Conjugated Polymers with Oligoethylene Glycol Side Chains for Improved Photocatalytic Hydrogen Evolution

Zhicheng Hu; Zhenfeng Wang; Xi Zhang; Haoran Tang; Xiaocheng Liu; Fei Huang; Yong Cao

doi:10.1016/j.isci.2019.02.007

Conjugated Polymers with Oligoethylene Glycol Side Chains for Improved Photocatalytic Hydrogen Evolution

iScience. 2019 Mar 29:13:33-42. doi: 10.1016/j.isci.2019.02.007. Epub 2019 Feb 15.

Authors

Zhicheng Hu¹, Zhenfeng Wang², Xi Zhang², Haoran Tang², Xiaocheng Liu², Fei Huang³, Yong Cao²

Affiliations

¹ Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, P. R. China; South China Institute of Collaborative Innovation, Dongguan 523808, PR China.
² Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, P. R. China.
³ Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, P. R. China; South China Institute of Collaborative Innovation, Dongguan 523808, PR China. Electronic address: msfhuang@scut.edu.cn.

Abstract

Conjugated polymers are emerging as promising organic photocatalysts for hydrogen evolution from water. However, it is still very challenging for conjugated polymers to realize highly efficient photocatalytic hydrogen evolution. Herein, we demonstrate an efficient strategy of hydrophilic side chain functionalization to boost the hydrogen evolution rates of conjugated polymers. By functionalizing conjugated polymers with hydrophilic oligo (ethylene glycol) monomethyl ether (OEG) side chains, a 90-fold improvement in hydrogen evolution rate has been achieved than that of alkyl-functionalized conjugated polymer. It is found that the OEG side chains interact robustly with Pt co-catalysts, resulting in more efficient charge transfer. Moreover, OEG side chains in conjugated polymers can adsorb H⁺ from water, resulting in significantly lowered energy levels on the surfaces of conjugated polymers, which enables cascade energy levels and enhances charge separation and photocatalytic performance. Our results indicate that rational side-chain engineering could facilitate the design of improved organic photocatalysts for hydrogen evolution.

Keywords: Electrochemical Energy Conversion; Organic Chemistry Methods; Polymer Chemistry; Polymers.