Electrochem

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

Electrically driven separation (EDS) technology with a high voltage (HV) alternating current source (AC) was used to remove glycerol and other contaminants from biodiesel in order to meet the ASTM D6751 and EN 14214 standards. Biodiesel was produced from a transesterification of refined palm oil and methanol using sodium methylate as a homogeneous catalyst. The effects of an Iron (Fe) electrode, including types of electrode configurations, vertical distance between electrodes, applied voltage, and separation time, were studied. Furthermore, the effects of the remaining catalyst and soap content in biodiesel phase were also investigated to improve the separating performance using the EDS technique. The EDS using HVAC and low amperage with a point-to-point electrode configuration showed the highest separation efficiency of 99.8%. The optimum vertical distance between electrodes was 3 cm, while the optimum applied voltage was 3 kV. The separation time of 240 s yielded the best separating performance, completely eliminating the unreacted catalyst, and the lowest of the normalized remaining soap value content was obtained. Considering all of this, the EDS technique had higher efficiency to remove glycerol and other contaminants than a conventional separation of gravitation settling. The final biodiesel product was produced with the high purity of 98.0 wt% after purification and met all standard specifications. Full article

Iron is a widely used metal due to its low cost and availability, but it is susceptible to corrosion in many circumstances. This corrosion can result in economic and environmental losses, and negatively affect the physical and chemical properties of the metal. This chapter provides a background on iron corrosion in archaeology and introduces various inhibitors used for its protection. It starts with a general overview of corrosion and metallurgy of iron, followed by an in-depth explanation of the mechanisms of iron corrosion in water and air. The chapter concludes with a review of different corrosion inhibitors, focusing on those made from natural plant extracts. Full article

Green corrosion inhibitors are of great interest due to their exciting and environmentally friendly behavior in mild steel corrosion control during and after the acid cleaning process. Herein, alkaloids were extracted from the stem of Ageratina adenophora and were ensured by qualitative chemical tests as well as spectroscopic test methods. The corrosion inhibition efficacy of the alkaloids against mild steel corrosion was evaluated by gravimetric, electrochemical and EIS measurement methods. In addition, the adsorption isotherm, free energy of adsorption and thermodynamic parameters of the process were evaluated. The investigations indicated the most promising inhibition efficacy of the alkaloids for mild steel corrosion. The adsorption isotherm study revealed that the adsorption of inhibitor molecules on the MS interface was manifested by dominant physisorption followed by chemisorption. Free energy and thermodynamic parameters are well suited to endothermic processes. Full article

In this paper, ZnO nanorods were synthesized by the hydrothermal method and used as anodes for zinc-silver batteries. The Tafel and EIS curve analysis results show that ZnO nanorods have better anti-corrosion and charge transport properties than ZnO powders. At 0.1 C discharge conditions, the ZnO electrode exhibits more stable cycle efficiency than the powder electrode; after 25 cycles, the capacity is higher by 95%. The superior electrochemical performance is due to the ZnO nanorods having the ability to conduct electrons and increase the surface area. Therefore, the possible growth mechanism of ZnO nanorods has been investigated. Full article

High levels of H₂O₂ in food can lead to oxidative stress. Which has been linked to a number of neurological diseases. Hence, its detection in beverages is essential. However, a complicated structure of the reaction medium of H₂O₂ makes the detection procedure very difficult. For this reason, sensitive strategic methods are required. In this study, quantification of H₂O₂ in milk and apple juice has been obtained via the electrochemical sensing platform based on GCE/SiO-CeONPs. Scanning Electron Microscopy (SEM), Cyclic voltammetry(CV), and electron impedance spectroscopy(EIS) were employed to characterize the composite. The kinetics investigation of the sensor with H₂O₂ revealed an a quasi-reversible one -electron adsorption process. Under optimized conditions, the Differential Pulse Voltammetry (DPV) in 0.1 M Phosphate buffer (PB) pH 5.5 of the H₂O₂ displayed a peak at 0.13 V vs. Ag/AgCl with the detection limits of 0.0004 µM, linearity range of 0.01–0.08 µM. The observed LOD values of this method for real samples were calculated to be 0.006 µM and 0.007 µM with LOQ of 0.02 µM for milk and apple juice, respectively. The recovery of the analyte was from 92 to 99%. Furthermore, due to good selectivity and stability, the benefit of this sensor is its applicability in multiple fields. Full article

In recent years, clean energy technologies that meet ever-increasing energy demands without the risk of environmental contamination has been a major interest. One approach is the utilization of plant leaves, which release redox-active NADPH as a result of photosynthesis, to generate photocurrent. In this work, we show for the first time that photocurrent can be harvested directly from the fruit of a cherry tree when associated with a bio-electrochemical cell. Furthermore, we apply electrochemical and spectroscopic methods to show that NADH in the fruit plays a major role in electric current production. Full article

Recently, ascorbic acid (AA) has been studied as an environment-friendly fuel for energy conversion devices. This review article has deliberated an overview of ascorbic acid electrooxidation and diverse ion exchange types of AA-based fuel cells for the first time. Metal and carbon-based catalysts generated remarkable energy from environment-friendly AA fuel. The possibility of using AA in a direct liquid fuel cell (DLFC) without emitting any hazardous pollutants is discussed. AA fuel cells have been reviewed based on carbon nanomaterials, alloys/bimetallic nanoparticles, and precious and nonprecious metal nanoparticles. Finally, the obstacles and opportunities for using AA-based fuel cells in practical applications have also been incorporated. Full article

Li and Mn-rich layered cathode (LLC) materials show great potential as the next generation cathode materials because of their high, practical and achievable specific capacity of ~250 mAh/g, thermal stability and lower raw material cost. However, LLC materials suffer from degradation of specific capacity, voltage fading due to phase transformation upon cycling and transition-metal dissolution, which presents a significant barrier for commercialization. Here, we report the effects of Ni content on the electrochemical performance, structural and thermal stability of a series of Co-free, LLC materials (Li_1.2Ni_xMn_0.8-xO₂, x = 0.12, 0.18, 0.24, 0.30 and 0.36) synthesized via a sol-gel method. Our study shows that the structure of the material as well as the electrochemical and thermal stability properties of the LLC materials are strongly dependent on the Ni or Mn content. An increase in the Ni to Mn ratio results in an increase in the average discharge voltage and capacity, as well as improved structural stability but decreased thermal stability. Full article

Catalyst layer defects and irregularities in catalyst-coated membrane (CCM) electrodes affect the lifetime of polymer electrolyte membrane fuel cells (PEMFCs) during their operation. Thus, catalyst layer defects are important concerns for fuel cell manufacturers and prompt the development of quality control systems with the aim of fabricating defect-free electrodes. Consequently, the objective of this study is to gain a fundamental understanding of the morphological changes of real catalyst layer defects that have developed during CCM production. In this paper, missing catalyst layer defects (MCLD) formed during the decal transfer process are investigated through a nondestructive method using reflected light microscopy. The geometric features of the defects are quantified, and their growth is measured at regular time intervals from beginning-of-life (BOL) to end-of-life (EOL) until the OCV has dropped by 20% of its initial value as per a DOE-designed protocol. Overall, two types of degradation are observed: surface degradation caused by catalyst erosion and crack degradation caused by membrane mechanical deformation. Furthermore, catalyst layer defects formed during the decal transfer process were found to exhibit a higher growth rate at middle-of-life (MOL-1) and stabilize by EOL. This type of study will provide manufacturers with baseline information to allow them to select and reject CCMs, ultimately increasing the lifetime of fuel cell stacks. Full article

Hydrogen production using an Anion exchange membrane (AEM) electrolyzer allows the use of non-platinum group metal catalysts for oxygen evolution reaction (OER). Nickel and Cobalt-based oxides are active in an alkaline environment for OER and are relatively inexpensive compared to IrO₂ catalysts used in Polymer electrolyte membrane (PEM) electrolysis. Mixed metal oxide catalysts NiFeO_x and NiFeCoO_x catalysts were synthesized by the coprecipitation method using NaOH. X-ray diffraction results showed mainly NiO diffraction peaks for the NiFeO_x catalyst due to the low concentration of Fe, for the NiFeCoO_x catalyst, NiCo₂O₄ diffraction peaks were observed. NiFeCoO_x catalysts showed a higher Anion exchange membrane water electrolysis (AEMWE) performance compared to NiFeO_x and commercial NiO, the highest current density at 2 V was 802 mA cm⁻² at 70 °C using 1 M KOH as an electrolyte. The effect of electrolyte concentration was studied by using 0.01 M, 0.1 M and 1 M KOH concentrations in an electrolysis operation. Electrochemical Impedance spectroscopy was performed along with the equivalent circuit fitting to calculate ohmic and activation resistances, the results showed a decrease in ohmic and activation resistances with the increase in electrolyte concentration. Commercially available AEM (Fumasep FAA-3-50 and Sustainion dioxide membrane X-37-50 grade T) were tested at similar conditions and their performance was compared. EIS results showed that X-37-50 offered lower ohmic resistance than the FAA-3-50 membrane. Full article