Two-dimensional condensation in camphor-10-sulphonic acid films at the mercury/electrolyte interface

Abstract

The electrosorption properties of camphor-10-sulphonic acid (CS) in different electrolytes (Na2SO4, LiC104, KNO3, KCI, KBr, KJ) were investigated experimentally by ac polarographic measurements at different temperatures. Depending on the type of electrolyte and on the temperature, film condensation was observed. The Frumkin interaction coefficient, determined from the critical degree of coverage, does not depend linearly on the reciprocal temperature as would be the case in correspondence to the temperature dependence of the pit width. This contradiction does not occur if the interaction coefficient is determined from the critical degree of coverage using the lattice gas model. The temperature dependence of the pit width of the differential capacity-potential curves, found in the experiment, can be theoretically described by both these models. The interaction coefficient in the models is inversely proportional to the temperature. Furthermore, the parameters of the standard free energy of adsorption, the interaction energy, the interaction coefficient of the Frumkin isotherm, the adsorption coefficient, and the maximal surface concentration of CS in the film were estimated and compared.

Organic compound adsorption on Au(111): Simultaneous SHG/electrochemical studies

“…[14][15][16] The formation of a two-dimensional layer at mercury electrodes was first reported by Sathyanarayana et al, [17][18][19] who stated that the adsorption is diffusion controlled. 20 Detailed studies of the kinetics of camphor film formation have been conducted by Retter et al 1,[21][22][23][24][25] Camphor adsorption on single crystalline electrodes was reported for bismuth by Paltusova et al who described pronounced adsorption peaks for smooth (111) surfaces. 26,27 Recently, Striegler investigated in detail the adsorption of camphor at single crystalline gold electrodes in various electrolytes using cyclic voltammetry and differential capacity measure-DOI: 10.1039/b110958h…”

Two-dimensional condensation in camphor-10-sulphonic acid films at the mercury/electrolyte interface

“…Part I [1] dealt with the phenomenon of film condensation of camphor-10-sulphonic acid (CS) in different electrolytes and at various temperatures using capacitance measurements. The experimental results of these measurements were discussed by applying the so-called "lattice gas model" and the "Frumkin model".…”