Department of Chemistry and Center for NanoScience (CeNS), University of Munich (LMU) , Butenandtstraße 5-13, 81377 Munich, Germany.
Institute of Energy and Climate Research (IEK-1) Materials Synthesis and Processing, Forschungszentrum Jülich GmbH , Wilhelm-Johnen-Straße, 52425 Jülich, Germany.
J Am Chem Soc. 2018 Feb 14;140(6):2085-2092. doi: 10.1021/jacs.7b06081. Epub 2018 Jan 29.
Light-driven water electrolysis at a semiconductor surface is a promising way to generate hydrogen from sustainable energy sources, but its efficiency is limited by the performance of available photoabsorbers. Here we report the first time investigation of covalent organic frameworks (COFs) as a new class of photoelectrodes. The presented 2D-COF structure is assembled from aromatic amine-functionalized tetraphenylethylene and thiophene-based dialdehyde building blocks to form conjugated polyimine sheets, which π-stack in the third dimension to create photoactive porous frameworks. Highly oriented COF films absorb light in the visible range to generate photoexcited electrons that diffuse to the surface and are transferred to the electrolyte, resulting in proton reduction and hydrogen evolution. The observed photoelectrochemical activity of the 2D-COF films and their photocorrosion stability in water pave the way for a novel class of photoabsorber materials with versatile optical and electronic properties that are tunable through the selection of appropriate building blocks and their three-dimensional stacking.
光驱动半导体表面的水分解是一种从可持续能源中产生氢气的很有前途的方法，但它的效率受到可用光吸收剂性能的限制。在这里，我们首次研究了共价有机框架（COFs）作为一类新型光电导体。所提出的二维 COF 结构由芳族胺官能化的四苯乙烯和噻吩基二醛构建块组装而成，形成共轭聚亚胺片，这些片在第三维上π 堆积以形成光活性多孔框架。高度取向的 COF 薄膜在可见光范围内吸收光，产生光激发电子，这些电子扩散到表面并转移到电解质中，导致质子还原和氢气的产生。观察到二维 COF 薄膜的光电化学活性及其在水中的光腐蚀性稳定性为一类新型的光吸收剂材料铺平了道路，这些材料具有通过选择适当的构建块及其三维堆叠来调节的多功能光学和电子性能。
