催化学报 ›› 2025, Vol. 75: 59-72.DOI: 10.1016/S1872-2067(25)64695-X

• 论文 • 上一篇    下一篇

铈基金属有机框架中受阻路易斯酸碱对的微环境调控及其催化加氢性能研究

徐鑫梦a,1, 席作帅a,1, 高鸿毅a,b,*(), 赵丹凤a, 刘志远a, 班涛a, 王静静a, 赵顺征c, 王戈a,*()   

  1. a北京科技大学材料科学与工程学院, 分子与微结构可控材料技术北京市重点实验室, 北京材料基因工程高精尖创新中心, 北京 100083
    b北京科技大学顺德创新学院, 广东顺德528399北京科技大学能源与环境工程学院, 北京 100083
    c北京科技大学顺德创新学院, 广东顺德528399北京科技大学能源与环境工程学院, 北京 100083
  • 收稿日期:2025-02-11 接受日期:2025-03-26 出版日期:2025-08-18 发布日期:2025-07-22
  • 通讯作者: *电子信箱: hygao@ustb.edu.cn (高鸿毅), gewang@ustb.edu.cn (王戈).
  • 作者简介:1共同第一作者.
  • 基金资助:
    国家自然科学基金(52373261);国家重点研发项目(2021YFB3500700);北京市自然科学基金(L233011)

Microenvironment modulation around frustrated Lewis pairs in Ce-based metal-organic frameworks for efficient catalytic hydrogenation

Xu Xinmenga,1, Xi Zuoshuaia,1, Gao Hongyia,b,*(), Zhao Danfenga, Liu Zhiyuana, Ban Taoa, Wang Jingjinga, Zhao Shunzhengc, Wang Gea,*()   

  1. aBeijing Advanced Innovation Center for Materials Genome Engineering, Beijing Key Laboratory of Function Materials for Molecule & Structure Construction, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
    bShunde Innovation School, University of Science and Technology Beijing, Shunde 528399, Guangdong, China
    cSchool of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China
  • Received:2025-02-11 Accepted:2025-03-26 Online:2025-08-18 Published:2025-07-22
  • Contact: *E-mail: hygao@ustb.edu.cn (H. Gao), gewang@ustb.edu.cn (G. Wang).
  • About author:1Contributed equally to this work.
  • Supported by:
    National Natural Science Foundation of China(52373261);National Key R&D Program of China(2021YFB3500700);Beijing Natural Science Foundation(L233011)

摘要:

催化加氢技术是合成化学与工业生产的核心环节, 其发展对推动绿色制造和可持续化学转型至关重要. 当前, 以储量丰富及环境友好型的非贵金属替代传统贵金属催化剂已成为加氢技术创新的关键方向, 不仅可显著降低生产成本, 对构建资源节约型催化体系也具有重要作用. 然而, 现有廉价金属催化剂普遍面临活性位点稳定性差和结构调控精度不足等瓶颈, 导致催化效率难以满足工业应用需求. 针对该挑战, 开发兼具高活性和优异稳定性的新型催化材料体系成为突破方向.

本研究采用单羧酸官能团配体竞争配位策略, 成功构建了一系列具有丰富固体受阻路易斯酸碱对(FLPs)的MOF-808-X(X分别为NH2, OH, Br和NO2)催化材料, 并将其应用于双环戊二烯(DCPD)和苯乙烯的加氢反应. 其中, FLPs位点作为主要的催化活性位点, 官能团X作为远程微环境, 通过调节FLPs位点的电子特性及酸碱性质改善其加氢活性. 通过核磁共振氢谱、同步辐射、傅里叶变换红外光谱及X射线光电子能谱等多种表征分析证实了具有X官能团的单羧酸配体通过取代H3BTC的方式被引入到MOF-808结构中, 从而在其框架中原位诱导出丰富的缺陷结构. 具有4f轨道电子的Ce与单羧酸配体竞争配位共同促进了MOFs中不饱和Ce(Ce-CUS, 路易斯酸(LA))与邻近的Ce-OH(路易斯碱(LB))位点的暴露, 从而产生了丰富的固态FLPs(Ce-CUS/Ce-OH)位点. 借助量子力学计算和程序升温脱附技术, 揭示了官能团X的电子特性对FLPs位点的影响机制. 给电子官能团的孤对电子通过分子骨架传递到FLPs位点, 增加了FLPs位点的极化强度, 降低了H2异裂所需的活化能. 这种电子调控效应显著提升了催化性能, 在100 °C、2 MPa H2条件下, MOF-808-NH2对DCPD和苯乙烯的转化率均达到100%, 与MOF-808相比分别提升10倍和3倍, 并且在循环使用5次后仍保持优异的结构稳定性和80%以上的加氢活性. 最后, 通过对氢裂解过程的动态监测, 阐明了H2在Ce-CUS/Ce-OH FLPs位点上的解离机理. 具体而言, Ce-CUS和Ce-OH分别与H-H的σ和σ*轨道作用, “推拉式”的协同促进了H-H键异裂.

综上, 本文通过在MOFs中精准构筑FLPs, 并精细调控其局部微环境, 成功实现了不饱和烯烃的高效加氢催化. 该研究不仅为MOFs中活性位点的精准设计提供了新思路, 更为非贵金属催化体系在绿色合成领域的应用拓展了理论依据与实践路径.

关键词: 受阻路易斯酸碱对, 微环境调控, 缺陷, 铈基MOFs, 催化剂, 加氢

Abstract:

The development of solid frustrated Lewis pairs (FLPs) catalysts with porous structures is a promising strategy for advancing green hydrogenation technologies and has garnered significant attention. Leveraging the diverse oxidation states and structural tunability of cerium-based metal-organic frameworks (Ce-MOFs), this study employed a competitive coordination strategy utilizing a single carboxylate functional group ligand to construct a series of MOF-808-X (X = -NH2, -OH, -Br, and -NO2) featuring rich solid-state FLPs for hydrogenation of unsaturated olefins. The -X functional group serves as a microenvironment, enhancing hydrogenation activity by modulating the electronic properties and acid-base characteristics of the FLP sites. The unique redox properties of elemental cerium facilitate the exposure of unsaturated Ce sites (Ce-CUS, Lewis acid (LA)) and adjacent Ce-OH (Lewis base (LB)) sites within the MOFs, generating abundant solid-state FLP (Ce-CUS/Ce-OH) sites. Experimental results demonstrate that Ce-CUS and Ce-OH interact with the σ and σ* orbitals of H-H, and this "push-pull" synergy promotes heterolytic cleavage of the H-H bond. The lone pair electrons of the electron-donating functional group are transmitted through the molecular backbone to the LB site, thereby increasing its strength and reducing the activation energy required for H2 heterolytic cleavage. Notably, at 100 °C and 2 MPa H2, MOF-808-NH2 achieves complete conversion of styrene and dicyclopentadiene, significantly outperforming MOF-808. Based on in-situ analysis and density functional theory calculations, a plausible reaction mechanism is proposed. This research enriches the theoretical framework for unsaturated olefin hydrogenation catalysts and contributes to the development of efficient catalytic systems.

Key words: Frustrated Lewis pairs, Microenvironment modulation, Defect, Ce-based metal-organic frameworks, Catalyst, Hydrogenation