An Electrochemical Study of the Oxidation of Hydrogen at Platinum Electrodes in Several Room Temperature Ionic Liquids
MetadataShow full item record
The electrochemical oxidation of dissolved hydrogen gas has been studied in a range of room-temperature ionic liquids (RTILs), namely [C2mim][NTf2], [C4mim][NTf2], [N6,2,2,2][NTf2], [P14,6,6,6][NTf2], [C4mpyrr]- [NTf2], [C4mim][BF4], [C4mim][PF6], [C4mim][OTf], and [C6mim]Cl on a platinum microdisk electrode of diameter 10 ím. In all cases, except [C6mim]Cl, a broad quasi-electrochemically reversible oxidation peak between 0.3 to 1.3 V vs Ag was seen prior to electrode activation ([C6mim]Cl showed an almost irreversible wave). When the electrode was pre-anodized (“activated”) at 2.0 V vs Ag for 1 min, the peak separations became smaller, and the peak shape became more electrochemically reversible. It is thought that the electrogenerated protons chemically combine with the anions (A-) of the RTIL. The appearance and position of the reverse (reduction) peak on the voltammograms is thought to depend on three factors: (1) the stability of the protonated anion, HA, (2) the position of equilibrium of the protonation reaction HA h H+ + A- , and (3) any follow-up chemistry, e.g., dissociation or reaction of the protonated anion, HA. This is discussed for the five different anions studied. The reduction of HNTf2 was also studied in two [NTf2]--based RTILs and was compared to the oxidation waves from hydrogen. The results have implications for the defining of pKa in RTIL media, for the development of suitable reference electrodes for use in RTILs, and in the possible amperometric sensing of H2 gas.
Showing items related by title, author, creator and subject.
Electrochemical Ammonia Gas Sensing in Nonaqueous Systems: A Comparison of Propylene Carbonate with Room Temperature Ionic LiquidsJi, X.; Banks, C.; Silvester, Debbie; Aldous, L.; Hardacre, C.; Compton, R. (2007)First, the direct and indirect electrochemical oxidation of ammonia has been studied by cyclic voltammetry at glassy carbon electrodes in propylene carbonate. In the case of the indirect oxidation of ammonia, its analytical ...
The electrochemical oxidation of hydrogen at activated platinum electrodes in room temperature ionic liquids as solventsSilvester, Debbie; Ward, K.; Aldous, L.; Hardacre, C.; Compton, R. (2008)The oxidation of hydrogen was studied at an activated platinum micro-electrode by cyclic voltammetry in the following ionic liquids: [C2mim][NTf2], [C4mim][NTf2], [N6,2,2,2][NTf2], [P14,6,6,6][NTf2], [C4mim][OTf], ...
Electrochemical reduction of benzoic acid and substituted benzoic acids in some room temperature ionic liquidsSilvester, Debbie; He, W.; Aldous, L.; Hardacre, C.; Compton, R. (2008)Using cyclic voltammetry, the electrochemical reduction of benzoic acid (BZA) has been studied at Pt and Au microelectrodes (10 and 2 μm diameter) in six room temperature ionic liquids (RTILs), namely [C2mim][NTf2], ...