Zwitterionic ionic liquids modulating two-dimensional hierarchically porous zeolitic imidazolate framework composites

Hypothesis: Two-dimensional hierarchically porous zeolitic imidazolate frameworks (H-ZIFs) show great promising applications in catalysis, gas separation, energy storage and sensing. Herein, a facile ionic liquid-modulation approach is proposed for constructing H-ZIFs nanosheets with tunable thickness. Experiments: Sulfo-functionalized zwitterionic ionic liquids (SFIL) have been designed as monodentate ligands to direct the formation of microporous nanosheets (ZIF-SFIL) in aqueous solution. Anions of SFIL have been tuned to modulate the coordination environment, enabling the control of the structure, thickness and pores of the nanosheets. Findings: SFIL is demonstrated to pre-coordinate with Zn(II) to induce micropores with high specific surface areas (up to 1176 m(2).g (1)) and accelerate the nucleation of crystals. The BF4 anion serves as a competitive ligand to partially replace SFIL to cause structural defects, thus yielding hierarchically porous ZIFSFIL nanosheets with high specific surface areas (270-466 m(2).g(-1)) and variable thicknesses (from ca. 58 nm to ca. 455 nm). Benefiting from the versatile designability and multifunctionality of ionic liquids, the strategy in this work offers a facile approach for designing and constructing multifunctional materials with hierarchical pores. (c) 2022 Elsevier Inc. All rights reserved.

Automated summary

This study proposes a facile ionic liquid-modulation approach for constructing two-dimensional hierarchically porous zeolitic imidazolate frameworks (H-ZIFs) nanosheets with tunable thickness. By tuning the anions of the ionic liquid, the structure, thickness, and pores of the nanosheets can be controlled. This strategy offers a facile approach for designing and constructing multifunctional materials with hierarchical pores.