Shimou Chen

Unravelling the Role of the Compressed Gas on Melting Point of Liquid Confined in Nanospace

Phase behaviors of the liquids in nanospaces are of particular interest to understand the thermodynamics of the liquid on the nanoscale and for their applications that involve the confined systems. However, in many cases, the inconsistent observations of melting point variation for confined liquids are often revealed by different groups. Ionic liquids are a special kind of liquid. Here, by using the merits of the nonvolatile nature of ionic liquids, we realized the encapsulation of ionic liquids inside of mesopores silica oxide nanoparticles with a complete removal of compressed gas under high-vacuum condition; the completely confined ionic liquid formed a crystalline-like phase. It was found that compressed gas plays an important role in changing the melting point of the confined ionic liquid.

Structural Analysis of [ChCl]m[ZnCl2]n Ionic Liquid by X-ray Absorption Fine Structure Spectroscopy

The components and structures of ionic liquid ChCl-ZnCl(2) in different ChCl:ZnCl(2) ratios were investigated using XAFS (X-ray absorption fine structure) technique. The average coordination number and distance of Zn species at different x(ZnCl(2)) (mole fraction of ZnCl(2) when synthesizing) were calculated. It is shown that x(ZnCl(2)) has a regular influence on the coordination number of Zn species, due to the change of anion forms and structures in the ChCl-ZnCl(2) ionic liquid. The possible forms and structures of Zn species in the ionic liquids were analyzed according to the coordination number. XAFS and DSC (differential scanning calorimetry) analysis imply that besides ZnCl(3)(-) and Zn(2)Cl(5)(-) anions, the Cl-Zn-Cl ion pair is a main species in the ionic liquid at higher x(ZnCl(2)). This newly discovered Zn species has substantial influence on the properties of the ionic liquid. From the analysis of the coordination numbers and coordination distance, a new mechanism of interactions between Ch(+) cation and Cl-Zn-Cl ion pairs or Cl(-) is proposed.

Improvement of Radiation Resistance and an Estimate of Solvated Electron Yield of the Ionic Liquid [Bmim]Cl by the Addition of FeCl3

Abstract The radiation stability of the ionic liquid 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) was investigated after 60Co &ggr; irradiation at doses up to 600 kGy. Thermal and spectroscopic analysis revealed the formation of a small quantity of radiolytic products and an evident change in the physicochemical properties of the ionic liquid. The presence of anionic FeCl4− (up to 5 mol%), as measured by UV-vis absorption, differential scanning calorimetry, and Raman spectroscopy, significantly improved the radiation resistance of [Bmim]Cl. The increased resistance may be due to the capture of a solvated electron (esolv−) by FeCl4− to form FeCl42− and results in the radiation protection of the organic cation. The radiation yield of the reductive species (Fe(II)) was estimated to be 0.217 ± 0.010 µmol/J (2.09 ± 0.10/100 eV), which is considered close to the radiation yield of the solvated electrons of [Bmim]Cl.

Influence of FeCl3 on radiation stability of ionic liquid BmimCl

This study investigates the effect FeCl3 on the radiation stability of the ionic liquid, 1-butyl-3-methylimidazolium chloride (BmimCl) over a wide dose range of 0 to 1000 kGy under γ-ray radiation. The ionic liquid species, BmimFeCl4, was formed by adding FeCl3 into BmimCl. The results showed that the presence of FeCl4− significantly improved the radiation resistance of BmimCl, wherein the effect was more pronounced at higher FeCl4− content. Meanwhile, under irradiation, Fe(II) was generated from Fe(III), which was reduced by solvated electron. In addition, the concentration of Fe(II) increased with low level of absorbed dose, but leveled off at higher doses. Moreover, the radiation yield of the solvated electrons of BmimCl was further estimated at approximately 0.358±0.01 μmol/J in BmimCl-7 mol% FeCl3 system.

Current status of the SSRF project

The Shanghai Synchrotron Radiation Facility (SSRF) is an intermediate energy light source under design and R&D at Shanghai National Synchrotron Radiation Center (SSRC). It is based on a 3.5 GeV electron storage ring with a circumference of 396 m, a beam current of 200-300 mA and a beam emittance of 5-12 nm/spl middot/rad. Since its R&D began in 1999, the design of the SSRF has been evolved smoothly towards a cost-effective machine required by its future users, and the prototypes of its key components have been manufactured and tested up to the design specifications. This paper reviews the design and R&D progress of the SSRF project and presents its current status.