PdCu二元合金纳米晶体的合成及其自组装

Synthesis and self-assembly of PdCu nanoalloys

采用胶体合成的方法,在十八烯、油胺的存在下,以1,2-十六烷基二醇作为还原剂直接还原乙酰丙酮铜和乙酰丙酮钯的混合物,得到高质量的PdCu合金纳米晶体。所合成的PdCu纳米晶体能够分散在正己烷或甲苯中形成稳定的胶体溶液,通过缓慢地蒸发溶剂,纳米晶体能够在基底上自组装成长程有序的二维(2D)超晶格。考察了反应温度对纳米晶体尺寸的影响,以及胶体溶液的浓度和溶剂的蒸发速率对自组装过程的影响,并采用X线衍射仪(XRD)、透射电镜(TEM)、场发射扫描电镜(FE-SEM)对所得纳米晶体及其自组装超晶格进行表征。结果表明:反应温度越高,PdCu纳米晶体的尺寸越小。240℃下,平均粒径为(3.9±0.2)nm;200℃下,平均粒径为(5.9±0.5)nm。超晶格中,PdCu纳米晶体是以六方密堆积(hcp)的方式排列。

The synthesis of high-quality PdCu bimetallic nanocrystals （NCs） was achieved by simultane- ous reduction of copper（ H ）-acetylacetonate and palladium（ II ）-acetylacetonate with 1, 2-hexadecane- diol in 1-octadecene in the presence of oleylamine. As-prepared PdCu was dissolved in hexane or toluene to form stable colloidal solution. As the solvent evaporated slowly from a droplet of such a colloid with appropriate concentration on a substrate, the nanocrystals could be self-assembled into long-range ordering 2D superlattices. The samples were characterized and analyzed by X-ray diffraction （XRD）, transmission electron microscope （TEM） and field emission scanning electron microscope （FE-SEM）. The results showed that variation of the reaction temperature affected the sizes of PdCu NCs. The average final size of PdCu NCs prepared at 240 ℃and 200 ℃ were （3.9 ± 0.2） nm and （5.9 ± 0.5 ） nm, PdCu NCs with spherieal shape finally formed hexagonal close-packed （hep） lattice.