Effect of Temperature on AuPd Nanoparticles Produced by Inert Gas Condensation
Effect of Temperature on AuPd Nanoparticles Produced by Inert Gas Condensation
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DOI：
10.1021/jp101003g
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发表时间：
2010-04-22
影响因子：
3.7
通讯作者：
Jose-Yacaman, Miguel
中科院分区：
文献类型：
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作者：
Perez-Tijerina, Eduardo;Mejia-Rosales, Sergio;Jose-Yacaman, Miguel
采用惰性气体冷凝技术，从靶上溅射材料，并在惰性冷凝区形成颗粒，合成了双金属纳米颗粒。在整个合成过程中，并结合大气条件的控制，将冷凝室后的区域保持在固定温度下，在700℃和1000℃下进行了多次实验，合成条件设定为制备直径为5 nm的纳米颗粒，所得纳米颗粒几乎都是二十面体形状，与平均尺寸偏差很小。我们利用高角度环形暗场和亮场扫描电子显微镜成像分析了这些粒子，其分辨率足以获得原子细节和测量平面之间的距离。从显微照片和它们的快速傅里叶变换模式中，我们发现晶格细节取决于热处理，在700℃下产生的粒子中有较大的晶格条纹位移。一维和二维电子能量损失谱分析表明，无论温度如何，粒子保持其二十面体形状，并且两种化学物质在粒子的整个体积中分布不均匀。但是没有形成核壳结构。
Bimetallic nanoparticles of AuPd were synthesized using the inert gas condensation technique, where the material is sputtered from a target and the particles are formed in an inert condensation zone. Throughout the synthesis process and jointly with the control of the atmosphere conditions, the region after the condensation chamber was kept at a fixed temperature, and several experimental runs were performed at 700 and 1000 degrees C. The synthesis conditions were set to produce particles of 5 nm of diameter, and almost all of the resulting nanoparticles were icosahedral in shape with small deviations from the mean size. We analyzed the particles by high-angle annular dark field and bright field scanning electron microscopy imaging with a resolution high enough to acquire atomic detail and to measure the distance between planes. From the micrographs and their fast Fourier transform patterns, we found that the lattice detail depends on the thermal treatment with larger lattice fringe displacements in the particles produced at 700 degrees C. Electron energy loss spectroscopy analysis in one and two dimensions shows that irrespective of the temperature the particles keep their icosahedral shape, and both chemical species are distributed nonuniformly all over the volume of the particles, but without forming core-shell structures.