Differential capacity curves at adsorption of organic ions

Adsorption kinetics of tetrabutylammonium cations on Bi() plane

“…[8,9,[11][12][13][14]. There is a weak dependence of C s on f [15,16,70] The dependence of phase angle δ (δ = arctan(|Z''|/Z')) on logf has a minimum at f ≥ 2×10 3 Hz (Fig. 4 (a)) and the δ,logf-plots have very well exposed plateaus with |δ| ≤ 80° at f ≤ 200 Hz, characteristic of nearly pure capacitance behaviour (|δ| = -90°).…”

“…1) Refs. [9][10][11][12][13][14][15]20,21], R ad in parallel to CPE means that a very slow adsorption-desorption process (i.e. a partial transfer process [1][2][3][4][5]) of the base electrolyte ions is possible.…”

“…However, the very high R ad values (R ad ≥ 15000 Ω cm 2 ) indicate that this process is very slow on Bi( 1 01 ) plane [1][2][3][4][5] and therefore the co-adsorption of the base electrolyte ions with TBN + cations can be neglected to a first approximation. On the other hand, R ad in parallel to the double layer capacitance can also be traced back to a slow "true" heterogeneous charge transfer process not related to the adsorption-desorption process of the electrolyte ions [9,[11][12][13][14][15][16]. However, the very low current density (j) values and very weak dependence of j on electrode potential, as well as very high R ad values indicate the absence of quick "true"…”

“…As for other real Bi single crystal plane electrodes [1][2][3], the impedance measured for Bi( 1 01 ) in the double layer region (no Faradaic current) follows a power law, such as that for the CPE [1][2][3][4][5]15,16,[20][21][22][23][24][25][26][27], with a value of the fractional exponent α ≥ 0.96, and the phase angle observed for the Bi single crystal planes is between -86° and -88°. To a first approximation, the values of α slightly lower than 1.0 can be explained by the very weak geometric and energetic inhomogeneities of the electrode surface (mainly on the nanoscopic and atomic scale) [1][2][3][4][5][15][16][17][18][19][20][21][22][23][24][25][26][27].…”

“…To a first approximation, the values of α slightly lower than 1.0 can be explained by the very weak geometric and energetic inhomogeneities of the electrode surface (mainly on the nanoscopic and atomic scale) [1][2][3][4][5][15][16][17][18][19][20][21][22][23][24][25][26][27]. Another explanation for the capacitance dispersion (α ≤ 1.0)…”