Electroreduction of Sulfur Dioxide in Some Room-Temperature Ionic Liquids
The mechanism of sulfur dioxide reduction at a platinum microelectrode was investigated by cyclic voltammetry in several room-temperature ionic liquids (RTILs)[C2mim][NTf2], [C4mim][BF4], [C4mim][NO3], [C4mim][PF6], and [C6mim][Cl] where [C2mim] is 1-ethyl-3-methylimidazolium, [C4mim] is 1-butyl-3-m...
| Main Authors: | , , , , |
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| Format: | Journal Article |
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American Chemical Society
2008
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| Online Access: | http://hdl.handle.net/20.500.11937/13904 |
| _version_ | 1848748473703202816 |
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| author | Barrosse-Antle, L. Silvester, Debbie Aldous, L. Hardacre, C. Compton, R. |
| author_facet | Barrosse-Antle, L. Silvester, Debbie Aldous, L. Hardacre, C. Compton, R. |
| author_sort | Barrosse-Antle, L. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | The mechanism of sulfur dioxide reduction at a platinum microelectrode was investigated by cyclic voltammetry in several room-temperature ionic liquids (RTILs)[C2mim][NTf2], [C4mim][BF4], [C4mim][NO3], [C4mim][PF6], and [C6mim][Cl] where [C2mim] is 1-ethyl-3-methylimidazolium, [C4mim] is 1-butyl-3-methylimidazolium, [C6mim] is 1-hexyl-3-methylimidazolium, and [NTf2] is bis(trifluoromethylsufonyl)imidewith special attention paid to [C4mim][NO3] because of the well-defined voltammetry, high solubility, and relatively low diffusion coefficient of SO2 obtained in that ionic liquid. A cathodic peak is observed in all RTILs between −2.0 and −1.0 V versus a silver quasi-reference electrode. In [C4mim][NO3], the peak appears at −1.0 V, and potential step chronoamperometry was used to determine that SO2 has a very high solubility of 3100 (±450) mM and a diffusion coefficient of 5.0 (±0.8) × 10-10 m2 s-1 in that ionic liquid. On the reverse wave, up to four anodic peaks are observed at ca. −0.4, −0.3, −0.2, and 0.2 V in [C4mim][NO3]. The cathodic wave is assigned to the reduction of SO2 to its radical anion, SO2-•. The peaks at −0.4 and −0.2 V are assigned to the oxidation of unsolvated and solvated SO2-•, respectively. The peak appearing at 0.2 V is assigned to the oxidation of either S2O42- or S2O4-•. The activation energy for the reduction of SO2 in [C4mim][NO3] was measured to be 10 (±2) kJ mol-1 using chronoamperometric data at different temperatures. The stabilizing interaction of the solvent with the reduced species SO2-• leads to a different mechanism than that observed in conventional aprotic solvents. The high sensitivity of the system to SO2 also suggests that [C4mim][NO3] may be a viable solvent in gas sensing applications. |
| first_indexed | 2025-11-14T07:05:36Z |
| format | Journal Article |
| id | curtin-20.500.11937-13904 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T07:05:36Z |
| publishDate | 2008 |
| publisher | American Chemical Society |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-139042018-03-29T09:06:09Z Electroreduction of Sulfur Dioxide in Some Room-Temperature Ionic Liquids Barrosse-Antle, L. Silvester, Debbie Aldous, L. Hardacre, C. Compton, R. The mechanism of sulfur dioxide reduction at a platinum microelectrode was investigated by cyclic voltammetry in several room-temperature ionic liquids (RTILs)[C2mim][NTf2], [C4mim][BF4], [C4mim][NO3], [C4mim][PF6], and [C6mim][Cl] where [C2mim] is 1-ethyl-3-methylimidazolium, [C4mim] is 1-butyl-3-methylimidazolium, [C6mim] is 1-hexyl-3-methylimidazolium, and [NTf2] is bis(trifluoromethylsufonyl)imidewith special attention paid to [C4mim][NO3] because of the well-defined voltammetry, high solubility, and relatively low diffusion coefficient of SO2 obtained in that ionic liquid. A cathodic peak is observed in all RTILs between −2.0 and −1.0 V versus a silver quasi-reference electrode. In [C4mim][NO3], the peak appears at −1.0 V, and potential step chronoamperometry was used to determine that SO2 has a very high solubility of 3100 (±450) mM and a diffusion coefficient of 5.0 (±0.8) × 10-10 m2 s-1 in that ionic liquid. On the reverse wave, up to four anodic peaks are observed at ca. −0.4, −0.3, −0.2, and 0.2 V in [C4mim][NO3]. The cathodic wave is assigned to the reduction of SO2 to its radical anion, SO2-•. The peaks at −0.4 and −0.2 V are assigned to the oxidation of unsolvated and solvated SO2-•, respectively. The peak appearing at 0.2 V is assigned to the oxidation of either S2O42- or S2O4-•. The activation energy for the reduction of SO2 in [C4mim][NO3] was measured to be 10 (±2) kJ mol-1 using chronoamperometric data at different temperatures. The stabilizing interaction of the solvent with the reduced species SO2-• leads to a different mechanism than that observed in conventional aprotic solvents. The high sensitivity of the system to SO2 also suggests that [C4mim][NO3] may be a viable solvent in gas sensing applications. 2008 Journal Article http://hdl.handle.net/20.500.11937/13904 10.1021/jp7109093 American Chemical Society restricted |
| spellingShingle | Barrosse-Antle, L. Silvester, Debbie Aldous, L. Hardacre, C. Compton, R. Electroreduction of Sulfur Dioxide in Some Room-Temperature Ionic Liquids |
| title | Electroreduction of Sulfur Dioxide in Some Room-Temperature Ionic Liquids |
| title_full | Electroreduction of Sulfur Dioxide in Some Room-Temperature Ionic Liquids |
| title_fullStr | Electroreduction of Sulfur Dioxide in Some Room-Temperature Ionic Liquids |
| title_full_unstemmed | Electroreduction of Sulfur Dioxide in Some Room-Temperature Ionic Liquids |
| title_short | Electroreduction of Sulfur Dioxide in Some Room-Temperature Ionic Liquids |
| title_sort | electroreduction of sulfur dioxide in some room-temperature ionic liquids |
| url | http://hdl.handle.net/20.500.11937/13904 |