The possibility of conjugate electroreduction of carbon dioxide and hydrogen in the presence of 2,2'-bipyridine and its N -substituted salts in the presence of acids with different pKa values was studied. It was revealed how the strength of the acid affects the efficiency of the process; in particular, it was determined that the presence of methylsulfonic acid in the system promotes the conjugate formation of hydrogen and the reduction of carbon dioxide to formic acid. Probable mechanisms for the reactions occurring have been proposed.

The possibility of the coupled electrochemical reduction of carbon dioxide and hydrogen in the presence of 2,2'-bipyridine and its N -substituted salts in the presence of acids with different p K a values was studied. It was found that the strength of the acid affects the efficiency of the process; in particular, methylsulfonic acid promotes the coupled hydrogen formation and the reduction of carbon dioxide to formic acid. Plausible mechanisms of the reactions that occurred have been proposed.

The electrochemical properties and electrocatalytic activity of 1,3-dimethyl-2-phenyl-1 H -benzo[ d ]imidazolium-3 iodide ( I ), a representative of a new class of organic metal-free electrocatalysts, in the reaction of formation of molecular hydrogen, in the presence of acids of various strengths (methanesulfonic acid (CH 3 SO 3 H), perchloric acid (HClO 4 ), and trifluoroacetic acid (CF 3 COOH)) have been studied. It is shown that the efficiency of the electrocatalytic process strongly depends on p K a of the acids used. Using gas chromatography and preparative electrolysis at half-wave potentials, it was shown that molecular hydrogen formed with high Faraday yields in all cases. The behavior of the catalytic wave on the cyclic voltammogram (CV), at various ratios of acid and catalyst concentrations in the presence of all acids is typical for the process proceeding according to a homogeneous mechanism. The mechanism of the process was studied by the density functional method (DFT), and its main intermediates were identified. The protonation of electrochemically generated radicals at the C-2 carbon atom of compound I , with the formation of a C-protonated radical cation, was shown to be the key stage of the electrocatalytic hydrogen evolution reaction (HER).

A study is performed of the electrocatalytic properties of 4,4'-bipyridine in the presence of acids of different natures (HBF 4 , HClO 4 , TsOH, CF 3 COOH). It is shown that p K acids are a key factor influencing the mechanism of the reactions taking place. The obtained electrochemical and electrocatalytic data are used to investigate the main mechanisms of the electrocatalytic production of molecular hydrogen, depending on the p K of the relevant acids. The same data are employed to calculate their thermodynamic and kinetic parameters.

A study is performed of the electrocatalytic properties of 2,2'-bipyridine in the presence of acids of different natures (HBF 4 , HClO 4 , TsOH, CF 3 COOH) and the nature of the synergistic effect. It is shown that the p K a of the acids greatly affect the mechanism of the reactions that occur. Based on electrochemical and electrocatalytic data obtained via cyclic voltammetry and preparative potentiostatic electrolysis, main mechanisms of the electrocatalytic production of molecular hydrogen are proposed that depend on the nature of the acids. The thermodynamic and kinetic parameters of the considered systems are calculated.

The adsorption of fluoride ions by a composite material based on aluminum oxide and cellulose is studied in detail. Adsorption equilibrium constants K, parameter Г∞, and ΔG0ad are calculated from Langmuir adsorption isotherms. The sorption characteristics are determined along with the kinetics and mechanism of the processes. The high sorption ability of the composite material based on alumina and cellulose is compared to that of sorbents described earlier.

Sorption properties of a composite based on microcrystalline cellulose and nanosized aluminum oxide film immobilized on its surface in removal of fluoride ions from water are studied. The optimal thickness of the sorbent layer at which the maximum sorption of fluoride ions occurs is 50 nm. The effects of various parameters, such as the solution pH and sorption time, on sorption are studied. The kinetic parameters of sorption and the rate-controlling step of the process are determined. The ion exchange mechanism of fluoride ion sorption onto the prepared sorbent is confirmed by IR spectroscopy.

The possibility of 10-methyl-9-phenylacridine iodide usage as a photocatalyst in the process of molecular hydrogen evolution in various aprotic solvents has been shown. A possible process scheme has been suggested. The influence of the acid nature and its concentration on the efficiency of the photocatalytic process has been revealed. It has been shown that the highest amount of molecular hydrogen is formed in presence of acids with intermediate pK.

The electrochemical behavior of three alloys of different composition in the system Al65Cu25Fe10 –хCrх is studied by the potentiodynamic method in alkaline and neutral media as a function of the number of quasi-crystalline phases. The chromium-containing alloys characterized by the presence of the quasi-crystalline (decagonal and icosahedral) components demonstrate the highest stability. It is shown that as the solution pH increases, the corrosion stability of samples decreases.

2,5-Disubstituted 1,4-bis(4,5-diphenyl-1H-imidazol-2-yl)benzenes have been synthesized, and their electrochemical properties have been studied by cyclic voltammetry, in particular the effect of substituents on the redox characteristics has been examined. The reversible electrochemical redox transformation quinone–biradical of the title compounds occurs at positive potentials.

The electrochemical behavior of five alloys of variable compositions in the Al65Cu25Fe10–хCr х system in dependence on the number of QC phases in acidic and alkaline media has been investigated by the potentiodynamic method. It has been established that the samples’ corrosion stabilities increase along with the increase of the solution pH. Higher stability was manifested by alloys with a predominant quasi-crystalline (dexagonal and icosahedral) structural component.

Quasicrystalline Al–Cu–Fe–Cr alloys have been prepared by mechanical activation. The morphology of powder particles has been investigated after thermomechanical processing under various conditions. We have identified the sequence of phase transformations in the quaternary alloys in the stability region of quasicrystalline phases and optimized conditions for obtaining a maximum fraction of a decagonal state in powder materials.

Phase equilibria in the Al–Cu–Fe system alloyed with 5% Cr were studied. Based on the data of X-ray powder diffraction analysis, electron microscopy, and differential thermal analysis, the effect of temperature on i ⇔ d phase transitions in alloys Al 65 Cu 25 Fe 5 Cr 5 and Al 70 Cu 20 Fe 5 Cr 5 . In the Al–Cu–Fe–Cr system, multiphase structures were detected; these structures are mixtures of quasi-crystalline and approximant phases, the contents and morphologies of which depend on the composition of the initial mixture and the crystallization rate.