Electrochemical kinetics of Ag|Ag+ and TMPD|TMPD+ in the room-temperature ionic liquid [C4mpyrr][NTf2]; toward optimizing reference electrodes for voltammetry in RTILs
The voltammetry and kinetics of the AgjAg+ system (commonly used as a reference electrode material in both protic/aprotic and RTIL solvents) was studied in the room-temperature ionic liquid N-butyl-Nmethylpyrrolidinium bis(trifluoromethylsulfonyl)imide, [C4mpyrr][NTf2] on a 10 ím diameter Pt electro...
| Main Authors: | , , , , , , , |
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| Format: | Journal Article |
| Published: |
American Chemical Society
2007
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| Online Access: | http://hdl.handle.net/20.500.11937/44524 |
| _version_ | 1848757026231943168 |
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| author | Rogers, E. Silvester, Debbie Ward Jones, S. Aldous, L. Hardacre, C. Russell, A. Davies, S. Compton, R. |
| author_facet | Rogers, E. Silvester, Debbie Ward Jones, S. Aldous, L. Hardacre, C. Russell, A. Davies, S. Compton, R. |
| author_sort | Rogers, E. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | The voltammetry and kinetics of the AgjAg+ system (commonly used as a reference electrode material in both protic/aprotic and RTIL solvents) was studied in the room-temperature ionic liquid N-butyl-Nmethylpyrrolidinium bis(trifluoromethylsulfonyl)imide, [C4mpyrr][NTf2] on a 10 ím diameter Pt electrode. For the three silver salts investigated (AgOTf, AgNTf2, and AgNO3, where OTf- ) trifluoromethanesulfonate, NTf2 - ) bis(trifluoromethylsulfonyl)imide, and NO3 - ) nitrate), the voltammetry gave rise to a redox couple characteristic of a “deposition/stripping” process at the platinum electrode surface. Using potential step chronoamperometry, the diffusion coefficients of AgOTf, AgNTf2, and AgNO3 were found to be 1.05, 1.17, and 5.00 10-11 m2 s-1. All three voltammograms were theoretically modeled to reveal surprisingly slow standard electrochemical rate constants, k0, of 2.0, 1.5, and 0.19 10-4 cm s-1 respectively for the Ag+jAg0 couple. As a potentially faster alternative to the AgjAg+ system, the voltammetry and kinetics of the TMPDjTMPD+¥ system (where TMPD ) N,N,N ¢,N¢-tetramethyl-p-phenylenediamine) was also studied, using neutral TMPD and two TMPD radical cation salts, with BF4 - and NTf2 - counter anions. Diffusion coefficients for TMPD, TMPD+¥BF4 -, and TMPD+¥NTf2 - were calculated to be 1.84, 1.35, and 1.43 10-11 m2 s-1 respectively, and a k0 value of 2.6-2.8 10-3 cm s-1 was obtained from theoretical fitting of the cyclic voltammetry. This number is an order of magnitude larger than that for the AgjAg+ system, allowing for the suggestion that the TMPDjTMPD+¥ system may be more suitable than the AgjAg+ system as a redox couple for use in reference electrodes for ionic liquids. |
| first_indexed | 2025-11-14T09:21:33Z |
| format | Journal Article |
| id | curtin-20.500.11937-44524 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T09:21:33Z |
| publishDate | 2007 |
| publisher | American Chemical Society |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-445242017-09-13T14:10:54Z Electrochemical kinetics of Ag|Ag+ and TMPD|TMPD+ in the room-temperature ionic liquid [C4mpyrr][NTf2]; toward optimizing reference electrodes for voltammetry in RTILs Rogers, E. Silvester, Debbie Ward Jones, S. Aldous, L. Hardacre, C. Russell, A. Davies, S. Compton, R. The voltammetry and kinetics of the AgjAg+ system (commonly used as a reference electrode material in both protic/aprotic and RTIL solvents) was studied in the room-temperature ionic liquid N-butyl-Nmethylpyrrolidinium bis(trifluoromethylsulfonyl)imide, [C4mpyrr][NTf2] on a 10 ím diameter Pt electrode. For the three silver salts investigated (AgOTf, AgNTf2, and AgNO3, where OTf- ) trifluoromethanesulfonate, NTf2 - ) bis(trifluoromethylsulfonyl)imide, and NO3 - ) nitrate), the voltammetry gave rise to a redox couple characteristic of a “deposition/stripping” process at the platinum electrode surface. Using potential step chronoamperometry, the diffusion coefficients of AgOTf, AgNTf2, and AgNO3 were found to be 1.05, 1.17, and 5.00 10-11 m2 s-1. All three voltammograms were theoretically modeled to reveal surprisingly slow standard electrochemical rate constants, k0, of 2.0, 1.5, and 0.19 10-4 cm s-1 respectively for the Ag+jAg0 couple. As a potentially faster alternative to the AgjAg+ system, the voltammetry and kinetics of the TMPDjTMPD+¥ system (where TMPD ) N,N,N ¢,N¢-tetramethyl-p-phenylenediamine) was also studied, using neutral TMPD and two TMPD radical cation salts, with BF4 - and NTf2 - counter anions. Diffusion coefficients for TMPD, TMPD+¥BF4 -, and TMPD+¥NTf2 - were calculated to be 1.84, 1.35, and 1.43 10-11 m2 s-1 respectively, and a k0 value of 2.6-2.8 10-3 cm s-1 was obtained from theoretical fitting of the cyclic voltammetry. This number is an order of magnitude larger than that for the AgjAg+ system, allowing for the suggestion that the TMPDjTMPD+¥ system may be more suitable than the AgjAg+ system as a redox couple for use in reference electrodes for ionic liquids. 2007 Journal Article http://hdl.handle.net/20.500.11937/44524 10.1021/jp0737754 American Chemical Society restricted |
| spellingShingle | Rogers, E. Silvester, Debbie Ward Jones, S. Aldous, L. Hardacre, C. Russell, A. Davies, S. Compton, R. Electrochemical kinetics of Ag|Ag+ and TMPD|TMPD+ in the room-temperature ionic liquid [C4mpyrr][NTf2]; toward optimizing reference electrodes for voltammetry in RTILs |
| title | Electrochemical kinetics of Ag|Ag+ and TMPD|TMPD+ in the room-temperature ionic liquid [C4mpyrr][NTf2]; toward optimizing reference electrodes for voltammetry in RTILs |
| title_full | Electrochemical kinetics of Ag|Ag+ and TMPD|TMPD+ in the room-temperature ionic liquid [C4mpyrr][NTf2]; toward optimizing reference electrodes for voltammetry in RTILs |
| title_fullStr | Electrochemical kinetics of Ag|Ag+ and TMPD|TMPD+ in the room-temperature ionic liquid [C4mpyrr][NTf2]; toward optimizing reference electrodes for voltammetry in RTILs |
| title_full_unstemmed | Electrochemical kinetics of Ag|Ag+ and TMPD|TMPD+ in the room-temperature ionic liquid [C4mpyrr][NTf2]; toward optimizing reference electrodes for voltammetry in RTILs |
| title_short | Electrochemical kinetics of Ag|Ag+ and TMPD|TMPD+ in the room-temperature ionic liquid [C4mpyrr][NTf2]; toward optimizing reference electrodes for voltammetry in RTILs |
| title_sort | electrochemical kinetics of ag|ag+ and tmpd|tmpd+ in the room-temperature ionic liquid [c4mpyrr][ntf2]; toward optimizing reference electrodes for voltammetry in rtils |
| url | http://hdl.handle.net/20.500.11937/44524 |