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Том 54, № 7 (2018)
- Год: 2018
- Статей: 6
- URL: https://journals.rcsi.science/1023-1935/issue/view/11864
Article
Electrochemical and Opto-Electronic Properties of Carbazole-Based Derivatives with Symmetric A–CZ–A Architecture
Аннотация
In this work novel bisheterocyclic derivatives of alkylcarbazole with A–CZ–A architecture are investigated (CZ stands for alkylcarbazole). The study presents their opto-electronic and electrochemical properties which influence on the possibility of their prospective application. Monomers undergo electropolymerisation with formation of conducting layer of polythiophene derivatives, while presence of chalcone moiety hampers the process. Two-step oxidation processes of polymers results in generation of polaron and bipolaron types of charge carriers on the macromoleculs’ chains. The charge is delocalized over center and side subunits (bithiophene or bithiazole one) in first stage of oxidation. It is possible to influence on the properties of the polymers and their composition by variation of synthesis condition like solvent polarity and applied potential boundaries. Obtained conducting polymers show high stability under ambient conditions. Their energy gap values are estimated with electrochemical and spectroscopic methods.
567-584
Preparation and Supercapacitive Performance of Lead Dioxide Electrodes with Three-Dimensional Porous Structure
Аннотация
The three-dimensional porous structure PbO2 electrodes (3D-PbO2 electrodes) were prepared in the lead nitrate solution by potentiostatically electrodeposition method using oxygen bubble as dynamic template, which can be used as the positive materials of the supercapacitors. The morphology and structure of 3D-PbO2 electrodes were characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD). The supercapacitive performance of 3D-PbO2 electrodes were investigated by cyclic voltammetry (CV), galvanostatic charge-discharge tests (GCD) and electrochemical impedance spectroscopy (EIS). The specific capacitance of 3D-PbO2 electrodes can reach 195.6 F g–1 at 0.2 A g–1, which is 2.8 times higher than that of Flat-PbO2 electrodes (68.8 F g–1). The charge transfer resistance (Rct) of 3D-PbO2 electrodes (8.21 Ohm cm–2) is lower than that of Flat-PbO2 electrodes (21.32 Ohm cm–2). The excellent supercapacitive performance of 3D-PbO2 electrodes can be attributed to the three-dimensional porous structure, which can enlarge the active surface area of lead dioxide electrodes and promote the electrolyte diffusion and electrons propagation.
585-591
Anodic Oxidation of Serine Anion on Smooth and Platinized Platinum
Аннотация
The anodic oxidation of serine anion on smooth (Pt) and platinized (Pt(Pt)) platinum electrodes is studied by the methods of cyclic and linear voltammetry, rotating disk electrode, coulometry, and reflectance IR spectroscopy. On both electrodes, the potential regions of electrochemical transformation of this amino acid are determined. It is shown that electrooxidation of serine proceeds with abstraction of 4 and 2 electrons on Pt and Pt(Pt) electrodes, respectively. It is found that the anodic oxidation of serine anions proceeds from the adsorbed state; a possible kinetic scheme of this process is proposed.
592-597
Hydrogen Evolution on Catalytically Active Electrodeposited Ni–Re Alloy: Electrochemical Impedance Study
Аннотация
Hydrogen evolution reaction on the catalytically active Ni–Re alloy is studied by the method of electrochemical impedance. The alloy was fabricated by the electrodeposition from the ammonium—citrate solutions. The experiments were performed in the 0.1 M sodium hydroxide solution. Based on the analysis of equivalent circuits, it is found that the absorption of hydrogen atoms on the Ni–Re cathode is controlled by diffusion. The parameters of structural elements of equivalent electric circuits are calculated, and the effect of cathodic overpotential on these parameters is analyzed.
598-603
Short Communications
Time Dependence of Current during Potentiostatic Growth of Clusters in Diffusion Mode of Electrodeposition
Аннотация
The fundamentally new model describes the initial current transients during the growth of clusters in the diffusion mode after instantaneous nucleation. The specific feature of the model is that it is based on the initial hemispherical diffusion of ions from bulk solution to the surface of growing clusters rather than on the period of Cottrell current decay. The subsequent overlapping of diffusion zones is taken into account by multiplying the current by a factor smaller than unity. The factor is equal to the ratio of true diffusion volume to the “extended” volume, which is equal to the overall volume of all diffusion hemispheres ignoring their overlapping. The results calculated by the model appeared to be rather close to those obtained using the conventional Scharifker–Hills–Mostany model, and, thus, confirm the correctness of this model. In this connection, the reasons for its inconsistency with the experimental data on the number of growing clusters remain unclear.
604-607
Electroactive Composite Pd–Polypyrrole and Its Catalytic Properties in the Reaction of Styryl Bromide Cyanation
Аннотация
A composite material in the form of powder is synthesized by a redox reaction in mixed aqueous solution of Pd(NH3)4Cl2 + pyrrole. The composite consists of polypyrrole globules with palladium nanoparticles uniformly distributed inside the latter. Being applied as a film on the electrode surface, both components of this material exhibit redox activity. Palladium particles inside the composite exhibit catalytic properties in cyanation of styryl bromides, a reaction widely used in fine organic synthesis.
608-611