Electrochemical kinetics of Ag|Ag+ and TMPD|TMPD+ in the room-temperature ionic liquid [C4mpyrr][NTf2]; toward optimizing reference electrodes for voltammetry in RTILs
MetadataShow full item record
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.
Showing items related by title, author, creator and subject.
Achievement of prolonged oxygen detection in room-temperature ionic liquids on mechanically polished platinum screen-printed electrodesLee, Junqiao; Arrigan, Damien; Silvester, Debbie (2016)The demonstration of prolonged amperometric detection of oxygen in room-temperature ionic liquids (RTILs) was achieved by the use of mechanical polishing to activate platinum screen-printed electrodes (Pt-SPEs). The RTILs ...
Identification of surface heterogeneity effects in cyclic voltammograms derived from analysis of an individually Addressable Gold Array Electrode.Lee, C.; Tan, Yong-jun; Bond, A. (2008)Voltammetric behavior at gold electrodes in aqueous media is known to be strongly dependent on electrode polishing and history. In this study, an electrode array consisting of 100 nominally identical and individually ...
Pawlak, Marcin; Grygolowicz-Pawlak, Ewa; Bakker, Eric (2010)We report here on the synthesis of poly(vinyl chloride) (PVC) covalently modified with ferrocene groups (FcPVC) and the electrochemical behavior of the resulting polymeric membranes in view of designing all solid state ...