Transfer coefficients and heterogeneous rate constants for cadmium(II) in various supporting electrolytes evaluated by phase-angle measurements with an a.c. polarograph

The mechanism of the Cd(II) reduction in 1 M fluoride, perchlorate and chloride solutions at the DME, a combined DC, AC admittance and demodulation study

“…The reduction of Cd(II) in perchlorate solutions has been studied several times with various methods [1,2,16]. So far, only standard rate constants (ksh) and overall transfer coefficients (et) have been reported.…”

“…As a result, there is available at present a large number of kinetic parameters, i.e. standard rate constants and transfer coefficients, obtained by different methods and in different laboratories [1,2]. Almost all of these data have been obtained on the supposition that the kinetics of the reduction obeys the Butler-Volmer equation.…”

Why halides enhance heterogeneous metal ion charge transfer reactions

“…We also model the desorption of Cd 2+ on Hg(111), but only in H 2 SO 4 and HCl, where rate data for Cd 0 /Cd 2+ is available. 12 Cd 2+ –anion complexes have been proposed as the adsorbing species on Hg electrodes in hydrohalic acids. 36,37 From Fig.…”

“…1. For example, heterogeneous charge transfer reactions including V 2+ /V 3+ , 5,6 Cr 2+ /Cr 3+ , 7,8 Fe 2+ /Fe 3+ , 9,10 and Eu 2+ /Eu 3+ , 11 and metal electrodeposition reactions, such as Cd 0 /Cd 2+ and Zn 0 /Zn 2+ , 12,13 show rate constants (k) that are up to 10 3 higher in the presence of chloride (Cl À ), bromide (Br À ), or iodide (I À ). Kinetic enhancement by halides is observed on many electrodes, including glassy carbon (GC), 14 Hg, 15 Au, 7,10 and Pt, 9,16 where the increase in k typically is the largest for I À , followed by Br À , and then Cl À .…”

On the selection of the most probable mechanism of the Cd(II) reduction at mercury from 1 M KF solution

“…Naturally, in the earlier literature the investigations were mainly focussed on the determination of the "classical" charge-transfer parameters ksh (standard heterogeneous rate constant) and a (cathodic transfer coefficient), either to compare the results obtained in different media [1], or to demonstrate the merits of a new method or technique [ 2--7]. Unfortunately, the data reported are often in serious disagreement, as can be seen in the well-known compilations of Tamamushi and Tanaka [ 8].…”