Defect-Assisted Deposition of Au on Ag for the Fabrication of Core–Shell Nanocubes with Outstanding Chemical and Thermal Stability
Defect-Assisted Deposition of Au on Ag for the Fabrication of Core–Shell Nanocubes with Outstanding Chemical and Thermal Stability
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DOI：
10.1021/acs.chemmater.8b04723
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发表时间：
2019-01
影响因子：
8.6
通讯作者：
Luo Zhang;Yun Zhang;Jaewan Ahn;Xin Wang;D. Qin
中科院分区：
文献类型：
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作者：
Luo Zhang;Yun Zhang;Jaewan Ahn;Xin Wang;D. Qin
我们报道了缺陷辅助沉积Au在Ag纳米立方体上生成具有3至8个原子层的Ag@Au核壳纳米立方体。在标准方案中，我们将Ag纳米立方体分散在含有聚（乙烯基吡咯烷酮）的乙二醇（EG）溶液中，然后在110 °C下滴定HAuCl 4水溶液。最初，HAuCl 4和Ag之间的电流置换反应允许Au在具有最高表面能的纳米立方体的边缘上沉积，因为侧面上的Ag原子以Ag（I）离子的形式溶解到水性悬浮液中以产生表面缺陷。然后这些缺陷成为Ag和Au原子共沉积的优先位点，所述Ag和Au原子来自反应溶液中的Ag（I）和Au（III）离子被EG共还原。一旦填充了缺陷位置，额外的Ag和Au原子将快速扩散穿过每个纳米立方体的整个表面，以产生具有由Ag-Au合金制成的相对薄的壳的纳米立方体。之后，化学还原...
We report the defect-assisted deposition of Au on Ag nanocubes for the generation of Ag@Au core–shell nanocubes with three to eight atomic layers. In a standard protocol, we disperse Ag nanocubes in an ethylene glycol (EG) solution containing poly(vinylpyrrolidone) and then titrate aqueous HAuCl4 at 110 °C. Initially, the galvanic replacement reaction between HAuCl4 and Ag allows the deposition of Au on the edges of the nanocubes with highest surface energy as the Ag atoms on the side faces are dissolved into the aqueous suspension in the form of Ag(I) ions to create surface defects. These defects then become preferential sites for the codeposition of Ag and Au atoms derived from the coreduction of both the Ag(I) and Au(III) ions in the reaction solution by EG. Once the defect sites have been filled, the additional Ag and Au atoms will rapidly diffuse across the entire surface of each nanocube for the generation of a nanocube with a relatively thin shell made of a Ag–Au alloy. Afterward, the chemical redu...