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Quinones as reversible electron relays in artificial photosynthesis


Rodenberg, Alexander; Orazietti, Margherita; Mosberger, Mathias; Bachmann, Cyril; Probst, Benjamin; Alberto, Roger; Hamm, Peter (2016). Quinones as reversible electron relays in artificial photosynthesis. ChemPhysChem, 17(9):1321-1328.

Abstract

We explore the potential of various hydroquinone/quinone redox couples as electron relays in a homogenous water reduction system between a Re-based photosensitizer and a sacrificial electron donor [tris-(2-carboxyethyl)-phosphine, TCEP]. By using transient IR spectroscopy, flash photolysis as well as stopped-flow techniques covering timescales from picoseconds to 100 ms, we determine quenching rates and cage escape yields, the kinetics of the follow-up chemistry of the semiquinone, the recombination rates, as well as the re-reduction rates by TCEP. The overall quantum yield of hydrogen production is low, and we show that the limiting factors are the small cage escape yields and, more importantly, the slow regeneration rate by TCEP in comparison to the undesired charge recombination with the reduced water reduction catalyst.

Abstract

We explore the potential of various hydroquinone/quinone redox couples as electron relays in a homogenous water reduction system between a Re-based photosensitizer and a sacrificial electron donor [tris-(2-carboxyethyl)-phosphine, TCEP]. By using transient IR spectroscopy, flash photolysis as well as stopped-flow techniques covering timescales from picoseconds to 100 ms, we determine quenching rates and cage escape yields, the kinetics of the follow-up chemistry of the semiquinone, the recombination rates, as well as the re-reduction rates by TCEP. The overall quantum yield of hydrogen production is low, and we show that the limiting factors are the small cage escape yields and, more importantly, the slow regeneration rate by TCEP in comparison to the undesired charge recombination with the reduced water reduction catalyst.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Department of Chemistry
Dewey Decimal Classification:540 Chemistry
Language:English
Date:4 May 2016
Deposited On:04 Aug 2016 07:19
Last Modified:05 Aug 2016 08:03
Publisher:Wiley-Blackwell Publishing, Inc.
ISSN:1439-4235
Publisher DOI:https://doi.org/10.1002/cphc.201501085
PubMed ID:26752324

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