Inter-clusters synergy in iron-organic frameworks for efficient CO2 photoreduction

• Published in: Applied catalysis. B, Environmental Vol. 300; p. 120487
• Main Authors: Wang, Yu-Jie, Wang, Hong-Juan, Luo, Fang, Yao, Shuang, Lu, Tong-Bu, Zhang, Zhi-Ming
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.01.2022; Elsevier BV
• Subjects: Carbon dioxide; Catalysts; Clusters; CO2 photoreduction; Dual-nuclear cluster; Inter-clusters synergy; Metal-organic framework; Metal-organic frameworks; Molecular structure; Photoreduction; Selectivity; Metal-organic framework; Dual-nuclear cluster; Inter-clusters synergy; CO2 photoreduction
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2021.120487

We introduced dual-nuclear clusters {Fe2(H2O)6(triazole)3} into Fe3-based metal-organic fromeworks (MOFs) via ligand substitution strategy. The resulting Fe2@Fe3-MOF molecular composites (Fe3-Fe2 and NH2-Fe3-Fe2) with fixed distance between two {Fe2(H2O)6(triazole)3} clusters for inter-clusters synergy can dramatically improve the activity and selectivity for CO2 reduction. The performance of Fe3-Fe2 and NH2-Fe3-Fe2 MOFs was much superior to most of the state-of-the-art MOF catalysts. [Display omitted] •Highly selective solar-driven conversion of CO2 to HCOOH.•Achieving the uniform distribution of dual-nuclear clusters via the ligand substitution, resulting in a series of isostructural frameworks.•Inter-clusters synergy mediated via the in situ formed H-bonds for CO2 reduction with high activity and selectivity. It is extremely desirable to explore molecular catalysts with precise structure for in-depth exploring structure-activity relationship of CO2 photoreduction. Herein, we demonstrate the precise encapsulation of dual-nuclear clusters {Fe2(H2O)6(triazole)3} into metal-organic frameworks (MOFs) via ligand substitution strategy, resulting in two Fe2@Fe3-MOF composites (Fe3-Fe2 and NH2-Fe3-Fe2). The fixed distance between two adjacent Fe3(μ3-O)Cl(H2O)2 nodes in the MOF matrix allows the Fe2-Tri clusters to be fixed at a predetermined distance to unveil the critical role in improving the activity and selectivity for CO2 reduction. The performance of Fe3-Fe2 and NH2-Fe3-Fe2 can reach to 309.3 and 395.5 μmol g−1 h−1 respectively, much superior to most of the state-of-the-art MOF catalysts. Such high activity and selectivity for formate generation can be attributed to the inter-clusters synergy mediated via in situ formed H-bonds and the cluster-framework cooperativity, supported by the results of DFT calculations and systemic experimental characterizations.