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卷 61, 编号 8 (2025)
Regular articles
ANHYDROUS HYDROGEN FLUORIDE AS A SOLVENT FOR ELECTROLYTES OF SUPERCAPACITORS OPERATING AT EXTREMELY LOW TEMPERATURES
摘要
In order to expand the range of electrolytes for low-temperature double-layer supercapacitors, the possibility of using a 2.5 M solution of PCl5 in anhydrous hydrogen fluoride as an electrolyte using electrodes made of activated carbon cloth CH-900-20 was investigated. It has been established that when the temperature decreases from +20 to –65°C, the specific capacity of activated carbon cloth in such an electrolyte decreases linearly from 225 to 200 F/g. Replacing PCl5 with P2O5 results in the appearance of water in the electrolyte due to neutralization and the appearance of a noticeable pseudo-capacitance at positive temperatures and a decrease in capacity at a temperature of –65°C.
Russian Journal of Electrochemistry. 2025;61(8):357-363
357-363
Специальный выпуск “Электрохимия на ХХII Менделеевском съезде общей и прикладной химии”, октябрь 2024 г., Сириус, РФ
DEVELOPMENT OF MAGNETRON PROTECTIVE COATINGS OF CHROMIUM NITRIDES AND CARBIDES ON TITANIUM BIPOLAR PLATES OF A FUEL CELL WITH A PROTON-EXCHANGE MEMBRANE
摘要
The article presents the results of a study of titanium bipolar plates of fuel cells with a proton-exchange membrane with functional coatings based on chromium nitride, carbide and carbonitride obtained by magnetron sputtering of a chromium target in argon plasma with different nitrogen and propane contents. The microstructure and morphology of pure CrN and CrС films on titanium and composite coatings of chromium carbonitride CrхNyСz were studied. It was shown that protective chromium carbide films obtained by adding propane to argon plasma exhibit increased contact surface resistance at the gas diffusion electrode-bipolar plate interface (CrС: ICR = 119.4 mOhm·cm2). However, for chromium carbonitride coatings this indicator is only 1.9 mOhm·cm2, which is lower than for pure CrС films and significantly lower than for uncoated titanium (Ti: ICR = 38.9 mOhm·cm2). This is an important indicator for using such bipolar plates in fuel cell power plants with high specific characteristics. Corrosion measurements performed using conventional techniques showed that the corrosion current for chromium carbonitride was less than 1 μA/cm2, which is better than uncoated titanium and pure CrN and CrC films.
Russian Journal of Electrochemistry. 2025;61(8):367-379
367-379
Ni–Co-BASED ELECTRODES FOR OXYGEN EVOLUTION REACTION IN ALKALINE WATER ELECTROLYSIS
摘要
An original method for producing Ni–Co electrodes is proposed in this paper. The electrochemical behavior of these electrodes was studied in an alkaline electrolysis cell. It was found that the obtained electrodes exhibit catalytic activity with respect to the oxygen evolution reaction, reducing the overvoltage of this process, for example, at high current densities and a temperature of 85°C by 390 mV compared to the Ni electrode. The advantage of the obtained electrodes is the absence of any coating on their surface that can peel off during operation, leading to irreversible degradation of the electrode. The studied Ni–Co electrodes were tested in 6 M KOH at a temperature of 85°C and a current density of 300 mA/cm2, i. e. under conditions as close as possible to operating conditions for alkaline electrolyzers for 500 hours. It was shown that after the tests, the electrode surface remained without visible signs of degradation such as cracking, delamination and other mechanical damage. At the same time, a small but irreversible increase in voltage is noted on the volt-ampere characteristics, which may indicate a decrease in the catalytic properties of the electrode surface.
Russian Journal of Electrochemistry. 2025;61(8):380-391
380-391
PROTECTIVE PROPERTIES OF ELECTROLITIC COATINGS BASED ON COBALT-MANGANESE SPINEL FOR SOLID OXIDE FUEL CELL INTERCONNECTS APPLICATION
摘要
Protective coatings based on cobalt-manganese spinel for solid oxide fuel cells (SOFC) interconnects made of stainless steel were obtained by non-stationary electrolysis. The main phase of the obtained coatings according to X-ray diffraction data is Co2MnO4. The evolution of the microstructure of the obtained coatings in the operating mode of the SOFC cathode chamber was studied. It was found that during the oxidation process, chromium and iron, which are components of the substrate, diffuse into the coating, oxidize, and the coating itself, after current life tests, is a mixture of Co2MnO4, Fe3O4 and Cr2O3 oxides. The study of the dependence of the area-specific resistant of the contact layer interconnect-cathode on the time spent under current load in the model conditions of the SOFC cathode chamber for 1000 hours on measuring assemblies at 850°C, under a current load of 0.5 A·cm–2, showed that the resistance is about 35 mOm⋅ cm–2.
Russian Journal of Electrochemistry. 2025;61(8):392-399
392-399
INVESTIGATION OF THE PROCESS OF ELECTROCATALYTIC STARCH OXIDATION IN AN ACIDIC ENVIRONMENT WITH OXIDANT REGENERATION IN SITU
摘要
The electrocatalytic oxidation of potato starch with potassium and sodium iodate in a two-chamber electrolytic cell with in situ oxidant regeneration on electrodes made of lead dioxide and glassy carbon in an acidic medium has been studied, depending on current density, substrate concentration, oxidant, and reaction temperature. The conditions for the production of oxidized starch, its dialdehyde (DAC), were determined: the electrolysis time was 120 min, the ultrasonic treatment time was 30 min, the substrate concentration was 13.3 g/l, the KIO3 oxidizer was 0.93 g/l, the current density was 25 mA/cm2, the carbonyl group content for PbO2 was 48% and for glassy carbon 56%. The products were identified by IR and NMR spectroscopy and X-ray diffractometry. It has been established that the temperature regime and ultrasound treatment of the initial starch have a significant effect on the periodate oxidation process. Analysis of the IR spectra shows that after electrochemical oxidation of starch, a new absorption band appears in the spectrum of the oxidized sample at 1730 cm–1, related to valence vibrations of the C=O bond of aldehydes. The kinetics of accumulation of starch oxidation products has been investigated. X-ray diffraction has shown a change in the ratio between the crystalline component amylose and starch amylopectin during periodate oxidation.
Russian Journal of Electrochemistry. 2025;61(8):400-413
400-413
EVALUATION OF ANTI-CORROSIVE EFFICIENCY OF OMEPRAZOLE BY ELECTROCHEMICAL METHODS
摘要
The release into the environment during disposal of unused and expired drugs, medical institution residues and waste, and pharmaceutical industry waste leads to its pollution and threat to public health. One of the methods for solving the problem of improper disposal of medicines is the possibility of using them as metal corrosion inhibitors. In this work, the anticorrosive protection of carbon steel in solutions of hydrochloric and sulfuric acids with the expired drug omeprazole was investigated using electrochemical methods. The studies were carried out using the methods of potentiodynamic polarization, electrochemical impedance spectroscopy and electrochemical diffusion technique. The concentration of omeprazole varied within 10–60 mg/L. According to polarization measurements, the protective effect of omeprazole at 40 mg/L reaches 84% in 1 M HCl solution and 92% in 0.5 M H2SO4 solution due to inhibition of both partial electrode reactions. According to impedance measurements, the protective effect values are 76% and 84%, respectively. The adsorption of omeprazole on steel, the surface coverage, and the subordination of adsorption to the Langmuir isotherm were estimated. The value of free energy of adsorption –ΔGoads was calculated. Using the electrochemical diffusion method, the diffusion of hydrogen released during corrosion into the metal and the inhibitory effect of omeprazole on this process were estimated.
Russian Journal of Electrochemistry. 2025;61(8):414-421
414-421
Special issue based on the reports at the 17th International Meeting “Fundamental and Applied Problems of Solid State Ionics” (Chernogolovka, June 16–23, 2024)
DIELECTRIC RELAXATION AND PROTON CONDUCTIVITY OF SUBSTITUTIONAL SOLID SOLUTIONS AND COMPOSITES BASED ON POLYANTIMONIC ACID CONTAINING NIOBIUM (5+) IONS2
摘要
The study is devoted to the synthesis of substitution solid solutions based on polyantimonic acid H2Sb2–xNbxO6∙nH2O, n ≥ 1, and composites H2Sb2–xNbxO6 ∙0.5yNb2O5∙nH2O, n ≥ 1, which have potential for use as components of low temperature fuel cell membranes. The samples were synthesised by the co-precipitation method. The dopant chosen was Nb5+ ions, which have a radius and electronegativity similar to those of Sb5+ ions. The elemental composition of the samples (Nb5+/Sb5+ ratio) was refined by X-ray fluorescence analysis and the limiting dopant concentration – H2Sb1.6Nb0.4O6∙nH2O, n ≥ 1 – was determined by X-ray phase analysis. Further increase of x leads to the formation of two-phase samples: substitution solid solutions with pyrochlore type structure and amorphous niobic acid. X-ray diffraction analysis using the Rietveld method was carried out on the substitution solid solutions, and the lattice parameter of the pyrochlore type structure was refined. The introduction of Nb5+ ions leads to an increase in the crystal lattice parameter for samples 0 < x ≤ 0.4. The analysis of the dielectric properties and the proton conductivity of the samples at a temperature of 25°C, relative humidity of 58% showed that the sample x = 0.6 has the best transport properties. The value of proton conductivity for the sample x = 0.6 is 11.5∙10–3 S/m, for polyantimonic acid and the limiting dopant concentration solid solution (x = 0.4) –7.2∙10–3 S/m and 5.0∙10–3 S/m respectively. When discussing the results, a possible mechanism of proton conductivity in the samples is given: correlated proton transport along a certain chain of hydrogen bonds through the channels of the pyrochlore structure and through the intergranular space where adsorbed water molecules and niobic acid particles are located.
Russian Journal of Electrochemistry. 2025;61(8):422-432
422-432