Temperature-Induced Molecular Rearrangement of an Ionic Liquid Confined in Nanospaces: An <i>in Situ</i> X-ray Absorption Fine Structure Study

Jiang, Fangling; Li, Cheng; Fu, Haiying; Wang, Chenyang; Guo, Xiao-Jing; Jiang, Zheng; Wang, Guozhong; Chen, Shimou

doi:10.1021/acs.jpcc.5b07325

Cited by 24 publications

(30 citation statements)

References 39 publications

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“…Their results indicate a confinement-induced melting temperature shift of the studied ILs, which agrees well with the experimental observations . A similar temperature-induced structural transformation was also reported for the 1-hexyl-3-methylimidazolium bromine ([C 6 mim]Br) IL confined in carbon nanotubes . Despite the progress, little has been reported about the structure–spectra relationship of confined ILs.…”

Section: Introductionsupporting

confidence: 87%

Structural Properties and Vibrational Spectra of Ethylammonium Nitrate Ionic Liquid Confined in Single-Walled Carbon Nanotubes

Zhou

Yang

et al. 2016

J. Phys. Chem. C

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The structures and relevant vibrational spectra of an ethylammonium nitrate (EAN) ionic liquid (IL) confined in single-walled carbon nanotubes (SWCNTs) with various diameters have been investigated in detail by using classical molecular dynamics simulation. Our simulation results demonstrate that the EAN IL confined in larger SWCNTs can form well-defined multishell structures with an additional cation chain located at the center. However, a different single-shell hollow structure has been found for both the cations and the anions in the 1 nm SWCNT. For the cations confined in SWCNTs, the CH3 groups stay closer to the nanotube walls because of their solvophobic nature, while the NH3 + groups prefer to point toward the central axis. Accordingly, the NO3 – anions tend to lean on the SWCNT surface with three O atoms facing the central axis to form hydrogen bonds (HBs) with the NH3 + groups. In addition, in the 1 nm SWCNT, the CH3 groups of cations exhibit an obvious blue shift of around 16 cm–1 for the C–H stretching mode with respect to the bulk value, and the N–H stretching mode of NH3 + groups is split into two characteristic peaks with one peak appearing at a higher frequency. Such a blue shift is attributed to the existence of more free space for the C–H bonds of confined CH3 groups, while the splitting phenomenon is due to the fact that more than 60% of the confined NH3 + groups have one dangling N–H bond. For the anions confined in the 1 nm SWCNT, the N–O stretching mode of NO3 – has a maximum red shift of around 24 cm–1 with respect to the bulk value, which is attributed to enhanced HBs between anions and cations. Our simulation results reveal a molecular-level correlation between confined structural configurations and the corresponding vibrational spectra changes for the ILs confined in nanometer scale environments.

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Section: Introductionsupporting

confidence: 87%

Structural Properties and Vibrational Spectra of Ethylammonium Nitrate Ionic Liquid Confined in Single-Walled Carbon Nanotubes

Zhou

Yang

et al. 2016

J. Phys. Chem. C

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“…Common experimental techniques include AFM, 116 − 123 scanning tunneling microscopy (STM), 124 , 125 differential scanning calorimetry, 126 , 127 NMR, 128 − 132 high-resolution TEM, 133 − 135 thermogravimetric analysis, 13 and X-ray diffraction. 126 , 136 In addition to direct experimental observations, researchers often use theoretical simulations to study the influence mechanism of e.g. the substrate shape, material, and applied electric field on the structures, properties, and functions of interfacial ILs.…”

Section: From the Bulk To The Interface: Z-bonds → Quasi-liquidsmentioning

confidence: 99%

“…100 K in comparison with that of bulk ILs. 126 , 135 Theoretical simulations 169 indicated that disordered bulk BmimBF 4 adopts an ordered microcrystal structure, inducing an abnormal enhancement of the melting point. Furthermore, the melting point of confined EmimPF 6 further increases with a decreasing radius of the CNT.…”

Section: From the Bulk To The Interface: Z-bonds → Quasi-liquidsmentioning

confidence: 99%

Insights into Ionic Liquids: From Z-Bonds to Quasi-Liquids

Wang

et al. 2022

JACS Au

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Ionic liquids (ILs) hold great promise in the fields of green chemistry, environmental science, and sustainable technology due to their unique properties, such as a tailorable structure, the various types available, and their environmentally friendly features. On the basis of multiscale simulations and experimental characterizations, two unique features of ILs are as follows: (1) strong coupling interactions between the electrostatic forces and hydrogen bonds, namely in the Z-bond, and (2) the unique semiordered structure and properties of ultrathin films, specifically regarding the quasi-liquid. In accordance with the aforementioned theoretical findings, many cutting-edge applications have been proposed: for example, CO 2 capture and conversion, biomass conversion and utilization, and energy storage materials. Although substantial progress has been made recently in the field of ILs, considerable challenges remain in understanding the nature of and devising applications for ILs, especially in terms of e.g. in situ /real-time observation and highly precise multiscale simulations of the Z-bond and quasi-liquid. In this Perspective, we review recent developments and challenges for the IL research community and provide insights into the nature and function of ILs, which will facilitate future applications.

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“…This can be explained as follows. Normally, RS is sensitive to nonpolar vibration such as vibration of the C-C bond [64]. In this case, for muscovite, the spectrum mainly reflects Si-O or Al-O vibration.…”

Section: Resultsmentioning

confidence: 99%

Intensive study on structure transformation of muscovite single crystal under high-doseγ-ray irradiation and mechanism speculation

et al. 2019

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Intensive study on structure transformation of muscovite single crystal under high-dose γ -ray irradiation is essential for its use in irradiation detection and also beneficial for mechanism cognition on defect formation within a matrix of clay used in the disposal of high-level radioactive waste (HLRW). In this work, muscovite single crystal was irradiated with Co-60 γ ray in air at a dose rate of 54 Gy min −1 with doses of 0–1000 kGy. Then, structure transformation and mechanism were explored by Raman spectrum, Fourier-transform infrared spectrum, X-ray diffraction, thermogravimetric analysis, CA, scanning electron microscope and atomic force microscopy. The main results show that variations in the chemical/crystalline structure are dose-dependent. Low-dose irradiation sufficiently destroyed the structure, removing Si–OH, thus declining hydrophilicity. With dose increase up to 100 kGy, CA increased from 20° to 40°. Except for hydrophilicity variation, shrink occurred in the (004) lattice plane which later recovered; the variation range at 500 kGy irradiation was 0.5% close to 0.02 Å. The main mechanisms involved were framework break and H 2 O radiolysis. Framework break results in Si–OH removal and H 2 O radiolysis results in extra OH introduction. The extra introduced OH probably results in Si–OH bond regeneration, lattice plane shrink and recovered surface hydrophilicity. The importance of framework break and H 2 O radiolysis on structure transformation is dose-dependence. At low doses, framework break seems more important while at high doses H 2 O radiolysis is important. Generally, variations in the chemical structure and surface property are nonlinear and less at high doses. This indicates using the chemical structure or surface property variation to describe irradiation is correct at low doses but not at high doses. This finding is meaningful for realizing whether muscovite is suitable for detecting high-dose irradiation or not, and mechanism exploration is efficient for identifying the procedure for defect formation within the matrix of clay used in disposal HLRW in practice.

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Temperature-Induced Molecular Rearrangement of an Ionic Liquid Confined in Nanospaces: An in Situ X-ray Absorption Fine Structure Study

Cited by 24 publications

References 39 publications

Structural Properties and Vibrational Spectra of Ethylammonium Nitrate Ionic Liquid Confined in Single-Walled Carbon Nanotubes

Structural Properties and Vibrational Spectra of Ethylammonium Nitrate Ionic Liquid Confined in Single-Walled Carbon Nanotubes

Insights into Ionic Liquids: From Z-Bonds to Quasi-Liquids

Intensive study on structure transformation of muscovite single crystal under high-doseγ-ray irradiation and mechanism speculation

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