In situ high pressure study of ZIF-8 by FTIR spectroscopy

Abstract

ZIF-8 as a promising storage material was investigated at high pressures up to ~39 GPa by in situ FTIR spectroscopy for the first time. Structural modifications are found to be reversible in a low-pressure region but irreversible in a high-pressure region. Overall, the ZIF-8 framework exhibits an unusual chemical stability even under extreme compression.

Adsorptive removal of arsenic from aqueous solution by zeolitic imidazolate framework-8 (ZIF-8) nanoparticles

“…XPS (a) Zn 2p, (b) N 1s, (c) O 1s and (d) As 3d core-level spectra of ZIF-8 nanoparticles before and after As(III) and As(V) adsorption. stretching of the imidazole, which accompanied with a wide strong peak between 2300 and 2500 cm −1 , whereas the intense and convoluted bands at 1350-1500 cm −1 are associated with the entire ring stretching [40]. In addition, we also can observe the Zn N stretch mode at 421 cm −1 [41].…”

Highly efficient removal of arsenic(III) from aqueous solution by zeolitic imidazolate frameworks with different morphology

“…The peaks at 1350-1500 cm −1 can be assigned to the stretching of the ring of the 2-methylimidazole. The peaks at 900-1350 cm −1 are contributed to the in-plane vibration of ZIFs while peaks at around 800 cm −1 are assigned to the out-plane bending [27]. As shown in Fig 6a, after As(III) adsorption, the wide band near 3000 cm −1 of the three ZIFs shift to higher frequency (3300 cm −1 ), indicating new bonding of the OH groups with higher energy are formed [29].…”

Identifying the Role of Terahertz Vibrations in Metal-Organic Frameworks: From Gate-Opening Phenomenon to Shear-Driven Structural Destabilization

“…Using synchrotron radiation farinfrared spectroscopy (SR-FIR) at Diamond Light Source (Oxfordshire, UK) allowed for THz data with high signal-tonoise ratio to be obtained down to 20 cm −1 (0.6 THz), i.e., the typically hard to gain low-frequency region. For example, current literature has only managed to obtain limited results for the mid-IR region of ZIF-8, describing the peaks below ∼800 cm −1 simply as "out-of-plane bending" and "beyond the limitations of equipment used" [21]. These challenges are overcome herein via SR-FIR techniques.…”

“…Even in materials as complex as MOFs, the variations are minor (e.g., Refs. [20,21]). Therefore, the real thrust of this work is to interrogate the lower energy vibrational bands observed in the far-infrared (FIR) region of the spectrum (<400 cm −1 ), with particular emphasis on the low-frequency vibrations under ∼ 3 THz (<100 cm −1 ).…”