Electrochemical science advances最新文献

In this work, new plasticized solid polymer electrolytes (SPEs) are developed using MC (methylcellulose) as a polymer host, and sodium iodide (NaI) as a dopant via the solution casting method. Ethyl carbonate (EC) is used as a plasticizing agent to improve the properties of the SPEs. Polarized optical microscopy analysis reveals that the surface morphology of the MC-NaI-EC films contained porous amorphous regions owing to the presence of EC. The complex formation between MC, NaI, and EC is confirmed by Fourier-transform infrared spectra. The addition of EC in the MC-NaI polymer salt matrix enhances the electrochemical properties of the prepared films. The highest ionic conductivity of 5.06×10⁻³ S/cm is achieved for the composition: MC+50 wt. % NaI +10 wt. % EC. The linear sweep voltammetry test reveals that the optimal plasticized-SPE can withstand up to 2.5 V. The ionic transference number analysis reveals that 99% of ions contribute to the total conductivity. The optimized SPE film and graphene oxide-based electrodes are used to manufacture a solid-state electrical double-layer capacitor. The coulomb efficiency of the supercapacitor cell is 100%, and the specific capacitance of the supercapacitor is found to be 18.56 F/g utilizing impedance data at low frequency.

In this study, glucose oxidase (GOx) was immobilized on the electrode surface by layer-by-layer and gel membrane technique and characterized the GOx immobilized film morphology, H₂O₂ permeability, and glucose response. Concanavalin A (Con A)-GOx multilayer electrodes showed higher glucose-related current response than GOx-bovine serum albumin gel membrane-coated electrode, a common modification method. The thin thickness of the Con A/GOx multilayer film efficiently catalyzed the enzymatic reaction, and H₂O₂ was produced near the electrode surface, resulting in an immediate electrode response.

A model for performance of an axially symmetric pore with the curved generatrix is developed. Oxygen transport along the pore axis and in the radial direction through a thin ionomer film separating the pore volume from the Pt/C surface is taken into account. A performance functional is formulated, and the Euler–Lagrange equation is solved numerically for an optimal pore shape. This shape is close to a cubic paraboloid converging toward the membrane. Polarization curves show superior performance of the optimal pore over the cylindrical pore of the same active (side) surface area. The results suggest the shape of optimal ionomer loading for low-Pt electrodes.

William Robert Grove was a British scientist, who developed a “gas voltaic battery” which was the forerunner of modern fuel cells. Thus, Grove is known as the “Father of the Fuel Cell”.

In his early study, Grove invented a novel electric cell (battery) named after him the Grove cell. This new kind of battery included zinc and platinum electrodes (operating as the anode and cathode, respectively) immersed in an acidic solution and separated with a porous ceramic membrane. This battery was demonstrated in 1839 at the Académie des Sciences meeting in Paris.

Later, in 1842, Grove invented the first fuel cell (named by him “gas voltaic battery”). This cell produced electrical energy by combining hydrogen and oxygen to water at separated electrodes in the process opposite to the water electrolysis. The first fuel cell prototype opened a new research and engineering area leading to modern fuel cells used in many practically important applications. It is interesting to note that the practical importance of fuel cells was not recognized at the beginning. Particularly, the Nobel Prize winner Wilhelm Ostwald described the Grove's gas battery in his famous book “Electrochemistry: History and Theory”, published in 1896, as “of no practical importance but quite significant for its theoretical interest.” The practical importance of the fuel cells was recognized later (Figure 1).

Acknowledging his scientific achievements Grove was knighted in 1872.

This article is part of a series featuring historic contributions in and around electrochemistry. At least one such article appears in every issue of Electrochemical Science Advances.

The author declares no conflict of interest.

Dionýz Ilkovič (Figure 1) was a Czechoslovak physicist and physical chemist. He made fundamental contributions to the theoretical background of polarography and electroanalytical chemistry in general.

Polarography is the first electroanalytical technique that performs a voltammetric study with a mercury-dropping electrode (Figure 2A). This technique was invented in 1922 by Czech physical chemist Jaroslav Heyrovský, who received the Nobel prize in 1959 for the polarography invention and its application to numerous electroanalytical studies. The polarography made the background for different electroanalytical methods, particularly cyclic voltammetry, and other modern voltammetric techniques.

The Ilkovic equation was highly important for the quantitative analysis of the polarographic measurements.

The author declares no conflict of interest.

Dear Editor,

From energy storage and conversion devices to electroplating and corrosion control, electrochemistry is all around us and continues to evolve, pushing boundaries and exploring new frontiers. One such exciting avenue is the exploration of electrochemistry in non-conventional electrolytes, which is the topic of this Special Collection containing five excellent contributions from the groups of Bingwei Mao and Jiawei Yang, Björn Braunschweig, Paramaconi Rodríguez, Ludwig Kibler, and Kenta Motobayashi.

Aqueous electrolytes have been the preferred, and remain the most frequent, choice for electrochemical systems, due to the ubiquity and ease of handling of water. However, attention is increasingly turning to non-conventional electrolytes, which include ionic liquids, deep eutectic solvents, organic solvents, molten salts, and solid electrolytes. They all present unique opportunities but also challenge our current understanding of the structure of electrode-electrolyte interfaces and how it affects electrochemical processes.

This special collection aims to highlight recent advancements, novel insights, and emerging trends in electrochemistry conducted using non-conventional electrolytes. The articles included herein provide a comprehensive overview of recent advances in our fundamental understanding of this rapidly evolving field. The contributions cover the structure of the electrode-electrolyte interface in ionic liquids and deep eutectics, as well as other non-conventional electrolytes (organic solvents, solid electrolytes, and brines), and applications like CO₂ reduction and cathodic corrosion.

The applications of non-conventional electrolytes are far-reaching. Energy storage devices have experienced significant advancements through the exploration of alternative electrolyte systems. In fact, lithium-ion batteries and other advanced batteries and supercapacitors require the use of non-aqueous solvents. The investigation of electrochemical processes at the nanoscale in non-aqueous environments has also opened up new avenues for catalysis and sensor development. Furthermore, the field of electrochemical synthesis has been revolutionized by the use of non-conventional electrolytes, enabling the synthesis of complex organic compounds and the development of sustainable chemical processes. The articles compiled in this special collection provide valuable insights into the fundamental principles governing electrochemical phenomena in these systems and pave the way for future breakthroughs and applications. We hope that they will serve as a valuable resource for scientists, engineers, and students interested in this fascinating field.

We would like to close this Editorial by expressing our heartfelt gratitude to all the authors for their exceptional contributions and to the reviewers for their meticulous evaluation and constructive feedback. Their expertise and dedication have ensured the quality and

Using bipolar electrochemistry, carbon paper (CP) is asymmetrically coated with copper metal. Subsequent anodic electrodissolution in a solution containing trimesic acid linkers results in HKUST-1 depositing on the carbon surface. The CP-MOF (metal organic framework) composite is then soaked in a pyrrole/isopropanol solution for several hours before undergoing oxygen/Cu-induced polymerization to fill the pores. Variations in the concentration and soaking time were investigated. X-ray diffraction shows the successful synthesis of HKUST-1 before and after pyrrole treatment. Scanning electron microscopy and optical microscopy suggest that the polymer is formed within HKUST-1 rather than as a coating. Further characterization by Fourier transform infrared, X-ray photoelectron spectroscopy, gas adsorption, and thermogravimetric analysis/differential thermal analysis were also carried out. Capacitance was found to increase with the concentration of pyrrole used to load HKUST-1. Higher concentrations also lead to more leaching of copper. Differential pulse voltammetry (DPV), galvanostatic charge discharge, and electrochemical impedance spectroscopy electrochemically studied the redox peaks, capacitance retention, and resistivity of the electrodes.

Manganese is an emerging concern in drinking water, due to its potential health and aesthetic effects. Although accurate and sensitive, spectroscopic techniques for Mn²⁺ detection are costly and not capable of rapid detection. Electrochemical methods, such as cathodic stripping voltammetry, have been intensively explored as portable low-cost methods for Mn²⁺ detection. Challenges of reliability and matrix interference are difficult to overcome with current electrochemical methods. Among the interference reagents, Fe²⁺ is one of the biggest challenges for Mn²⁺ detection. Herein, a new method based on multiplex chronoamperometry at potentials between 0.9 and 1.4 V by a multichannel potentiostat is explored for its ability for interference resistance and applicability for Mn²⁺ detection in real drinking water samples. Compared to conventional one-channel electrochemical techniques, the multiplex method generates a reliable pattern that is unique to the sample components. The interference between Mn²⁺ and Fe²⁺ is investigated and the results are promising even at 100:1 Fe²⁺:Mn²⁺ concentrations. The detection limit determined for the multiplex method was 25.3 μM, and the optimum recovery rate in a real drinking water sample was 99.8%.

A profound understanding of the solid/liquid interface is central in electrochemistry and electrocatalysis, as the interfacial properties ultimately determine the electro-reactivity of a system. Although numerous electrochemical methods exist to characterize this interface under operating conditions, tools for the in-situ observation of the surface chemistry, that is, chemical composition and oxidation state, are still scarce, and currently exclusively available at synchrotron facilities. Here, we demonstrate the ability of laboratory-based near-ambient pressure X-ray photoelectron spectroscopy to track changes in oxidation states in-situ with respect to the applied potential. In this proof-of-principle study with polycrystalline gold (Au) as the best-studied electrochemical standard, we show that during the oxygen evolution reaction (OER), at high OER overpotentials, Au³⁺ governs the interfacial chemistry, while, at lower overpotentials, Au⁺ dominates.

A model for the transient electrochemical performance of a conical pore in the cathode catalyst layer of a low–Pt PEM fuel cell is developed. The pore is separated from the Pt surface by a thin ionomer film. A transient equation for the oxygen diffusion along the pore coupled to the proton conservation equation in the ionomer film is derived. Numerical solution of the static equations shows superior electrochemical performance of a conical pore as compared to cylindrical pore with equivalent electrochemically active surface area. Equations for the pore impedance are derived by linearization and Fourier–transform of transient equations. The conical pore impedance is calculated and compared to the impedance of equivalent cylindrical pore. It is shown that the pore shape affects the frequency dependence of impedance.