd nanoparticles and their effects on catalysis.
Controlling surface ligand density and core size of alkanethiolate-capped Pd nanoparticles and their effects on catalysis.
复制标题
DOI：
10.1021/la302653u
复制
发表时间：
2012-10-09
期刊：
影响因子：
--
通讯作者：
Shon YS
中科院分区：
文献类型：
--
作者：
Gavia DJ;Shon YS
本文系统地研究了硫醇配体包覆的Pd纳米粒子（PdNPs）的表面配体密度/核尺寸与催化性能的关系。进行了由S-十二烷基硫代硫酸钠产生的PdNP的两相合成中的系统变化。通过透射电子显微镜（TEM）、热重分析（TGA）、1H NMR和UV-vis光谱对所得PdNPs进行表征。S-十二烷基硫代硫酸钠（Bunte盐）的摩尔当量的降低导致形成具有较低表面配体密度和较大颗粒核心尺寸的纳米颗粒。四正辛基溴化铵的摩尔当量的降低或反应温度的升高产生具有更高的表面配体密度和更小的颗粒核心尺寸的纳米颗粒。随着NaBH 4摩尔当量的减少，颗粒核心尺寸增加。不同的表面配体密度和平均核尺寸的各种PdNP的催化研究表明，PdNP组合物和周转频率（TOF）的烯丙醇异构化之间的强相关性。具有较低表面配体覆盖率和较大核尺寸的优化的“好”PdNPs以高活性和选择性催化各种烯丙醇异构化为羰基类似物。
This article presents systematic investigations on the relationship between the catalytic property and the surface ligand density/core size of thiolate ligand-capped Pd nanoparticles (PdNPs). The systematic variations in the two-phase synthesis of PdNPs generated from sodium S-dodecylthiosulfate were performed. The resulting PdNPs were characterized by transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and 1H NMR and UV–vis spectroscopy. The decrease in the molar equivalent of sodium S-dodecylthiosulfate (Bunte salts) resulted in the formation of nanoparticles with lower surface ligand density and larger particle core size. A decrease in the molar equivalent of tetra-n-octylammonium bromide or an increase in reaction temperature generated nanoparticles with higher surface ligand density and smaller particle core size. As the molar equivalent of NaBH4 decreased, the particle core size increased. The catalysis studies on various PdNPs with different surface ligand density and average core size showed a strong correlation between the PdNP composition and the turnover frequency (TOF) of the isomerization of allyl alcohol. Optimized “good” PdNPs with lower surface ligand coverage and larger core size catalyzed the isomerization of various allyl alcohols to carbonyl analogues with high activity and selectivity.