Synthesis of Au core Au/Ag alloy shell nanoparticles using branched Au nanoparticles as seeds
Synthesis of Au core Au/Ag alloy shell nanoparticles using branched Au nanoparticles as seeds
复制标题
DOI：
10.1039/c0ce00018c
复制
发表时间：
2011
期刊：
影响因子：
3.1
通讯作者：
Xinling Tang;M. Tsuji
中科院分区：
文献类型：
--
作者：
Xinling Tang;M. Tsuji
以分枝状Au纳米粒子为晶种，通过两步还原法制备了新型Au核Au/Ag合金壳粒子（记为Au@Au/Ag）。在第一步中，从HAuCl 4/甲酸铵（AF）/聚（乙烯基吡咯烷酮）（PVP）混合物的水溶液制备支化Au晶种。在第二步中，AgNO 3在N，N-二甲基甲酰胺（DMF）中在支化Au种子和PVP存在下被还原。然后形成具有较少数量的短分支的较大的分支颗粒。通过透射电镜（TEM）、高分辨电镜（HR）-TEM、X射线能谱（EDS）和X射线衍射（XRD）分析，讨论了其晶体结构和生长机理。结果表明，在140 °C加热DMF溶液3 h的过程中，Au晶种中细小的长枝熔化，Ag+缓慢还原为Ag 0，形成了Au/Ag合金壳层。通过观察在DMF中不存在AgNO 3的情况下Au核颗粒上从细分支到球形颗粒的形状变化来确认细Au分支的融合。
Novel Au core Au/Ag alloy shell particles denoted as Au@Au/Ag were prepared through the following two-step reduction method using branched Au nanoparticles as seeds. In the first step, branched Au seeds were prepared from an aqueous solution of an HAuCl4/ammonium formate (AF)/poly(vinylpyrrolidone) (PVP) mixture. In the second step, AgNO3 was reduced in N,N-dimethylformamide (DMF) in the presence of branched Au seeds and PVP. Then larger branched particles with smaller numbers of short branches were formed. On the basis of transmission electron microscopic (TEM), high-resolution (HR)-TEM, energy dispersed X-ray spectroscopic (EDS) and XRD data, crystal structures and their growth mechanisms were discussed. It was found that Au/Ag alloy shells were formed by simultaneous occurrence of melt of fine long branches in Au seeds and slow reduction of Ag+ to Ag0 during heating the DMF solution at 140 °C for 3 h. The fusion of fine Au branches was confirmed by observing shape change from fine branches to spherical particles on Au core particles in DMF without the presence of AgNO3.