Liquid/liquid interfacial potential influence on electrocatalysis at electrodes modified by an organic phase

ANYL 18

Maurice L'Her, maurice.lher@univ-brest.fr1, Catherine Elleouet1, François Quentel1, Mickäel Rimboud Rimboud1, Evangéline Njanja2, and Achille Nassi2. (1) Department of Chemistry, CNRS UMR 6521, Université de Bretagne Occidentale, France, C.S. 93837, 29238 Brest cedex, France, (2) Department of Chemistry, Université de Yaoundé I, Yaoundé, Cameroon
Solid electrodes modified by an organic phase (polymer, ionic liquid, organic solvent layer) immiscible with water and containing a redox compound, Mo, are often used for the oxidation or reduction of substrates dissolved in aqueous media, in devices for electrosynthesis or electroanalytical purposes. The interfacial potential across the liquid/liquid interface plays a leading role and can be shifted by 0.8 V, using different electrolytes, corresponding to a 77 kJ tremendous change in the electrode reaction Gibbs energy. This will be illustrated by voltammetry of a LuIIIbisphthalocyanine in a thin film of nitrobenzene deposited on a graphite electrode, in the presence of various electrolytes in the organic and aqueous phases. The important influence of the interfacial potential on electrocatalytic processes will be illustrated by the spectacular shifts of the two redox potentials of the bisphthalocyanine and the resulting modification of the catalytic reactions with the aqueous ferri- and ferrocyanide ions.