Influence of the 2-methylimidazole/zinc nitrate hexahydrate molar ratio on the synthesis of zeolitic imidazolate framework-8 crystals at room temperature

Abstract

The effect of the 2-methylimidazole (Hmim)/zinc nitrate hexahydrate (Zn) molar ratio on the physicochemical characteristics of the zeolitic imidazolate framework-8 (ZIF-8) was investigated. ZIF-8 crystals were synthesized by mixing Hmim with Zn at room temperature without any additives in methanol solution. It was found that Hmim/Zn molar ratio had significant influence on the crystallinity, yield, particle size and porosity of ZIF-8. The samples synthesized at low Hmim/Zn molar ratio showed a cubic shape, whereas at higher Hmim/Zn ratios truncated rhombic dodecahedron or rhombic dodecahedron morphologies were obtained. The particle size is decreased upon increasing the Hmim/Zn molar ratio. Besides, higher Hmim/Zn molar ratio in a certain range resulted in improving crystallinity, yield, surface area and micropore volume of ZIF-8. The ZIF-8 crystals produced at Hmim/Zn molar ratio of 8 exhibited the best characteristics. The present work provides new insights in relation to the role of Hmim/Zn molar ratio on the synthesis process of ZIF-8.

Evaluation of Structural Properties and Catalytic Activities in Knoevenagel Condensation Reaction of Zeolitic Imidazolate Framework-8 Synthesized under Different Conditions

“…No conspicuous difference was noticed in the XRD peaks of the samples; however, their relative crystallinities slightly decrease as the meIm/Zn molar ratio increases from 64.4/8 to 100/8. ese findings are well consistent with those reported by Zhang et al [24].…”

“…However, the intensity of diffraction peaks in Z-B(DMF) is higher than that in Z-A(MeOH), and this means that Z-B(DMF) has higher symmetric planes. e FT-IR spectra of both Z-A(MeOH) and Z-B(DMF) are displayed in Figure 1(b), and the findings are consistent with earlier reported results [19,23,24]. e bands at 3122 cm −1 and 2920 cm −1 are associated with the aromatic and the aliphatic C-H asymmetric stretching vibrations, respectively.…”

A microporous carbon derived from metal‐organic frameworks for long‐life lithium sulfur batteries

“…As shown in Figure 1A, the prepared ZIF-8 precursor gives very fine MOF structure, where six peaks located at 7 , 10 , 12.5 , 14.5 , 16.2 , and 17.8 could be clearly observed, all of which could correspond to (011), (002), (112), (022), (013), and (222) lattice planes of ZIF-8, respectively. 38 When the ZIF-8 was annealed at high temperature and followed hydrochloric acid treatment, two broad peaks around 28 and 43 were detected, which could be indexed to (002) and (101) lattice planes of carbon. The very wide FWHM of the peaks indicates very low graphitization degree of the ZIF-8 derived MC, which may be caused by the numerous micropore defects in the carbon matrix.…”

“…XRD measurement was firstly applied to investigate the phase transformation from ZIF‐8 to MC and S/MC composites. As shown in Figure A, the prepared ZIF‐8 precursor gives very fine MOF structure, where six peaks located at 7°, 10°, 12.5°, 14.5°, 16.2°, and 17.8° could be clearly observed, all of which could correspond to (011), (002), (112), (022), (013), and (222) lattice planes of ZIF‐8, respectively . When the ZIF‐8 was annealed at high temperature and followed hydrochloric acid treatment, two broad peaks around 28° and 43° were detected, which could be indexed to (002) and (101) lattice planes of carbon.…”

Metal Organic Framework-Polyethersulfone Composite Membrane for Iodine Capture

“…ZIF-8 was prepared following a previously published method [ 25 , 26 ] with minor modifications. In brief, 0.5872 g (1.974 mmol) of zinc nitrate hexahydrate (Zn(NO 3 ) 2 6H 2 O) was dissolved in 12 mL of MeOH while 1.2978 g (15.808 mmol) of the ligand 2-methylimidazole was dissolved in 28 mL of NH 4 OH.…”