Zhang Lei, Wang Yi, Tong Limin, Xia Younan
The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University , and School of Chemistry and Biochemistry, Georgia Institute of Technology , Atlanta, Georgia 30332, United States.
Langmuir. 2013 Dec 17;29(50):15719-25. doi: 10.1021/la4040722. Epub 2013 Dec 5.
Silver nanocrystals with uniform sizes were synthesized in droplet microreactors through seed-mediated growth. The key to the success of this synthesis is the use of air as a carrier phase to generate the droplets. The air not only separates the reaction solution into droplets but also provides O2 for the generation of reducing agent (glycolaldehyde). It also serves as a buffer space for the diffusion of NO, which is formed in situ due to the oxidative etching of Ag nanocrystals with twin defects. For the first time, we were able to generate Ag nanocrystals with controlled sizes and shapes in continuous production by using droplet microreactors. For Ag nanocubes, their edge lengths could be readily controlled in the range of 30-100 nm by varying the reaction time, the amount of seeds, and the concentration of AgNO3 in the droplets. Furthermore, we demonstrated the synthesis of Ag octahedra in the droplet microreactors. We believe that the air-driven droplet generation device can be extended to other noble metals for the production of nanocrystals with controlled sizes and shapes.
通过种子介导生长法在微滴反应器中合成了尺寸均匀的银纳米晶体。这种合成方法成功的关键在于使用空气作为载气来产生微滴。空气不仅将反应溶液分离成微滴，还为还原剂（乙醇醛）的生成提供氧气。它还作为原位形成的NO扩散的缓冲空间，NO是由于具有孪晶缺陷的Ag纳米晶体的氧化蚀刻而产生的。首次，我们能够通过使用微滴反应器连续生产出尺寸和形状可控的Ag纳米晶体。对于Ag纳米立方体，通过改变反应时间、种子量和微滴中AgNO₃的浓度，其边长可以很容易地控制在30 - 100 nm范围内。此外，我们还展示了在微滴反应器中合成Ag八面体。我们相信，空气驱动的微滴生成装置可以扩展到其他贵金属，用于生产尺寸和形状可控的纳米晶体。
