To separately explore the importance of hydrophilicity and backbone planarity of polymer photocatalyst, a series of benzothiadiazole-based donor–acceptor alternating copolymers incorporating alkoxy, linear oligo(ethylene glycol) (OEG) side chain, and backbone fluorine substituents is presented. The OEG side chains in the polymer backbone increase the surface energy of the polymer nanoparticles, thereby improving the interaction with water and facilitating electron transfer to water. Moreover, the OEG-attached copolymers exhibit enhanced intermolecular packing compared to polymers with alkoxy side chains, which is possibly attributed to the self-assembly properties of the side chains. Fluorine substituents on the polymer backbone produce highly ordered lamellar stacks with distinct π–π stacking features; subsequently, the long-lived polarons toward hydrogen evolution are observed by transient absorption spectroscopy. In addition, a new nanoparticle synthesis strategy using a methanol/water mixed solvent is first adopted, thereby avoiding the screening effect of surfactants between the nanoparticles and water. Finally, hydrogen evolution rate of 26 000 µmol g−1 h−1 is obtained for the copolymer incorporated with both OEG side chains and fluorine substituents under visible-light irradiation (λ > 420 nm). This study demonstrates how the glycol side chain strategy can be further optimized for polymer photocatalysts by controlling the backbone planarity.
Bibliographical noteFunding Information:
S.A. and Z.W. contributed equally to this work. The authors thank Yongju Hong and Prof. Kwangyeol Lee for their assistance in the analysis of transmission electron microscopy‐EDS and Jung Hoon Choi (Korea Basic Science Institute, Ochang, Biochemical analysis team) for the high resolution electrospray ionization quadrupole time‐of‐flight mass spectrometer analysis. This work was supported by Natioanl Research Foundation of Korea grants funded by the Korea government (2021K2A9A2A12000245, 2021R1A2C2004670, 2019R1A2C2085290, 2019R1A6A1A11044070, and 2021R1C1C1009032). The authors appreciate the Pohang Accelerator Laboratory (PAL) for providing the 3C and 10A2 beamlines used in this study.
© 2022 Wiley-VCH GmbH.
- hydrogen evolution
- polymer semiconductors
ASJC Scopus subject areas
- Engineering (miscellaneous)
- Materials Science(all)