Russian Journal of Electrochemistry最新文献

The corrosion of low-carbon steel in 1 M HCl + 1 M H₃PO₄ solution containing Fe(III) salts is studied under conditions of natural and forced convection. In this environments, partial reactions of iron anodic ionization, H⁺ and Fe(III)-cation cathodic reduction on steel occur. The first two reactions pass under kinetic control; the last one is diffusion-controlled. A composition of 4.5 mM IFKhAN-92 + 0.5 mM KNCS + 200 mM urotropine is studied as a steel corrosion inhibitor in this environments. In the solutions under consideration, the three-component inhibitor slows down all partial reactions involving steel and, as a consequence, its corrosion, which is a result of the polymolecular protective layer formation on the metal surface. The empirical dependence of the steel corrosion rate on the flow intensity of such media is described by the linear equation k = k_st + λw^1/2, where k_st is the steel corrosion rate in a static medium, w is the rotation velocity of the propeller mixer creating the medium flow, λ is the empirical coefficient characterizing the rate of increase of steel corrosion increment. The presence of a three-component-inhibitor additive in acid solutions containing Fe(III) salts reduces the values of k_st and λ parameters significantly, indicating that it slows down the metal corrosion in both static and dynamic environments. The 1 M HCl + 1 M H₃PO₄ solution added with the studied three-component inhibiting composition is shown to be able using as a medium for cleaning low-carbon steel surfaces from mineral deposits, resistant to the Fe(III) salts’ accumulation.

The state-of-the-art in investigations in the field of cathode materials based on lithium–cobalt double phosphate for lithium-ion rechargeable batteries is surveyed. The specific features of the LiCoPO₄ crystal structure, the transfer rate of charge carriers, the main synthetic methods of preparation, and the electrochemical characteristics of LiCoPO₄-based cathodes such as discharge capacity, charge–discharge rate, and cyclability are considered. The electrochemical characteristics of lithium-ion batteries based on LiCoPO₄ can be considerably improved by using nanosized and composite materials, doping with different cations, and using electrolytes stable at high potentials. The average working potential of LiCoPO₄ is ~4.8 V vs. Li/Li⁺, the discharge capacity at 0.1 С approaches its theoretical value (167 mAh/g).

In marine and industrial environments, zinc-rich coatings based on cathodic protection properties are among the most widely used and recommended coatings for the protection of metal surfaces from corrosion. Nevertheless, there is a paucity of research examining the electrochemical characteristics of water-based inorganic zinc-rich coatings and solvent-based epoxy zinc-rich coatings. Therefore, this paper presents a comparative analysis of the electrochemical properties of a solvent-based epoxy zinc-rich coating and a water-based inorganic zinc-rich coating. The objective of this study was to systematically examine the anticorrosion properties of bothcoatings using the following methods: open circuit potential (OCP), low-frequency impedance modulus, and electrochemical impedance spectroscopy (EIS) curve. The experimental results demonstrated that both coatings offered effective cathodic protection to the metal substrate. Comparatively, the water-based inorganic zinc-rich coating displayed a superior cathodic protection effect, which is attributed to its loose and porous structure. The distribution of zinc powder during the coating preparation enhanced the filling of internal voids within the coating system, promoting electrical connectivity between the zinc powder and the metal substrate, as well as among the zinc particles themselves. This interaction increased the utilization efficiency of zinc powder within the coating, thereby improving its cathodic protection capabilities. These findings contribute to the theoretical understanding of the protective mechanisms of zinc-rich coatings.

In this study, carbon felt-supported PbO₂ (CF/PbO₂) anodes were modified via doping Ce, Bi and La. The incorporation of these metal dopants significantly refined the β-PbO₂ grain size, increased the oxygen evolution overpotential, and reduced the charge transfer resistance of CF/PbO₂ anodes. Among the modified anodes, the CF/La–PbO₂ anode exhibited superior electrocatalytic oxidation performance, achieving a p-nitrophenol (p-NP) degradation efficiency of exceeding 99% within 90 min of electrolysis. Even after 10 consecutive cycles, the CF/La–PbO₂ anode maintained excellent stability, with a p-NP efficiency over 96%. The results of quenching experiments and electrochemical characterizations revealed that the degradation behaviour of p-NP on the modified anodes was dominated by direct electron transfer, but not active species-mediated oxidation. Furthermore, GC–MS analysis identified several intermediates, and a plausible degradation pathway involving hydroxylation, ring cleavage, and mineralization was proposed. Overall, the incorporation of La, Ce, and Bi—particularly La—significantly enhanced both the electrocatalytic activity and stability of CF/PbO₂ anodes, showing their potential as promising anode material for treatment of organic pollutants.

Battery technology serves as the primary energy storage system in the modern world. The global market share of Li-ion batteries (LIBs) has rapidly increased due to the demand in day-to-day life, which has attracted the scientific community towards this research area. Polymer electrolytes (PEs) are a key component of LIBs, which are categorized into three types: solid polymer electrolytes (SPEs), gel polymer electrolytes (GPEs), and composite polymer electrolytes (CPEs). When these PEs are integrated into batteries with inorganic fillers, ionic liquid (IL), nanomaterials, and plasticizers, they enhance the electrochemical stability window, ionic conductivity, transport number, and mechanical robustness of PEs. The choice of PEs in batteries depends on the selection criteria of polymer host types, such as PEO, PVDF, PVA, PMMA, PVP, PAN, and chitosan, as well as metal salts, including LiClO₄, LiTFSI, LiPF₆, LiBF₄, and LiBOB, are discussed. This review presents a detailed study of SPEs, GPEs, and CPEs, examining their performance in terms of ionic conductivity and transport number, to improve the efficiency and safety of LIBs.

Electrooxidation of acetaldehyde (ethanal) in aqueous and ethanol alkaline solution on Pd-modified glassy carbon and silver electrode was studied. The suppression of alcohol oxidation in the presence of aldehyde in solution was shown. This effect was used to estimate the possibility of selective detection of aldehyde in the presence of alcohol. The ability of quantitative detection of acetaldehyde in 1, 4, and 12 M ethanol solutions was demonstrated, while the qualitative analysis remains impossible by the use of Pd catalyst due to its activity in ethanol oxidation reaction in blank solutions.

Developing highly efficient and robust catalysts as anode materials is crucial for improving the electrocatalytic degradation of dye wastewater, yet it remains a significant challenge. Here, a reduced graphene oxide-tin (rGO–Sn) nanocomposite was synthesised as an advanced anode material and applied to a low-cost electrode (graphite felt) through a dip-coating method. The physico-chemical and electrochemical analyses were performed to elucidate the properties and validate the successful synthesis of nanomaterials and modified electrodes. Benefitting from the incorporation of highly conductive rGO together with high oxygen evolution potential (OEP) of Sn, the rGO–Sn modified GF exhibits improved electrocatalytic properties by demonstrating lower charge transfer resistance, R_ct (4.601 Ω), higher specific capacitance (0.056 mF cm^–2) and OEP at 1.490 V when compared with unmodified graphite felt (38.664 Ω, 0.033 mF cm^–2 and 1.253 V). The improvement of electrochemical properties results in enhanced efficiency in electro-degradation performance, achieving a 92.44 ± 0.94% removal of the dye Congo red after 2 h of reaction in contrast to the 60.14 ± 0.71% removal by unmodified GF. Moreover, the enhanced mechanical strength contributed by rGO and the elevated oxidation resistance provided by Sn, which safeguards the underlying substrate, significantly prolongs the service lifetime of the modified GF to 6.8 h, as compared to the unmodified GF’s 1.2 h. This study opens up new avenues for improving the performance of low-cost electrodes through an easy coating method of rGO–Sn since cost is a major concern for the EO process.

So-called anode-free sodium batteries represent a very promising version of post-lithium era devices. The present brief review considers their principal features (both advantages and disadvantages). The main problems connected with their development are phenomena of dendrite formation and encapsulation. These problems could be solved via improvement of negative electrode current collectors (enhancing of their sodiophilicity), as well as the electrolytes’ optimization, in particular, for the development of high-quality solid electrolyte interphases (SEI).

The anodic formation of silver oxide in 0.1 M KOH deaerated alkaline solution at the alloys of the Ag–Pd system, including those with increased structural surface disorder due to its preliminary anodic modification in 0.01 M HNO₃ + 0.09 M KNO₃ deaerated solution is studied. The anodic modification includes silver selective dissolution at potentials below the critical value, hence, not causing destruction of the alloy structure. As a result of the anodic modification, the alloy surface is depleted in silver, but enriched with structural defects, primarily vacancies, which leads to an increase in surface roughness and in the free energy of the system as a whole. The oxide formed anodically on such a surface is expected to change a number of parameters, primarily related to its structure and electronic structure. In this paper, the electronic parameters of Ag(I) oxide are considered, namely, the type and concentration of its structural defects, as well as the flat-band potential. The work is aimed at the determining of the electronic parameters of Ag(I) oxide anodically formed in 0.1 M KOH on the Ag–Pd system alloys with an atomic fraction of palladium from 0.05 to 0.30 and different levels of structural ordering of the surface. The surface roughness was found to increase by a factor of 3–17 in the process of anodic modification, depending on the alloy initial bulk composition. With the increasing of palladium concentration, the particle sizes of the anodically formed Ag(I) oxide increased slightly, and the particle number decreased. The concentration of donor defects in the structure of the Ag(I) oxide and its flat-band potential increased with increasing both palladium bulk content in the alloy and its structural surface disorder.

The thermodynamic properties of a high-temperature (HT) modification of Ag₈SiSe₆ and solid solutions Ag₈Si_{1 – x}Sn_xSe₆ are studied using the EMF method with the solid Ag⁺-conducting electrolyte Ag₄RbI₅. Based on the EMF measurements of concentration cells such as

(left( {-} right){text{Ag}}left( {text{s}} right)left| {{text{A}}{{{text{g}}}_{{text{4}}}}{text{Rb}}{{{text{I}}}_{{text{5}}}}left( {text{s}} right)} right|left( {{text{Ag}{-}text{in alloy}}} right)left( + right),,,,,,,,,(1))

the linear equations for the temperature dependence of EMF are obtained in the temperature interval of 300–450 К and the partial thermodynamic functions of silver in alloys are calculated. Based on the data on solid-state equilibria in the system Ag–Si–Sn–Se, the equations for the potential-generating reactions responsible for these partial molar functions are obtained and the integral thermodynamic functions of formation and entropy are calculated for the HT-Ag₈SiSe₆ and solid solutions with a composition x = 0.2, 0.4, 0.6, and 0.8.