催化学报

催化学报

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混合价态MIL-88A(Fe)@BiOBr异质结中全空间电场介导的电荷迁移用于高效光催化降解有机污染物

周彪a,*, 陈建伟c, 种亚楠b,*, 严克友c,*   

  1. a湖北师范大学城市与环境学院, 湖北黄石 435500;
    b大湾区大学物质科学学院, 东莞市先进材料与大型科学设施交叉科学重点实验室, 广东东莞 523000;
    c华南理工大学环境与能源学院, 发光材料与器件国家重点实验室, 广东广州 510000
  • 收稿日期:2025-10-09 接受日期:2025-01-26
  • 通讯作者: *电子信箱: Zhoubiao93@hbnu.edu.cn (周彪), chongyn@gbu.edu.cn (种亚楠), kyyan@scut.edu.cn (严克友).
  • 基金资助:
    湖北省自然科学青年基金(2025AFB270); 湖北省教育厅中青年人才项目基金(Q20242502); 广东省基础与应用基础研究基金(2024A1515110037).

Full-space electric field-mediated charge migration in mixed-valence MIL-88A(Fe)@BiOBr heterostructures for efficient photocatalytic pollutant removal

Biao Zhoua,*, Jianwei Chenc, Yanan Chongb,*, Keyou Yanc,*   

  1. aCollege of Urban and Environmental Sciences, Hubei Normal University, Huangshi 435500, Hubei, China;
    bDongguan Key Laboratory of Interdisciplinary Science for Advanced Materials and Large-Scale Scientific Facilities, School of Physical Sciences, Great Bay University, Dongguan 523000, Guangdong, China;
    cSchool of Environment and Energy, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510000, Guangdong, China
  • Received:2025-10-09 Accepted:2025-01-26
  • Contact: *E-mail: Zhoubiao93@hbnu.edu.cn (B. Zhou), chongyn@gbu.edu.cn (Y. Chong), kyyan@scut.edu.cn (K. Yan).
  • Supported by:
    Natural Science Foundation of Hubei Province (2025AFB270), the Research Project of Hubei Provincial Department of Education (Q20242502), and the Guangdong Basic and Applied Basic Research Foundation (2024A1515110037).

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摘要： 随着工业化与城市化进程加快, 有机废水的处理已成为可持续发展和人类健康面临的关键问题. 半导体光催化降解技术是一种高效、绿色的污染物去除策略, 但其实际应用仍受限于光生电荷载流子复合快、活性位点不足以及吸附与光催化过程耦合弱等挑战. 金属-有机框架(MOF)材料因其可调的孔隙结构、高比表面积和功能多样性, 在光催化领域展现出巨大潜力. 然而, MOF材料内部及界面缓慢的电荷传输动力学限制了其降解效率. 因此, 开发能够协同增强电荷分离、最大化活性位点暴露并集成吸附-光催化过程的MOF基异质结构体系至关重要.
本文通过连续的原位水解与还原策略, 合理构建了晶面工程化的混合价态MIL-88A(FeⅡ/FeⅢ)@BiOBr异质结构(m-MIL-88A@BiOBr). 其中, 暴露(100)晶面的m-MIL-88A纳米棒被超薄BiOBr纳米片(主要暴露(001)晶面)包覆. 研究表明, Fe(Ⅱ)的引入不仅增强了m-MIL-88A体相内的电荷迁移率, 还使其功函数较原始MIL-88A降低了0.08 eV, 从而将界面电场强度提升了2.2倍. 这种增强的体相电荷迁移与强化的界面电场, 与BiOBr自身(001)与(110)晶面间固有的体电场协同作用, 共同构建了全空间电场, 实现了光生电子的定向迁移. 优化后的m-MIL-88A@BiOBr-3催化剂表现出优异的卡马西平(CBZ)光催化降解性能, 其反应速率常数高达0.023 min‒1, 分别是原始MIL-88A和BiOBr的6.99倍和2.15倍. 此外, 该催化剂展现出广泛的环境适用性, 可高效矿化四环素、偶氮染料等多种结构各异的污染物. 通过X-射线光电子能谱、紫外光电子能谱、开尔文探针力显微镜和密度泛函理论计算等系统表征, 证实了混合价态FeⅡ/FeⅢ簇建立的电子传递链, 强化了界面内建电场, 并揭示了电子遵循BiOBr-(001) → BiOBr-(110) → m-MIL-88A-(100)的Type-II路径进行全空间电场介导的定向转移. 机理研究表明, •OH和•O2-是降解过程中的主要活性物种, 并基于福井函数计算提出了CBZ可能的降解路径.
综上, 本工作通过价态调控与晶面工程的双重策略, 在MOF基异质结中实现了体电场与界面电场的协同调制, 为设计具有高效定向电荷转移能力的光催化体系提供了新思路, 对推动MOF基材料在环境修复中的实际应用具有重要意义.

关键词: 金属-有机框架, BiOBr, 混合价态, 全空间电场, 有机污染物

Abstract: Metal-organic frameworks (MOFs) offer an ideal platform for constructing heterostructures to catalyze organic pollutant degradation. However, sluggish charge transfer dynamics within the bulk and at interfacial regions limit removal efficiency. Herein, we engineered a full-space electric field in BiOBr-nanosheet-coated mixed-valence MIL-88A(FeII/FeIII) (m-MIL-88A@BiOBr) heterostructures via charge polarization to overcome this limitation. Specifically, this full-space electric field originates from the synergistic interplay of a bulk electric field (BEF) and an interfacial electric field (IEF), collectively driving the directional flow of photogenerated electrons. Simultaneously, mixed-valent FeII/FeIII metalloclusters establish electron-transfer chains, enhancing charge mobility and IEF intensity. The optimized m-MIL-88A@BiOBr-3 catalyst exhibited exceptional photocatalytic degradation rate constant of 0.023 min-1 for carbamazepine (CBZ) removal, surpassing pristine MIL-88A and BiOBr by factors of 6.99 and 2.15, respectively. Notably, m-MIL-88A@BiOBr-3 demonstrates broad environmental applicability, efficiently mineralizing structurally diverse pollutants (tetracycline, azo dyes, etc.). This work provides critical insights for regulating charge transport in MOF-based heterojunctions.

Key words: Metal-organic frameworks, BiOBr, Mixed-valence, Full-space electric field, Organic pollutants