Influence of the Nature of the Alkali Metal Cations on the Electrical Double-Layer Capacitance of Model Pt(111) and Au(111) Electrodes

Batyr Garlyyev; Song Xue; Sebastian Watzele; Daniel Scieszka; Aliaksandr S Bandarenka

doi:10.1021/acs.jpclett.8b00610

Influence of the Nature of the Alkali Metal Cations on the Electrical Double-Layer Capacitance of Model Pt(111) and Au(111) Electrodes

J Phys Chem Lett. 2018 Apr 19;9(8):1927-1930. doi: 10.1021/acs.jpclett.8b00610. Epub 2018 Apr 3.

Authors

Batyr Garlyyev¹, Song Xue¹, Sebastian Watzele¹, Daniel Scieszka^{1

2}, Aliaksandr S Bandarenka^{1

2}

Affiliations

¹ Physik-Department ECS , Technische Universität München , James-Franck-Str. 1 , D-85748 Garching , Germany.
² Nanosystems Initiative Munich (NIM) , Schellingstraße 4 , 80799 Munich , Germany.

PMID: 29595987
DOI: 10.1021/acs.jpclett.8b00610

Abstract

Understanding the properties of the electrical double layer (EDL) is one of the interdisciplinary topics that plays a key role in the investigation of numerous natural and artificial systems. We present experimental evidence about the influence of the nature of the alkali metal cations on the EDL capacitance for two model electrodes, Pt(111) and Au(111), in 0.05 M AMClO₄ ( AM: Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺) electrolytes using impedance spectroscopy measurements. Our data show that counterintuitively the differential EDL capacitance of both electrodes measured close to their potentials of zero charge increased linearly in the presence of alkali metal cations as Li⁺ < Na⁺ < K⁺ < Rb⁺ < Cs⁺. We also estimated the effective concentrations of these cations at the EDL, which appeared ∼80 times higher than their bulk concentrations. We believe that these findings should be of importance for theoretical modeling of the EDL and better understanding and faster design of new functional systems for numerous applications.