Hydrogen production in aromatic and aliphatic ionic liquids.
Surajdevprakash B Dhiman1, George S Goff, Wolfgang Runde
1Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, USA.
The Journal of Physical Chemistry. B
|May 17, 2013
Summary
Radiolysis of ionic liquids [N1114][Tf2N] and [emim][Tf2N] with different radiation types shows molecular hydrogen yields depend on particle track structure. Yields increased with protons and helium ions for [emim][Tf2N] but not [N1114][Tf2N].
Area of Science:
- Radiochemistry
- Materials Science
- Physical Chemistry
Background:
- Ionic liquids (ILs) are promising materials for various applications.
- Understanding their response to radiation is crucial for safety and performance.
- Molecular hydrogen is a key product in IL radiolysis.
Purpose of the Study:
- To investigate the radiolytic production of molecular hydrogen in two ILs: [N1114][Tf2N] and [emim][Tf2N].
- To determine the influence of particle track structure (gamma rays, protons, helium ions) on hydrogen yield.
- To assess the radiation stability of these ILs.
Main Methods:
- Irradiation of ILs with gamma rays, 2-10 MeV protons, and 5-20 MeV helium ions.
- Quantification of molecular hydrogen yields using gas chromatography.
- Analysis of IL degradation using FTIR and UV-vis spectroscopy.
Main Results:
- Molecular hydrogen is the dominant gaseous product in both ILs.
- Gamma ray radiolysis yields were 0.73 and 0.098 molecules/100 eV for [N1114][Tf2N] and [emim][Tf2N], respectively.
- Hydrogen yields increased significantly with protons and helium ions for [emim][Tf2N], but remained constant for [N1114][Tf2N].
- Slight degradation of ILs was observed via FTIR and UV-vis spectroscopy.
Conclusions:
- The yield of radiolytic hydrogen in ILs is dependent on the incident particle's track structure.
- [emim][Tf2N] shows a greater sensitivity to particle type compared to [N1114][Tf2N].
- These ILs exhibit some degree of radiation stability, though degradation occurs at higher energy depositions.
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