Build-in electric field in CuWO4/covalent organic frameworks S-scheme photocatalysts steer boosting charge transfer for photocatalytic CO2 reduction

Qing Niu; Qiaoshan Chen; Guocheng Huang; Liuyi Li; Yunhui He; Jinhong Bi

doi:10.1016/j.jcis.2023.04.013

Build-in electric field in CuWO₄/covalent organic frameworks S-scheme photocatalysts steer boosting charge transfer for photocatalytic CO₂ reduction

J Colloid Interface Sci. 2023 Aug:643:102-114. doi: 10.1016/j.jcis.2023.04.013. Epub 2023 Apr 7.

Authors

Qing Niu¹, Qiaoshan Chen², Guocheng Huang³, Liuyi Li⁴, Yunhui He⁵, Jinhong Bi⁶

Affiliations

¹ Department of Environmental Science and Engineering, Fuzhou University, Minhou, Fujian 350108, PR China; Key Laboratory of Eco-materials Advanced Technology, College of Materials Science and Engineering, Fuzhou University, Minhou, Fujian 350108, PR China.
² Department of Environmental Science and Engineering, Fuzhou University, Minhou, Fujian 350108, PR China.
³ Department of Environmental Science and Engineering, Fuzhou University, Minhou, Fujian 350108, PR China. Electronic address: sysuhgc@gmail.com.
⁴ Key Laboratory of Eco-materials Advanced Technology, College of Materials Science and Engineering, Fuzhou University, Minhou, Fujian 350108, PR China.
⁵ Fujian College Association Instrumental Analysis Center of Fuzhou University, Minhou, Fujian 350108, PR China.
⁶ Department of Environmental Science and Engineering, Fuzhou University, Minhou, Fujian 350108, PR China; State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Minhou, Fujian 350108, PR China. Electronic address: bijinhong@fzu.edu.cn.

PMID: 37054545
DOI: 10.1016/j.jcis.2023.04.013

Abstract

Covalent organic frameworks (COFs) are crystalline porous materials with enormous potential for realizing solar-driven CO₂-to-fuel conversion, yet the sluggish transfer/separation of photoinduced electrons and holes remains a compelling challenge. Herein, a step (S)-scheme heterojunction photocatalyst (CuWO₄-COF) was rationally fabricated by a thermal annealing method for boosting CO₂ conversion to CO. The optimal CuWO₄/COF composite sample, integrating 10 wt% CuWO₄ with an olefin (C═C) linked COF (TTCOF), achieved a remarkable gas-solid phase CO yield as high as 7.17 ± 0.35 μmol g^-1h^-1 under visible light irradiation, which was significantly higher than the pure COF (1.6 ± 0.29 μmol g^-1h^-1). The enhanced CO₂ conversion rate could be attributable to the interface engineering effect and the formation of internal electric field (IEF) directing from TTCOF to CuWO₄ according to the theoretical calculation and experimental results, which also proves the electrons transfer from TTCOF to CuWO₄ upon hybridization. In addition, driven by the IEF, the photoinduced electrons can be steered from CuWO₄ to TTCOF under visible light irradiation as well-elucidated by in-situ irradiated X-ray photoelectron spectroscopy, verifying the S-scheme charge transfer pathway over CuWO₄/COF composite heterojunctions, which greatly foster the photoreduction activity of CO₂. The preparation technique of the S-scheme heterojunction photocatalyst in this study provides a paradigmatic protocol for photocatalytic solar fuel generation.

Keywords: CO(2) reduction; Covalent organic frameworks; CuWO(4); Photocatalysis; S-scheme.