Electrochem, Volume 4, Issue 2 (June 2023) – 10 articles

Chronoamperometric curves for the oxidation of a ferrocenyl derivative via a potential step, calculated using the Cottrell equation, showed less diffusion-controlled currents on a platinum wire electrode. This lower deviation cannot be explained via Butler–Volmer heterogeneous kinetics, but was ascribed to the negatively capacitive current associated with a redox reaction. The deviation in fully oxidized electrical potential corresponds to the non-zero concentration at the electrode surface, which cannot be predicted using the Nernst equation. This equation expresses the relationship between the electrical potential and activity at the electrode surface rather than the concentration. The diffusion equation determines the relationship between the current and surface concentration rather than activity. Negative capacitance or a non-zero concentration may arise from structure formation on the electrode owing to dipole–dipole interactions, which are similar to the generation of double-layer capacitance, including frequency dispersion. Following this concept, we derive expressions for a lowered diffusion-controlled current and time-dependent surface concentration. The negatively capacitive current shows the time dependence of t^−0.9, which is similar to the decay of double-layer capacitive currents. The surface concentration decays with t^−0.4-dependence. Full article

The present study focuses on the electrochemical sensing of amoxicillin (AMX, as a model antibiotic drug) and its interaction with Uropathogenic E. coli (UPEC) bacteria (as a model pathogen) under physiological conditions. The electrochemical sensor probe is formulated by nanostructured gold wires (AuNWs) embedded in a carbon nanofiber–chitosan (CNF-CHIT) matrix. The synthesis of AuNWs is characterized by scanning electron microscopy (SEM), UV-Visible spectrophotometry, and X-ray photoelectron spectroscopy (XPS). The CNF-CHIT/AuNW-modified system is characterized by SEM and XPS. Initially, the CNF-CHIT/AuNW electrode was utilized for the sensing of AMX; later, in the antibiotic drug-assisted sensing of UPEC, i.e., in the presence of AMX, the interaction of UPEC was studied. The modified electrode showed appreciable sensitivity for AMX sensing; also, the interaction of AMX with UPEC is studied at two different conditions. One, at a fixed concentration of AMX (100 µM) and different concentrations of UPEC bacteria (0.6–1.2 × 10⁶ CFU/mL), and another with incubation time (1 h–1 h 35 min) for bacterial reaction. The electrochemical antimicrobial resistance developed by UPEC, which is inherent in the sensing of AMX, is the key concept for the detection of pathogens. Full article

Electrochemotherapy (ECT) has evolved significantly during the last decade, expanding treatment indications from superficial skin lesions to advanced-stage, deep-seated tumors in hard-to-reach areas. Electrodes have also shown steady technological improvement throughout the years. Besides standard and VEG (variable geometry electrode) electrodes, the introduction of laparoscopic electrodes has brought on a new era in ECT treatment, making the minimally invasive approach a reality. The exact role of ECT in the oncological dashboard is yet to be determined; however, increased tumor response, pain relief, and a low number of adverse events may yield the way for more widespread application of the technique with possible further inclusion of ECT in international oncological guidelines. The aim of this review is to give an overview on the current status of ECT in deep-seated tumor treatment and shed light on its emerging role in local anticancer therapy. Full article

A study of keracyanin chloride (KC) electrochemical behavior in an aqueous buffer solution using screen-printed carbon electrodes (SPCEs) and glassy carbon electrodes (GCEs) was performed. Cyclic voltammetry (CV) and square-wave voltammetry (SWV) were used to analyze the electrochemical response of KC under studied conditions. A clear redox wave was observed for KC, primarily due to the oxidation of the catechol 3′,4′-dihydroxyl group of its ring B, with a minor redox wave from oxidation of the hydroxyl groups in ring A. Compared to GCEs, using modified SPCEs resulted in two-fold amplification in the electrochemical oxidation signal of KC. Using SPCEs as a working electrode could provide high sensitivity in the quantification of KC and the ability to gauge KC quantification to significantly lower detection limits. Full article

Ammonium dihydrogen phosphate (ADP) single crystals along with the incorporated 0.5 and 1% L-lysine, an organic molecule which possesses a good nonlinear response, were grown with the vision to meet the requirements of the optoelectronic industry. The inclusion of the L-lysine molecule in the crystal was confirmed by the XRD and EDX. The experiment not only confirms the inclusion level of the impurity but also the capability of the amino acid molecule to bond hydrogen within the crystal facet. A minor decrease in lattice parameters was reported for all ADP: L-lysine crystals compared with pure ADP. The structures of the grown crystals were identified as tetragonal with the space group I42d by the single-crystal XRD analysis. Vibrational signatures and functional groups were confirmed using FTIR spectroscopy. The thermal stability and decomposition temperatures of 0.5 and 1% L-lysine-added crystals were measured by TG/DTA and found to be 203 °C and 207 °C, respectively. The UV–visible transmission spectra prove a higher transparency for doped crystals as compared to pure crystals; therefore, these doped crystals can be considered the best option for the frequency doubling process in a broad range of visible and near-IR spectra. The improved hardness of the doped crystals was confirmed by the Vickers hardness data. The nonlinear optical (NLO) behaviour investigated using a second-harmonic generation (SHG) technique, indicating an efficient quadratic nonlinear coefficient of ADP: Lysine crystals at a 1064 nm initial wavelength, shows about 1.5-fold higher efficiency compared with undoped ADP. Full article

This paper focuses on an industrial application where renewable power produced by photovoltaic panels is exploited to feed a pneumatic transport plant. The proposed system requires the careful management of the energy flows involved since it includes the interaction with the electric grid and with an electrochemical storage (battery) rather than the correct choice of the photovoltaic panel and battery itself. A dedicated control system needs to be developed in order to accord together these energetic flows, also providing a degree of flexibility to implement different control logics. The methodology employed in the research is simulation, which through the construction of a model in Matlab Simulink is able to reproduce the behavior of the system components and their energetic interactions for a long time period. The aim of the research is to provide a tool for assessing the energetic convenience of different battery–PV panel combinations. Moreover, an economical assessment of the proposed system is provided and compared to the traditional setup. Simulation results show that the proposed system provides energy savings with respect to a traditional grid-powered plant. The economic assessment shows that the system becomes convenient over the traditional setup within a time frame compatible with an average PV panel’s useful life. Full article

Polysaccharide-based natural polymer electrolyte membranes have had tremendous consideration for the various energy storage operations including wearable electronic and hybrid vehicle industries, due to their unique and predominant qualities. Furthermore, they have fascinating oxygen functionality results of a higher flexible nature and help to form easier coordination of metal ions thus improving the conducting profiles of polymer electrolytes. Mixed operations of the various alkali and alkaline metal–salt-incorporated biopolymer electrolytes based on different polysaccharide materials and their charge transportation mechanisms are detailly explained in the review. Furthermore, recent developments in polysaccharide electrolyte separators and their important electrochemical findings are discussed and highlighted. Notably, the characteristics and ion-conducting mechanisms of different biopolymer electrolytes are reviewed in depth here. Finally, the overall conclusion and mandatory conditions that are required to implement biopolymer electrolytes as a potential candidate for the next generation of clean/green flexible bio-energy devices with enhanced safety; several future perspectives are also discussed and suggested. Full article

The unique properties of metal-organic frameworks (MOFs) such as their large surface area and high porosity have attracted considerable attention in recent decades. The MOFs are a promising class of materials for developing highly efficient biosensors due to these same properties. This bibliometric analysis focused on the use of MOFs as enzyme-coupled materials in biosensor construction and aimed to provide a comprehensive overview of the research field by analyzing a collected database. The analysis included identifying the countries that have published the most, the most prominent applications, and trends for future directions in the field. The study used three databases with different numbers of documents, differentiated by research areas, with refinements made to the search as needed. The results suggest that MOF-derived biosensors are a growing field, with the Republic of China emerging as a significant contributor to research in this area. The study also used computational processing of trend analysis and geocoding to reveal these findings. Full article

With the surge of electric vehicles, fast charging has become one of the major challenges for the development of Li-ion and Li metal batteries. The degradation of battery electrodes at fast charging has been identified as among the gating factors. While there have been extensive studies on anode and cathode degradation modes, not sufficient efforts have been made to dive deep into the kinetics of battery charging and its influence on electrode degradation, especially during fast charging. This review presents a comprehensive yet concentrated perspective into such issues. By tracing back to the kinetic origins of battery charging, it is revealed that the intrinsic properties of electrode active materials and the microstructures of electrode are of great importance in determining electrode kinetics. Most of the electrode degradation modes are closely related to the high overpotentials and the spatial inhomogeneity in Li concentration and pertinent characteristics, which are results of the sluggish electrode kinetics during fast charging. Approaches to mitigate electrode degradation are summarized from the aspect of improving electrode kinetics and circumventing detrimental side reactions. Full article

Water pollution has badly affected human health, aquatic life, and the ecosystem. The purity of surface water can be measured in terms of dissolved oxygen (DO) measurements. Hence, it is desirable to have a portable and simple-to-use dissolved oxygen sensor. One possible remedy is an electrochemical sensor. Thus, we proposed an ITO-IrOx electrocatalyst for an effective and interference-free DO sensor utilizing the principle of oxygen reduction reaction (ORR). The ITO-IrOx was characterized using cyclic voltammetry (CV), scanning electron microscopy (SEM), electrochemical impedance spectrometry (EIS), X-ray photoelectron spectroscopy (XPS), and reflectance spectroscopy-based techniques. Reflectance spectra of the ITO-IrOx electrode showed the photoresist capability. The EIS spectra revealed lower charge transfer resistance for the ITO-IrOx electrode in ORR. The IrOx film on ITO exhibited a quick (one electron, α = 1.00), and reversible electron transfer mechanism. The electrode demonstrated high stability for oxygen sensing, having a limit of detection (LOD) of 0.49 ppm and interference-free from some common ions (nitrate, sulphate, chloride etc.) found in water. Full article