Polarization Engineering of Covalent Triazine Frameworks for Highly Efficient Photosynthesis of Hydrogen Peroxide from Molecular Oxygen and Water

Chongbei Wu; Zhenyuan Teng; Chao Yang; Fangshuai Chen; Hong Bin Yang; Lei Wang; Hangxun Xu; Bin Liu; Gengfeng Zheng; Qing Han

doi:10.1002/adma.202110266

Polarization Engineering of Covalent Triazine Frameworks for Highly Efficient Photosynthesis of Hydrogen Peroxide from Molecular Oxygen and Water

Adv Mater. 2022 Jul;34(28):e2110266. doi: 10.1002/adma.202110266. Epub 2022 Jun 5.

Authors

Chongbei Wu¹, Zhenyuan Teng², Chao Yang³, Fangshuai Chen¹, Hong Bin Yang^{4

5}, Lei Wang⁶, Hangxun Xu⁶, Bin Liu^{4

5}, Gengfeng Zheng³, Qing Han¹

Affiliations

¹ Key Laboratory of Cluster Science, Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, Department of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, P. R. China.
² Department of Applied Chemistry, Faculty of Engineering, Kyushu Institute of Technology, Kitakyushu, 804-8550, Japan.
³ Laboratory of Advanced Materials, Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai, 200438, P. R. China.
⁴ School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore, 637459, Singapore.
⁵ Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore.
⁶ Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, 230022, P. R. China.

PMID: 35524761
DOI: 10.1002/adma.202110266

Abstract

Two-electron oxygen photoreduction to hydrogen peroxide (H₂ O₂ ) is seriously inhibited by its sluggish charge kinetics. Herein, a polarization engineering strategy is demonstrated by grafting (thio)urea functional groups onto covalent triazine frameworks (CTFs), giving rise to significantly promoted charge separation/transport and obviously enhanced proton transfer. The thiourea-functionalized CTF (Bpt-CTF) presents a substantial improvement in the photocatalytic H₂ O₂ production rate to 3268.1 µmol h^-1 g^-1 with no sacrificial agents or cocatalysts that is over an order of magnitude higher than unfunctionalized CTF (Dc-CTF), and a remarkable quantum efficiency of 8.6% at 400 nm. Mechanistic studies reveal the photocatalytic performance is attributed to the prominently enhanced two-electron oxygen reduction reaction by forming endoperoxide at the triazine unit and highly concentrated holes at the thiourea site. The generated O₂ from water oxidation is subsequently consumed by the oxygen reduction reaction (ORR), thereby boosting overall reaction kinetics. The findings suggest a powerful functional-groups-mediated polarization engineering method for the development of highly efficient metal-free polymer-based photocatalysts.

Keywords: charge separation and transfer; covalent triazine frameworks; photosynthesis of hydrogen peroxide; polarization engineering; thio(urea) functional groups.

Abstract

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