本文要点：
通过类光芬顿反应产生的自由基在修复复杂水环境中的新兴有机污染物方面显示出巨大的潜力。然而，由光激发的电子和空穴之间的库仑相互作用引起的激子效应降低了这些系统中载流子的利用效率。
在本研究中，作者发展了铜单原子负载的共价有机框架(CuSA/COFs)作为调控激子效应的模型。依赖于温度的光致发光和超快瞬态吸收光谱表明，将苊单元引入连接体(CuSA/Ace-COF)显著降低了激子结合能(Eb)。
这种改性不仅增强了过氧单硫酸盐在Cu活性位点的吸附，而且促进了快速电子转移并促进了选择性羟基自由基的产生。与CuSA/Obq-COF (Eb = 25.6 meV)相比，CuSA/Ace-COF (Eb = 12.2 meV)显示磺胺甲恶唑降解的假一级速率常数增加了39.5倍(0.434min-1)。
这项工作为通过连接工程调控单原子催化剂中的激子行为以降解EOCs提供了见解。
Fig. 1 | Structure and synthesis. Illustrations for the structure and synthesis of COFs and CuSA/COFs.
Fig. 2 | Characterization of the chemical structure and morphology. a FTIR spectra of linker monomers and COFs. b 13C ss-NMR spectra of Obq-COF and AceCOF. SEM images of c CuSA/Obq-COF and d CuSA/Ace-COF; the insets show the corresponding TEM and EDS elemental mapping images. AC-HAADF-STEM images of e CuSA/Obq-COF and f CuSA/Ace-COF, with the yellow circle highlighting the single-atom Cu feature.
Fig. 3 | Characterization of the coordination structures and chemical states. a Cu K-edge XANES spectra and b FT k2-weighted χ(k)-function of EXAFS of CuSA/ Ace-COF, Cu-foil, CuO, and CuPc. c EXAFS fitting curves of CuSA/Ace-COF in R space; the insets show the corresponding structure. d N 1 s XPS spectrum and e Cu 2p XPS spectrum of CuSA/COFs. f Calculated charge density difference for CuSA/ Obq-COF and CuSA/Ace-COF with the isosurfaces value of 0.001 e/Å, where yellow represents electron-rich regions and green represents electron-deficient regions.
Fig. 4 | Photo-Fenton performance and ROS identification.
Fig. 5 | Exciton dissociation and free charge carrier dynamics. a UV-Vis diffuse reflectance spectra of CuSA/COFs. Steady-state PL spectra with a function of the reciprocal temperature of b CuSA/Obq-COF and c CuSA/Ace-COF; the insets display the PL spectra at varying temperatures. 2D pseudo-color maps of d CuSA/Obq-COF and e CuSA/Ace-COF, and their corresponding fs-TA spectra under several representative probe delays:f CuSA/Obq-COF and g CuSA/Ace-COF. Kinetics decay profile probed at 520 nm of h CuSA/Obq-COF and i CuSA/Ace-COF.
Fig. 6 | Enhanced mechanism and environmental application.
https://doi.org/10.1038/s41467-025-56103-6
