Understanding structure-activity relationships in linear polymer photocatalysts for hydrogen evolution.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 30470759.
- Also identified by DOI 10.1038/s41467-018-07420-6 and PMC identifier 6251929.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Conjugated polymers have sparked much interest as photocatalysts for hydrogen production. However, beyond basic considerations such as spectral absorption, the factors that dictate their photocatalytic activity are poorly understood. Here we investigate a series of linear conjugated polymers with external quantum efficiencies for hydrogen production between 0.4 and 11.6%. We monitor the generation of the photoactive species from femtoseconds to seconds after light absorption using transient spectroscopy and correlate their yield with the measured photocatalytic activity. Experiments coupled with modeling suggest that the localization of water around the polymer chain due to the incorporation of sulfone groups into an otherwise hydrophobic backbone is crucial for charge generation. Calculations of solution redox potentials and charge transfer free energies demonstrate that electron transfer from the sacrificial donor becomes thermodynamically favored as a result of the more polar local environment, leading to the production of long-lived electrons in these amphiphilic polymers.