International Journal of Electrochemical Science最新文献

Gastrodia elata, a traditional Chinese medicinal herb, undergoes processing with ginger to enhance its therapeutic properties. This study investigated the impact of ginger processing on the quality control of G. elata using electrochemical fingerprint technology and high-performance liquid chromatography (HPLC). The electrochemical fingerprint conditions were optimized, and the fingerprints of raw and ginger-processed G. elata samples were compared. The HPLC analysis revealed significant changes in the contents of gastrodin, parishin A, and parishin B after processing. The electrochemical fingerprints exhibited distinct differences between raw and ginger-processed samples, with improved batch-to-batch consistency in the latter. Principal component analysis and hierarchical cluster analysis demonstrated the correlation between the electrochemical fingerprints and HPLC results. The findings highlight the potential of electrochemical fingerprint technology as a complementary tool to HPLC for the comprehensive quality assessment of G. elata. This study provides valuable insights into establishing standardized processing protocols and quality control strategies for G. elata, emphasizing the importance of combining multiple analytical techniques for ensuring the consistency, safety, and efficacy of herbal medicines.

Na₃(VOPO₄)₂F (NVOPF) has become one of the most promising cathodes of the large-scale application of sodium-ion batteries (SIBs) owning to its high working voltage and high discharging specific capacities properties. However, the immature synthetic routes, the tedious preparation process as well as high preparation cost restrict its promotion and application to some extent. In this work, the pure NVPOF was successfully prepared by liquid phase coordination chemistry combined with co-precipitation method based on theoretical speculation. The sodium storage performances are optimized by adjusting the key process parameters such as the pH value of solutions, the catalogue of pH regulators and the solution concentrations. When pH value of the solution is 4.50, oxovanadium sulfate solution concentration lies at c_[v] = 1.5 mol L⁻¹, the as-prepared NVPOF outperforms the optimal performances. The NVPOF cathode material synthesized under the optimized conditions boasts a perfect NASICON sodium-storage structure, spherical or quasi spherical morphology. In detail, the specific capacity is 110 mAh g⁻¹ at 0.1 C and the discharging voltage is 3.86 V. The first coulombic efficiency is 91.4 %, and the specific capacity decay from 97 mAh g⁻¹ to 87 mAh g⁻¹ with 91.3 % capacity retention after 300 cycles in the half-cell system. This large-scale co-precipitation synthesis of NVOPF will provide new guidance for the development and application of cathode materials for SIBs.

The inhibitive effect of lemon verbena (lemon v.) extract as a green corrosion inhibitor (CI) for mild steel (st37) in 0.5 M H₂SO₄ and 1 M HCl media at room temperature is investigated by employing electrochemical current noise (ECN), electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, and scanning electron microscopy (SEM). The achievements demonstrated that the inhibition efficiency increases with increasing the extract concentration up to 2000 ppm in 0.5 M H₂SO₄ and up to 2500 ppm in 1 M HCl solutions and decreases with an increase in temperature. The ECN results show when Lemon V. extract is included to both acidic media, the values of commotion charges (Q) diminished. The least value of the Q is 15 and 60 mCoul in H₂SO₄ and HCl media, respectively. The EIS measurements depicted that by addition of the inhibitors up to a certain concentration, the charge transfer resistance increases up to 186 Ω cm⁻² in H₂SO₄ and 350 Ω cm⁻² in HCl, besides the double layer capacitance (C_dl) decreases. Potentiodynamic polarization assessments indicated that Lemon V. acts as mixed type inhibitor. Certain thermodynamic parameters were determined based on the temperature impact on inhibition and corrosion processes. The extract adsorption on the surface of the alloy follow the Langmuir adsorption pattern. A mixed mode of adsorption was observed, wherein the extract in H₂SO₄ and HCl predominantly underwent chemisorption. Thermodynamic parameters indicated spontaneous adsorption and exothermic process with increasing entropy in H₂SO₄ and decreasing entropy in HCl. SEM investigation also validated the adsorption performance of the inhibitor.

Significant progress in the investigation of non-Newtonian Williamson and Casson boundary layer flow has led us to explore the extension of non-Newtonian Williamson and Casson hydromagnetic boundary layer flow in an electrically conductive fluid subjected to a strong magnetic field and a uniform thermal field. This study is divided into two interconnected parts. The first part converts the nonlinear system governing the Partial Differential Equations into a simpler, nonlinear, ordinary differential equation. It is then analyzed using the Akbari Ganji method (AGM). The output data from the first part, solved using AGM, is compared and evaluated with the output data from the second part, solved with the assistance of finite element (FEM) methods. This research validates previous works with current methodologies. Subsequently, changes in temperature and concentration parameters, influenced by variations in magnetic parameters, are obtained and analyzed through three-dimensional charts. Upon reviewing the results, it is observed that the distribution of concentration and temperature is dependent on the distribution of the magnetic parameter, with an increase in concentration and temperature being influenced by the rise in the magnetic parameter. Other parameters are also examined, each of which is elaborated upon below. The effects of Bi1, Sr, and Sc parameters on temperature are investigated, and design points for achieving optimal and effective design are presented in the graph. Some applications of magnetohydrodynamics and non-Newtonian fluids include improving fluid pumping technologies. Using magnetohydrodynamics in non-Newtonian fluid pumping systems can help improve efficiency and reduce energy costs. Additionally, enhancing the efficiency of heat transfer systems using magnetohydrodynamics can help improve efficiency and reduce energy losses in these systems.

With the increasing dependence on traditional energy sources, the demand for renewable energy sources, and the concern for environmental sustainability, clean energy sources such as tidal and wave energy have attracted much attention as renewable and stable forms of energy, The review focuses on the advancements and prospects of triboelectric nanogenerators (TENGs) for harvesting ocean energy. TENGs, known for their flexibility and adaptability in harsh marine environments, show promising potential for converting low-frequency oceanic kinetic energy into electrical energy. The paper examines various TENG configurations, including solid-solid and solid-liquid interfaces, and highlights innovations such as spherical, bionic, and hybrid structures that enhance energy conversion efficiency. Additionally, it discusses material modifications, including surface treatments and chemical doping, to improve TENG performance and durability. The review also addresses challenges such as corrosion resistance and low power output, emphasizing the need for ongoing research in material science and structural optimization. This comprehensive analysis provides a scientific foundation for the development of sustainable ocean energy technologies.

Water electrolysis serves as a crucial pathway for the generation of renewable hydrogen energy, with the oxygen evolution reaction (OER) demanding more energy compared to the hydrogen evolution reaction (HER). Consequently, we prepared cobalt-based selenide composite materials (CS/XC-Ni) through chemical doping and heterojunction construction. CS/XC-Ni demonstrated outstanding OER performance when exposed to alkaline electrolytes. Specifically, at a current density of 10 mA·cm⁻², the overpotential was 334 mV, and the overpotential at a current density of 50 mA·cm⁻² was 435 mV, with a Tafel slope of 94 mV·dec⁻¹. Density functional theory (DFT) calculations indicate that the introduction of Ni optimizes the catalyst's O adsorption capability, while the construction of heterogeneous interfaces reduces the energy barrier of the rate-determining step. This demonstrates the great potential of Co/XC-Ni in oxygen evolution, providing new insights for the design and synthesis of efficient oxygen evolution catalysts.

The corrosion inhibition process during acid pickling in petroleum industries often employs toxic chemicals, facing stringent environmental regulations. This study explores a sustainable alternative by investigating the inhibitory effects of eco-friendly food waste extracts, namely Prunus domestica seeds (P.S) and Okra stems (O.St), on B7 grade steel corrosion in 1.0 M HCl aqueous solution, simulating an acid pickling environment. The corrosion inhibition efficiency was estimated via both electrochemical methods, including electrochemical impedance spectroscopy and potentiodynamic polarization techniques, and chemical methods, such as weight loss measurements. Fourier transform infrared spectroscopy (FTIR) and Gas chromatography-mass spectrometry (GC-MS) elucidated the extracts' main functional groups and potential chemical constituents. Remarkably, both extracts exhibited a maximum inhibitory efficiency of up to 80 %. Adsorption isotherms were employed to analyze the inhibition mechanisms, including Langmuir and Flory–Huggins models, alongside the Kinetic-thermodynamic model. Activation parameters have been obtained using Arrhenius and transition state equations. The synthesis of the activated complex is characterized as an endothermic process, as evidenced by the positive values of enthalpy of activation (ΔH*). Conversely, negative entropy of activation (ΔS*) values indicate that the activated complex signifies a process of association rather than separation. Quantum chemical calculations identified potential active inhibitor compounds within the extracts. The quantum parameters, including ionization potential, electronegativity, softness, and hardness of the chemical constituents of the extracts, were calculated using DFT with the B3LYP/6–31 G(+) method. This study underscores the innovative approach of utilizing waste food extracts as corrosion inhibitors, addressing environmental concerns while offering practical implications for industrial applications.

ZIF-67 is a Co-based zeolitic imidazolate framework material with both redox metal active sites and organic functional groups. Single walled carbon nanohorns (SWCNHs) is a novel horn-shaped carbon nanomaterial with abundant carbon active sites and high conductivity. SWCNHs@ZIF-67 heterostructure composites were prepared by environmental-friendly method with ZIF-67 as core and SWCNHs as shell, then were fixed on the surface of glassy carbon electrode (GCE) to obtain the electrochemical sensing platform for detecting H₂O₂. The as-proposed sensor (SWCNHs@ZIF-67/GCE) demonstrates excellent electrocatalytic performance for the reduction of H₂O₂ with two linearity scopes (0.50–150 µM, 150–400 µM) and a low detection limit of 0.15 μM, which is attributed to the synergistic electrocatalytic effect between ZIF-67 and SWCNHs. The as-fabricated sensor was satisfactorily used for H₂O₂ analysis in plasma samples, revealing an immense potential application in vitro assay of H₂O₂.

In order to reveal the effect of fluoride ions (F⁻) on the passive film corrosion resistance and composition of CoCrMo dental prosthesis. The passivity of casting Vitallium 2000 CoCrMo series alloy was systematically studied by adopting electrochemical and surface techniques. The results show that F⁻ have a certain effect on the passive film corrosion resistance of casting CoCrMo in oral environment, and the increase of F⁻ concentration weakens the passive film corrosion resistance. With the increase of F⁻ concentration, the open circuit potential moves negatively, the corrosion current density increases, the polarization resistance decreases, and the defect density in the passive film increases. With the extension of immersion time, the corrosion resistance of alloy will be enhanced and shows: AS > AS + 0.5 wt% NaF > AS + 1 wt% NaF. The addition of F⁻ can decrease Co, Cr and Mo peaks sharply and promote the dissolution of the passive film. The result of present study could regulate and guide the application dose of oral fluorine-containing products.

Ion implantation is a versatile and green material surface modification technology that modifies the structure of target-neat surface by bombardment of non-metal or heavy metal ions. A new Au nanoparticle loaded ITO (AuNPs/ITO) electrodes was prepared by ion implantation and thermal annealing method in this work. The obtained nanoparticles were characterized by Scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and electrochemical methods. The direct electrocatalysis of Myoglobin (MB) was reported. It was found that after annealing at 500 °C for 2 h, the damage part of the implanted sample was eliminated. The surface coverage of MB on the MB/AuNPs/ITO electrode and the MB/annealed-AuNPs/ITO electrode was 4.35× 10⁻¹¹ mol·cm⁻² and 1.23 × 10⁻¹⁰ mol·cm⁻², respectively. The results show that this composite method can be used to fabricate an electrocatalytic biosensor.