Influence of Mixed 6-Thioguanine-Nonionic Surfactant Adsorption Layers on Kinetics and Mechanism of Bi(III) Ion Electroreduction

Influence of mixed 2-thiocytosine–ionic surfactants adsorption layers on kinetics and mechanism of Bi(III) ions electro reduction: use of the nanostructured R-AgLAFE

The nanostructured cyclically refreshable liquid amalgam film silver-based electrode (R-AgLAFE) was applied to study of the Bi(III) electrode process in the presence of 2-thiocytosine and selected ionic surfactants. The application of voltammetrictechniques (SWV, CV, DC), as well as electrochemical impedance spectroscopy (EIS) allowed the determination of the kinetic which in turn, defined the 2-thiocytosine catalytic effect and also their correlation in the presence of surfactants. The presence of mixed 2-thiocytosine-CTAB and 2-thiocytosine-SDS adsorption layers affects the mechanism and kinetics of Bi(III) ions electro-reduction process in chlorate(VII). CTAB and SDS change the dynamics of the catalytic impact of 2-thiocytosine on Bi(III) ions electro reduction. In both cases, the Bi–(RS–Hg) complex plays a key role, as it is the 2-thiocytosine that dominates in the establishment of the adsorption equilibria of the studied mixed adsorption layers.

Electroreduction of Bi(III) ions in the aspect of expanding the “cap-pair” effect: the role of the nanosized active complexes

The paper discusses the electroreduction of Bi(III) ions in the aspect of expanding the “cap-pair” effect.

The “cap-pair” rule is associated with the acceleration of the electrode’s processes by organic substances. The interpretation of the “cap-pair” effect mechanism was expanded to include the effect of supporting electrolyte concentration on the acceleration process and the type of electrochemical active as well as used protonated organic substances. It has also been shown that the phenomena occurring at the electrode/solution interface can influence a change in the dynamics of the electrode’s process according to the “cap-pair” rule.

Nicotinamide as a Catalyst for Zn2+ Electroreduction in Acetate Buffer

The paper presents the catalytic influence of nicotinamide on Zn2+ electroreduction. Changes in differential capacitance curves of the double layer Hg/acetate buffer pH = 6.0 as well as changes in zero charge potential values indicate nicotinamide adsorption with the aromatic ring on the electrode surface. This adsorption is responsible for its catalytic influence on the kinetics of Zn2+ ion electroreduction from the acetate buffer solution. The effect is stronger with increasing nicotinamide concentration. It is confirmed by the following factors: the increase in standard electrode rate constants, the reduction in the distance between anode and cathodic peaks on CV voltamperograms, and the decrease in activation resistance associated with the electrode reaction for nicotinamide solutions relative to those obtained in the case of reference solution. A very high catalytic capacity of vitamin B3 on Zn2+ ion electroreduction kinetics from pH = 6.0 acetate buffer can be explained by the formation of an active complex on the surface of the mercury electrode: Zn2+ nicotinamide, which can be described as a bridge facilitating electron exchange.