Chinese Journal of Catalysis ›› 2025, Vol. 75: 59-72.DOI: 10.1016/S1872-2067(25)64695-X

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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)

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