第一作者：Haokun Bai
通讯作者：全燮 教授
通讯单位：大连理工大学环境科学与技术学院
DOI:10.1016/j.apcatb.2024.124790
本文研究了纳米细化对催化剂电子结构的调节作用，这种作用会影响高级氧化过程（AOP）的效率。在二维镍铁层双氢氧化物膜（NiFeM）的亚纳米层间通道内进行了基于过一硫酸盐（PMS）的高级氧化过程。理论计算表明，这种层间限制使催化剂金属 d 带中心上移，从而加强了对 PMS 的吸附以及催化剂与 PMS 分子之间的电子转移。这项工作体现了层间限制对催化剂电子结构的调节作用，为设计具有卓越环境修复、能源转换和化学合成能力的催化剂提供了启示。
Fig. 1. (a) SEM image of the surface of catalytic NiFeM, EDS mapping of NiFeLDH nanosheet, and (inset) photograph of NiFeM. (b) AFM image of NiFeLDH nanosheet. (c-f) Cross-sectional SEM image of NiFeM with different catalyst loading. (g) XRD patterns of NiFeM in wet and dry state. (h) Illustration of the d-spacing between neighboring NiFeLDH nanosheets in NiFeM.
Fig. 2. Catalytic performance of interlayer-confined NiFeM. (a) SMX removal by NiFeM as a function of catalyst loading and PMS dosage. (b) SMX removal by sole PMS, NiFeM rejection, PVDF membrane/PMS and NiFeM/PMS system. (c) SMX removal as a function of retention time and (inset) pseudo-first-order reaction constant by NiFeM. (d) Comparison of first-order reaction constant k among different catalytic systems. (e) SMX removal with different pH values and background anions by NiFeM/PMS system. Conditions: [SMX]=2 mg L−1, [PMS]=0.33 mM, pH=initial, [anions]=5 mM, [HA] = 5 mg L−1, water flux=34 L m−2 h−1.
Fig. 3. (a) EPR spectra of PMS and NiFeM/PMS system. (b) SMX removal of NiFeM with different radical scavengers. Conditions: [SMX]=2 mg L−1, [PMS]=0.33 mM, pH=initial, water flux= 34 L m−2 h−1. (c) Comparison of radical concentration in non-confined (batch) and confined system. (d) Comparison of Rct values of non-confined (batch) and confined system.
Fig. 4. (a) SMX removal by NiFeM, NiFeM-7 Å and NiFeM-21.5 Å. (b) Energy profile of PMS decomposition on the surface and within the 3.7 Å interlayer spacing of NiFeLDH nanosheets. (c) PDOS results of NiFeLDH nanosheets with different interlayer spacings, where d-band center position is marked with red dashed line. (d) Electron density difference and electron transfer number between PMS and NiFeLDH nanosheets with different interlayer spacings. (e) Adsorption energies of PMS on NiFeLDH nanosheets with different interlayer spacings.
Fig. 5. (a) Pollutants removal in actual pharmaceutical wastewater by sole PMS and NiFeM/PMS system. (b) TOC removal of actual pharmaceutical wastewater. Conditions: for (a), TOC=9.4 mg L−1; [PMS]=0.33 mM, pH=initial, water flux=34 L m−2 h−1; for (b), [PMS]=3.3 mM, pH=initial, water flux=17 L m−2 h−1.
纳米纤化策略被认为是一种有效的方法，可推动纳米技术的发展，消除水处理过程中新出现的污染物。从根本上说，了解纳米融合对催化剂催化行为的影响至关重要。本研究揭示了纳米级空间（即层间限制）对催化剂电子结构的调节作用，通过上移金属 d 带中心来增强过一硫酸盐基 AOP 的吸附和电子转移，从而实现超快水净化。本研究中开发的膜平台不仅被证明是在其定义明确的纳米限定通道内系统探索纳米纤化介导效应的理想范例，而且还实现了绿色、多功能和可持续的水处理。未来的研究还需要在其他方面，如密闭催化剂的结构演化、催化剂与基底之间的电子金属-支撑相互作用（EMSI）等，揭示纳米簇拥的内在机制，相信这将为催化剂的设计提供指导，从而有效消除水和废水处理中的微污染物。
Haokun Bai, Lanlan Liang, Shuo Chen, Hongtao Yu, Xie Quan, Modulating electronic structure of NiFe layered double hydroxide membrane by interlayer-confinement for enhanced water decontamination, Applied Catalysis B: Environment and Energy, 2025, https://doi.org/10.1016/j.apcatb.2024.124790
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