Conjugated π Electrons of MOFs Drive Charge Separation at Heterostructures Interface for Enhanced Photoelectrochemical Water Oxidation

Xuewei Wang; Wenming Sun; Yang Tian; Kun Dang; Qimeng Zhang; Zhurui Shen; Sihui Zhan

doi:10.1002/smll.202100367

Conjugated π Electrons of MOFs Drive Charge Separation at Heterostructures Interface for Enhanced Photoelectrochemical Water Oxidation

Small. 2021 Apr;17(14):e2100367. doi: 10.1002/smll.202100367. Epub 2021 Mar 10.

Authors

Xuewei Wang¹, Wenming Sun², Yang Tian¹, Kun Dang¹, Qimeng Zhang¹, Zhurui Shen³, Sihui Zhan⁴

Affiliations

¹ Department of Chemistry, Analytical Instruments Center, Beijing Key Laboratory for Optical Materials and Photonic Devices, Capital Normal University, 105 North Road of Western Third Ring, Haidian District, Beijing, 100048, P. R. China.
² College of Science, China Agricultural University, Beijing, 100193, P. R. China.
³ School of Materials Science and Engineering, Nankai University, Tianjin, 300350, P. R. China.
⁴ MOE Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, P. R. China.

PMID: 33690986
DOI: 10.1002/smll.202100367

Abstract

Photoanode material with high efficiency and stability is extensively desirable in photoelectrochemical (PEC) water splitting for green/renewable energy source. Herein, novel heterostructures is constructed via coating rutile TiO₂ nanorods with metal organic framework (MOF) materials UiO-66 or UiO-67 (UiO-66@TiO₂ and UiO-67@TiO₂ ), respectively. The π electrons in the MOF linkers could increase the local electronegativity near the heterojunction interface due to the conjugation effect, thereby enhancing the internal electric field (IEF) at the heterojunction interface. The IEF could drive charge transfer following Z-scheme mechanism in the prepared heterostructures, inducing photogenerated charge separation efficiency increasing as 156% and 253% for the UiO-66@TiO₂ and UiO-67@TiO₂ , respectively. Correspondingly, the UiO-66@TiO₂ and UiO-67@TiO₂ enhanced the photocurrent density as approximate two- and threefolds compared with that of pristine TiO₂ for PEC water oxidation in universal pH electrolytes. This work demonstrates an effective method of regulating the IEF of heterojunction toward further improved charge separation.

Keywords: charge separation; heterojunction; metal organic framework; photoanode; water oxidation.

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Review

Abstract

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