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Schwinghammer, Katharina ; Hug, Stephan ; Mesch, Maria B. ; Senker, Jürgen ; Lotsch, Bettina V.:
Phenyl-Triazine Oligomers for Light-Driven Hydrogen Evolution.
In: Energy & Environmental Science.
Bd. 8
(2015)
Heft 11
.
- S. 3345-3353.
ISSN 1754-5706
DOI: https://doi.org/10.1039/c5ee02574e
Abstract
The design of stable, yet highly tunable organic photocatalysts which orchestrate multi-step electron transfer reactions is at the heart of the newly emerging field of polymer photocatalysis. Covalent triazine frameworks such as the archetypal CTF-1 have been theorized to constitute a new class of photocatalytically active polymers for light-driven water splitting. Here, we revisit the ionothermal synthesis of CTF-1 by trimerization of 1,4-dicyanobenzene catalyzed by the Lewis acid zinc chloride and demonstrate that the microporous black polymer CTF-1 is essentially inactive for hydrogen evolution. Instead, highly photoactive phenyl-triazine oligomers (PTOs) with higher crystallinity as compared to CTF-1 are obtained by lowering the reaction temperature to 300 degrees C and prolonging the reaction time to 4150 hours. The low reaction temperature of the PTOs largely prevents incipient carbonization and thus results in a carbon-to-nitrogen weight ratio close to the theoretical value of 3.43. The oligomers were characterized by MALDI-TOF and quantitative solid-state NMR spectroscopy, revealing variations in size, connectivity and thus nitrile-to-triazine ratios depending on the initial precursor dilution. The most active PTO samples efficiently and stably reduce water to hydrogen with an average rate of 1076 (+/- 278) mmol h(-1) g(-1) under simulated sunlight illumination, which is competitive with the best carbon nitride-based and purely organic photocatalysts. The photocatalytic activity of the PTOs is found to sensitively depend on the polymerization degree, thus suggesting a prominent role of the unreacted nitrile moieties in the photocatalytic process. Notably, PTOs even show moderate hydrogen production without the addition of any co-catalyst.
Weitere Angaben
| Publikationsform: | Artikel in einer Zeitschrift |
|---|---|
| Begutachteter Beitrag: | Ja |
| Institutionen der Universität: | Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Chemie > Lehrstuhl Anorganische Chemie III > Lehrstuhl Anorganische Chemie III - Univ.-Prof. Dr. Jürgen Senker Fakultäten Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Chemie Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Chemie > Lehrstuhl Anorganische Chemie III |
| Titel an der UBT entstanden: | Nein |
| Themengebiete aus DDC: | 500 Naturwissenschaften und Mathematik > 540 Chemie |
| Eingestellt am: | 26 Jul 2016 12:17 |
| Letzte Änderung: | 25 Mär 2024 08:00 |
| URI: | https://eref.uni-bayreuth.de/id/eprint/33643 |