Franz Evanie, Kunz Anne, Oberhof Nils, Heindl Andreas H, Bertram Manon, Fusek Lukas, Taccardi Nicola, Wasserscheid Peter, Dreuw Andreas, Wegner Hermann A, Brummel Olaf, Libuda Jörg
Interface Research and Catalysis, Erlangen Center for Interface Research and Catalysis, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058, Erlangen, Germany.
Institute of Organic Chemistry, Justus-Liebig-Universität, Heinrich-Buff-Ring 17, 35392, Giessen, Germany.
ChemSusChem. 2022 Sep 20;15(18):e202200958. doi: 10.1002/cssc.202200958. Epub 2022 Jul 27.
Molecular solar thermal (MOST) systems combine solar energy conversion, storage, and release in simple one-photon one-molecule processes. Here, we address the electrochemically triggered energy release from an azothiophene-based MOST system by photoelectrochemical infrared reflection absorption spectroscopy (PEC-IRRAS) and density functional theory (DFT). Specifically, the electrochemically triggered back-reaction from the energy rich (Z)-3-cyanophenylazothiophene to its energy lean (E)-isomer using highly oriented pyrolytic graphite (HOPG) as the working electrode was studied. Theory predicts that two reaction channels are accessible, an oxidative one (hole-catalyzed) and a reductive one (electron-catalyzed). Experimentally it was found that the photo-isomer decomposes during hole-catalyzed energy release. Electrochemically triggered back-conversion was possible, however, through the electron-catalyzed reaction channel. The reaction rate could be tuned by the electrode potential within two orders of magnitude. It was shown that the MOST system withstands 100 conversion cycles without detectable decomposition of the photoswitch. After 100 cycles, the photochemical conversion was still quantitative and the electrochemically triggered back-reaction reached 94 % of the original conversion level.
分子太阳能热（MOST）系统在简单的单光子单分子过程中实现太阳能的转换、存储和释放。在此，我们通过光电化学红外反射吸收光谱（PEC - IRRAS）和密度泛函理论（DFT）研究了基于氮杂噻吩的MOST系统中电化学触发的能量释放。具体而言，以高度取向热解石墨（HOPG）作为工作电极，研究了从富能的（Z）-3-氰基苯基氮杂噻吩到其贫能的（E）-异构体的电化学触发的逆反应。理论预测存在两个可及的反应通道，一个是氧化通道（空穴催化），另一个是还原通道（电子催化）。实验发现，在空穴催化的能量释放过程中，光异构体发生分解。然而，通过电子催化反应通道可以实现电化学触发的逆转换。反应速率可通过电极电位在两个数量级范围内进行调节。结果表明，MOST系统经受住了100次转换循环，光开关没有可检测到的分解。100次循环后，光化学转换仍然是定量的，并且电化学触发的逆反应达到了原始转换水平的94%。
