Anchoring Highly Unsaturated Nickel(II) Sites into a Metal-Organic Framework for Simultaneous High C2H2 Adsorption and Separation

Yi-Zhan Hao; Hui-Min Wen; Yi-Hong Yu; Xu Zhang; Yuanjing Cui; Banglin Chen; Bin Li; Guodong Qian

doi:10.1002/anie.202506055

Anchoring Highly Unsaturated Nickel(II) Sites into a Metal-Organic Framework for Simultaneous High C₂H₂ Adsorption and Separation

Angew Chem Int Ed Engl. 2025 Jul;64(27):e202506055. doi: 10.1002/anie.202506055. Epub 2025 May 6.

Authors

Yi-Zhan Hao^#¹, Hui-Min Wen^#², Yi-Hong Yu¹, Xu Zhang³, Yuanjing Cui¹, Banglin Chen^{4

5}, Bin Li¹, Guodong Qian¹

Affiliations

¹ State Key Laboratory of Silicon and Advanced Semiconductor Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China.
² College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, 310014, China.
³ Jiangsu Engineering Laboratory for Environmental Functional Materials, School of Chemistry and Chemical Engineering, Huaiyin Normal University, Huaian, 223300, China.
⁴ Fujian Provincial Key Laboratory of Polymer Materials, College of Chemistry and Materials, Fujian Normal University, Fuzhou, 350007, China.
⁵ Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, College of Chemistry and Materials Science, Zhejiang Normal University, Jinhua, 321004, China.

^# Contributed equally.

PMID: 40293872
DOI: 10.1002/anie.202506055

Abstract

Separation of acetylene (C₂H₂) from carbon dioxide (CO₂) remains a challenge to achieve both high C₂H₂ uptake and selectivity for a single material. Porous materials with open metal sites (OMSs) have been widely employed to separate various gas mixtures; however, routine OMSs often show the limitation in C₂H₂/CO₂ separation due to the comparable binding affinity with the two gases. Herein, we report a new strategy of anchoring highly unsaturated nickel(II) sites into a large-pore MOF (Ni²⁺@NOTT-101-(COOH)₂) for simultaneously improving C₂H₂ adsorption and selectivity. The coordination geometry of the anchored Ni²⁺ ion was accurately determined by SCXRD studies, featuring a two-coordination model with highly unsaturated OMSs after the activation. This highly unsaturated Ni²⁺ ion can provide additional binding sites to improve C₂H₂ adsorption and also enable highly selective binding of C₂H₂ over CO₂ through the specific and strong π- complexation interactions, as revealed by gas-loaded SCXRD studies and theoretical simulations. This metalated MOF thus exhibits both significantly enhanced C₂H₂ uptake (201.4 cm³ g^-1) and C₂H₂/CO₂ selectivity (25.7) than the pristine NOTT-101-(COOH)₂ (148.0 cm³ g^-1 and 3.8) at 298 K and 1 bar, making an unprecedented balance between C₂H₂ adsorption and selectivity to overcome the trade-off challenge. Breakthrough experiments on equimolar C₂H₂/CO₂ mixtures afford both the top-tier dynamic selectivity (14.4) and C₂H₂ productivity of 114.5 L kg^-1 (>99.5% purity) at ambient conditions.

Keywords: Acetylene purification; Gas separation; Metalation; Open metal sites; Porous materials.

Abstract

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