SEMINAR
The State Key Lab of
High Performance Ceramics and Superfine Microstructure
Shanghai Institute of Ceramics, Chinese Academy of Sciences
中 国 科 学 院 上 海 硅 酸 盐 研 究 所 高 性 能 陶 瓷 和 超 微 结 构 国 家 重 点 实 验 室
2016年度国家重点实验室特邀学术报告

Single-Molecule, Single-Particle Chemistry of Photocatalysts

Tetsuro MAJIMA

The Institute of Scientific and Industrial Research, Osaka University

时间：2016年4月25日（星期一）下午2: 00

地点： 4号楼14楼第一会议室

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联系人：孙 静（2717）王文中（5295）　　

　　Abstract

　　To develop efficient TiO2 photocatalytic reactions, it is important to reveal and understand the molecular interactions and the mechanism of chemical reactions at heterogeneous interfaces of TiO2 photocatalysts. We have been investigating TiO2 photocatalytic reactions using single-molecule fluorescence imaging techniques and gain information related to spatial and temporal heterogeneities of TiO2 photocatalysts in the reactions, which are always masked by ensemble averaging.

　　Single-molecule fluorescence microscopy has been used to visualize TiO2 photocatalytic reactions at the heterogeneous interface in the nanometer scale. We synthesized novel fluorogenic probes to selectively observe the catalytic reactions. Such probes are designed to become fluorescent upon the reaction with target species under the photoirradiation. The position of individual fluorescent products can be determined with several tens nanometers spatial resolution by two-dimensional Gaussian fitting. In addition, the quantitative analysis of fluorescence intensity trajectory or fluctuation can reveal the underlying properties of individual catalysts.

　　We prepared nanometer- and micrometer-sized crystals of TiO2 photocatalysts, and explore the photocatalytic reactions on individual catalysts by single-molecule fluorescence microscopy with newly developed redox-responsive fluorogenic probes. From the analysis of spatial distribution of reactive sites, the relationship between surface structures and chemical reactivity were elucidated. From the quantitative analysis of on/off duration times, we also determined the turnover frequency of individual catalysts, adsorption and dissociation rates, interfacial electron transfer rates, and temporal fluctuation of reaction efficiency.

　　The proper understanding of structures and reactions at heterogeneous interfaces can develop the general concept of chemistry and help advance the emerging applications of nanocatalysts for environmentally and economically sustainable uses.

　　Prof. Majima was the President of the Japanese Photochemistry Association, President of the Photobiology Association of Japan, President of the Asia Oceania Society on Photobiology, General Secretary and Treasurer of the Asia Oceania Society on Photobiology, Senior Editor of Langmuir, Editorial Advisory Board of ACS Applied Materials & Interfaces. He is in the International Editorial Board of Rapid Communication in Photoscienece, Korean Society of Photoscience, Editorial Board of ChemPlusChem, union of 16 European Chemical Societies, Wiley VHC, Associate Editor of Photochemistry and Photobiology, Wiley VHC, Co-Chair of ChemPlusChem. He has published 450 original papers. He won the Award of The Japanese Photochemistry Association, the Lectureship Award of The Japanese Photochemistry Association, the BCSJ Award of The Chemical Society of Japan, the Award of Osaka University President, the Award of Japanese Society of Radiation Chemistry, the Award of Japanese Society for Photomedicine and Photobiology, The 1st Merit Award of Korean Society of Photoscience, the Award of the Photobiology Association of Japan.