报告题目：Nanostructured organic semiconductors for visible light photocatalysis
报 告人：Dr. Kai Zhang Max Planck Institute for Polymer Research
Sunlight is a clean and inexhaustible source of renewable energy. Especially, the visible range of the solar spectrum accounts for 44% of the total energy as opposed to only 3% from the ultraviolet (UV) light. Inspired by nature’s ability to convert solar energy in photocatalytic processes, organic chemists have developed a vast number of photocatalysts in order to mimic the nature process. As a result, many molecular inorganic, transition metal-based complexes or organic dye compounds that absorb significantly in the visible spectrum were intensely studied to harvest solar energy and catalyze organic photochemical reactions. Nevertheless, there are still some intrinsic drawbacks associated with these homogeneous systems, for instance, high cost, toxicity of these rare metals, as well as limited availability in nature, and their additionally required post-reaction purification step for catalyst removal. It is therefore of great desire to develop stable, reusable and transition metal-free photocatalysts for organic synthesis. Compared to homogeneous catalysts, heterogeneous catalysts enjoy the advantage that they can be easily recycled by simple filtration due to their insoluble nature.
In this talk, a new class of non-metallic, organic semiconductor-based materials, in particular, conjugated nanoporous polymers, combining photoactive π-electron backbone and highly porous properties, will be presented as an efficient and stable platform for heterogeneous visible light-promoted chemical transformations. A structural design principle and important properties of the novel materials such as porosity, morphology or energetic band positions will be discussed. Example photoredox reaction such as molecular oxygen activation reaction, C-C or C-N bond formations, reductive dehalogenation reaction and direct bromination reaction on aromatic compounds will be shown. [1, 2, 3]
1. S. Ghasimi, S. Prescher, Z. J. Wang, K. Landfester, J. Yuan, K. A. I. Zhang,Angew.Chem. Int. Ed.2015, 54, 14549.
2. Z. J. Wang, S. Ghasimi, K. Landfester, K. A. I. Zhang,Adv. Mater.2015, 27, 6265–6270.
3. R. Li, Z. J. Wang, L. Wang, B. C. Ma, S. Ghasimi, H. Lu, K. Landfester, K. A. I. Zhang,ACS Catalysis2016, 6, 1113-1121.
Kai Zhang did his undergraduate and master study from 2002 to 2007 in the Department of Chemistry at the University of Cologne, Germany. He completed his PhD in 2010 under the supervision of Professor Bernd Tieke in Cologne, and also in the group of Professor Peter Skabara at the University of Strathclyde, Glasgow, UK, working on novel conjugated polymers. From 2011 to 2013, he worked as a postdoctoral researcher with Professor Markus Antonietti at the Max Planck Institute of Colloids and Interfaces in Potsdam, Germany. In the beginning of 2013 he joined the Max Planck Institute for Polymer Research (MPI-P) as a research group leader. Currently, Kai is leading the laboratory of photocatalysis at MPI-P. His research activity is mainly focused on photo- or electroactive porous polymer materials for catalytic studies.