Enhancing gas adsorption and separation capacity through ligand functionalization of microporous metal-organic framework structures

Yonggang Zhao, Haohan Wu, Thomas J. Emge, Qihan Gong, Nour Nijem, Yves J. Chabal, Lingzhu Kong, David C. Langreth, Hui Liu, Heping Zeng, Jing Li

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148 Citations (Scopus)

Abstract

Hydroxyl- and amino- functionalized [Zn(BDC)(TED) 0.5] ·2DMF·0.2H 2O leads to two new structures, [Zn(BDC-OH)(TED) 0.5]·1.5DMF·0.3H 2O and [Zn(BDC-NH 2)(TED) 0.5]·xDMF·yH 2O (BDC=terephthalic acid, TED=triethylenediamine, BDC-OH=2-hydroxylterephthalic acid, BDC-NH 2=2-aminoterephthalic acid). Single-crystal X-ray diffraction and powder X-ray diffraction studies confirmed that the structures of both functionalized compounds are very similar to that of their parent structure. Compound [Zn(BDC)(TED) 0.5]·2DMF·0.2H 2O can be considered a 3D porous structure with three interlacing 1D channels, whereas both [Zn(BDC-OH)(TED) 0.5]·1.5DMF·0. 3H 2O and [Zn(BDC-NH 2)(TED) 0.5] ·xDMF·yH 2O contain only 1D open channels as a result of functionalization of the BDC ligand by the OH and NH 2 groups. A notable decrease in surface area and pore size is thus observed in both compounds. Consequently, [Zn(BDC)(TED) 0.5]·2DMF·0. 2H 2O takes up the highest amount of H 2 at low temperatures. Interestingly, however, both [Zn (BDC-OH)(TED) 0.5] ·1.5DMF·0.3H 2O and [Zn(BDC-NH 2)(TED) 0.5] ·xDMF·yH 2O show significant enhancement in CO 2 uptake at room temperature, suggesting that the strong interactions between CO 2 and the functionalized ligands, indicating that surface chemistry, rather than porosity, plays a more important role in CO 2 adsorption. A comparison of single-component CO 2, CH 4, CO, N 2, and O 2 adsorption isotherms demonstrates that the adsorption selectivity of CO 2 over other small gases is considerably enhanced through functionalization of the frameworks. Infrared absorption spectroscopic measurements and theoretical calculations are also carried out to assess the effect of functional groups on CO 2 and H 2 adsorption potentials.

Original languageEnglish
Pages (from-to)5101-5109
Number of pages9
JournalChemistry - A European Journal
Volume17
Issue number18
DOIs
Publication statusPublished - Apr 26 2011

Keywords

  • adsorption
  • functionalization
  • gas separation
  • gas storage
  • metal-organic framework

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry

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    Zhao, Y., Wu, H., Emge, T. J., Gong, Q., Nijem, N., Chabal, Y. J., Kong, L., Langreth, D. C., Liu, H., Zeng, H., & Li, J. (2011). Enhancing gas adsorption and separation capacity through ligand functionalization of microporous metal-organic framework structures. Chemistry - A European Journal, 17(18), 5101-5109. https://doi.org/10.1002/chem.201002818