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Heterogeneous Electron-Transfer Rates for the Reduction of Viologen Derivatives at Platinum and Bismuth Electrodes in Acetonitrile

Lookup NU author(s): Dr Ben Horrocks



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim The standard heterogeneous rate constants for the reduction of a series of viologen derivatives with a range of inter-ring torsion angles were measured at Bi and Pt electrodes. The electrode potentials for the first one-electron reduction of the viologens vary from −684 mV to −1070 mV vs. Ag/0.01 m Ag+; this enabled a comparison of the behaviour of metallic (Pt) and semi-metallic (Bi) electrodes over a wide range of applied potentials. The differential capacitance (6.5 μF cm−2) of Bi/MeCN,TBAPF6 interfaces at the potential of zero charge (pzc=−0.60 V) is at least an order of magnitude greater than that calculated on the basis of the bulk Bi carrier density (3×1017 cm−3) and the differential capacitance (9.5 μF cm−2) of Pt/MeCN interfaces at their pzc (−0.43 V) is of the same order. The series of viologen derivatives exhibited simple one-electron redox behaviour and showed similar rate constants at Pt (1.8×10−4–1.6×10−3 cm s−1) and Bi electrodes (1.1×10−4–1.9×10−3 cm s−1) after application of the Frumkin correction. These results demonstrate that the density of states at the Bi surface is much higher than in bulk. Finally, the Frumkin-corrected standard rate constants were observed to be inversely correlated with the inter-ring torsion angle of the viologens.

Publication metadata

Author(s): Cook SK, Horrocks BR

Publication type: Article

Publication status: Published

Journal: ChemElectroChem

Year: 2017

Volume: 4

Issue: 2

Pages: 320-331

Print publication date: 01/02/2017

Online publication date: 24/10/2016

Acceptance date: 24/10/2016

Date deposited: 26/04/2017

ISSN (print): 2196-0216

Publisher: Wiley-VCH Verlag


DOI: 10.1002/celc.201600536

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