第一作者：Xinchun Ye
通讯作者：陈德志 教授
通讯单位：南昌航空大学环境与化学工程学院
DOI:10.1016/j.cej.2024.158906
去除复杂水基质中新出现的微污染物通常需要过量的氧化剂和/或能量输入，导致成本效益低，并可能造成二次污染。因此，实现目标微污染物的选择性氧化以达到水净化的目的是有意义的，但也是具有挑战性的。本文构建了一个从 MnFe2O4 纳米片阵列到碳布（CC）物质的内置电场（BIEF），在该电场中，电子从 Mn 和 Fe 原子转移到邻近的 C 原子，从而导致 Mn 和 Fe 位点的 d 带正向移动，费米级电子密度增加。在 BIEF 的影响下，MnFe2O4 对过氧化单硫酸盐（PMS）的活化几乎百分之百地转向了非自由基途径。此外，DFT 计算显示，PMS 的吸附能力显著增强，这导致从 PMS*直接生成 1O2 所需的能垒降低，从而开辟了一种新的途径。所需的能障降低，从而开辟了一条从 PMS* 到 1O2 的新途径。所制造的 Fenton-like 氧化系统对富电子有机微污染物具有选择性氧化作用。这项研究加深了人们对 BIEF 激活 PMS 背后驱动力的理解，并为创新尖晶石-碳催化剂的设计提供了新的见解。
Fig. 1. a) Synthesis scheme, b) XRD pattern, c) SEM and d, e) HRTEM images, and f) element mapping of MnFe2O4/CC.
Fig. 2. a) ACT degradation curves in different systems (Conditions: [ACT] = 0.01 g/L, [catalyst] = 0.1 g/L, [PMS] = 0.3 mM, T = 30 °C); b) PDOS of CC, MnFe2O4 and MnFe2O4/CC; c) charge difference distribution at the interface of MnFe2O4/CC, red and yellow indicate charge accumulation and depletion; d) work function of CC, MnFe2O4 and MnFe2O4/CC; e) schematic of electron transfer driven by energy band differences; f) schematic of electron transfer in BIEF. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)
Fig. 3. a) Effects of quenchers on kobs of ACT degradation; b-d) EPR spectra for DMPO−/OH, DMPO − and TEMP−; e) UV–Vis absorption spectra of DPBF in the MnFe2O4/CC/PMS system (Conditions: [DPBF] = 30 µM, [catalyst] = 0.1 g/L, [PMS] = 0.3 mM, T = 30 °C); f) ACT degradation in D2O and H2O solution by MnFe2O4/CC/PMS system (Conditions: [ACT] = 0.01 g/L, [catalyst] = 0.1 g/L, [PMS] = 0.3 mM, T = 30 °C); g) HPLC curves of typical products generated by the oxidation of FFA in MnFe2O4/CC/PMS system (Conditions: [FFA] = 5 mM, [catalyst] = 0.1 g/L, [PMS] = 0.3 mM, T = 30 °C); h) contribution for ACT degradation by different pathways.
Fig. 4. a, b) In situ Raman spectra; c) DFT calculation of adsorption energies of ACT and PMS on MnFe2 O4/CC; d) i-t curves, and e) OCP curves of CC, MnFe2O4 and MnFe2O4/CC; f) currents of the MnFe2O4/CC, MnFe2 O4, and CC-based GOS systems after adding ACT; g) ACT degradation curves by pre-oxidized catalysts in the presence of quenchers (Conditions: [ACT] = 0.01 g/L, [catalyst] = 0.1 g/L, [quencher] = 5 mM, T = 30 °C); h) in situ Raman spectra after FFA injection; i) Gibbs free energies of PMS* decomposition on the surface of MnFe2O4/CC.
Fig. 5. a) kobs values of different pollutants degradation in the MnFe2O4/CC/PMS system; b) currents after adding different pollutants in the MnFe2O4/CC-based GOS system; c) OCP curves and d) falling potentials of the MnFe2O4/CC electrode; e) correlation between the ln(kobs) and the falling potentials; f) kobs in the coexistence of multi-pollutants; g) energy gaps between LUMO of PMS* and HOMO of pollutants; h) correction between the calculated gaps and ln(kobs) of pollutants. Conditions: [pollutant] = 0.01 g/L, [catalyst] = 0.1 g/L, [PMS] = 0.3 mM, T = 30 °C.
Fig. 6. a) Possible degradation pathways of ACT in the MnFe2O4/CC/PMS system; b) schematic diagram of continuous oxidation system; c) metal ion leaching and degradation efficiency of ACT by the MnFe2O4/CC/PMS continuous oxidation system. Conditions: [ACT] = 0.01 g/L, [catalyst] = 0.1 g/L, [PMS] = 0.3 mM, flow rate = 1 mL min−1 ; temperature = 30 °C.
通过在 CC 中的碳纤维表面原位生长 MnFe2O4 纳米片阵列，成功设计了一种自支撑 MnFe2O4/CC 催化剂。在 MnFe2O4 和碳基底的界面上存在 BIEF 可以改善 PMS 的非辐射活化（1O2 和直接电子转移）。实验和 DFT 计算证实，1O2 和电子转移均来自表面络合的 PMS*。此外，BIEF 的存在有效地减少了 PMS 的消耗和金属离子的沥滤。此外，1O2 和 ETP 主导的非降解途径对富含电子的有机污染物的去除具有高度选择性。最后，提出了 ACT 的三种可能降解途径，序氧化结果表明，制备的 MnFe2O4/CC 自支撑催化剂在 PMS-AOPs 水处理方面表现出卓越的潜力。这项研究为设计用于活化 PMS 的尖晶石氧化物-碳催化剂提供了一种新方法，并加深了对 BIEF 活化 PMS 背后驱动力的理解。
Xinchun Ye, Dezhi Chen, Quanzhi Zhang, Tianlin Zhou, Jian-Ping Zou, Shenglian Luo, Enhanced and synergistic catalytic activation through spinel-carbon built-in electric field: A novel pathway for generating 1O2, Chemical Engineering Journal, 2025, https://doi.org/10.1016/j.cej.2024.158906
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