Construction of Layer-Blocked Covalent Organic Framework Heterogenous Films via Surface-Initiated Polycondensations with Strongly Enhanced Photocatalytic Properties

Yuxiang Zhao; Shengfei Li; Guangen Fu; Haoyong Yang; Shengxu Li; Daheng Wu; Tao Zhang

doi:10.1021/acscentsci.3c01195

Construction of Layer-Blocked Covalent Organic Framework Heterogenous Films via Surface-Initiated Polycondensations with Strongly Enhanced Photocatalytic Properties

ACS Cent Sci. 2024 Jan 29;10(4):775-781. doi: 10.1021/acscentsci.3c01195. eCollection 2024 Apr 24.

Authors

Yuxiang Zhao^{1

2}, Shengfei Li¹, Guangen Fu^{1

2}, Haoyong Yang^{1

2}, Shengxu Li^{1

2}, Daheng Wu^{1

2}, Tao Zhang^{1

2}

Affiliations

¹ Key Laboratory of Marine Materials and Related Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China.
² University of Chinese Academy of Sciences, Beijing 100049, China.

Abstract

Imine-linked covalent organic frameworks (COFs) usually show high crystallinity and porosity, while vinyl-linked COFs have excellent semiconducting properties and stability. Therefore, achieving the advantages of imine- and vinyl-linkages in a single COF material is highly interesting but remains challenging. Herein, we demonstrate the fabrication of a layer-blocked COF (LB-COF) heterogeneous film that is composed of imine- and vinyl-linkages through two successive surface-initiated polycondensations. In brief, the bottom layer of imine-linked COF film was constructed on an amino-functionalized substrate via Schiff-base polycondensation, in which the unreacted aldehyde edges could be utilized for initiating aldol polycondensation to prepare the second layer of vinyl-linked COF film. The resultant LB-COF film displays excellent ordering due to the crystalline templating effect from the bottom imine-linked COF layer; meanwhile, the upper vinyl-linked COF layer could strongly enhance its stability and photocatalytic properties. The LB COF also presents superior performance in photocatalytic uranium extraction (320 mg g^-1), which is higher than the imine-linked (35 mg g^-1) and the vinyl-linked (295 mg g^-1) counterpart. This study provides a novel surface-initiated strategy to synthesize layer-blocked COF heterogeneous films that combine the advantages of each building block.