表面等离激元增强光催化反应的SERS光谱探究

In this project, we focus on the hot topic of the plasmon-enhanced photocatalytic reactions as the research objective. Our studies involve, (1) to build an in situ surface-enhanced Raman scattering (SERS) detection microfluidic platform for photocatalytic systems, (2) to prepare metal nanostructures or metal-semiconductor hetero-junctions as photocatalysts, (3) to develop new plasmon-enhanced photocatalytic reaction systems, and (4) to employ the SERS technique to explore the mechanism and process of plasmon-enhanced photocatalytic reactions. SERS as a characterization method can insight into plasmon-enhanced photocatalytic reactions at the molecular level. By means of SERS monitoring, the photocatalytic activity of anisotropic metal nanostructures will be investigated. Condition changes acting on the catalytic reactions and the catalytic mechanism will be revealed. The significance of this project presents as (1) the development and establishment of a new and special SERS detection platform for photocatalysis studies. (2) Through the metal LSPR tuning, the visible light harvesting will be enhanced. Metal nanostructures can promote the photo-induced charge separation at the metal/semiconductor interface, improving the catalytic activity. New type plasmonic catalysts will be developed. (3) Breakthrough from the plasmon-enhanced photocatalytic reaction only containing the transformation from p-aminothiophenol/ 4-nitrobenzenethiol to 4,4’-dimercaptoazobenzene by a metal organic semiconductor system, which is of great significance for the understanding of the catalytic mechanism.

本项目以等离激元增强光催化化学反应这一热点问题为研究对象，构建适用于光催化体系SERS原位检测的芯片研究平台，制备等离激元金属纳米结构或金属-半导体异质结为催化剂，发展等离激元增强光催化反应的新体系，利用SERS技术探究等离激元增强光催化反应的机制和过程。SERS作为表征手段能够在分子层级直接洞察等离激元光催化反应。通过对催化反应的监控，研究各向异性的金属纳米结构的光催化活性，获得条件变化对催化的敏感性，揭示其催化机理。该设想的研究意义在于（1）发展和建立全新的、专属于等离激元增强光催化反应的原位SERS检测平台。（2）通过金属微纳米结构的LSPR调控，增强可见光捕获作用。金属纳米结构可促进金属/半导体界面上的光诱导电荷分离，提高催化活性。发展新型等离激元催化剂。（3）突破等离激元增强光催化体系单一的局面，丰富催化体系，这对于等离激元增强催化机制的认识具有重要意义。

光催化反应过程是吸收光子，进而在催化剂内产生局域电场，导致电子和空穴的产生、分离并传输到催化剂表面，最终在表面完成氧化-还原反应。等离激元材料的引入，对光催化反应过程的各个阶段都会产生显著影响。本项目利用表面增强拉曼光谱（SERS）技术探究等离激元增强光催化反应的过程和机制。SERS和等离激元增强光催化现象二者存在多方面的共性：二者的本质均源于表面等离激元共振效应和电荷转移效应；二者均采用贵金属作为研究要素；均以光为驱动力和必要条件。这些理论和实验方面的共性确保两种效应可同时发生、同步观测。本项目研究丰富了等离激元增强光催化的实验模型体系，将金属有机电荷转移复合物与金属纳米结构复合，对认识和理解光催化过程、调控光催化体系有一定的参考意义。该研究建立了等离激元增强光催化的化学反应新体系（Ag-TCNQF4→Ag2-TCNQF4的转变）；构筑了微流控液滴芯片SERS分析平台、光纤光极的原位SERS检测平台；发展了多种SERS基底；发展了两种以上具有光电响应的有机电荷转移共晶体系，并利用高压光谱等技术研究其电荷转移机制。受项目资助发表学术论文17篇，会议论文16篇，授权专利2项，申请专利2项；资助硕士论文6本，博士论文5本；资助国内国际会议21次，相关内容作邀请报告3次，口头报告7次。获第二十届全国分子光谱学术会议及第二届国际表面增强拉曼光谱会议优秀墙报奖。