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Polymer electrolyte was used as a medium for testing the performance of microband electrodes under conditions of linear diffusion. Cyclic voltammetry (CV) and chronoamperometry (CA) experiments were performed in a highly viscous medium, where diffusion rates are much slower than in fluid solutions. The log i vs. log v (CV) or log i vs. log t (CA) relationships with the current equation confirmed the existence of such conditions, yielding slope values that were lower than the expected 0.5. This could indicate an impure linear diffusion profile, i.e., some contribution from radial diffusion (edge effects). However, the desired value of 0.5 was obtained when performing these tests in monomeric solvents of similar viscosities, such as glycerol or propylene glycol. These results led to the conclusion that the current equations, which are based on Fick's laws, may not be applicable for polymer electrolytes, where various obstructions to free diffusion result in a more complicated process than for monomeric solvents. [ABSTRACT FROM AUTHOR]

There have been many studies on the significant correlation between the hydrogen peroxide content of different tissues or cells in the human body and the risk of disease, so the preparation of biosensors for detecting hydrogen peroxide concentration has been a hot topic for researchers. In this paper, palladium nanoparticles (PdNPs) and laser-induced graphene (LIG) were prepared by liquid-phase pulsed laser ablation and laser-induced technology, respectively. The complexes were prepared by stirring and used for the modification of screen-printed electrodes to develop a non-enzymatic hydrogen peroxide biosensor that is low cost and mass preparable. The PdNPs prepared with anhydrous ethanol as a solvent have a uniform particle size distribution. The LIG prepared by laser direct writing has good electrical conductivity, and its loose porous structure provides more adsorption sites. The electrochemical properties of the modified electrode were characterized by cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy. Compared with bare screen-printed electrodes, the modified electrodes are more sensitive for the detection of hydrogen peroxide. The sensor has a linear response range of 5 µM–0.9 mM and 0.9 mM–5 mM. The limit of detection is 0.37 µM. The above conclusions indicate that the hydrogen peroxide electrochemical biosensor prepared in this paper has great advantages and potential in electrochemical catalysis. [ABSTRACT FROM AUTHOR]

Voltammetry and chronoamperometry are used to study the effect of the solution composition on the desorption behavior of self-assembled monolayers of alkanethiols with approximately the same chain length but different terminal groups of thiols (R: –CH3, –CH2OH, and –NH2). The hydrophilic properties of the terminal groups for the studied thiols increased in the –CH3 –NH2 ≤ –CH2OH series. It is found that the anionic and cationic composition of electrolyte affected significantly the electrochemical stability and blocking ability of self-assembled monolayers of thiols with different terminal groups. It is established that the electrochemical stability and blocking ability of the self-assembled monolayers decreased in the Li+, Na+, K+ series in alkaline solutions regardless of the thiol terminal group. The cation nature in perchlorate and chloride solutions manifested itself only for thiol with the –NH2 terminal group. The shape of cathodic voltammograms changed for this thiol when passing from alkaline to and Сl– medium, possibly owing to a change in the amino group protonation degree. [ABSTRACT FROM AUTHOR]

A potentiostat is necessary to achieve accurate control of potentials in an electrochemical cell for most electroanalytical techniques. While lab-built potentiostats with specific design objectives such as low manufacturing cost and field portability have been developed in recent years, there remain a lack of accessible potentiostats that prioritize measurement quality, user-friendliness, and adaptability for general laboratory use. In response, we present Opensens, an open-source, multi-purpose potentiostat that can function independently or as part of an instrument suite. The Opensens can perform accurately the Fe3+/Fe2+ redox couple experiments as well as the ascorbic acid (AA) detection comparing with the commercial apparatus. [ABSTRACT FROM AUTHOR]

Increased evidence has documented a direct association between Ciprofloxacin (CFX) intake and significant disruption to the normal functions of connective tissues, leading to severe health conditions (such as tendonitis, tendon rupture and retinal detachment). Additionally, CFX is recognized as a potential emerging pollutant, as it seems to impact both animal and human food chains, resulting in severe health implications. Consequently, there is a compelling need for the precise, swift and selective detection of this fluoroquinolone-class antibiotic. Herein, we present a novel graphene-based electrochemical sensor designed for Ciprofloxacin (CFX) detection and discuss its practical utility. The graphene material was synthesized using a relatively straightforward and cost-effective approach involving the electrochemical exfoliation of graphite, through a pulsing current, in 0.05 M sodium sulphate (Na2SO4), 0.05 M boric acid (H3BO3) and 0.05 M sodium chloride (NaCl) solution. The resulting material underwent systematic characterization using scanning electron microscopy/energy dispersive X-ray analysis, X-ray powder diffraction and Raman spectroscopy. Subsequently, it was employed in the fabrication of modified glassy carbon surfaces (EGr/GC). Linear Sweep Voltammetry studies revealed that CFX experiences an irreversible oxidation process on the sensor surface at approximately 1.05 V. Under optimal conditions, the limit of quantification was found to be 0.33 × 10−8 M, with a corresponding limit of detection of 0.1 × 10−8 M. Additionally, the developed sensor's practical suitability was assessed using commercially available pharmaceutical products. [ABSTRACT FROM AUTHOR]

The type of catalyst support affects platinum activity and durability in direct methanol fuel cells (DMFCs). In this study, Sb with 0, 4, 8 and 12% doped SnO2 on carbon cloth (CC) support at ultra-low platinum loading (0.04 mg cm−2) is prepared. The results show that the modification of support and the use of Sb-doped SnO2 improve the electrochemical activity of the prepared electrodes. Scanning electron microscopy (SEM) indicates that the doping of SnO2 with Sb decreases the average particle size of Pt. The X-ray diffraction (XRD) patterns show that incorporating Sb and Pt nanoparticles into SnO2 would not damage the tetragonal rutile structure. The highest electrochemical surface area (ECSA) of electrodes in the acidic environment is obtained in Sb of 4%. The highest current density of 15.5 mA cm−2 is obtained at the peak potential of 0.71 V for Pt@Sb4-SnO2-CC electrode in the methanol oxidation reaction while its value is 1.2 times higher than Pt@CC. The chronoamperometry analysis and CO stripping voltammetry show that this electrode has the highest tolerance to CO. The electrochemical impedance spectroscopy demonstrates that the minimum charge transfer resistance of 17.6 (Ω cm2) is acquired for the Pt@Sb4-SnO2-CC electrode. In the active DMFC test, the high power and current density of this electrode are 11 mW cm−2 and 66 mA cm−2, respectively, at the cell voltage of 0.2 V. [ABSTRACT FROM AUTHOR]

A miniature L-glutamate (L-Glu) biosensor is described based on Prussian blue (PB) modification with improved stability by using self-assembled monolayers (SAMs) technology and polydopamine (PDA). A gold microelectrode (AuME) was immersed in NH2(CH2)6SH-ethanol solution, forming well-defined SAMs via thiol-gold bonding chemistry which increased the number of deposited Prussian blue nanoparticles (PBNPs) and confined them tightly on the AuME surface. Then, dopamine solution was dropped onto the PBNPs surface and self-polymerized into PDA to protect the PB structure from destruction. The PDA/PB/SAMs/AuME showed improved stability through CV measurements in comparison with PB/AuME, PB/SAMs/AuME, and PDA/PB/AuME. The constructed biosensor achieved a high sensitivity of 70.683 nA µM−1 cm−2 in the concentration range 1–476 µM L-Glu with a low LOD of 0.329 µM and performed well in terms of selectivity, reproducibility, and stability. In addition, the developed biosensor was successfully applied to the determination of L-Glu in tomato juice, and the results were in good agreement with that of high-performance liquid chromatography (HPLC). Due to its excellent sensitivity, improved stability, and miniature volume, the developed biosensor not only has a promising potential for application in food sample analysis but also provides a good candidate for monitoring L-Glu level in food production. [ABSTRACT FROM AUTHOR]

Flexible polymer electrolytes with efficient electrochemical characteristics were necessary to meet the requirements of smart electronics technology and foldable electronics. It is both important and difficult to design and construct a flexible lithium polymer electrolyte with higher ionic conductivity and better dielectric properties for use in electrochemical storage devices because of the need to increase storage capacity and electrochemical stability. This research describes the inclusion of Nickel oxide nanoparticles (n-NiO), which are environmentally benign, doped lithium flexible polymer electrolytes (n-FLPEs), via the solution-cast method with polymer matrices of poly (vinylidene fluoride-hexafluoropropylene) (PVdF-HFP), poly (ethylene oxide) (PEO), which is a biodegradable polymer, as well as Lithium trifluoromethanesulfonate (LiCF3SO3). When n-NiO is incorporated into FLPEs, the ionic conductivity increases by a factor of nearly four and a half. The εʹmax value increased four times, and ε″max value increased seventeen times owing to n-NiO inclusion. We used cyclic voltammetry (CV) and chronoamperometry (CA) to study the charge carrier buildup, ionic strength, and transference number in the optimal n-FLPE membrane. n-FLPEs have been shown to be electrochemically stable and capable of transporting ions due to chemical shifts in functional groups illustrated by X-ray photoelectron spectroscopy (XPS) investigations. The significance of the [υs(SO3)] mode in ionic conductivity has been extensively addressed. We analysed the FESD's discharging behaviour at a 0.04 C assessment, or an average current during discharge of 5.128 mA over 25 h. [ABSTRACT FROM AUTHOR]

A newly synthesized series of bimetallic CPM-37(Ni,Fe) metal–organic frameworks with different iron content (Ni/Fe ≈ 2, 1, 0.5, named CPM-37(Ni2Fe), CPM-37(NiFe) and CPM-37(NiFe2)) demonstrated high N2-based specific SBET surface areas of 2039, 1955, and 2378 m2 g−1 for CPM-37(Ni2Fe), CPM-37(NiFe), and CPM-37(NiFe2), having much higher values compared to the monometallic CPM-37(Ni) and CPM-37(Fe) with 87 and 368 m2 g−1 only. It is rationalized that the mixed-metal nature of the materials increases the structural robustness due to the better charge balance at the coordination bonded cluster, which opens interesting application-oriented possibilities for mixed-metal CPM-37 and other less-stable MOFs. In this work, the CPM-37-derived α,β-Ni(OH)2, γ-NiO(OH), and, plausibly, γ-FeO(OH) phases obtained via decomposition in the alkaline medium demonstrated a potent electrocatalytic activity in the oxygen evolution reaction (OER). The ratio Ni : Fe ≈ 2 from CPM-37(Ni2Fe) showed the best OER activity with a small overpotential of 290 mV at 50 mA cm−2, low Tafel slope of 39 mV dec−1, and more stable OER performance compared to RuO2 after 20 h chronopotentiometry at 50 mA cm−2. [ABSTRACT FROM AUTHOR]

By mimicking biological olifactory systems, sensors have been reported for the identification of important odorants at low concentration levels in complex environments. Herein a rapid and label-free olfactory sensor based on porous anodic alumina (PAA) nanochannels and the human odorant binding protein s(OBP2b) is reported for odorants. The OBP2b proteins were assembled on the surface of the PAA nanochannels by a Schiff base reaction and the recognition and connection of target with the OBP2b proteins led to steric hindrance inside the PAA nanochannels, resulting in a decreased anodic current due to the indicator, potassium ferricyanide. Using the PAA nanochannels with 55 nm pore diameter as the optimal reaction platform and the OBP2b proteins as the recognition element, the chronoamperometry allowed sensitive determination of ethyl acetate, lauric acid, and vanillin. Furthermore, odorants released by fruit samples were also detected by the developed sensor. Consequently, this sensitive and simple strategy provides an efficient and promising approach for environmental and biological sensing. [ABSTRACT FROM AUTHOR]

In this article, we present the synthesis of binary CdAl4O7/CdO nanocomposites using green tea extracts and green chemistry methods for high-performance hydrogen storage. The green tea extract contains bioactive compounds (polyphenols) that act as reducing agents, which facilitate the reaction between metal ions and water. By examining the structural and morphological characteristics of the obtained substrates using scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR), it was demonstrated that the nanocomposites were successfully synthesized. We evaluated the electrochemical performance of the synthesized CdAl4O7/CdO nanocomposites using a three-electrode chronopotentiometry system. According to the results, the synthesized nanocomposites are capable of storing 1750 mAh/g of hydrogen at a constant current of 1 Amp. By using green tea extract as a natural structure-directing agent, the CdAl4O7/CdO nanocomposite can be developed more sustainably as high-performance hydrogen storage materials. Ultimately, this work contributes to the advancement of sustainable energy storage through the synthesis of a promising new material. [ABSTRACT FROM AUTHOR]

Pholcodine, an anti-tussive medication widely used as an over-the-counter, OTC drug, has recently faced restrictions in several countries. This paper presents a sensitive electrochemical approach for pholcodine detection. The electrochemical method involved fabricating a graphene nanoplatelets electrode, incorporating polythiophene nanospheres polymer to promote electron transfer and increase the activated surface area. Characterization of the fabricated electrode was performed using transmission electron microscopy, ATR-Fourier-transform infrared spectroscopy, X-ray crystallography, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy. The electrochemical behavior of pholcodine with the fabricated electrode was investigated using cyclic voltammetry, chronoamperometry, square wave voltammetry (SWV), and differential pulse voltammetry (DPV). The developed electrode led to a linear response for pholcodine ranging from 10 to 45 mg/L with detection limits of 1.41 and 1.51 mg/mL for SWV and DPV, respectively and quantification limits of 4.27 and 4.57 mg/L for SWV and DPV, respectively. The proposed method has accurately recovered pholcodine in spiked serum samples with a recovery percentage ranging from 1.2 to 2.9%. The optimized method is found to be accurate, precise, and robust by applying validation parameters provided by International Council for Harmonization. Two green metrics were computed to assess the method's greenness, the findings showed that the developed method is environmentally friendly with minimum sample preparation steps. Article highlights: Fabrication of electrochemical electrode using graphene nanoplatelets modified with polythiophene nanospheres. Voltammetric analysis of pholcodine using square wave voltammetry and differential pulse voltammetry with method validation according to International Council for Harmonization (ICH) guidelines. Assessment of the method's greenness using two green assessment tools; analytical GREEness metric (AGREE) and complementary green analytical procedure index (ComplexGAPI) software tools. [ABSTRACT FROM AUTHOR]

Next-generation alkaline water electrolyzers will be based on zero-gap configuration to further reduce costs related to technology and to improve performance. Here, anodic porous transport layers (PTLs) for zero-gap alkaline electrolysis are prepared through a facile one-step electrodeposition of Ni,Fe,Co-based layered double hydroxides (LDH) on 304 stainless steel (SS) meshes. Electrodeposited LDH structures are characterized using Scanning Electron Microscopy (SEM) confirming the formation of high surface area catalytic layers. Finally, bi and trimetallic LDH-based PTLs are tested as electrodes for oxygen evolution reaction (OER) in 1 M KOH solution. The best electrodes are based on FeCo LDH, reaching 10 mA cm−2 with an overpotential value of 300 mV. These PTLs are also tested with a chronopotentiometric measurement carried out for 100 h at 50 mA cm−2, showing outstanding durability without signs of electrocatalytic activity degradation. [ABSTRACT FROM AUTHOR]

A direct electrochemical sensor based on covalent organic frameworks (COFs)/platinum nanoparticles (PtNPs) composite was fabricated for the detection of ofloxacin (OFX) in water. Firstly, the COF material was synthesized via the condensation reaction of 1,3,5-tris(4-aminophenyl)benzene (TAPB) with terephthalaldehyde (TPA) and integrated with PtNPs by in situ reduction. Then, TAPB-TPA-COFs/PtNPs composite was loaded onto the surface of the glassy carbon electrode (GCE) by drip coating to construct the working electrode (TAPB-TPA-COFs/PtNPs/GCE). The electrochemical performance of TAPB-TPA-COFs/PtNPs/GCE showed a significant improvement compared with that of TAPB-TPA-COFs/GCE, leading to a 3.2-fold increase in the electrochemical signal for 0.01 mM OFX. Under optimal conditions, the TAPB-TPA-COFs/PtNPs/GCE exhibited a wide linear range of 9.901 × 10−3–1.406 µM and 2.024–15.19 µM with a detection limit of 2.184 × 10−3 µM. The TAPB-TPA-COFs/PtNPs/GCE-based electrochemical sensor with excellent performance provides great potential for the rapid and trace detection of residual OFX. [ABSTRACT FROM AUTHOR]

Quinones are electrochemical probes which are used for a large range of applications including bioenergetics. One electrochemical feature of quinones is their possible slow electron transfer kinetics. In this article we compared several quinones towards electron transfer kinetics and the ability of anodic pretreatment to increase electron transfer rate constant. Rotating disk electrode and chronoamperometry measurements were used to revisit their electrochemical behavior. Additionally, the number of electrons exchanged as a function of the characteristic time was used as a proxy to investigate kinetic limitations. A model was suggested to rationalize our results. Beyond a classification of quinones regarding the kinetic and thermodynamic ability of the hydroquinone form to be re‐oxidized, some intrinsic physicochemical properties were identified from our model (such as a time dependency of the exchanged number of electrons) to characterize such important redox mediators. [ABSTRACT FROM AUTHOR]

A flow-through biosensor system for the determination of uric acid was developed on the platform of flow-through electrochemical cell manufactured by 3D printing from poly(lactic acid) and equipped with a modified screen-printed graphite electrode (SPE). Uricase was immobilized to the inner surface of a replaceable reactor chamber. Its working volume was reduced to 10 μL against a previously reported similar cell. SPE was modified independently of the enzyme reactor with carbon black, pillar[5]arene, poly(amidoamine) dendrimers based on the p-tert-butylthiacalix[4]arene (PAMAM-calix-dendrimers) platform and electropolymerized 3,7-bis(4-aminophenylamino) phenothiazin-5-ium chloride. Introduction of the PAMAM-calix-dendrimers into the electrode coating led to a fivefold increase in the redox currents of the electroactive polymer. It was found that higher generations of the PAMAM-calix-dendrimers led to a greater increase in the currents measured. Coatings consisted of products of the electropolymerization of the phenothiazine with implemented pillar[5]arene and PAMAM-calix-dendrimers showing high efficiency in the electrochemical reduction of hydrogen peroxide that was formed in the enzymatic oxidation of uric acid. The presence of PAMAM-calix-dendrimer G2 in the coating increased the redox signal related to the uric acid assay by more than 1.5 times. The biosensor system was successfully applied for the enzymatic determination of uric acid in chronoamperometric mode. The following optimal parameters for the chronoamperometric determination of uric acid in flow-through conditions were established: pH 8.0, flow rate 0.2 mL·min−1, 5 U of uricase per reactor. Under these conditions, the biosensor system made it possible to determine from 10 nM to 20 μM of uric acid with the limit of detection (LOD) of 4 nM. Glucose (up to 1 mM), dopamine (up to 0.5 mM), and ascorbic acid (up to 50 μM) did not affect the signal of the biosensor toward uric acid. The biosensor was tested on spiked artificial urine samples, and showed 101% recovery for tenfold diluted samples. The ease of assembly of the flow cell and the low cost of the replacement parts make for a promising future application of the biosensor system in routine clinical analyses. [ABSTRACT FROM AUTHOR]

A Ni–Fe binary alloy ingot, prepared by conventional vacuum smelting, was adopted as substrate in this work to fabricate the anode for water splitting. To improve the surface roughness of anode surface, the electrode was firstly subjected to anodic leaching in a simple KSCN solution. The as-leached electrode was subsequently activated through linear sweep voltammetry in 1 M KOH solution with or without 0.33 M urea addition to finish the final step for electrode preparation. The as-prepared anode delivers the 10 mA cm−2 current density at an overpotential of 284 mV for oxygen evolution reaction (OER) and at 1.361 V (RHE) for urea oxidation reaction (UOR), respectively. No apparent change of OER and UOR performance was observed after chronopotentiometric aging. The more complex UOR behavior was analyzed to elucidate the synergy among all constituents functioning through direct or indirect mechanisms for the half-reaction on this binder-free, self-supporting and substrate-rejuvenating anode. • Anode for OER and UOR was prepared by leaching of Ni2Fe ingot in KSCN solution. • Chronopotentiometric aging was used to stabilize composition and performance. • Indirect or regeneration mechanism owing to Ni-based (oxy)hydroxide was proposed. • Reactivity of Fe-containing species and nickel hydroxide carbonate was evaluated. [ABSTRACT FROM AUTHOR]

High‐entropy alloys (HEAs) have offered wide opportunities for materials discovery, property optimization, and application exploration. In spite of some encouraging progress, manipulating HEAs with functional morphology/mesostructure and controlled chemical orderliness remains a big challenge. In this manuscript, a powerful and general strategy to synthesizing libraries of mesoporous high‐entropy intermetallics (MHEIs) with controlled orderliness in both mesoscopic and atomic levels is reported for the first time. Final products feature an ordered polyhedral morphology and double‐gyroid mesostructure as well as long‐range L10 intermetallic phase and HEA composition, delivering multiple advantages for enhancing electrochemical performance in oxygen reduction reaction (ORR) and single rechargeable zinc–air battery. Specifically, MHEI‐PtPdFeCoNi affords remarkable ORR activity (0.63 A mg−1 for mass activity and 1.01 mA cm−2 for specific activity) and superior stability (≈87% activity retained for 50 000 cycles and chronoamperometry tests) compared with the MHEAs with disordered atomic arrangement and commercial Pt/C. The excellent performance comes from the optimized surface HEA multimetallization as well as ordered intermetallic and mesoporous structure that changes the chemisorption of O*/OH* intermediates and lowers the overall energy barrier of oxygen reduction. [ABSTRACT FROM AUTHOR]

Recent experiments have demonstrated that 1T phase of transition-metal dichalcogenides exhibits superior electro-catalytic activity for hydrogen evolution reaction (HER). Herein, we compare the HER performance of as obtained 2H-phase MoSe 2 (bare) with hydrothermally synthesized 1T-2H mixed phase MoSe 2 and its composites with reduced graphene oxide. Obtained MoSe 2 /rGO composite has displayed a Tafel slope of 55 mV dec−1 compared with mixed-phase (113 mV dec−1) and 2H–MoSe 2 (125 mV dec−1, bare). Composite of MoSe 2 with very small amount of rGO has shown increased HER activity with low overpotential (88 mV at 10 mA cm−2), smaller Tafel slope, longer durability and high value of turn over frequency. The weight ratio between MoSe 2 and rGO is crucial in determining the HER performance of the composite. The Present work offers a facile and attractive methodology for enhancing the HER performance of 2D materials-based electrocatalysts. • MoSe 2 /rGO composites were synthesized via facile hydrothermal route. • Presence of 1T/2H–MoSe 2 phase improved the catalytic properties. • Weight ratio between MoSe 2 and rGO plays a key role in HER kinetics. • MoSe 2 /rGO composite with ideal weight ratio possesses lower Tafel slope (55 mVdec−1). • Lower overpotential and charge transfer resistance give smaller Tafel slope in composite. [ABSTRACT FROM AUTHOR]

In this investigation the effect of temperature on catalytic oxidation of ethanol on multi‐metallic PdCoNi/C nano‐composite bearing reduced palladium loading, have been studied over the temperature range 20 °C to 80 °C. The structure, composition and surface morphology of the catalyst regime were determined through the respective techniques like XRD, EDX and TEM while electro‐catalytic parameters were evaluated by the help of voltammetry, chronoamperometry, impedance spectroscopy and ion‐chromatography. The apparent activation energies (Ea) of ethanol oxidation reaction (EOR) were drastically reduced over PdCoNi/C compared to Pd/C reflecting the energy efficiency of ternary matrix furnished with only 35 % Pd loading and the rest 65 % being cheaper transition metals. The long term poisoning rates warrant improved stability of PdCoNi/C and also figure out the robustness of the catalyst even at 20 °C. The Ea value is remarkably reduced, rendering appreciable mass activity in terms of current density per mg of Pd at each of the temperatures studied. The incorporation of transition metals Co and Ni onto Pd becomes particularly effective in orienting the EOR proceed through carbonate pathway as reflected by the columbic efficiency in terms of oxidation product yield ~5 times higher, compared to single Pd catalyst throughout the temperature range. [ABSTRACT FROM AUTHOR]

The present work evaluates the effect of Co content on the microstructure and corrosion performance of Al–Co alloys of various compositions (2–32 wt% Co), fabricated by flux-assisted stir casting. A preliminary investigation on the effect of heat treatment (600 °C, up to 72 h) on the microstructure and corrosion behavior of Al–20 wt% Co and Al–32 wt% Co was also conducted. The Al– (2–10) wt% Co alloys were composed of acicular Al9Co2 particles uniformly dispersed in an Al matrix. The Al–20 wt% Co and Al–32 wt% Co alloys additionally contained Al13Co4 blades enveloped in Al9Co2 wedges. Heat treatment of Al–20 wt% Co and Al–32 wt% Co led to a significant reduction in the volume fraction of Al13Co4 and a decrease in hardness. Al–Co alloys with high Co content (10–32 wt% Co) exhibited greater resistance to localized corrosion in 3.5 wt% NaCl, but lower resistance to general corrosion compared to the (0–5 wt% Co) alloys. Heat treatment led to a slight increase in the corrosion resistance of the Al–Co alloys. The microstructure of the produced alloys was analyzed and correlated with the corrosion performance. Finally, corrosion mechanisms were formulated. [ABSTRACT FROM AUTHOR]

The microscopic arrangement of alloys has a significant influence on their electrical, thermal, mechanical, and catalytic properties. In this respect, we have developed nickel-cobalt alloy films by electrodeposition on an ITO glass substrate while examining nucleation and growth processes during the first steps of electrocrystallization. Energy Dispersive X-ray Spectroscopy (EDX) approved stoichiometry (1,1) of the alloy elaborated. X-ray diffraction (XRD) showed that the Co-Ni binary electrodeposited at different potentials crystallizes in a cubic structure that belongs to the Pm3̅m space group. From chronoamperometry and cyclic voltammetry curves, we concluded that the Co-Ni/ITO system is quasi-reversible, with diffusion of Ni2+ and Co2+ cations being the controlling step. The ascending part of the current-time transients investigation has shown that the Ni-Co electrodeposition mechanism is characterized by instantaneous nucleation in line with 3D growth. This result is confirmed by comparison of the experimental chronoamperometry data with the theoretical models of Scharifker and Hills on the one hand, and Bewick, Fleischmann, and Thirsk on the other. [ABSTRACT FROM AUTHOR]

This study reports, for the first time, the utilization of two-dimensional (2D) tellurium (Te) nanosheets for the efficient nonenzymatic detection of hydrogen peroxide (H2O2). H2O2 acts as a pivotal biomarker with widespread applications across environmental, biological, industrial, and food processing domains. However, an excessive accumulation of H2O2 in the body poses a severe threat to human life. Consequently, the imperative need for a selective, sensitive, and cost-effective sensing platform for H2O2 detection has gained paramount significance. Employing a low-cost and straightforward hydrothermal method, Te nanosheets were synthesized to address the escalating demand for a reliable detection platform. The as-synthesized Te nanosheets are characterized through Raman spectroscopy and atomic force microscopy techniques. The electrochemical performance of the Te nanosheets integrated onto a glassy carbon (Te-GC) electrode was thoroughly investigated using cyclic voltammetry, differential pulse voltammetry, and chronoamperometry. The experiments were designed to evaluate the response of the Te-GC electrode in the presence and absence of H2O2, alongside its performance in the detection of other pertinent interfering analytes. The sensor shows a limit of detection of 0.47 µM and a sensitivity of 27.2 µA µM−1 cm−2 towards H2O2. The outcomes of this study demonstrate the efficacy of Te nanosheets as a promising material for nonenzymatic H2O2 detection in urine samples. The simplicity and cost-effectiveness of the hydrothermal synthesis process, coupled with the notable electrochemical performance of the Te/GC electrode, highlight the potential of Te nanosheets in the development of a robust sensing platform. This research contributes to the ongoing efforts to enhance our capabilities in monitoring and detecting H2O2, fostering advancements in environmental, biomedical, and industrial applications. [ABSTRACT FROM AUTHOR]

ABSTRACTIn order to find a green and safe solution as the base solution for the quantitative detection of glucose, the neutral solution Na2S2O3 was selected as the base solution. A three-electrode electrochemical system was designed. In this system, the working electrode was copper sheet, the counter electrode was platinum electrode, and the reference electrode was saturated KCl calomel solution electrode. Cyclic voltammetry (CV) and chronoamperometry(i-t) methods were used for the experiment. CV scanning results showed that glucose could produce the oxidation-reduction reaction on the surface of the copper electrode, and the parameters of i-t were adjusted. According to the results of i-t scanning, the quantitative detection model of glucose was established. The model was [Formula: see text]. The regression parameter R2 was 0.99672. Glucose was tested with different base solutions. Results showed that Na2S2O3 solution was a good base solution. The i-t control experiments showed that the proposed method were effective in Na2S2O3 solution.

In this study, we demonstrate the electrodeposition of copper nanoparticles (NPs) on pencil graphite electrodes (PGEs) utilizing sodium dodecyl sulphate (SDS) as a soft template. The utilization of the surfactant had an impact on both the physical arrangement and electrochemical characteristics of the modified electrodes. The prepared Cu-SDS/PGE electrodes had hierarchical dendritic structures of copper NPs, thereby increasing the surface area and electrochemical catalytic activity in comparison with Cu/PGE electrodes. The Cu-SDS/PGE electrode showed excellent catalytic activity in reducing hydrogen peroxide, resulting in the sensitive and selective detection of hydrogen peroxide. The electrode exhibited a good sensitivity of 21.42 µA/µM/cm2, a lower limit of detection 0.35, and a response time of less than 2 s over a wide range spanning 1 µM to 1 mM of hydrogen peroxide concentrations. The electrodes were also highly selective for H2O2 with minimal interference from other analytes even at concentrations higher than that of H2O2. The approach offers the benefit of electrode preparation in just 5 min, followed by analysis in 10 min, and enables for the quantitative determination of hydrogen peroxide within 30 min. This can be achieved utilizing a newly prepared, cost-effective electrode without the need for complex procedures.

Gas permeability, the product of gas diffusivity and Henry's gas-absorption constant, of ionomer membranes is an important transport parameter in fuel cell and electrolyzer research as it governs gas crossover between electrodes and perhaps in the catalyst layers as well. During transient operation, it is important to divide the gas permeability into its constituent properties as they are individually important. Although transient microelectrode measurements have been used previously to separate the gas permeability into these two parameters, inconsistencies remain in the interpretation of the experimental techniques. In this work, a new interpretation methodology is introduced for determining independently diffusivity and Henry's constant of hydrogen and oxygen gases in ionomer membranes (Nafion 211 and Nafion XL) as a function of relative humidity using microelectrodes. Two time regimes are accounted for. At long times, gas permeability is determined from a two-dimensional numerical model that calculates the solubilized-gas concentration profiles at a steady state. At short times, permeability is deconvoluted into diffusivity and Henry's constant by analyzing transient data with an extended Cottrell equation that corrects for actual electrode surface area. Gas permeability and diffusivity increase as relative humidity increases for both gases in both membranes, whereas Henry's constants for both gases decrease with increasing relative humidity. In addition, results for Nafion 211 membranes are compared to a simple phase-separated parallel-diffusion transport theory with good agreement. The two-time-regime analysis and the experimental methodology can be applied to other electrochemical systems to enable greater precision in the calculation of transport parameters and to further understanding of gas transport in fuel cells and electrolyzers.

This research investigates the impact of electrochemical activation on cobalt-tin (Co x -Sn 100-x) bimetallic nanocatalysts for the methanol oxidation reaction (MOR) in acidic conditions. Two electroactivation protocols, namely activation in a phosphate buffer (PB) solution and in-situ activation, using chronoamperometry, were developed. The electrochemical performance of the MOR electrocatalyst was evaluated through cyclic voltammetry analysis within a specific electrode potential range. Optimal activation conditions for the PB solution were achieved at a pH of 3.0 and an activation potential of −1.3 V (vs. Ag/AgCl), while the in-situ activation process showed the best results at an activation potential of −0.7 V (vs. Ag/AgCl). Both the in-situ and PB electroactivated Co 65 –Sn 35 catalysts exhibited significant enhancements in MOR activity, with the in-situ activation resulting in a 10-fold increase and the PB activation leading to an 8.5-fold increase. The proposed mechanism for this substantial enhancement involves simultaneous hydrogen evolution and water electrolysis during the electroactivation treatments of the Co 65 –Sn 35 electrocatalyst. In fact, the formation of OH ads species during the electroactivation treatment could provide a fraction of OH ads which was essential for the MOR. These findings might present opportunities for the engineering and design of bimetallic noble metal-free nanocatalysts for efficient utilization in high-performance acidic direct methanol fuel cells (DMFCs). • Phosphate buffer (PB) and in-situ electroactivation developed for Co 65 –Sn 35 nanocatalyst. • In-situ and PB-activated Co 65 –Sn 35 catalysts show 10-fold and 8.5-fold MOR activity increase respectively. • Optimal activation achieved at pH 3.0 and −1.3 V (vs. Ag/AgCl) for PB, −0.7 V for in-situ. • Local pH increases at the electrode – electrolyte interface due to acidic HER. • Simultaneous hydrogen evolution and water electrolysis generate H 2 O ads and crucial OH ads for MOR. [ABSTRACT FROM AUTHOR]

Electrochemical methods offer unique advantages for chemical synthesis, as the reaction selectivity may be controlled by tuning the applied potential or current. Similarly, measuring the current or potential during the reaction can provide valuable mechanistic insights into these reactions. The aim of this tutorial review is to explain the use of cyclic voltammetry and chronoamperometry to interrogate reaction mechanisms, optimize electrochemical reactions, or design new reactions. Fundamental principles of cyclic voltammetry and chronoamperometry experiments are presented together with the application of these techniques to probe (electro)chemical reactions. Several diagnostic criteria are noted for the use of cyclic voltammetry and chronoamperometry to analyze coupled electrochemical–chemical (EC) reactions, and a series of individual mechanistic studies are presented. Steady state voltammetric and amperometric measurements, using microelectrodes (ME) or rotating disk electrodes (RDE) provide a means to analyze concentrations of redox active species in bulk solution and offer a versatile strategy to conduct kinetic analysis or determine the species present during (electro)synthetic chemical reactions. [ABSTRACT FROM AUTHOR]

Neodymium Indium sulphide (Nd4In5S13) photoactive electrode was produced by spin‐coating for photoelectrochemical cell. The photoactive electrode is analysed for its crystalline, structural and elements makeup in addition to its optical and electrical responses. A 56 nm sized orthorhombic crystallite was found and geometrical compact structures were observed. The presence of chief elements with core levels of In3d, Nd4d and S2p were detected. The bandgap energy was found to be 4.1 eV. Electrochemical investigations were performed to evaluate the photoactive efficiency of the electrode. Photo‐cyclic voltammetry present a specific capacitance under illumination to be 570 Fg−1, as contrasting to 481 Fg−1 when in dark. A photocurrent density of 282 mA cm−2 was obtained from photo‐linear sweep voltammetry. It had also been discovered that the transient chronoamperometry provided a photocurrent density of 46.1 mA cm−2. Whereas electrical impedance spectroscopy presented internal resistance (Rs) to be 232 Ω. All scan rates show an increase in the specific capacitance of photo‐electrode when illuminated. The research created an effective photo‐electrode for renewable energy structures. It can be posited that the study presented a pragmatic photoelectrode, which had the potential to be employed in sustainable energy frameworks, including but not limited to photovoltaics, supercapacitors, and photoelectrochemical solar cells. [ABSTRACT FROM AUTHOR]

In this study, practical application for the industrial-scale hydrogen evolution reaction (HER) process is established using sustainable Cu 2 CoSnS 4 embedded in paper-working electrodes. The Cu 2 CoSnS 4 is produced using a solvent-free solid-phase approach. The effect of a wide pH range of electrolytes on working electrodes for hydrogen evolution reactions is also investigated. The Cu 2 CoSnS 4 embedded paper-working electrodes exhibit goodelectrocatalytic activity for hydrogen evolution reaction with low overpotential values of 233, 310, and 261 mV vs RHE at 10 mA/cm 2 in 0.5 M H 2 SO 4 ,1 M KOH, and 1 M PBS, respectively. These designed electrodes exhibit high double-layer capacitance and electrochemical surface area for a wide pH range. In acidic, alkaline and neutral environments, the catalyst-embedded paper electrodes explicit high turnover frequencies of 2.15 s−1, 2.75 s−1, and 2.11 s−1, respectively. The temperature-dependent hydrogen evolution reaction is studied to calculate the activation energy of the cathodic electrode. Utilising chrono-amperometry for about 118 h in an acidic media, which shows that electrodes have a high degree of stability. In comparison to other previously reported work on catalyst-embedded electrodes, the Cu 2 CoSnS 4 embedded paper-working electrodes offer excellentpotential for HER activity across a wide pH range and are suitable for industrial application. • Cu 2 CoSnS 4 embedded paper working electrodes are developed for hydrogen generation. • The electrodes exhibit universal pH hydrogen evolution reaction. • Electrodes shows excellent stability upto 40hr for continuous hydrogen generation. • The electrode displays good stability at current density more than 200 mA/cm2. [ABSTRACT FROM AUTHOR]

This study aims to evaluate the effect of cerium nitrate as an additive to the polymerization solution on the physico-chemical and anti-corrosion properties of sol–gel γ-glycidoxypropyltriethoxysilane polymers (GPS) applied onto AA2024-T3 aluminum alloy. The polymerization solution was prepared from a mixture of silane precursor and Ce(NO3)3 with a concentration ranging from 0 to 10−1 M. The coatings were electrodeposited by chronoamperometry at an applied potential of − 0.80 V/SCE. Their morphologies were examined by Scanning Electron Microscopy (SEM). The relative chemical compositions were characterized using Attenuated Total Reflectance Infrared Spectroscopy (FTIR-ATR) and X-ray Diffraction (XRD). Electrochemical impedance spectroscopy (EIS) was carried out to assess coating corrosion behaviors in a 5 × 10−2 M NaCl solution. Results showed that the addition of Ce(NO3)3 affected the uniformity, roughness, and thickness of the electrodeposited coatings. Furthermore, cerium improved the anti-corrosion performance of GPS film, particularly at a concentration of 3.3 × 10−2 M. This corrosion resistance resulted mainly from blocking the corrosion activity of the damaged surface through the formation of protective Ce oxides/hydroxides. [ABSTRACT FROM AUTHOR]

The electrolytic refining of crude tin is generally carried out in the fluorosilicic acid (H2SiF6) system with the assistance of bone glue and β-naphthol. However, the high saturated vapor pressure and low stability of H2SiF6 present environmental concerns and do not align with sustainable development goals. In this paper, the electrochemical behavior of tin on a glassy carbon (GC) electrode was studied in a relatively green and environmentally friendly methanesulfonic acid (MSA) system. Bone glue, sodium lignosulfonate, and β-naphthol were used as additives to make the deposit morphology smooth and to ensure grain refinement. The electrochemical reduction process of Sn2+ in an MSA system is a quasi-reversible process controlled by diffusion. The apparent activation energy E a = 14.189 kJ/mol for the ion diffusion of Sn2+ was further calculated. The results of chronoamperometry showed that the electrocrystallization of Sn2+ on the GC electrode gradually tended to three-dimensional instantaneous nucleation with the increase in applied potential. The morphology and phase of the deposits were analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that the deposits were uniform and dense pure tin. This work elucidates the electrochemical behavior of tin in a methanesulfonic acid system. [ABSTRACT FROM AUTHOR]

Development of stable and advanced functionality is highly desirable for designing an electrochemical sensor for detecting a hazardous analyte. By employing a facile urea-assisted chemical precipitation method, nanocube-shaped copper (II) oxide (CuO NC) was obtained. The physiochemical characterizations of CuO NC were carried out by utilizing characterization techniques to analyze the morphology, crystal structure, elemental compositions, and functional groups present in the prepared catalyst. The prepared monoclinic CuO NC was employed for the electrochemical quantification of hydroxylamine at an applied potential of 0.6 V. The as-synthesized material achieved a lower detection limit of 0.8 μM with a linear detection range of 5–5000 μM and a sensitivity of 612 μA mM−1 cm−2. CuO NC had been successfully employed as a modifier for practical application toward the sensing of hydroxylamine in domestic pond water and ground water samples. [ABSTRACT FROM AUTHOR]

Herein we demonstrated the preparation of sulphur-doped graphene (SG) prepared via hydrothermal route. The resulted material is used for making highly sensitive and selective electrochemical sensor platform for accurate quantification of Hydrogen Peroxide (H2O2). Structural features and surface morphology of synthesised materials are fully examined using High resolution Transmission electron microscopy (HRTEM), Scanning electron microscopy (SEM), FT-IR and Raman spectroscopy techniques. In addition to that, electrochemical techniques like cyclic voltammetry (CV) and chronoamperometry (CA) are used to quantify the electron transfer kinetics and electro catalytic activity, these results inveterate it is due to strong electron donating ability of doped sulphur (S) atom and edge plane sites in SG that promotes the electron transfer process at electrode-electrolyte interface. The SG modified glassy carbon electrode (SG/GCE) exhibited finite selectivity; sensitivity stability with a regression coefficient (R2) value is 0.99 towards H2O2 estimation. The above observation conclude that these results are finest report to scrutinise the electrochemical properties of Graphene network by doping with Sulphur atom and it served as an important benchmark for the development of inexpensive SG based sensor platforms for electrochemical biosensor applications. [ABSTRACT FROM AUTHOR]

This work aims to demonstrate that chronoamperometry is a valuable tool for determining diffusivities in all‐solid‐state nanometer‐thick cells. The transient current in chronoamperometry of electrochemical cells under constant voltage is described by firstly considering purely capacitive processes, defined by RC circuit equations, and then purely diffusive processes, by Cottrell's equations. The physical meaning of the equations has been amply described in liquid cells with porous electrodes but scarcely in solid‐state cells. Thus, we studied Metal/Insulator/Metal nano‐cells with Ru and Au electrodes, Yttria Stabilized Zirconia (YSZ) electrolyte at temperatures between 50 and 170°C and voltages between 0.5 V and 1.5 V, where non‐Faradaic processes occur. The calculated diffusive and capacitive contributions at different temperatures obey the Arrhenius law. The activation energy was associated with vacancies, the major carrier during electrical transport. The analysis discusses other parameters, such as capacitance, effective concentration, and leakage current. The experimental diffusivity of YSZ electrolytes was compared with diffusivity values obtained by the statistical moment method. [ABSTRACT FROM AUTHOR]

Glycerol is a by-product obtained in the transesterification reaction together with biodiesel, a necessary renewable fuel. The presence of glycerol in fuel can bring up environmental harm and engine damage, making fuel quality control important. In this context, composite electrodes (CE) were developed with low-cost materials like syringes, copper wire, graphite, and paraffin. The surface of composite electrodes was modified with reduced graphene oxide (RGO) and hydroxide nickel (Ni(OH)2). SEM, EDX, Raman, and FT-IR ATR characterized the developed material. The electrooxidation of glycerol in an alkaline medium containing 0.10 M of NaOH was investigated by CV. In the presence of glycerol, the modified electrode increased the anodic and cathodic peak current with an anodic peak potential shift to 0.54 V. The electrodes were employed in a study of the determination of glycerol in real biodiesel samples by a chronoamperometric technique. The modified electrode showed a sensitivity of 1.63 × 103 µA mM and a LOD for glycerol of 2.24 × 10–5 M (R = 0.996). The mean response time of the modified electrodes to glycerol was 1.85 s. These electrodes show good reproducibility and competitive detection limit compared to the literature. The proposed method presented satisfactory results, with 94.98 and 100.39% sample recoveries. [ABSTRACT FROM AUTHOR]

A promising approach for noninvasive medical diagnosis may be to measure the VOCs produced by metabolic changes or pathological disorders in human sweat, such as measuring the acetone levels in the presence of diabetes. Acetone is a by‐product of fat catabolism and serves as an indicator of ketosis and diabetes. The measurement of acetone may be used instead of glucose monitoring. Current research aims to develop and improve noninvasive methods of detecting acetone in sweat that are accurate, sensitive, and stable. The carbon nanotubes (CNTs)–copper oxide (CuO) nanocomposite (NC) improves direct electron transport to the electrode surface in this study. The complex‐precipitation method is used to make this NC. X‐ray diffraction (XRD) and scanning electron microscopy (SEM) are used to investigate the crystal structure and morphology of the prepared catalyst. Using cyclic voltammetry (CV) and amperometry, the electrocatalytic activity of the as‐prepared catalyst is evaluated. The electrocatalytic activity in artificial sweat solution is examined at various scan rates and acetone concentrations. The detection limit of the CNTs‐CuO NC catalyst is 0.05 mm, with a sensitivity of 16.1 mA cm−2 µm−1 in a linear range of 1–50 mm. Furthermore, this NC demonstrates a high degree of selectivity for various biocompounds found in sweat, with no interfering cross‐reactions from these species. The CNT‐CuO NC, as produced, has good sensitivity, rapid reaction time (2 s), and stability, indicating its potential for acetone sensing. [ABSTRACT FROM AUTHOR]

Total electrical conductivity of CaF2–SiO2–CaO–TiO2 welding fluxes has been investigated using the four-electrode method, and the underpinning conductive mechanisms have been clarified. To quantify the contribution of the electronic/ionic conductivity to the total electrical conductivity, electronic transference numbers have been measured using the stepped potential chronoamperometry method. The results show that electronic and ionic conductivity of the fluxes increases with higher temperature, thereby increasing the total electrical conductivity, which indicates that conductivity in the molten fluxes is a thermally activated process. Higher TiO2 content favors electronic conductivity as improved Ti3+/Ti4+ mass ratio facilitates electron hopping. However, electronic conductivity decreases with increasing TiO2 content, which is accompanied by the enhanced degree of depolymerization of the silicate network. In addition, the conductive mechanism of the fluxes is controlled by an electronic-ionic mixed mode. The increased value of electronic conductivity is significantly greater than the reduced value of ionic conductivity with higher TiO2 content, resulting in a net increase for the total electrical conductivity. [ABSTRACT FROM AUTHOR]

In this work, bismuth oxychloride with a rose‐type flower shape was successfully synthesised using the easy and low‐cost successive ionic layer adsorption and reaction process. The tetragonal crystalline structure with a flower‐like shape and thickness of 150‐nm nanosheets was used as electrode material in an exciting approach for the photoelectrochemical discoloration reaction of methyl orange. The structure, morphology and optical properties of the obtained bismuth oxychloride sample were evaluated through X‐ray diffraction, Raman spectroscopy, the Brunauer–Emmett–Teller method, diffuse reflectance ultraviolet–visible spectroscopy and scanning electron microscopy. Through photoelectrochemical characterisation measurements (linear sweep voltammetry, chronoamperometry and electrochemical impedance spectroscopy techniques), the bismuth oxychloride electrode showed remarkable electroactivity under ultraviolet light irradiation. The methyl orange discoloration reaction, performed under ultraviolet light incidence and potential application of −0.5 V (vs silver/silver chloride) for 60 minutes, produced a higher degradation percentage (ca. 82%) and kobs of 29 × 10−3 min−1. [ABSTRACT FROM AUTHOR]

Dynamic electrochemical impedance spectroscopy (dEIS), an extension of conventional EIS, was used for rapid measurements of initiation of localised corrosion on 3005 aluminium alloys with different Mn (1.08–1.39 wt. %) and Cu (0.15–0.22 wt. %) content by evaluating the onset and evolution of a Faradaic process observed in 0.5 M Na2SO4+0.1 M NaCl. Differences between samples were detected with highest sensitivity from the charge transfer resistance during chronoamperometry at ca. 120 mV above the corrosion potential. These differences were caused by differences in pitting initiation, and correlated well with filament density from a filiform corrosion (FFC) test of samples coated with a 20 μm epoxy topcoat. The observation can be explained by the role of pitting in FFC initiation and the similarity in FFC propagation with pit growth. The results suggest that dEIS is an efficient method for screening alloys for their FFC susceptibility. [ABSTRACT FROM AUTHOR]

One reason for the interest in surface modification of magnetite nanoparticles is to create a physical barrier that inhibits their agglomeration and enhances their dispersion. The other reason is to provide different functionalities to the surface. Various functional groups, such as silanes, amines, and hydroxyls, have been successfully utilized as alternatives to functionalize the surface of magnetite. In this study, pyrogallol was selected to be chemically bonded to the surface of magnetite nanoparticles by bridging two of its hydroxyl groups to the iron of magnetite, leaving one extra hydroxyl group in the molecule for further electrochemical characterization. Therefore, we investigated the electrochemical behavior of pyrogallol in solution and when attached to magnetite nanoparticles. Our results include cyclic voltammetry and chronoamperometry of pyrogallol in solution and on pyrogallol-modified magnetite nanoparticles in media with different pH values on a gold electrode. The functionalization of magnetite was confirmed by TGA and FTIR techniques. Additionally, the size of the modified magnetite-pyrogallol nanoparticles was determined by TEM. The attached pyrogallol molecules on modified magnetite-pyrogallol nanoparticles allowed for the production of a stable colloidal suspension that prevented oxidation and agglomeration. We detailed a mechanism of oxidation of pyrogallol that is consistent with the experimental electrochemical results. Finally, we presented an electrochemical characterization of modified pyrogallol-modified magnetite nanoparticles in supernatant and centrifuged solutions. [ABSTRACT FROM AUTHOR]

Electrochemical oxidation is a low-toxicity, fast-reacting technology that is easy to employ. This technology has great promise for improving the sustainability and efficiency of wastewater treatment by eliminating dyes and other organic contaminants. In this study, a cathodic electrodeposition technique was used to effectively synthesize pure Cu-MOF on a Pt electrode. Fourier-Transform Infrared Spectroscopy (FTIR), Ultraviolet -Visible Spectroscopy (UV-Vis), Scanning Electron Microscopy (SEM), Energy-Dispersive X-Ray (EDX), and X-Ray Diffraction (XRD) were used to evaluate the synthesized Copper-Metal Organic Framework (Cu-MOF). The electrochemical degradation of tartrazine dye in an aqueous KCl solution under various conditions was used to evaluate the electrochemical efficiency of the Cu-MOF/Pt electrode. Tartrazine (Tz) degradation as a function of time has been adjusted for the influence of operational parameters such as the type of supporting electrolyte, pH of the solution, accumulation time, and applied potential. Based on the results, the acid medium (pH=3) was the most beneficial medium for the active degradation of Tz dye at optimal operating conditions. It was found that 99 % of the dye had disappeared following 20 min of electrolysis. The optimal potential for the degradation of Tz was 1.4 V of the applied potential since it has no negative impacts on the energy consumption or stability and durability of the electrodes. The Tz degradation was fitted to pseudo-first-order kinetics with a rate constant of 0.124 min-1. The findings demonstrated that Cu-MOF/Pt has a good electrochemical efficiency of 99 %, and the electrode recovery, reproducibility, and reusability have all been researched. A computational investigation used the Lee/Yang/Parr (B3LYP) level, 6-311++ G(d,p), as the basis for function set calculation to demonstrate the electrochemical destruction of Tz by the HClO radical. The results showed that the experimentally predicted mechanism and the theoretically determined mechanism agreed remarkably well. According to the proposed mechanism, Cu-MOF functions as a catalyst in the degradation of Tz, where it discharges water to produce HO• radicals, which are physically adsorbed on the Cu-MOF/Pt surface. Cu-MOF(HO•) combines with Cl− ions presence in water to form Cu-MOF(HClO) which attacks Tz dye in the azo bond (–N=N–) and degrades it into CO2 and H2O.

Molten salts such as 2LiF-BeF2 (FLiBe) have been proposed as coolants for advanced nuclear fission and fusion reactors. Critical to the design, licensing and operation of these reactors is characterization and understanding of the chemical behavior and mass transport of activation and fission products, corrosion products, and other solutes in the coolant. Electrochemical techniques are a powerful suite of tools for probing these phenomena. The design of an experimental cell for molten salt electrochemistry is described herein. As a demonstration of this design, details of the experimental methods used to conduct electrochemical experiments with molten FLiBe with addition of LiH are provided. Decommissioning of the cell is considered from the point of view of decontamination and waste generated. Main features of the cell include:•Suitable for operation up to 800 °C; suitable for operation inside and outside of a glovebox.•Enables sweep gas, gas sampling and analysis; enables addition of solid and liquid materials during operation.•Supports a variety of electrode materials and arrangements.

This paper describes the design and development of a novel electrochemical biosensor for measuring glycerol in wine. Our initial detailed studies were aimed at deducing the optimum conditions for biosensor operation by conducting hydrodynamic voltammetric and amperometric studies. The resulting voltammograms revealed a maximum electrocatalytic current at 0.0 V vs. Ag/AgCl, which we used for all further studies. We also examined the effect of pH (8–10) on the amperometric responses of different glycerol concentrations over a range of 0.04 to 0.20 mM. Based on our findings, we propose that pH 9 would be suitable as the supporting electrolyte for further studies with the amperometric biosensor. The biosensor was constructed by immobilising 10 units of GLDH and 660 μg NAD+ onto the MB-SPCE surface using glutaraldehyde (GLA) as a cross-linking agent. Calibration studies were performed with glycerol over the 1.0–7.5 mM concentration range. Chronoamperometry was the electrochemical technique chosen for this purpose as it is convenient and can be performed with only 100 μL of sample directly deposited onto the biosensor’s surface. In the current study, we observed linear calibration plots with the above standard solutions using current measurements at a selection of sampling times along the chronoamperograms (30–340 s). We have evaluated the glycerol biosensor by carrying out an analysis of commercially available red wine. Overall, these findings will form a platform for the development of novel rapid technology for point-of-test evaluation of glycerol in the production and quality control of wine.