scholarly journals Double Layer at the Pt(111)–Aqueous Electrolyte Interface: Potential of Zero Charge and Anomalous Gouy–Chapman Screening

2020 ◽  
Vol 59 (2) ◽  
pp. 711-715 ◽  
Author(s):  
Kasinath Ojha ◽  
Nakkiran Arulmozhi ◽  
Diana Aranzales ◽  
Marc T. M. Koper
Keyword(s):  
Double Layer ◽  
Aqueous Electrolyte ◽  
Potential Of Zero Charge ◽  
Electrolyte Interface ◽  
Zero Charge ◽  
Interface Potential

scholarly journals Hidden Assumption of Gouy-Chapman-Stern Model

2020 ◽  
Author(s):  
Chenkun Li ◽  
Jun Huang
Keyword(s):  
Double Layer ◽  
Potential Gradient ◽  
Frequency Dispersion ◽  
Diffuse Layer ◽  
Compact Layer ◽  
Potential Of Zero Charge ◽  
Electrolyte Interface ◽  
Zero Charge ◽  
Serial Connection ◽  
Zero Potential

Understanding the double layer at the electrode-electrolyte interface is a long-standing challenge in electrochemistry. The orthodox Gouy-Chapman-Stern (GCS) model and its many derivatives invariably picture the double layer as a serial connection of a compact layer and a diffuse layer. We unravel herein that the serial connection tacitly prescribes a zero potential gradient at the solution-side boundary, which is, rigorously speaking, invalid. The bearing of this problematic assumption is pinpointed by comparing the double-layer impedance, which is analytically solved at the potential of zero charge, derived from the original and amended GCS models. Specifically, in the amended GCS model, the capacitance of the compact layer now shows frequency dispersion. The deviation between the original and amended models is greater when the double layer is confined in narrower space.

scholarly journals Hidden Assumption of Gouy-Chapman-Stern Model

2020 ◽  
Author(s):  
Chenkun Li ◽  
Jun Huang
Keyword(s):  
Double Layer ◽  
Potential Gradient ◽  
Frequency Dispersion ◽  
Diffuse Layer ◽  
Compact Layer ◽  
Potential Of Zero Charge ◽  
Electrolyte Interface ◽  
Zero Charge ◽  
Serial Connection ◽  
Zero Potential

Understanding the double layer at the electrode-electrolyte interface is a long-standing challenge in electrochemistry. The orthodox Gouy-Chapman-Stern (GCS) model and its many derivatives invariably picture the double layer as a serial connection of a compact layer and a diffuse layer. We unravel herein that the serial connection tacitly prescribes a zero potential gradient at the solution-side boundary, which is, rigorously speaking, invalid. The bearing of this problematic assumption is pinpointed by comparing the double-layer impedance, which is analytically solved at the potential of zero charge, derived from the original and amended GCS models. Specifically, in the amended GCS model, the capacitance of the compact layer now shows frequency dispersion. The deviation between the original and amended models is greater when the double layer is confined in narrower space.

The electrical double-layer properties of the mica (muscovite)-aqueous electrolyte interface

1981 ◽  
Vol 34 (6) ◽  
pp. 1177 ◽  
Author(s):  
JS Lyons ◽  
DN Furlong ◽  
TW Healy
Keyword(s):  
Zeta Potential ◽  
Double Layer ◽  
Electrical Double Layer ◽  
Negative Charge ◽  
Aqueous Electrolyte ◽  
Streaming Potential ◽  
Electrolyte Interface ◽  
Muscovite Mica ◽  
Silica Alumina ◽  
Flow Apparatus

Electrophoresis and streaming potential data are reported for crushed and sheet muscovite mica respectively. For streaming potential measurements a newly designed radial flow apparatus was used. Measurements on crushed mica show that both aluminium and silicon leach out of the mica. Leached aluminium and silicon may readsorb to confer increased positive and negative charge respectively on the mica. Electrophoresis data indicate that leaching of aluminium occurs more rapidly than of silicon. Aging experiments on sheet mica show leaching effects to be much slower than on crushed mica. Streaming potential measurements on freshly cleaved mica sheets showed that (i) the zeta- potential depended strongly on electrolyte (KCl) concentration; (ii) the zeta-potential was relatively independent of pH and (iii) monovalent cations were adsorbed in the sequence H+ > Cs+ > K+ > Na+ > Li+, whilst Ca2+ adsorbed more strongly than K+. It is proposed that the structure of the electrical double layer at the mica/electrolyte interface results from the distribution of all ions between the diffuse layer, the Stern plane (hydrated) and more critically the lattice holes of the silica-alumina basal plane.

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