Electrochemically Triggered Energy Release from an Azothiophene‐Based Molecular Solar Thermal System. Issue 18 (27th July 2022)

• Record Type: Journal Article
• Authors: 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
• Is Part Of: ChemSusChem. Volume 15:Issue 18(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-07-27
• Subjects: Electrochemistry -- Energy Storage -- Photochemistry -- Photoswitches -- Solar Thermal Fuels; Green chemistry -- Periodicals; Sustainable engineering -- Periodicals; Chemistry -- Periodicals; Chemical engineering -- Periodicals; 660
• DOI: 10.1002/cssc.202200958
• Languages: English
• ISSNs: 1864-5631

Abstract

Abstract: 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. Abstract : Molecular Solar Thermal (MOST) : MOST systems combine solar energy conversion, storage, and release in a single molecule. One class of MOST systems, azothiophenes, could be photo‐isomerized from the ( E ) into the high‐energy ( Z )‐state. Triggering the energy release electrochemically enabled a direct control of the release rate and provided excellent cyclability.