Russian Journal of Electrochemistry最新文献

The ionic pairing of 1-butyl-3-methylimidazolium tetrachloroferrate [Bmim] [FeCl₄] magnetic ionic liquid in two plasticizers ethylene carbonate (EC), propylene carbonate (PC) separately and combination of (EC–PC) has been studied by ATR Infrared spectroscopy. Spectra were taken in the IR range 600 to 4000 cm^–1. For experimental analysis plasticizer concentration range of 0.5 to 2.0 mol was used. The interaction of [Bmim] with these plasticizers (EC, PC and EC + PC) modifies the Hydrogen bonding. The complex and broad bands in FTIR after interactions is an indication of ionic pairing.

The content of Bromhexine HCl in pharmaceutical formulation was determined using adsorptive stripping voltammetry with a glassy carbon electrode (GCE) modified by electrochemical reduced graphene oxide (ErGO/GCE). The results revealed that the electrochemical oxidation of bromhexine HCl on the ErGO/GCE electrode is an irreversible process and adsorptive on the surface of the electrode. The optimal conditions included Britton–Robinson buffer at pH 5.5, an accumulation potential of 0 V, an accumulation time of 60 s, a scan rate of 0.025 V/s, and a linear concentration range from 1 × 10^–8 to 5 × 10^–6 mol L^–1. The method demonstrated high sensitivity with a limit of detection (LOD) of 2.7 × 10^–9 mol L^–1 and a limit of quantification (LOQ) of 9 × 10^–9 mol L^–1. It exhibited good repeatability with a relative standard deviation (RSD) of less than 5%, and high accuracy with recovery values ranging from 96 to 105%. The method was successfully applied to the determination of Bromhexine HCl in pharmaceutical formulations.

The binding interactions of (E)-2,4-di-tert-butyl-6-(((4-phenoxyphenyl)imino)methyl)phenol (TBIP) with bovine serum albumin (BSA), human serum albumin (HSA), and calf thymus DNA (CT-DNA) were investigated using square-wave voltammetry (SWV) at pH 7.40, as well as molecular docking (MD) application. In addition, the physicochemical properties, pharmacokinetic characteristics, toxicity potencies and biological targets of TBIP were predicted by using pkCSM and Swiss Target Prediction online tools. The ADMET properties of TBIP were compared to those of other analogue Schiff bases ((E)-1-((4-phenoxyphenylimino)methyl)naphthalen-2-ol, abbreviated as PMNO, and (E)-1-[(2-phenoxyphenylimino)methyl]naphthalen-2-ol, abbreviated as 2-PPMN). According to the SWV results, the decreased cathodic peak current of TBIP in the presence of aforementioned bio-molecules (BMs) indicated that it interacts with them. Moreover, the electrochemical results showed that BSA has a higher binding constant in the comparison to HSA and DNA, respectively, and also reveal that TBIP forms biomolecular complexes in the molar ratio of 1 : 1. On the other hand, the binding constants of TBIP to these biomolecules were also evaluated according to those of the bio-molecule (BM) complexes of PMNO, 2-PPMN, doxorubicin (Dox) and ethidium (Et⁺). The MD outcomes suggest that both hydrophobic and π-cation interactions were formed in the interaction between TBIP and HSA while only the hydrophobic interactions contributed to stabilizing the TBIP–BSA complex. In addition, the MD analysis of TBIP with A-DNA compound showed the binding affinity (BA) of −7.4 kcal mol⁻¹ with two H-bonds and four π–π interactions when compared to B-DNA with BA of −7.9 kcal mol⁻¹ and one H-bond. Finally, MD results exhibited that TBIP is a minor groove binder and H-bond interactions have paramount effect in the stabilities for its complexes with A- and B-DNA, respectively. The order in the estimated BA values of these BMs with TBIP was observed as follows: BSA>HSA>B-DNA>A-DNA. The BA values of TBIP to A- and B-DNA were compared with well-known DNA intercalators such as Dox and Et⁺. TBIP exhibited lower BA values than Dox, though higher than Et⁺. Finally, the differences observed in albumin-binding in comparison to PMNO analogue with 2-naphthol moiety appear to be mostly related to the steric effects of the tertiary butyl groups.

Herein, a CC@Fe₃O₄ nanowire-modified carbon cloth composite was constructed to investigate the interfacial chemistries and catalytic features pertaining to lithium polysulfides. The carbon cloth sheathed by one-dimensional Fe₃O₄ nanowires provides abundant polar active sites as well as highly conductive electron pathways. The CC@Fe₃O₄ composite exhibits a suppressed shuttle effect of lithium polysulfides. Visual adsorption experiments and UV-visible spectroscopy confirm the strong chemical bonding between CC@Fe₃O₄ and lithium polysulfides. X-ray photoelectron spectroscopy reveals the formation of Fe–S and Li–O interfacial bonds, which stabilizes a dual-site chemical anchoring mechanism. The polysulfide redox kinetics, evaluated in symmetrical cells, demonstrate that Fe₃O₄ nanowires serve as efficient catalysts to accelerate the electrochemical conversion of sulfur species. Benefiting from these features, the composite delivers higher Li⁺ diffusion coefficients and lower charge-transfer resistance. These results verify that CC@Fe₃O₄ establishes a chemically regulated and catalytically active interface, enabling simultaneous immobilization and rapid conversion of lithium polysulfides. This work provides a mechanistic insight into polar metal-oxide nanowire hosts and offers guidance for the rational design of advanced sulfur cathodes for lithium-sulfur batteries.

The gas diffusion layer (GDL) is a representative porous medium governing coupled heat and mass transfer in proton exchange membrane fuel cells (PEMFCs), where the through-plane porosity distribution critically affects reactant transport, water migration, and thermal behavior. To clarify the regulation mechanisms of porosity gradients on multi-physical transport, a three-dimensional PEMFC model is established. Uniform, exponential-gradient, and linear-gradient cathode GDL structures are systematically compared in terms of mass transport, heat transfer and electrochemical coupling characteristics. The results reveal that through-plane porosity gradients reconstruct the spatial distribution of effective diffusion resistance, eventually redistributing oxygen transport, water vapor removal, liquid water accumulation, and heat dissipation within the porous medium. Compared with the uniform GDL, the linear-gradient structure mitigates oxygen concentration decay near the CL, suppresses local water accumulation, and reduces the through-plane temperature gradient, resulting in more uniform heat–mass coupling. In contrast, exponential gradients induce locally intensified resistance due to abrupt porosity variations, leading to constrained transport regulation. Unlike previous studies focusing mainly on porosity size or averaged performance, this work demonstrates that the continuity and smoothness of through-plane porosity gradients govern the redistribution of transport resistance and reaction intensity. These findings provide mechanistic guidance for designing gradient structured porous media in coupled heat and mass transfer systems.

Results of determination of the diffusion coefficient of the [Bi-EDTA]^– complex ion in aqueous electrolytes are shown. Two independent methods are compared, namely, the measurements of the limiting diffusion current on a rotating disk electrode and the analysis of transient processes within the framework of the chronoamperometric method. Considering an electrochemical system complicated by a high overpotential of metal nucleation on the glassy carbon electrode, the possibility of evaluating the diffusion coefficient from cyclic voltammetry data is assessed using the Cottrell equation for describing the descending branch of the voltammogram. The experimentally measured diffusion coefficient of the [Bi-EDTA]^– complex ion is found to be (3.8 ± 0.2) × 10⁻⁶ cm²/s. The obtained results are of significant importance for optimizing the electrodeposition conditions for bismuth-containing alloys and compounds with controlled stoichiometry from EDTA-based electrolytes.

In this study, the aim is to investigate the effect of various factors on wide temperature anode oxidation, which can save energy in anode oxidation process of aluminum alloy and determined the optimum anode oxidation process index. When the aluminum alloy 6061 is anodized in an electrolyte solution with oxalic acid and nickel salt added to the sulfuric acid solution, the surface characteristics of the samples anodized at 35°C are similar to those of the samples anodized by the present method at 20°C, so that the allowable temperature range of anode oxidation can be increased to 10°C and the energy consumed for cooling of the electrolyte during the anode oxidation can be significantly reduced.

Aqueous zinc-ion batteries (ZIBs) have attracted considerable attention due to their outstanding safety and cost-effectiveness; however, further exploration of cathode materials remains necessary. This study investigates the preparation of WO₃·0.33H₂O with various nanostructures through the hydrothermal method using different raw materials. WO₃·0.33H₂O synthesized with the structure-guiding agent dodecyl benzene sulfonic acid (DBSA) exhibits a snowflake spherical structure, facilitating the insertion and extraction of Zn²⁺. The initial specific discharge capacity reaches 76.455 mA h g^–1 at a current density of 50 mA g^–1, surpassing that of WO₃·0.33H₂O (57.715 mA h g^–1) prepared with nitric acid, despite both samples sharing identical crystal shapes. Following cycling at high current densities, both samples recover their initial levels of current density and exhibit similar capacity decay (only 2 mA h g^–1). Consequently, nanostructured WO₃·0.33H₂O demonstrates exceptional electrochemical performance, suggesting its potential application in aqueous zinc-ion batteries.

New results on the behavior of a mechanically renewable graphite electrode in dimethylformamide (DMF) solutions of a surface-inactive electrolyte (KPF₆) are obtained using cyclic voltammetry (CVA) and impedance methods and compared with the earlier results on the same electrode in aqueous and propylene carbonate (PC) solutions of analogous electrolytes. It is shown that the potential intervals of ideal polarizability on the graphite electrode in DMF and PC solutions are quite similar and substantially exceed the interval observed in aqueous solutions. A principal difference of the capacitance curves (С vs. Е dependences) measured on the graphite electrode from those observed on mercury and mercury-like metals is that in the potential region corresponding to the positive surface charges, the capacitance of the graphite electrode is much lower (by a factor of 1.5–2). This is attributed to manifestation of semiconductor properties of the graphite electrode. This conclusion fully agrees with the practically negligeable effect of the solvent nature on the semiconductor parameters (flat band potential and the number of charge carriers in the conduction band of the graphite electrode material under study) calculated using an original procedure proposed earlier for processing experimental data.

The electroreduction processes of azo (–N=N–) and nitro (–NO₂) moieties of 4-(4-diethylamino-phenylazo)-1-(4-nitrobenzyl)pyridinium bromide (DPB) in Britton–Robinson (B–R) buffers (pH 2.0–12.0) were studied via cyclic voltammetry (CV), square wave voltammetry (SWV), differential pulse polarography (DPP) and sampled direct current (or Tast) polarography (DCP). The polarograms of DPB monitored one cathodic peak/wave across the entire pH range, representing the simultaneous reduction together of ‒N=N– and –NO₂ groups. However, the voltammograms of DPB showed a second irreversible peak at a more negative value than that of its main irreversible signal owing to the possible reduction of the C−N⁺ center. The influences of pH, scan rate and frequency on both the potential and current values of the reduction signals of DPB were investigated. A plausible reduction mechanism of DPB is proposed and discussed in light of the observed electrochemical findings.