Enriching Silver Nanocrystals with a Second Noble Metal

报 告 人：秦冬 副教授（佐治亚理工学院）

报告时间：2017年7月4日（星期二）下午14:00

报告地点：南京工业大学江浦校区浦江楼302会议室

报告摘要：Silver is perhaps the best choice of material for plasmonics and related applications owing to its relatively low cost and favorable dielectric functions. Over the past two decades, significant progress has been made in the synthesis of Ag nanocrystals with controlled shapes and sizes to tailor their properties and thus optimize their performance in a range of applications. In particular, Ag nanocrystals have been prepared with sharp features (e.g., edges and corners) on the surface to drastically augment their surface-enhanced Raman scattering (SERS) activity. However, the sharp features tend to vanish due to the high susceptibility of Ag toward oxidative etching. As another pitfall, Ag is limited in terms of catalytic application as it only shows activity toward oxidation reactions such as epoxidation, not reduction reactions. One can address the aforementioned limitations of Ag nanocrystals by introducing a second noble metal (M) such as Au, Pd, or Pt to generate Ag-M bimetallic nanocrystals. In this talk, I will introduce two approaches to using Ag nanocrystals as seeds for the selective deposition of M. When the M atoms are selectively deposited on the edges of a Ag nanocrystal, a Ag@M core-frame nanocrystal is formed. In this structure, the excellent plasmonic and SERS properties of the Ag core are well retained while the deposited M can bring in new catalytic capabilities. Alternatively, when the M atoms are conformally deposited on the entire surface, a Ag@M core-shell nanocrystal is created. In this case, the M shell can greatly improve the chemical stability of the particle, in addition to the new catalytic properties associated with M. If the shell is kept below 1–2 nm thick, the excellent plasmonic and SERS properties of the Ag core can still be leveraged. Significantly, both SERS and catalytic properties can be integrated in the core-frame and core-shell nanocrystals to offer a unique probe for in situ detection and analysis of catalytic reactions by SERS.

个人简历：

秦冬，佐治亚理工学院材料科学与工程学院、化学与生物化学学院双聘副教授。其先后于复旦大学和宾夕法尼亚大学获得学士和博士学位，并在哈佛大学开展博士后研究工作，合作导师为George M. Whitesides教授。随后在华盛顿大学西雅图分校和华盛顿大学圣路易斯分校学习和工作，在此期间获得了MBA学位。2012年开始加入佐治亚理工学院，开展关于纳米材料合成与控制、表面增强拉曼光谱检测以及纳米催化等方面的研究。

研究方向：

纳米材料，表面增强拉曼光谱（SERS），软刻蚀，自组装，胶体物理与化学

研究成果：

迄今为止，秦冬教授在Chem. Rev.，J. Am. Chem. Soc., Angew. Chem., Adv. Mater., Nano. Lett.等国际著名期刊上发表论文60余篇，被引用超过6000次，H指数30。