第一作者：Zhixiong Yang
通讯作者：张高科 教授
通讯单位：武汉理工大学资源与环境学院
DOI:10.1016/j.jmst.2024.06.053
在基于过一硫酸盐（PMS）的异相 Fenton 类反应中，环境友好型铁催化剂在降解水中新出现的污染物方面引起了广泛关注，但其一直存在催化活性低的缺点。在此，我们通过简单的溶热法成功制备了具有裸露{011}面和富硫空位的磁性灰铁矿（Fe3S4）纳米片（FS-1）。在可见光照射下，FS-1活化PMS对甲硝唑的降解率分别比暴露{011}面和贫硫空位的Fe3S4纳米片和暴露{112}面的Fe3S4纳米包体高出2.93和4.48。电化学分析和理论计算的结果表明，所制备的 FS-1 裸露的 {011} 面提供了更多吸附 PMS 的活性位点，表面丰富的硫空位加速了氧化剂和催化剂之间的电子转移。这种协同效应大大降低了与 PMS 活化相关的能量势垒，从而增加了单线态氧的生成。此外，还分别通过理论计算和高效液相色谱-质谱法详细探讨了甲硝唑的降解机制和途径，包括羟乙基裂解、反硝化和羟基化。这项工作为提高环境友好型铁基催化剂的催化性能提供了启示。
Fig. 1. XRD patterns (a), EPR spectra (b), S 2p spectra of high-resolution XPS spectra (c) for the prepared samples. TEM images of FS-1 (d), FS-0 (e), and FS-B (f). HAADF-STEM images and corresponding elemental mappings of Fe and S of FS-1 (g). HRTEM image (insert: SAED pattern) of FS-1 (h). FS-0 (i), and FS-B (j).
Fig. 2. Degradation of MNZ (a), corresponding degradation rate of MNZ (b) under different reactive systems. UV–Vis. Absorbance spectral variations of MNZ in the FS-0/PMS/Vis system (c). TOC removal rate for the degradation of MNZ in the different systems (d). MNZ solution: 20 mg/L, 100 mL; PMS: 0.1 g/L; catalyst: 0.03 g/L; light source: LED lamp (420 nm).
Fig. 3. Effect of irradiation wavelength on MNZ degradation by FS-1/PMS/Vis system (a). Optical properties characterization of FS-1 (b). Electrochemical impedance spectra (c), and transient current response density (d) of FS-1/PMS system in dark and visible light irradiation.
Fig. 4. Effect of catalyst dosage (a), PMS dosage (b), pH (c), and anion (d) on MNZ degradation by FS-1/PMS/Vis system. MNZ solution: 20 mg/L, 100 mL; anion concentration: 10 mM.
Fig. 5. Effect of different quenchers on MNZ degradation by FS-1/PMS/Vis system (a). EPR spectra for 1O2 signal (b), and SO4•−, O2•− signal (c). Electrochemical impedance spectra for prepared catalysts (d). Chronopotentiometry curves of different electrodes with the addition of different substances (e). Effect of different gas atmospheres on MNZ degradation by FS-1/PMS/Vis system (f). MNZ solution: 20 mg/L, 100 mL; PMS: 0.1 g/L; catalyst: 0.03 g/L; light source: LED lamp (420 nm).
Fig. 6. Density of states of Fe3S4 with {011} facet and sulfur vacancy, Fe3S4 with {011} facet, and Fe3S4 with {112} facet (a). Calculated adsorption energy (Eads) of PMS molecules on Fe3S4 with exposed {011} facet and sulfur vacancy (b), Fe3S4 with exposed {011} facet (c), and Fe3S4 with exposed {112} facet (d). Potential energy for PMS decomposition to two key reaction intermediates (e). Proposed reaction process for 1O2 generation (f).
在这项研究中，我们发现在活化 PMS 的过程中，通过同时引入具有高催化活性的暴露面和硫空位，有效地提高了铁基催化剂的催化活性。在可见光照射下，具有暴露{011}面和富硫空位的磁性Fe3S4活化PMS对甲硝唑的降解率分别比具有暴露{011}面和贫硫空位的Fe3S4纳米片和具有暴露{112}面的Fe3S4纳米包体高出2.93和4.48。具有暴露的{011}面和富硫空位的 Fe3S4 催化性能优越的原因如下。首先，具有高活性的裸露事实可提供更多支持 PMS 吸附的位点，进一步显著改善 PMS 的解离和活性物种的生成。其次，丰富的硫空位可以介导电子转移，促进 Fe3+/Fe2+ 循环。此外，1O2 介导的非自由基途径实现了污染物的高效降解，在可见光的帮助下，Fe3S4 暴露的{011}面和丰富的硫空位激活了 PMS。这项工作通过刻面工程和缺陷工程调节了磁性Fe3S4的微观结构，从而构建了一种具有优异催化性能的铁基催化剂，进一步赋予了其在类芬顿体系中的巨大潜力。
Zhixiong Yang, Hui Wang, Xiaobin Hao, Lieyu Zhang, Yuan Li, Gaoke Zhang, Regulating facet exposure and sulfur vacancy in magnetic greigite nanosheet for boosting heterogeneous Fenton-like reaction towards efficient degradation of metronidazole under visible light irradiation: Synergistic enhancement effect, DFT calculations and mechanism insight, Journal of Materials Science & Technology, 2025, https://doi.org/10.1016/j.jmst.2024.06.053
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