离子液体在大气压等离子体中稳定性研究

doi:10.3964/j.issn.1000-0593(2019)05-1372-05

Abstract
References
Related Citation (15)

Download: PDF (2238 KB)
Export: BibTeX | EndNote (RIS)

Abstract The stability of three Ionic liquids ([Bmim]HSO₄, HSO₄ and [Bmim]BF₄) in DBD (Dielectric Barrier Discharge) Plasma under atmospheric pressure was investigated by using the OES (Optical Emission Spectrometer), UV-Vis (Ultraviolet and Visible Spectrophotometer), FTIR(Fourier Transform Infrared Spectroscopy) and NMR (Nuclear Magnetic Resonance) techniques. The influences of the stability of three Ionic liquids on the crystal phase structure of TiO₂ were also studied by preparation of TiO₂ with DBD plasma under atmospheric pressure using three kinds of Ionic liquids as assistant, respectively. The results showed that the position and quantity of argon argon plasma emission spectra peak did not change when three kinds of ionic liquid were introduced in DBD plasma. This indicated that the three ionic liquids of above did not evaporate in the plasma area and form excited species. However, the intensity argon emission peak decreased obviously. Both FTIR and UV-Vis spectrospecy of [Bmim]HSO₄ and HSO₄ showed no difference before and after plasma discharge. This indicated that the [Bmim]HSO₄ and HSO₄ were stable in plasma. There was no significant difference in the infrared spectra of [Bmim]BF₄ before and after plasma treatment. However, the position of the absorption peak in the UV-Vis spectra of [Bmim]BF₄ before and after plasma treatment had a large shift, and the analysis of ¹H NMR showed that all the peaks shifted to right 0.2 units approximately. That indicated that the structure of some [Bmim]BF₄ changed in plasma. The XRD spectra of HSO₄-TiO₂ and [Bmim]HSO₄-TiO₂, which were prepared by DBD plasma under atmospheric pressure using [Bmim]HSO₄ and HSO₄ as assistant respectively, showed that all the diffraction peaks were the same as the standard spectra of anatase TiO₂, and this indicated that HSO₄-TiO₂ and [Bmim]HSO₄-TiO₂ were pure anatase. However, The XRD spectra of[Bmim]BF₄-TiO₂, which were prepared by DBD plasma under atmospheric pressure using [Bmim]BF₄ as assistant, showed that the diffraction peaks at round 24.1° shifted to lower 2θ values, while the diffraction peaks at around 48.0° shifted toward higher 2θ values. The shift of the diffraction peak for [Bmim]BF₄-TiO₂ samples indicated that lattice imperfection was formed due to F doping. The fluorine atoms entered into the lattice of TiO₂, therefore breaking the equilibrium of original TiO₂ atoms and varying the inter planar crystal spacing of anatase TiO₂. This revealed that same of [Bmim]BF₄ were broken down in plasma. The formation of F doped TiO₂ photocatalyst also indirectly proved the instability of ionic liquid [Bmim]BF₄ in atmospheric pressure plasma, and this results were the same with the analysis of UV-Vis and ¹H NMR. The formation of F-doped TiO₂ photocatalytic materials also indirectly proved the instability of ionic liquid [Bmim]BF₄ in atmospheric pressure plasma, which was consistent with the results of NMR and UV-Vis. It was also proved that ionic liquids play an important role in the formation of pure anatase crystals and the promotion of highly reactive photocatalysis materials under the action of plasma. It provides an important experimental and theoretical basis for the preparation of high performance nano-materials by plasma-assisted ionic liquids.

Key words：Cold plasma; Ionic liquid; Dielectric barrier discharge; TiO₂ photocatalytic material

Received: 2018-03-30 Accepted: 2018-08-16

ZTFLH:

O531

Corresponding Authors: ZHANG Xiu-ling E-mail: xiulz@sina.com

Cite this article:

URL:

https://www.gpxygpfx.com/EN/10.3964/j.issn.1000-0593(2019)05-1372-05 OR https://www.gpxygpfx.com/EN/Y2019/V39/I05/1372