Russian Journal of Electrochemistry最新文献

A poly L-arginine/β-cyclodextrin molecularly imprinted polymer-modified graphite electrode (PL-Arg/β-CD MIPs/GE) was developed for sensitive acetaminophen detection. The sensor achieved a wide linear range of 0.1–200 μmol L^–1 and a low detection limit of 0.022 μmol L^–1, attributed to synergistic enrichment and electron transfer. It demonstrated excellent selectivity, reproducibility, and high recovery (98.20–102.80%) in real-sample analysis, showing great promise for practical drug monitoring applications.

Owing to the high specific surface area and adjustable pore size distribution, biomass-derived carbon nano-onions (CNOs) have lately aroused the interest of researchers in supercapacitor applications. Herein, we employ ajwain oil-derived, porous CNOs for supercapacitor applications. In this study, carbon nano-onions (CNOs) are synthesized through a simple, scalable, one-step “wick-and-oil” flame method followed by KOH activation. Microstructural analysis reveals monodisperse carbon nanoparticles with high porosity, attributed to the long-chain hydrocarbons and active components such as phenolic carvacrol and thymol present in ajwain oil, which contribute to high carbon yield and improved ion diffusion pathways. Electrochemical studies are performed using a three-electrode setup in 6 M KOH electrolyte. The CNO electrodes exhibits excellent charge transfer properties, achieving a specific capacitance of ~ 276.2 F g^–1 at 1 A g^–1. The charge storage mechanism has analyzed through surface- and diffusion-controlled contribution analysis. At lower scan rates, diffusion charge contribution is more dominant, whereas at higher scan rates, a significant surface charge contribution of 88.4% at 100 mV s^–1 demonstrated rapid electrochemical kinetics and superior rate capability. The surface-based charge contribution transformed into diffusion-based charge contribution when transiting from high scan rate to low scan rates. Thus, these findings highlight that analyzing surface and diffusion charge contributions provides valuable insights for optimizing and enhancing supercapacitor performance.

Hydrogen evolution catalysts based on sodium-pectate nickel carbonized complexes are developed. These catalysts are promising for use in water electrolyzers. The leading catalyst with the sodium ions’ 25%-substitution for nickel cations, carbonized to 280°C, is identified. The cathodic current density with this catalyst at a cell voltage of 2.5 V and temperature of 80°C equals 49% of that obtained with the commercial Pt20%/C cathode catalyst.

The work is devoted to the development and practical application of a surrogate model of electrochemical machining of the outer workpiece cylindrical surface using a tool-electrode with a partially insulated surface. The model earlier developed by the authors and the method of its numerical solution were used as the original mathematical model. The approximations of the results of numerical simulation of the primary distribution of current density were used. In contrast to the original mathematical model, which requires time-consuming calculations for each set of process parameters (the minimum interelectrode gap, the workpiece radius, the angle of active area of partially insulated tool electrode), the developed surrogate model enables performing all necessary calculations using the analytical dependences. The surrogate model enables more precise determining the rational modes of electrochemical machining, which provide the required compromise between the accuracy and productivity of the process, using significantly lower computational resources.

Acidithiobacillus thiooxidans is an extremophilic bacterium adapted to highly acidic, metal-rich environments. While its role in extracellular electron transfer (EET) has gained interest, the contribution of type IV pilins (T4P) remains poorly understood. In this study, we electrochemically characterized two recombinant pilins from A. thiooxidans, PilA (major) and PilV (minor), to explore their potential involvement in redox activity. Using a three-electrode electrochemical setup, PilV displayed a distinct anodic response at ~0.95 V with a peak current of ~75 µA, indicating high redox responsiveness. In contrast, PilA showed a broader oxidation range (0.55–1.1 V) and a weaker signal (~50 µA). These differences correlate with the surface accessibility of electroactive amino acids (EAAs), particularly tyrosine. Structural modeling revealed that while both pilins contain aromatic residues, in PilA they are partially buried within an α-helix, whereas in PilV they are more exposed in the globular domain. This spatial arrangement likely enhances PilV’s capacity for direct electron transfer. Altogether, our findings suggest that PilV’s structure is better suited for redox coupling with solid surfaces, supporting its potential role in EET and highlighting its relevance in future studies of microbial electron transport in extreme environments.

To address the challenge regarding nitrate pollution from agriculture and industry, we developed a novel integrated system featuring a bimetallic membrane electrode assembly (Pt|Nafion|Pt–Cu) coupled with a suspended Pd–Cu/activated carbon (AC) catalyst for the nitrate reduction reaction (NRR) in low-conductivity media. This design leverages a synergistic mechanism, combining electrochemical reduction and catalytic hydrogenation for enhanced efficiency. The system demonstrated exceptional performance, achieving a high observed rate constant (k_obs = 43.2 × 10⁻³ min⁻¹) alongside superior product selectivity; notably low nitrite accumulation (15.8%) and high ammonia yield (63.3%) during batch electrolysis. This performance underscores the effectiveness of utilizing in situ electro-generated hydrogen, activated by the Pd–Cu/AC catalyst, in conjunction with Cu-surface modification for efficient and selective nitrate removal. Furthermore, the structural and chemical robustness of the electrode assembly was confirmed through comprehensive characterization via scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and powder X-ray diffraction (PXRD) pre- and post-electrolysis. This work presents a promising, sustainable strategy for water remediation and the recovery of valuable nitrogen products.

The issue of high energy consumption in the industrial production of zinc electrodes has always been a significant concern, and the main focus of improvement is on the modification of the anode. Based on this, the study proposes to first epitaxially grow strong-binding and high-conductivity lead antimony alloy substrates α-PbO₂ transition layer on Pb–0.6% Sb alloy substrate to effectively prevent substrate passivation. By preparing a β-PbO₂ deposition surface layer doped with CNTs and ZrO₂ to further address the issues of substrate passivation and low anode electrocatalytic activity. Thus to form a new type of Pb–0.6% Sb/α-PbO₂/β-PbO₂–CNTs(ZrO₂) composite anode with better corrosion resistance, long service life, and high catalytic activity. Through testing, the composite anode demonstrated a low oxygen evolution overpotential of 579 mV and a low charge transfer resistance of 0.459 Ω, and demonstrated a current efficiency of 91.7% at a high current density of 500 A m⁻². Besides, the energy consumption for producing one–ton cathodic zinc was calculated as 2216.9 kW h. Therefore, the research provides strategies for the study of energy consumption in zinc electrowinning and other related applications.

A Schiff base compound, designated as L₃, was successfully synthesized and thoroughly analyzed through various characterization techniques, including Fourier-transform infrared (FT-IR) spectroscopy, and elemental composition analysis. Its corrosion inhibition properties for XC70 carbon steel in 1 M HCl solution were assessed using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) methods. The investigation examined the impact of both L₃ concentration and temperature on its performance. Results indicated a direct correlation between increased concentration and temperature and improved inhibition efficiency (IE%), which reached a maximum of 84% at 10^–4 M. PDP measurements revealed that L₃ functions as a mixed-type inhibitor, affecting both anodic and cathodic processes. EIS data demonstrated that rising L₃ concentrations enhanced the charge transfer resistance (R_ct) from 104.3 to 251.2 Ω cm², while reducing the double-layer capacitance (C_dl) from 108.6 to 63.64 µF cm^–2, suggesting strong inhibitor adsorption at the metal-solution interface. Thermodynamic parameters such as (Delta G_{{{text{ads}}}}^{^circ }) , ΔH_a, E_a, and ΔS_a were calculated to clarify the inhibition mechanism, indicating that L₃ adsorption occurs via chemisorption. Furthermore, the adsorption behavior followed the Langmuir isotherm model. Finally, quantum chemical analyses were carried out to interpret how the electronic structure of L₃ influences its corrosion inhibition performance.

The effect of components of the Ru(NH₃)₆Cl₃/Ru(NH₃)₆Cl₂ redox-pair on the dynamics of octanethiol monolayer formation on gold from aqueous thiol-containing solutions in 0.1 M NaClO₄ is studied by cyclic voltammetry. In this work, the method for assessing the adsorption activity of the components of the [Ru(NH₃)₆]^3+/2+ redox-pair by the octanethiol dense monolayers on gold formation time was used. The introduction of the redox pair components into a thiol-containing solution is shown to lead to an increase in the formation time of octanethiol-monolayer insulating films and to the less stable monolayers’ formation. The inhibitory effect of hexaamineruthenium(II)/(III) ions decreased with increasing of octanethiol concentration in the solution. A difference in the adsorption activity of the ions composing the [Ru(NH₃)₆]^3+/2+ redox-pair on gold in the presence of octanethiol is found: [Ru(NH₃)₆]³⁺ ions are better adsorbed than [Ru(NH₃)₆]²⁺ ones. A comparative assessment of the adsorption activity of two redox-pairs—[Ru(NH₃)₆]^3+/2+ and ({text{Fe(CN}})_{6}^{{{{3 - } mathord{left/ {vphantom {{3 - } {4 - }}} right. kern-0em} {4 - }}}})—is performed. It was shown that a typical redox pair [Ru(NH₃)₆]^3+/2+, in contrast to the redox pair ({text{Fe(CN}})_{6}^{{{{3 - } mathord{left/ {vphantom {{3 - } {4 - }}} right. kern-0em} {4 - }}}}), can be considered a test one, since the ions of this system are weakly adsorbed on the gold surface and make but insignificant impact on the thiol monolayer self-assembling process. The octanethiol and the hexaamineruthenium(II)/(III) and ferro-ferricyanide ions can be ranged, according to their adsorption activity on the gold electrode, as follows: octanethiol > [Fe(CN)₆]^3– ≈ [Fe(CN)₆]^4– ( gg ) [Ru(NH₃)₆]³⁺ > [Ru(NH₃)₆]²⁺.

In this study, a simple and inexpensive hydrothermal method was used to synthesize Ga₂O₃, Ga₂O₃/N-doping Carbon (N–C), and Ga₂O₃/N–C/rGO composites. Various characterization techniques were used, including XRD, FESEM, UV-Vis, FTIR, and electrochemical characterization, including CV and EIS. XRD showed the formation of cubic phases of gallium oxide. FESEM showed a spherical structure for these composites. The UV-Vis results show that the optical absorption decreases with N-doping Carbon of Ga₂O₃ and the optical absorption further decreases with rGO doping of Ga₂O₃/N–C. The FTIR results indicate the formation of the desired structures. CV results are consistent with the redox reactions performed. The impedance test shows that the resistance of the Ga₂O₃ sample decreases with N–C doping and the resistance of the Ga₂O₃/N–C sample also decreases with rGO doping. Ga₂O₃/N–C and Ga₂O₃/N–C/rGO exhibited a capacity of 593.2 and 734.1 mA h g^–1, respectively. These findings suggest that these composites are appropriate options for implementation as anodes in lithium-ion batteries.