文献速递|合肥工业大学JHM:锚定单原子Fe-N4位点的尺寸匹配分层多孔碳材料用于PMS活化:关键活性物种和催化机理

第一作者：Haoran Tian

通讯作者：崔康平 教授

通讯单位：合肥工业大学资源与环境工程学院

DOI:10.1016/j.jhazmat.2023.132647

本研究以废弃生物质为碳前驱体，实现了具有明确 Fe-N4 配位结构的铁酞菁（FePc）分子的稳定分散和锚定。在热解过程中，利用 KOH 的蚀刻效应和温度控制，实现了碳基质孔径分布的调控，成功制备了高金属原子负载的铁单原子催化剂。在不同的操作条件下，对活化 PMS 去除土霉素（OTC，一种典型的抗生素）的催化性能进行了评估。随后，进行了淬灭实验以评估活性物种在反应体系中的贡献，并通过探针分析和电子自旋共振实验进一步确定了活性物种的种类。此外，通过理论计算结合实验结果，提出了其活化 PMS 的可能催化机理。该研究为单原子催化剂的制备提供了一种通用策略，并为基于 PMS 的活化催化氧化机理开辟了思路，从而实现 AOPs 对污染物的降解。

Fig. 1. Schematic diagram of catalyst preparation.

Fig. 2. XRD patterns (a) and Raman patterns (b) of different catalysts and FePc; N contents and types of different catalysts (c); high-resolution N 1 s (d) and Fe 2p spectra (e) of catalysts; HADDF-STEM images of Fe-SAC-BC700 (f), Fe-SAC-BC (g) and Fe-NAP-BC (h).

Fig. 3. SEM (a), TEM(b) and HAADF-STEM (c) images of Fe-SAC-BC; EDX mapping images of Fe-SAC-BC (d-g); XANES at the Fe K-edge and (h) FT-EXAFS of Fe foil, FeO, Fe2O3, FePc, and Fe-SAC in R space; Comparison between the experimental and fitting results of the FT-EXAFS of Fe-SAC-BC in (k) R space and (j) k space.

Fig. 4. (a) Degradation of OTC in various systems (Catalysts: 0.1 g/L, OTC: 10 mg/L, PMS: 1 mM/L pH=7, T = 25 ℃; (b) Zeta potential of Fe-SAC-BC; (c) Effect of pH on the degradation of OTC by Fe-SAC-BC/PMS system (Fe-SAC-BC: 0.1 g/L, OTC: 10 mg/L, PMS: 1 mM/L pH=3–11, T = 25 ℃); (e) Effect of PMS addition concentration on the degradation of OTC by Fe-SAC-BC/PMS system (Fe-SAC-BC: 0.1 g/L, OTC: 10 mg/L, PMS: 0.2–1 mM/L pH=7, T = 25 ℃); (f) Linear relationship between PMS concentration and apparent rate constants; (g) Effect of catalyst dosing on the degradation of OTC by Fe-SAC-BC/PMS system (Fe-SAC-BC: 0.05–0.4 g/L, OTC: 10 mg/L, PMS: 1 mM/L pH=7, T = 25 ℃; (i) Effect of free radical scavengers on OTC degradation in FeC-SAC-BC/PAM system;(j) Transformation of DMSO2 at different reaction times;(k) Effect of SCN-, 1, 10-phenanthroline and K2Cr2O7 on the degradation of OTC by Fe-SAC-BC/PMS system; (d), (h) EPR mapping in different catalytic systems; (i) In situ ATR-FTIR mapping of Fe-SAC-BC/PMS system.

Fig. 5. (a), (b) High-performance liquid chromatography/electrospray ionization tandem mass spectrometry full-scan chromatogram and the molecular ion mass spectra of PMSO and PMSO2 before and after the catalytic reaction (c); (d) Mass spectral analyses of the 18O-labeled or unlabeled PMSO2 generated in the Fe-SAC-BC/PMS system; (e), (f) Continuous injection of OTC and PMS current reactions on BC, Fe-NAP-BC and Fe-SAC-BC working electrodes;.

Fig. 6. PDOS analysis of Fe (II)-N4, Fe (III)-N4 and PMS adsorbed at the central site of iron atoms; (b) Charge difference density diagram of PMS adsorbed on Fe (II)-N4 and Fe (III)-N4; (c), (d) Schematic diagram of a two-dimensional slice of the differential charge density; (e) Different reaction pathways and transition states of PMS molecules in different configurations of Fe-N4 sites; (f) Possible electron transfer mechanism between OTC, Fe-SAC-BC and PMS.

Fig.7. 3D-EEM fluorescence spectra of actual wastewater treated by Fe-SAC-BC/PMS system (a), (b) and (c); Recycling performance of Fe-SAC-BC (d); leaching concentration of Fe ions in ten cycles of Fe-SAC-BC/PMS system (e); catalytic degradation of OTC by Fe-SAC-BC/PMS system in real water samples (f); catalytic degradation performance of Fe-SAC-BC/PMS system for different pollutants (g); molecular structure of OTC, BPA, NFX and CAM (h).