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Probing TCNQ‐mediated Metal Reduction Reactions at Liquid‐liquid Interface with SECM
Author(s) -
Nieminen Eemi,
Kazimova Nargiz,
Murtomäki Lasse
Publication year - 2020
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.201900571
Subject(s) - ities , scanning electrochemical microscopy , chemistry , metal , aqueous solution , electrolyte , aqueous two phase system , phase (matter) , electrochemistry , kinetics , analytical chemistry (journal) , stoichiometry , metal ions in aqueous solution , tetracyanoquinodimethane , electron transfer , ion , inorganic chemistry , electrode , molecule , cyclic voltammetry , organic chemistry , physics , quantum mechanics
Metal reduction at the interface between two immiscible electrolyte solutions (ITIES) has been studied with scanning electrochemical microscopy (SECM). Metal cations in the aqueous phase are reduced by 7,7,8,8‐tetracyanoquinodimethane anion (TCNQ − ) residing in the oil phase, methyl isobutyl ketone (MIBK). TCNQ − is formed at the SECM tip by reducing TCNQ, which results in a positive feedback loop between the tip and the ITIES when an electron is donated to a metal cation. The effect of the Galvani potential difference on the rate of the interfacial electron transfer was investigated, establishing the potential difference either by an additional substrate electrode in the aqueous phase or by an a common ion in both phases. It is shown that the Galvani potential difference as a driving force does enable TCNQ − mediated Cu 2+ reduction. Finite element method (FEM) simulations were run to provide information on the reaction kinetics and stoichiometry.