TY - JOUR
T1 - Potential-Modulated Ion Distributions in the Back-to-Back Electrical Double Layers at a Polarised Liquid|Liquid Interface Regulate the Kinetics of Interfacial Electron Transfer
AU - Gamero-Quijano, Alonso
AU - Manzanares, José A.
AU - Ghazvini, Seyed M.B.H.
AU - Low, Paul J.
AU - Scanlon, Micheál D.
N1 - Publisher Copyright:
© 2022 The Authors. ChemElectroChem published by Wiley-VCH GmbH.
PY - 2023/2/1
Y1 - 2023/2/1
N2 - Biphasic interfacial electron transfer (IET) reactions at polarisable liquid|liquid (L|L) interfaces underpin new approaches to electrosynthesis, redox electrocatalysis, bioelectrochemistry and artificial photosynthesis. Herein, using cyclic and alternating current voltammetry, we demonstrate that under certain experimental conditions, the biphasic 2-electron O2 reduction reaction can proceed by single-step IET between a reductant in the organic phase, decamethylferrocene, and interfacial protons in the presence of O2. Using this biphasic system, we demonstrate that the applied interfacial Galvani potential difference (Formula presented.) provides no direct driving force to realise a thermodynamically uphill biphasic IET reaction in the mixed solvent region. We show that the onset potential for a biphasic single-step IET reaction does not correlate with the thermodynamically predicted standard Galvani IET potential and is instead closely correlated with the potential of zero charge at a polarised L|L interface. We outline that the applied (Formula presented.) required to modulate the interfacial ion distributions, and thus kinetics of IET, must be optimised to ensure that the aqueous and organic redox species are present in substantial concentrations at the L|L interface simultaneously in order to react.
AB - Biphasic interfacial electron transfer (IET) reactions at polarisable liquid|liquid (L|L) interfaces underpin new approaches to electrosynthesis, redox electrocatalysis, bioelectrochemistry and artificial photosynthesis. Herein, using cyclic and alternating current voltammetry, we demonstrate that under certain experimental conditions, the biphasic 2-electron O2 reduction reaction can proceed by single-step IET between a reductant in the organic phase, decamethylferrocene, and interfacial protons in the presence of O2. Using this biphasic system, we demonstrate that the applied interfacial Galvani potential difference (Formula presented.) provides no direct driving force to realise a thermodynamically uphill biphasic IET reaction in the mixed solvent region. We show that the onset potential for a biphasic single-step IET reaction does not correlate with the thermodynamically predicted standard Galvani IET potential and is instead closely correlated with the potential of zero charge at a polarised L|L interface. We outline that the applied (Formula presented.) required to modulate the interfacial ion distributions, and thus kinetics of IET, must be optimised to ensure that the aqueous and organic redox species are present in substantial concentrations at the L|L interface simultaneously in order to react.
KW - interface between two immiscible electrolyte solutions (ITIES)
KW - interfacial electron transfer
KW - oxygen reduction reaction
KW - polarised liquid|liquid interface
KW - potential of zero charge (PZC)
UR - http://www.scopus.com/inward/record.url?scp=85144895559&partnerID=8YFLogxK
U2 - 10.1002/celc.202201042
DO - 10.1002/celc.202201042
M3 - Article
AN - SCOPUS:85144895559
SN - 2196-0216
VL - 10
SP - e202201042
JO - ChemElectroChem
JF - ChemElectroChem
IS - 3
M1 - e202201042
ER -