Characterization and catalytic activity of core-shell structured gold/palladium bimetallic nanoparticles synthesized by the sonochemical method
Characterization and catalytic activity of core-shell structured gold/palladium bimetallic nanoparticles synthesized by the sonochemical method
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DOI：
10.1021/jp994255e
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发表时间：
2000-06-29
影响因子：
3.3
通讯作者：
Maeda, Y
中科院分区：
文献类型：
--
作者：
Mizukoshi, Y;Fujimoto, T;Maeda, Y
这是一篇关于利用高强度超声波在金（III）和钯（II）离子水溶液中照射引起的空化现象制备纳米金/钯双金属颗粒的报道。通过透射电子显微镜和纳米区能量色散x射线光谱分析，发现该粒子由金核和钯壳组成。在样品溶液中加入十二烷基硫酸钠是纳米颗粒生成的稳定剂，也是贵金属离子还原物质的重要来源。钯壳的厚度和金核的大小似乎取决于贵金属离子浓度的比例。超声化学和放射化学产物的形态差异表明，核壳结构的形成可能受到超声物理效应的影响，如有效的搅拌、微射流或空化泡破裂过程中的冲击波。双金属纳米粒子对4-戊烯酸的氢化反应活性高于具有相应金/钯比的单金属纳米粒子混合物。当金钯比为1:4时，双金属颗粒的活性比相同条件下制备的单金属钯纳米颗粒的活性高约3倍。
This is a report regarding the preparation of nanosized gold/palladium bimetallic particles utilizing a cavitation phenomenon induced by irradiation of high-intensity ultrasound in an aqueous solution of gold(III) and palladium(II) ions. The particles are found to be composed of gold-core and palladium-shell by a transmission electron microscopic and nanoarea energy-dispersive X-ray spectroscopic analyses. Sodium dodecyl sulfate added to the sample solution is found to be a stabilizer for the nanoparticles generated as well as an important source of reducing species for noble metal ions. The thickness of a palladium shell and the size of a gold core seem to depend on the ratio of the concentrations of noble metal ions. The morphological differences in the sonochemical and radiochemical products suggest that the formation of a core-shell structure can be affected by the physical effects of ultrasound, such as effective stirring, microjet stream, or shock wave during the collapse of a cavitation bubble. Bimetallic nanoparticles show higher activities for the hydrogenation of 4-pentenoic acid than for those of the mixtures of monometallic nanoparticles with a corresponding gold/palladium ratio. When the gold/palladium ratio is 1:4, the activity of the bimetallic particles is about three times higher than that of palladium monometallic nanoparticles prepared under the same conditions.