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The Solvent Effect on H2O2 Generation at Room Temperature Ionic Liquid|Water Interface |
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| Authors: | Dr Justyna Kalisz Dr Wojciech Nogala Dr Wojciech Adamiak Mateusz Gocyla Prof Hubert H Girault Prof Marcin Opallo |
| Institution: | 1. Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland;2. Laboratoire d'Electrochimie Physique et Amaytique, Ecole Polytechnique Federale de Lausanne, EPFL, Valais, Wallis, Rue d'Industrie 17, 1950 Sion, Switzerland |
| Abstract: | H2O2 is a versatile chemical and can be generated by the oxygen reduction reaction (ORR) in proton donor solution in molecular solvents or room temperature ionic liquids (IL). We investigated this reaction at interfaces formed by eleven hydrophobic ILs and acidic aqueous solution as a proton source with decamethylferrocene (DMFc) as an electron donor. H2O2 is generated in colorimetrically detectable amounts in biphasic systems formed by alkyl imidazolium hexafluorophosphate or tetraalkylammonium bis(trifluoromethylsulfonyl)imide ionic liquids. H2O2 fluxes were estimated close to liquid|liquid interface by scanning electrochemical microscopy (SECM). Contrary to the interfaces formed by hydrophobic electrolyte solution in a molecular solvent, H2O2 generation is followed by cation expulsion to the aqueous phase. Weak correlation between the H2O2 flux and the difference between DMFc/DMFc+ redox potential and 2 electron ORR standard potential indicates kinetic control of the reaction. |
| Keywords: | ORR decamethylferrocene oxygen reduction SECM ion transfer |