第一作者：蒋龙波 副教授
通讯作者：蒋龙波 副教授
通讯单位：湖南大学环境科学与工程学院
DOI:10.1016/j.apcatb.2024.124881
这项研究的重点是光生空穴（h+）在可见光辅助的光催化过硫酸盐（PMS）活化过程中介导活性物种生成的机制。研究人员合成了葡萄糖酸亚铁衍生的掺铁碳点（Fe-CDs），并通过淬灭实验、ESR光谱和DFT计算研究了h+在光催化PMS活化降解对乙酰氨基酚过程中的重要作用。在 PMS（0.2 mM）和 Fe-CDs（12 μg/L）添加量较低的情况下，Fe-CDs/PMS/Vis 系统能在 20 分钟内实现对对乙酰氨基酚（15 μM）100% 的降解。Fe-CDs上的Fe3+位点降低了PMS生成SO5--的活化能，提高了体系中h+的浓度和利用率，使h+直接活化PMS成为介导-OH和1O2生成的主要途径。这项工作为进一步研究光催化PMS活化过程中h+介导的活性物种调控以去除微污染物提供了机理启示。
Fig. 1. (a) Schematic graph of Fe-CDs and CDs. (b) TEM images and (c) Lattice fringe of Fe-CDs. (d) TEM images and (e) Lattice fringe of CDs. (f)−(h) EDS elemental mapping of Fe-CDs.
Fig. 2. (a) XRD pattern, (b) FTIR spectra and (c) Raman spectra of CDs and Fe-CDs. High-resolution XPS spectra of (d) C 1 s and (e) O 1 s of CDs and Fe-CDs. High-resolution XPS spectra of (f) Fe 2p of Fe-CDs. (g) UV–Vis diffuse reflectance spectra of CDs and Fe-CDs. (h) Time resolved fluorescence spectrum of CDs and Fe-CDs.
Fig. 3. (a) Photoluminescence spectra of CDs and Fe-CDs. (b) Electrochemical impedance spectroscopy spectra of CDs and Fe-CDs. (c) Mott-Schottky plots of CDs and Fe-CDs. (d) Energy band structures of CDs and Fe-CDs. (e) Tafel slope of CDs and Fe-CDs. (f) Linear sweep voltammetry curves of CDs and Fe-CDs under dark and light.
Fig. 4. ACE degradation of (a) Fe-CDs and (b) CDs in different systems. Effect of different dosage of (c) Fe-CDs, (d) PMS and (e) initial pHs on ACE degradation. (f) Degradation on various contaminants by Fe-CDs/PMS/Vis system. (experimental conditions: [Fe-CDs]0 = 12 μg/L, [PMS]0 = 0.2 mM, [ACE]0 = 15 μM, initial pH = 5.84; except indicated). (g) Different oxidants in Fe-CDs/Vis systems on ACE degradation. ([PMS]0 = [H2O2]0 = [PDS]0 = [SPC]0 = 0.2 mM, [Fe-CDs]0 = 12 μg/L, [ACE]0 = 15 μM, initial pH = 5.84.) Effect of different (h) cations and humic acid (HA) and (i) anions on ACE degradation. ([Initial concentration]0 = 10 mM).
Fig. 5. (a) Quenching experiment. (experiment condition: [MeOH]0 = 300 mM, [IPA]0 = 200 mM, [NaN3]0 = 20 mM, [EDTA−2Na]0 = [K2Cr2O7]0 = [p−BQ]0 = [AO]0 = 10 mM, [DMSO]0 = 30 mM). (b) Concentration and the conversion (η) of PMSO and PMSO2. (c) Contribution of different reactive oxygen species (ROS) in Fe-CDs/PMS/Vis system. ESR spectra of (d) TEMP−h+, (e) TEMP−1O2 and (f) DMPO−•OH/SO4−• adducts in CDs/PMS/Vis and Fe-CDs/PMS/Vis system.
Fig. 6. (a) Molecule structure of ACE. (b) Highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of ACE. (c) f+, (d) f−, and (e) f0 index isosurface on ACE molecule. (f) The electrostatic potential (ESP) distributions of ACE. (g) Possible degradation pathway of ACE in Fe-CDs/PMS/Vis system.
这项研究报告了一种以 FG 为前驱体，通过简单的一步法合成 Fe-CDs 的合成策略。对比实验表明，Fe-CDs/PMS/Vis体系在pH值、阳离子和阴离子共存、腐植酸、污染物类型、催化剂剂量和PMS剂量等不同条件下具有令人满意的协同催化性能。淬灭实验和 ESR 实验表明，Fe-CDs/PMS/Vis 体系以 h+ 为主导，在 -OH 和 1O2 的共同作用下发生 ACE 降解。根据表征和实验结果，h+ 对 HSO5- 的活化可能是产生 -OH 和 1O2 的主要决定步骤。DFT 计算分析结果表明，Fe-CDs 上的 Fe3+ 位点对 h+ 起主导作用，这使得 PMS 的活化能低于 CD，从而促进了 h+ 与 PMS 的充分接触。在可见光照射下，Fe-CDs 上的 Fe3+ 位点通过光诱导电子形成有效的铁循环，从而有效地活化了 PMS。本研究提出的 Fe-CDs/PMS/Vis 系统是一种有效的有机污染物降解过程，并为高效激活 PMS 和 h+ 主导的光催化过程提供了新的见解。
Longbo Jiang, Songru Xie, Haoyun Chen, Jinjuan Yang, Xinyu Wang, Wenqin Li, Xin Peng, Zhibin Wu, Hou Wang, Jiajia Wang, Xingzhong Yuan, Visible-light-promoted peroxymonosulfate activation for ACE degradation: Overlooked role of photogenerated hole, Applied Catalysis B: Environment and Energy, 2025, https://doi.org/10.1016/j.apcatb.2024.124881
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