image: Ce-MOFs based solid frustrated Lewis pairs (FLPs) were designed via a competitive coordination strategy using single-carboxylate ligands. Functional groups (–NH2, –OH, –Br, –NO2) modulate the Ce–CUS/Ce–OH acid–base sites, enhancing H₂ heterolytic cleavage through a “push-pull” effect. The optimized MOF-808-NH₂ achieves complete conversion of styrene and dicyclopentadiene at 100 °C and 2 MPa, providing an efficient pathway for green olefin hydrogenation catalysis.
Credit: Chinese Journal of Catalysis
Frustrated Lewis pairs (FLPs) comprising unquenched Lewis acid (LA) and Lewis base (LB) sites have emerged as a revolutionary concept in catalysis, enabling hydrogen activation and hydrogenation reactions without precious metals. While homogeneous FLP systems have shown promise, their instability and recovery challenges limit industrial applicability. Recent advances in solid FLP catalysts, particularly within porous frameworks like metal-organic frameworks (MOFs), offer a solution by combining stability with tunable active sites. However, precise control over the spatial and electronic properties of FLPs remains a critical hurdle for optimizing catalytic performance.
A research team led by Prof. Gao and Prof. Wang from the University of Science and Technology Beijing has developed a groundbreaking strategy to engineer FLPs within cerium-based MOFs (Ce-MOFs). By leveraging Ce’s unique redox properties and structural flexibility, the team constructed a series of defect-rich MOF-808-X materials (X = -NH2, -OH, -Br, -NO2) using a competitive coordination approach with functionalized monocarboxylate ligands. These MOFs feature abundant Ce-CUS (LA) and Ce-OH (LB) sites, forming spatially confined FLPs that synergistically cleave H2 via a "push-pull" mechanism, offering an efficient route for green olefin hydrogenation catalysis. The related results were published in Chinese Journal of Catalysis (DOI: 10.1016/S1872-2067(25)64695-X).
Electron-donating groups (e.g., -NH2) enhance LB strength by redistributing electron density to Ce-OH sites, lowering the activation energy for H2 heterolysis. MOF-808-NH2 achieved 100% conversion of styrene and dicyclopentadiene at 100°C and 2 MPa H2, outperforming unmodified MOF-808 by 3 fold. In-situ DRIFTS and XPS confirmed the formation of Ce–Hδ- and O–Hδ+ intermediates during H2 activation, while DFT calculations revealed a low energy barrier (0.404 eV) for H2 dissociation on MOF-808-NH2.
This study not only advances the fundamental understanding of FLP catalysis but also provides a blueprint for designing non-precious-metal hydrogenation catalysts. The team’s approach, combining defect engineering with ligand functionalization, could be extended to other MOF systems for diverse catalytic applications, from fine chemical synthesis to renewable energy storage.
About the journal
Chinese Journal of Catalysis is co-sponsored by Dalian Institute of Chemical Physics, Chinese Academy of Sciences and Chinese Chemical Society, and it is currently published by Elsevier group. This monthly journal publishes in English timely contributions of original and rigorously reviewed manuscripts covering all areas of catalysis. The journal publishes Reviews, Accounts, Communications, Articles, Highlights, Perspectives, and Viewpoints of highly scientific values that help understanding and defining of new concepts in both fundamental issues and practical applications of catalysis. Chinese Journal of Catalysis ranks among the top six journals in Applied Chemistry with a current SCI impact factor of 17.7. The Editors-in-Chief are Profs. Can Li and Tao Zhang.
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Journal
Chinese Journal of Catalysis
Article Title
Microenvironment modulation around frustrated Lewis pairs in Ce-based metal-organic frameworks for efficient catalytic hydrogenation
Article Publication Date
6-Aug-2025