Molecular Engineering of Fully Conjugated sp 2 Carbon-Linked Polymers for High-Efficiency Photocatalytic Hydrogen Evolution

• Published in: ChemSusChem 2020-02, Vol.13 (4), p.672-676
• Main Authors: Huang, Tao, Lin, Xi, Liu, Yang, Zhao, Jiwu, Lin, Huan, Xu, Ziting, Zhong, Shuncong, Zhang, Chunjie, Wang, Xuxu, Fu, Xianzhi, Long, Jinlin
• Format: Article
• Language: English
• ISSN: 1864-5631; 1864-564X
• DOI: 10.1002/cssc.201903334

The diverse nature of organic precursors offers a versatile platform for precisely tailoring the electronic properties of semiconducting polymers. In this study, three fully conjugated sp carbon-linked polymers have been designed and synthesized for photocatalytic hydrogen evolution under visible-light illumination, by copolymerizing different C -symmetric aromatic aldehydes as knots with the 1,4-phenylene diacetonitrile (PDAN) linker through a C=C condensation reaction. The hydrogen evolution (HER) is achieved at a maximum rate of 30.2 mmol g  h over a polymer based on 2,4,6-triphenyl-1,3,5-triazine units linked by cyano-substituted phenylene, with an apparent quantum yield (AQY) of 7.20 % at 420 nm. Increasing the degree of conjugation and planarity not only extends visible-light absorption, but also stabilizes the fully conjugated sp -carbon-linked donor-acceptor (D-A) polymer. Incorporating additional electron-withdrawing triazine units into the D-A polymer to form multiple electron donors and acceptors can greatly promote exciton separation and charge transfer, thus significantly enhancing the photocatalytic activity.