报告题目：Interfacial Ligand Dynamics, Chemistry, and Photochemistry on Plasmonic Nanoparticle Surfaces: More Complicated Than We Thought?
报 告 人：王辉教授
报告时间：2018年7月12日（周四）15:00
报告地点：尚贤楼402 报告厅
主 持 人：赖敏教授
欢迎广大师生踊跃参加！
江苏省大气海洋光电探测重点实验室
物理与光电工程学院
2018年7月11日
报告摘要:
This presentation focuses on interesting catalytic and photocatalytic molecular transformations at the interfaces between surface-capping ligands and plasmonic nanoparticles. The interfacial adsorption, desorption, and exchange behaviors of capping ligands on nanotextured nanoparticle surfaces exhibit phenomenal site-to-site variations essentially dictated by the local surface curvatures, resulting in heterogeneous thermodynamic and kinetic profiles remarkably more sophisticated than those associated with ligand binding to atomically flat surfaces of planar substrates. We use surface-enhanced Raman scattering (SERS) as a plasmon-enhanced spectroscopic tool with unique time-resolving and molecular fingerprinting capabilities to quantitatively correlate the interfacial ligand dynamics with detailed molecular structures in real time under a diverse set of ligand adsorption, desorption, and exchange conditions at both equilibrium and non-equilibrium states, which enables us to delineate the effects of nanoscale surface curvature on the binding affinity, cooperativity, structural ordering, and the adsorption/desorption/exchange kinetics of monolayer organothioland multilayer aryl ligands on colloidal Au nanoparticles.
I will also share some new insights on the facet-dependent catalytic properties of free-standing Au nanoparticles. We have recently demonstrated that desired plasmonic and catalytic properties can be integrated on the same particle by controllably creating high-index facets on individual sub-wavelength metallic nanoparticles. The capabilities to both nanoengineer high-index facets and fine-tune the plasmon resonances through deliberate particle geometry controlopen up unique opportunities for us to study, in great detail, the facet-dependent interfacial molecular transformations on Au nanocatalysts using SERS as a time-resolved spectroscopic tool.
Finally, I will further talk about our latest progress on developing quantitative mechanistic understanding of plasmonic hot electron-driven photocatalytic reactions. It has been recently observed that the energetic hot electrons generated during plasmon decay can be harnessed to drive or enhance a series of interesting photochemical reactions on metallic nanoparticle surfaces. However, the detailed mechanisms of these plasmon-driven reactions still remain poorly understood and under intense debate. We use SERS as a unique approach to precisely monitor, in real time and one-particle-at-a-time, the plasmon-driven photocatalytic reactions at the molecule-nanoparticle interfaces. This approach allows us to pinpoint - with unprecedented precision and detail - the effects of plasmon excitations, molecular adsorption states, local field enhancements, and photothermal processes on the pathways and kinetics of the photocatalytic reactions. The insights gained from this work shed light on the mechanistic complexity of plasmon-driven photocatalysis and provide key design principles for the next generation plasmonicphotocatalysts.
报告人简介:
王辉教授，目前就职于南卡罗来纳大学化学与生物化学系。2001年和2003年在南京大学分别获得化学学士和分析化学硕士学位，2007年在莱斯大学获得物理化学（纳米科学领域）博士学位。2007年至2010年在德克萨斯大学奥斯汀分校从事单分子光谱领域的博士后研究。2010年开始就职于南卡罗来纳大学化学与生物化学系并于2016年获得永久职位。主要研究领域：表面等离子体光子学、表面增强拉曼光谱、电催化等。在包括PNAS、Advanced Materials、Nano Letters、JACS、Accounts of Chemical Research等顶尖期刊已发表论文60多篇，总引用5200多次，H指数36，17篇论文引用超过100次。获得了“Breakthrough Star Award, University of South Carolina System (2014) ”、“ National Science Foundation CAREER Award (2013)”、“ Honorable Mention Award of IUPAC Prize for Young Chemists – IUPAC”等奖励。