Electrochemical science advances最新文献

Nano-sized bubbles (NBs: nanobubbles) have attracted attention in various fields such as physics, engineering, medicine and agriculture for fundamental and practical reasons. Atomic force microscopy (AFM) has revealed the occurrence of NBs and discovered their flattened shape. However, their dynamic behaviours have not yet been discussed much owing to the slow scanning speed. The existence of these energetically unfavourable structures is still controversial owing to the lack of studies on bubble-like behaviour of NB such as aggregation, growth and dissolution. Recently developed high-speed AFM (HS-AFM) can observe nano-interface phenomena at a speed of 0.5 frame s⁻¹. In this study, HS-AFM was applied to electrolytic H₂ NBs. We successfully observed NB nucleation, growth and dissolution during a potential scan. Image analysis revealed flattened nuclei with heights of less than 10 nm. The NBs remained stable for a short period after the hydrogen evolution stopped, and they rapidly dissolved at the anodic potential. As the potential sweep was repeated, the number of NB nuclei increased. This is the first study showing the dynamic motion of NBs during the potential sweep by AFM. Videos captured by HS-AFM make NB existence more certain. This research contributes not only to the NB study but also to the clarification of the gas evolution mechanism on electrodes.

This study aims to investigate the electrochemical properties of usnic acid (UA), a secondary metabolite commonly biosynthesized by a variety of lichen species, and its biosynthetic precursor methylphloroacetophenone (MPA). During cyclic and differential pulse voltammetry, well-defined anodic peaks were observed for UA and MPA in 0.04 M Britton–Robinson buffer solution (pH 5) containing 20% (v/v) acetonitrile. The absence of cathodic peaks during the reverse voltammetric scans revealed that both oxidation reactions are chemically irreversible. Scan rate studies demonstrate that UA oxidation is an adsorption-controlled process, whereas the oxidation of MPA molecules occurs as a diffusion-controlled process. For both molecules, the number of electrons transferred during the oxidation was calculated to be 3. Differential pulse voltammetry results demonstrate that the anodic peak for the two molecules is markedly influenced by the solution pH and the same numbers of protons and electrons are involved in the oxidation process of the molecules. Based on the evidence generated by the electrochemical studies, oxidation mechanisms are proposed for UA and MPA, which involves a two-step electron loss with a hydration reaction taking place in between. This study provides an understanding of the bioactivity mechanisms of these two natural products.

The dynamics of the structural changes in the electrochemical double layer at the interface between a Ag(111) electrode and 0.1 M KOH electrolyte have been probed using surface X-ray diffraction measurements. The X-ray measurements utilised a lock-in amplifier technique to obtain a time resolution down to the millisecond scale. Two potential step regions were explored in an attempt to separate the dynamics of the reversible adsorption/desorption of hydroxide species (OH_ad) and the subsequent cation (K⁺) ordering in the double layer. By probing different positions in reciprocal space, sensitive to different structural changes, the time-dependent response of the electrode surface was probed and time constants for the different associated processes were obtained.

Platinum nanoparticles deposited on a silicon-doped niobium suboxide support provided the catalyst known as Pt/NbOS. This was compared to the commercial Pt/C electrocatalyst in the ethanol and methanol oxidation reactions for use in direct alcohol fuel cells. Cyclic voltammetry and electrochemical impedance spectroscopy demonstrate that the employment of the metal oxide support provides higher peak oxidation currents and smaller charge transfer resistances during alcohol oxidation. Carbon monoxide (CO) stripping experiments showed enhanced removal of CO by Pt/NbOS compared to Pt/C. Pt/NbOS shows its smallest apparent activation energies of 13.3 and 11.9 J mol^-1, for methanol and ethanol oxidation respectively, which are 38% and 27% lower than those of Pt/C at the same potentials. This increased activity of Pt/NbOS is attributed to the strong metal-support interactions between the active Pt nanoparticles and the NbOS support which demonstrate its utility in replacing Pt/C in methanol and ethanol fuel cells.

Rapid and reliable on-site pathogen testing is crucial for diagnosing and managing human health. Nucleic acids (NAs) containing genetic information are valuable target molecules for pathogen testing, and sensitive and rapid detection of NAs using electrochemical approaches has been intensively investigated. Detection approaches for NAs are diverse and compatible with current gene amplification methods and continue to expand with the development of novel functional materials and molecules. The variety of electrochemical sensing devices also continues to expand, and more practical testing is being pursued. This review outlines the latest detection approaches and basic guidelines for NA detection. Furthermore, this review provides an overview of electrochemical sensing devices that utilize novel and unique materials and functions and comprehensively discusses their advantages.

The replacement of conventional lithium-ion batteries with solid-state batteries is currently under investigation by many players both from academia and industry. Sulfide-based electrolytes are among the materials that are regarded as most promising, especially for application in the transport sector. The performance of anode, cathode, and solid electrolyte materials of this type of solid electrolyte is typically evaluated using manually assembled cells such as Swagelok cells, EL-CELLs, and in-house built pressure devices. Coin cells, however, are often disregarded. Though coin cells cannot accurately predict how a material will perform in an end-use application battery cell format, they are easy to assemble and can provide reproducible data compared to the other cell types, which make them an interesting option for testing the materials under conditions more relevant for their envisioned application. The coin cell preparation method presented in this work has been evaluated interlaboratory for reproducibility and, in addition, can be modified depending on the optimization parameters of the solid electrolyte, cathode material, bilayer comprised on cathode and solid electrolyte, lithium metal anode, and cell in general. Besides, an interlab round-robin test (RRT) is carried out between four laboratories, measuring defined electrochemical tests of sulfide solid-state batteries in coin cell configuration. This RRT for the preparation of coin cell solid-state batteries with sulfide solid electrolyte, lithium nickel manganese cobalt oxides cathode, and lithium metal anode is intended for academic researchers and provides guidelines of research in this field.

As a subfield of artificial intelligence (AI), machine learning (ML) has emerged as a versatile tool in accelerating catalytic materials discovery because of its ability to find complex patterns in high-dimensional data. While the intricacy of cutting-edge ML models, such as deep learning, makes them powerful, it also renders decision-making processes challenging to explain. Recent advances in explainable AI technologies, which aim to make the inner workings of ML models understandable to humans, have considerably increased our capacity to gain insights from data. In this study, taking the oxygen reduction reaction (ORR) on {111}-oriented Pt monolayer core–shell catalysts as an example, we show how the recently developed theory-infused neural network (TinNet) algorithm enables a rapid search for optimal site motifs with the chemisorption energy of hydroxyl (OH) as a single descriptor, revealing the underlying physical factors that govern the variations in site reactivity. By exploring a broad design space of Pt monolayer core–shell alloys ($��\sim �17�,�000�$ candidates) that were generated from $��\sim �1500�$ thermodynamically stable bulk structures in existing material databases, we identified novel alloy systems along with previously known catalysts in the goldilocks zone of reactivity properties. SHAP (SHapley Additive exPlanations) analysis reveals the important role of adsorbate resonance energies that originate from $��s�p�$-band interactions in chemical bonding at metal surfaces. Extracting physical insights into surface reactivity with explainable AI opens up new design pathways for optimizing catalytic performance beyond active sites.

Chemical additive and physical template-free electrochemical methods to prepare carbon-supported nanostructures of catalyst metals represent an emerging technology. Formation of the metal nano/microstructures depends not only on the electrochemical method/parameters but also on the nature of the underlying carbon material. Here, we present a comparative evolution of unevenly distributed coral-like aggregates of nanocuboid-shaped gold nanostructures (AuNCBs) on the oxidised form of boron, nitrogen-doped carbon nanoonions (oxi-B,N-CNO) compared to evenly distributed bud-like aggregates of cubic shaped gold nanostructures on bare glassy carbon electrode under a similar electrochemical approach. The synthesis method provided the best availability of the surface active sites, whereas the shape of the structures showed a direct influence of both outer-sphere and inner-sphere electron transfer reactions. The higher sensitivity of AuNCBs@oxi-B,N-CNO compared to individual components and bare carbon/gold electrodes toward the inner-sphere oxidative reaction of N-acetyl-L-cysteine (NAC) was exploited in order to develop an electrochemical assay method with sensitivity and linear dynamic range of (4.70 ± 0.25) × 10⁻⁴ C∙cm⁻²∙mM⁻¹ and 0.2–2.5 mM, respectively in acetate buffer (pH 4.45). Furthermore, the sensor design was deployed in the quantitation of NAC in pharmaceutical preparations, resulting in 89%–106% recovery.

The utilization of electrochemical and advanced oxidation technologies for industrial wastewater (IW) treatment has grown in popularity during the last two decades. The effectiveness of several methods for treating IW, including hydrogen peroxide (H₂O₂), direct-current (DC) and alternating-current (AC)-electrocoagulation (EC), and the combination of H₂O₂ with DC/AC-EC (H₂O₂-DC/AC-EC) processes were all investigated. In comparison to the H₂O₂, DC/AC-EC, and H₂O₂-DC/AC-EC technologies, the results showed that the H₂O₂-AC-EC process produced 100% total colour and 100% chemical oxygen demand (COD) removal efficiency with a low power consumption of 4.4 kWhm⁻³. The H₂O₂/AC-EC technology was optimized for treating IW using a response surface methodology approach based on a central composite design using a five-factor level. Utilizing statistical and mathematical techniques, the optimum parameters were determined to minimize consumption of power (1.02 kWhm⁻³) and maximum COD elimination (75%). The experimental parameters comprised the following: H₂O₂ of 600 mg/L, current of 0.65 Amp, pH of 7.6, COD of 1600 mg/L, and treatment time (TT) of 1.26 h. When using a Fe/Fe electrode combination with the wastewater pH of 7, the COD removal efficiency was shown to be enhanced by increasing the TT, current and H₂O₂, and decreasing the COD concentration. The synergistic impact, quantified as the combined efficiency of eliminating % COD utilizing the H₂O₂, AC-EC, and H₂O₂/AC-EC procedures, was found to be 15.75%. Therefore, employing a hybrid H₂O₂-AC-EC approach is considerably more effective in treating IW.