Authors
Liqun Song, Pingjian Wang, Zhihua Zhang, Yaming Hao, Jing Zhao, Zhonghai Lin, Mingwen Zhao, Anabel E Lanterna, Yingcai Fan
Published in
Small (Weinheim an der Bergstrasse, Germany). Pages e73438. Apr 17, 2026. Epub Apr 17, 2026.
Abstract
Covalent organic frameworks (COFs) are ideal for overall photocatalytic water splitting (OWS) due to modular design, ordered π-conjugated structures, and tunable optoelectronic properties. However, weak driving force and rapid photogenerated carrier recombination limit their performance. Using two experimentally synthesized COFs (TTA-BTPA, TAPB-BTPA) as models, we propose 2D COFs with in-plane/out-of-plane dual polarities as an effective solution. First-principles calculations show imine bond-induced in-plane polarity and vertical asymmetry-derived out-of-plane polarity split bilayer energy levels, forming dual type-II band alignment. This synergy enhances intra/inter-layer charge separation, suppressing carrier recombination compared to in-plane-only monolayers. The built-in electric field boosts the driving force by reducing the hydrogen reduction potential. Nonadiabatic molecular dynamics (NAMD) confirms a dual type-II mechanism, and the calculated TTA-BTPA bilayer's carrier lifetime (37.57 ns) is 6.61 times that of its monolayer (5.69 ns). Both bilayers exhibit excellent visible-light absorption, split pure water without external bias, and achieve the theoretical up-limit of solar-to-hydrogen (STH) efficiency >10%. Our work elucidates polarity synergy's role and provides theoretical guidance for high-performance 2D COF-based OWS photocatalysts.
PMID:
41996026
Bibliographic data and abstract were imported from PubMed on 17 Apr 2026.
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