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We synthesized 2‐(1‐1,2‐dicarbadodecaboranyl(12))‐6,6,12,12‐tetramethyl‐7,8,11,12‐tetrahydro‐6H,10H‐phenaleno[1,9‐fg]pyrido[3,2,1‐ij]quinoline (4), a julolidine‐like pyrenyl‐o‐carborane, with pyrene substituted at the 2,7‐positions on the HOMO/LUMO nodal plane. Using solid state molecular structures, photophysical data, cyclic voltammetry, DFT and LR‐TDDFT calculations, we compare o‐carborane and B(Mes)2 (Mes=2,4,6‐Me3C6H2) as acceptor groups. Whereas the π‐acceptor strength of B(Mes)2 is sufficient to drop the pyrene LUMO+1 below the LUMO, the carborane does not do this. We confirm the π‐donor strength of the julolidine‐like moiety, however, which raises the pyrene HOMO‐1 above the HOMO. In contrast to the analogous pyrene‐2‐yl‐o‐carborane, 2‐(1‐1,2‐dicarbadodecaboranyl(12))‐pyrene VI, which exhibits dual fluorescence, because the rate of internal conversion between locally‐excited (LE) and charge transfer (CT) (from the pyrene to the carborane) states is faster than the radiative decay rate, leading to a thermodynamic equilibrium between the 2 states, 4 shows only single fluorescence, as the CT state involving the carborane as the acceptor moiety in not kinetically accessible, so a more localized CT emission involving the julolidine‐like pyrene moiety is observed. [ABSTRACT FROM AUTHOR]

We investigated sex differences in dopamine (DA) release in the nucleus accumbens (NAc) and dorsolateral striatum (DLS) using a chronic 16-channel carbon fiber electrode and fast-scan cyclic voltammetry (FSCV). Electrical stimulation-induced (ES; 60 Hz) DA release was recorded in the NAc of single- or pair-housed male and female rats. When core (NAcC) and shell (NAcS) were recorded simultaneously, there was greater ES DA release in NAcC of pair-housed females compared with single females and males. Housing did not affect ES NAc DA release in males. In contrast, there was significantly more ES DA release from the DLS of female rats than male rats. This was true prior to and after treatment with methamphetamine. Furthermore, in castrated (CAST) males and ovariectomized (OVX) females, there were no sex differences in ES DA release from the DLS, demonstrating the hormone dependence of this sex difference. However, in the DLS of both intact and gonadectomized rats, DA reuptake was slower in females than that in males. Finally, DA release following ES of the medial forebrain bundle at 60 Hz was studied over 4 weeks. ES DA release increased over time for both CAST males and OVX females, demonstrating sensitization. Using this novel 16-channel chronic FSCV electrode, we found sex differences in the effects of social housing in the NAcS, sex differences in DA release from intact rats in DLS, and sex differences in DA reuptake in DLS of intake and gonadectomized rats, and we report sensitization of ES-induced DA release in DLS in vivo. [ABSTRACT FROM AUTHOR]

Here, we report the systematical synthesis of zeolite‐templated carbon (ZTC) supported Ru and Rh mono‐ or bi‐metallic electrocatalysts towards hydrogen evolution reaction (HER). The zeolite A or ZSM‐5 derived ZTC supports and metal sites were adjusted, and all electrocatalysts outperformed the commercial Pt/C electrocatalyst for HER performance. In particular, the RhRu/(ZTC/ZSM5) sample exhibited superior catalytic performance with the overpotential of 24.8 mV@10 mA ⋅ cm−2, and outstanding stability with 1 mV drop after 20000 cyclic voltammetry circles. This work offers a simple impregnation method for the synthesis of highly performed HER electrocatalysts supported on porous zeolite‐templated carbon. [ABSTRACT FROM AUTHOR]

An electrochemical method with high faradaic efficiency was developed for the ruthenium‐catalyzed C8‐regioselective aroylation of quinoline N‐oxides under oxidant‐free conditions by using aryl α‐ketoacids as the aroylation reagent. A series of 8‐aroylquinoline N‐oxides were effectively synthesized in moderate‐to‐excellent yields. Furthermore, the proposed method was successfully applied to the gram‐scale synthesis of a tubulin polymerization inhibitor. Additionally, a plausible reaction mechanism for the decarboxylation radical acylation was proposed on the basis of the results of cyclic voltammetry and control experiments. Overall, this method provides a novel solution for the C8‐regioselective aroylation of quinoline N‐oxides. [ABSTRACT FROM AUTHOR]

Many biological processes rely on endogenous electric fields (EFs), including tissue regeneration, cell development, wound healing, and cancer metastasis. Mimicking these biological EFs by applying external direct current stimulation (DCS) is therefore the key to many new therapeutic strategies. During DCS, the charge transfer from electrode to tissue relies on a combination of reversible and irreversible electrochemical processes, which may generate toxic or bio‐altering substances, including metal ions and reactive oxygen species (ROS). Poly(3,4‐ethylenedioxythiophene) (PEDOT) based electrodes are emerging as suitable candidates for DCS to improve biocompatibility compared to metals. This work addresses whether PEDOT electrodes can be tailored to favor reversible biocompatible charge transfer. To this end, different PEDOT formulations and their respective back electrodes are studied using cyclic voltammetry, chronopotentiometry, and direct measurements of H2O2 and O2. This combination of electrochemical methods sheds light on the time dynamics of reversible and irreversible charge transfer and the relationship between capacitance and ROS generation. The results presented here show that although all electrode materials investigated generate ROS, the onset of ROS can be delayed by increasing the electrode's capacitance via PEDOT coating, which has implications for future bioelectronic devices that allow longer reversibly driven pulse durations during DCS. [ABSTRACT FROM AUTHOR]

In this study, the performance of a binder‐free LiNi0.6Co0.2Mn0.2O2 (NMC622) positive electrode utilizing single‐walled carbon nanotubes (SWCNTs) is investigated and compared to the conventional state‐of‐the‐art NMC622 composite positive electrode. The binder‐free electrode has been prepared without using toxic and expensive N‐Methyl‐2‐pyrrolidone (NMP) solvent and it is free‐standing that allows a wider range of applications such as flexible devices. Electrochemical techniques such as cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge–discharge reveal that the binder‐free positive electrode performance is similar to the conventional composite cathodes, deducing that only ≈1% of SWCNTs perform well not only as a conductive agent but also as a binder. The NMC622 composite electrode with SWCNTs provided specific capacity of 135.8 mAh g−1 at a 5C rate during discharge, with above 97% capacity retention after the rate capability test in a half cell. [ABSTRACT FROM AUTHOR]

Keggin‐type polyoxometalates (POMs), (n‐Bu4N)4[AsVMo11O40] (AsVMo11) and (n‐Bu4N)4H[AsV2Mo10O40] (AsV2Mo10), have been immobilised with the conducting polymer poly (3,4‐ethylenedioxythiophene) (PEDOT) on the surface of the glassy carbon electrode via chronocoulometry technique. The voltammetric behaviour of these modified electrodes was investigated with cyclic voltammetry and electrochemical quartz crystal microbalance (EQCM). The resulting films showed the surface adsorbed behaviour and dependence on the pH of the electrolyte solution. By using AC impedance, it was found that the resulting POM‐doped PEDOT films were highly conductive. The redox switching stability of the polymer films was investigated, and it was found that the AsVMo11/PEDOT hybrid film is significantly more stable for continuous potential sweep than the AsV2Mo10/PEDOT hybrid film. Additionally, the EQCM measurements confirm that during the redox potential cycling, the anions in the supporting electrolyte replace the POMs anion doped onto the film. [ABSTRACT FROM AUTHOR]

The toxicity of 4-nitrophenol (4-NP) is one of the most common threats to the environment; therefore, developing a simple and sensitive analytical method to detect 4-NP is crucial. In this study, we prepared the Nd(OH)3/VSe2 nanocomposite using the simple hydrothermally assisted ultrasonication method and it was used to detect the 4-NP. Different characterization techniques were used to investigate the morphological and chemical compositions of Nd(OH)3/VSe2 nanocomposite. All of these investigations revealed that Nd(OH)3 nanoparticles were finely dispersed on the surface of the VSe2 nanosheet. The electrical conductivity of our prepared samples was evaluated by the electrochemical impedance spectroscopic technique. The CV and DPV methods were used to explore the electrochemical activity of 4-NP at the Nd(OH)3/VSe2/GCE sensor which exhibited a wide linear range (0.001 to 640 µM), low limit of detection (0.008 µM), and good sensitivity (0.41 µA µM−1 cm−2), respectively. Additionally, Nd(OH)3/VSe2/GCE sensor was tested in water samples for the detection of 4-NP, which exhibited good recovery results. The Nd(OH)3/VSe2 electrode material is a novel one for the electrochemical sensor field, and the obtained overall results also proved that our proposed material is an active material for sensor applications. [ABSTRACT FROM AUTHOR]

Fe-Zn alloys for degradable vascular stents were prepared via electrodeposition technique. The effect of the concentration of the complexing agent sodium citrate (C6H5Na3O7·2H2O) in the plating solution on the solution state, alloy composition, and microstructure was investigated. The complexation mechanism of Fe3+, Fe2+ and Zn2+ by C6H5Na3O7·2H2O was analyzed using cyclic voltammetry. In vitro degradation properties of the alloy were evaluated through electrochemical and static immersion methods. Results showed that an increase of C6H5Na3O7·2H2O concentration led to a decrease in pH change of the plating solution, deposition rate, and cathodic current efficiency. With increasing concentration of C6H5Na3O7·2H2O, the reduction potential of Zn2+ gradually shifted positively while the reduction potential difference with Fe2+ decreased; this resulted in increased Zn content in the alloy and reduced grain size indicating promotion of co-deposition by C6H5Na3O7·2H2O. However, excessive sodium citrate caused an increase in the reduction potential difference between Fe2+ and Zn2+ leading to decreased Zn content as well as coarsened grains suggesting significant influence on alloy composition from complexing agent concentration. Alloys with different compositions exhibited a single α(Fe) phase with a (211) preferred orientation crystal plane. Polarization curves, electrochemical impedance spectra, and long-term immersion experiments indicated that the corrosion sensitivity of the alloys increased and the corrosion rate elevated with an increase in Zn content in the alloys. These results indicate that reasonable control over the complexing agent, C6H5Na3O7·2H2O, is expected to obtain Fe-Zn materials for biodegradable stents with good microstructure and performances. [ABSTRACT FROM AUTHOR]

The structural and electronic properties of the dimethylmethylene‐bridged P‐heterotriangulene have been systematically modulated by functionalization of its phosphorus center. The optoelectronic properties of the obtained derivatives in solution were characterized by UV/Vis absorption and emission spectroscopy, cyclic voltammetry and 31P NMR spectroscopy. The solid state structures were analyzed by X‐ray crystallography. The experimental results were corroborated by density functional theory calculations which revealed the crucial influence of the axial substitution on the bowl‐shaped geometry of the phosphorus‐centered polycyclic scaffold, which is proportional to the s‐character of the P−X bond. The advantage of the bowl‐shaped P‐heterotriangulene scaffold was demonstrated by successful co‐crystallization with fullerene C60. [ABSTRACT FROM AUTHOR]

Metal organic frameworks (MOFs) have become highly promising materials for a wide range of applications because of their distinct characteristics and structural adaptability. The utilization of MOFs in composite materials has the potential to expand their range of applications. This study focuses on the development of an iron-doped zinc metal organic framework (Fe@Zn-MOF-2) using a previously synthesized zinc-based MOF. The efficacy of Fe@Zn-MOF-2 was investigated for sensing Gd3+ and acetophenone, as well as its potential as an electrode material for energy storage devices. The photoluminescence sensing experiments showed a significant improvement in the efficiency of sensing Gd3+ and acetophenone when using the Fe@Zn-MOF-2 composite. The composite achieved sensing efficiencies of 97.73% and 98.45%, respectively, which were higher than the efficiencies of 33.25% and 35.71% observed when using only the Zn-MOF. Furthermore, both materials exhibited substantial disparities in specific capacitance when examined as energy storage electrodes through the methods of cyclic voltammetry (CV), galvanostatic charge–discharge (GCD) analysis, and electrochemical impedance spectroscopy (EIS). Fe@Zn-MOF-2 exhibits a specific capacitance of 318.09 F g−1, while the Zn-MOF has a specific capacitance of 33.00 F g−1. Fe@Zn-MOF-2 exhibits a specific capacitance retention of 94.57% after undergoing 2000 cycles in cyclic voltammetry. The results emphasize the capability of Fe@Zn-MOF-2 for versatile uses in sensing and energy storage. [ABSTRACT FROM AUTHOR]

To realize the on-line detection of pH value of heterogeneous systems and provide stable reference potential, the polydopamine modified Ag/AgCl solid film reference electrode was developed by magnetron sputtering deposition of silver film and chlorination of NaClO solution to obtain AgCl layer and dopamine deposition modification film. The stability, reversibility and cyclic voltammetry characteristics of polydopamine modified electrodes with deposition times of 4, 8, 12 and 16 h were compared in phosphate buffered saline (PBS) solution. The results show that the standard deviation of response potential of reference electrode in PBS solution is about 1.00 mV. It can recover to relatively stable potential in different pH buffer solutions, and the deviation of the reference electrode is less than 5.00 mV with good reversibility. The response potential drift is small in 50 cyclic voltammetry tests. According to the sensitivity of the reference electrode ranging from 2.00 to 2.50 mV/pCl, the polydopamine modified electrode is not sensitive to chloride ion concentration, which confirms that the polydopamine modified reference electrode is feasible. The reference electrode with deposition time of 12 h has the best comprehensive performance in various tests. The application tests illuminate that the reference electrode is more suitable for the detection of pH of cultivation substrate. [ABSTRACT FROM AUTHOR]

The electrochemical and electrocatalytic properties of 1-hydro-1,10-phenanthrolinium and 1,10-dihydro-1,10-phenanthrolinium perchlorates in formation of molecular hydrogen in the presence of CF3COOH were studied by cyclic voltammetry. The presence of hydrogen atoms at nitrogen atoms in the heterocyclic compounds strongly influences the electrochemical properties of the compounds and the efficiency of the electrocatalytic process. In going from 1-hydro-1,10-phenanthrolinium perchlorate to 1,10-dihydro-1,10-phenanthrolinium perchlorate, the process efficiency increases (TOF and TON values are higher), despite identical mechanisms. The reaction mechanisms were studied by DFT, and the key intermediates were revealed. [ABSTRACT FROM AUTHOR]

Edible Swiftlet Nest (ESN) is a swiftlet's saliva product that contains many beneficial compounds. However, improper washing leaves behind toxic nitrite content. To ensure its absence, sensitive and accurate methods are needed, such as UV-Vis spectrophotometry. However, long analysis time and complicated maintenance, limit its further use. In this research, cyclic voltammetry was developed as an alternative analysis method for nitrite content in ESN. The results show that the LOD and LOQ of this method are 0.658529 ppm and 1.995544 ppm, respectively. Compared to this value, analysis using UV-visible spectrophotometry shows lower LOD and LOQ values, respectively 0.061579 ppm and 0.186602 ppm. [ABSTRACT FROM AUTHOR]

A carbon paste sensor was modified with sepiolite clay particles (SC/CPE) to quantify the bicalutamide (BICA). BICA's probable oxidation mechanism and the interaction between calf thymus DNA (dsDNA) were investigated (in aqueous medium, pH 4.8) for the first time. Cyclic voltammetry (CV), Electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM) were used for the investigation of surface morphology and electrochemical characteristics. The effect of the amount of SC, supporting electrolyte, and pH was optimized. Under optimum conditions, the developed sensor exhibited a linear response between 0.223 and 20.0 μM. The detection of the limit was found to be 0.069 μM. The sensor was successfully applied to quantify BICA in biological and pharmaceutical samples. Finally, cyclic voltammetry (CV) and differential pulse voltammetry (DPV) provided new insight into the interaction between BICA and ds‐DNA. The kinetic parameters for the free DNA, diffusion coefficient (D), heterogeneous rate constant (ks), and electrode surface concentration (Γ) were calculated to be 4.22×10−5 cm2 s−1, 0.57 s−1 and 7.67×10−9 mol cm−2, respectively. The (ds‐DNA)‐BICA complex parameters were 4.56×10−6 cm2 s−1, 0.70 s−1, and 1.61×10−9 mol cm−2. In addition, binding constant (K) and Gibbs free energy change (ΔG°) were 6.02×105 M−1 and −32.97 kJ mol−1, respectively. [ABSTRACT FROM AUTHOR]

In this study, TiO2 was prepared via a solid-state chemical reaction and used as an anode for magnesium/lithium hybrid-ion batteries. The X-ray diffraction characterization of the synthesized titanium dioxide demonstrated that the material consists of 10% TiO2(B) and 90% anatase phases. Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) measurements showed the lowest charge transfer resistance and the highest capacity for batteries assembled with 9 mM LiCl because of the activation effect of the Cl− anion. In general, TiO2 as anode material in Mg2+/Li+-ion mixed solutions demonstrated sluggish electrochemical kinetics and a rate constant obtained from the EIS data of 1.05 × 10−8 cm s−1. From the cyclic voltammetry measurements, it was found that the capacity of the magnesium-lithium battery has more pseudocapacitance characteristics than the mixed-controlled process, as in other studies. The investigated TiO2||0.05 M Mg(ClO4)2 + 0.009 M LiCl/AN||Mg hybrid-ion battery demonstrated a capacity of approximately 25 mAh g−1 after 50 cycles at 35 mA g−1 current. [ABSTRACT FROM AUTHOR]

Strengthening OH adsorption on electrocatalyst is crucial to promote the rate‐determining water dissociation step of alkaline hydrogen evolution reaction (HER), whereas too‐intensified OH adsorption will poison the active sites instead. This dilemma remains one of the major challenges for improving the electrocatalysts' alkaline HER activities. Herein, a surprising finding that the strongly adsorbed OH on an ultrafine quinary PtCoCuNiZn nanoalloy can be facilely desorbed via a unique gradient OH desorption pattern is reported, which tremendously boosts its alkaline HER activity. Theoretical simulations unravel that the ultrafine PtCoCuNiZn nanoalloy possesses versatile metal sites for adsorbing OH and the strongly adsorbed OH can be gradiently transferred to desorb from the ultrafine PtCoCuNiZn nanoalloy with moderate energy barriers for each transfer step that is the gradient OH desorption. In the meanwhile, the unique gradient OH desorption mode on the ultrafine PtCoCuNiZn nanoalloy is also experimentally evidenced by the in situ Raman spectroscopy and cyclic voltammetry measurements. This finding offers a fresh opportunity to expedite the alkaline HER without compromising the OH adsorption strength on electrocatalysts, which thus maximally promotes their water dissociation properties and unlocks the full potential of their alkaline HER activities. [ABSTRACT FROM AUTHOR]

Microbial fuel cells (MFCs) are green technology capable of generating direct current while simultaneously treating wastewater. Although in most studies, catholytes used in MFC reactors are either phosphate buffer, direct oxygen or air cathodes. In this study, the effect of different organic loads in synthetic wastewater (equivalent to the organic load present in low- and medium-strength wastewater) as anolyte and acidic water as catholyte on cell voltage, current, power generation, and chemical oxygen demand (COD) removal efficiency with a mixed bacterial culture inoculum as biocatalyst have been accessed. Results showed a positive effect of using acidic water (pH 2) as catholyte with increasing organic load in each cycle on cell voltage, current density, and volumetric power density generation. Among all the cycles, Cycle 5 with 5.35 g/L COD load generated highest cell voltage of 205.55 mV, continuous current density, and volumetric power density of 60.45 mA/m2 and 84.50 mW/m3 , respectively, with 93.85% COD removal efficiency and 77.38% Coulombic efficiency (CE). Although none of the cyclic voltammograms (CVs) showed any oxidation peak but reduction peaks were observed in Cycles 3, 4, and 5 with 1.60, 3.21, and 5.35 g/L organic load. Cycle 5 showed two sharp reduction peaks, which can be attributed to growth of mixed bacterial culture, and 16S microbiome profiling confirmed the dominance of two unclassified species, one of Sphingomonas and the other of Burkholderia, which may have contributed to the occurrence of the two sharp reduction peaks in Cycle 5. This study demonstrates that acidic water (pH 2) can be used as an effective catholyte along with species from Sphingomonas and Burkholderia genera in treatment of synthetic wastewater with COD equivalent to low- and medium-strength domestic wastewater and bioelectricity generation. Practical Applications: Conventional wastewater treatment technologies are not sustainable to treat huge quantities of low- and medium-strength wastewater because they are cost-intensive and energy-driven processes that also release a large quantity of sludge, leading to sludge disposal problem. Moreover, they do not yield energy or any other valuable by-product. Results from our study shows that MFC can be effectively used to reduce 68.83% of total dissolved solids (TDS) and 93.85% of COD content of synthetic wastewater equivalent to low- and medium-strength wastewater, thereby efficiently treating the wastewater and also solving the problem of huge amounts of sludge generation and disposal. In the process of wastewater treatment, our study was also able to generate 84.50 mW/m3 of power density, making it an energy-yielding technology. Usage of an inexpensive mixed microbial culture inoculum as a biocatalyst (dominance of Sphingomonas and Burkholderia species) in this work showed that biocatalysts can be used as alternative to expensive metal catalysts in treatment of low- and medium-strength wastewater. During practical application of this study's findings, synthetic wastewater can be replaced with any low- and medium-strength wastewater, be it of kitchen, domestic, or municipal origin, and acidic water as catholyte can be replaced with acidic wastewater effluents of any industry to simultaneously treat two type of wastewaters and generate bioelectricity. [ABSTRACT FROM AUTHOR]

The incorporation of different ferrocene scaffolds into the peptide sequences induces the formation of hydrogen-bond-based secondary structural elements that are frequently observed in natural peptides and proteins. There are three simple ferrocene scaffolds for conjugation with amino acids and peptides that serve as templates for ferrocene peptidomimetics, namely ferrocene-1,1′-dicarboxylic acid (Fcd, I), 1′-aminoferrocene-1-carboxylic acid (Fca, III), and ferrocene-1,1′-diamine (Fcda, V). Here, we have investigated their ability to induce the turn structure upon conjugation with Val, Leu, and Phe. Furthermore, we also wanted to determine whether the branched side chains of Val, Leu, and Phe interfere with intramolecular hydrogen bonding (IHB). For these purposes, we performed a detailed spectroscopic analysis by measuring the concentration, temperature, and solvent dependence of the IR, NMR, and CD spectra. The effect of the different ferrocene scaffolds on the antioxidant activity of the prepared peptides was tested using the DPPH and ABTS methods, and was further rationalized using electrochemical measurements. It was found that the ferrocene scaffold has the greatest influence on the hydrogen bonding pattern, while the influence of the side branches of the amino acids is less relevant. [ABSTRACT FROM AUTHOR]

Three novel conjugated molecules have been synthesized: 2‐(fluoranthen‐3‐yliminomethyl)‐3,4‐ethylenedioxythio‐phene (EIF), 2‐(fluoranthen‐3‐yliminomethyl) thiophene (TIF), and 2‐(fluoranthen‐3‐yliminomethyl) fluorene (FIF). Optical properties were obtained from electronic absorption and emission spectra in DMSO solution. The solvatochromic properties of the molecules have been studied in different solvents. Electrochemical properties were studied by cyclic voltammetry in a Bu4NBF4 (0.1 M)/MeCN organic solution. As part of investigations to explain the nature of electronic transition process, we have performed geometry optimization of both the ground and the vertical excitation states, using the DFT B3LYP/6‐311G (d, p) and TD‐DFT (CPCM)/B3LYP/6‐311G (d, p) approaches, respectively. Theoretical calculations closely match the experimental findings. Results show that EIF, TIF and FIF are potential candidates to be used as electron transport layer in Organic Light‐Emitting Diodes (OLEDs). [ABSTRACT FROM AUTHOR]

In-situ synthesis of a ternary nanocomposite based on Ag-Fe3O4/rGO by utilizing Azadirachta indica leaf extract as a reducing agent has been carried out. The morphological, EDX, and structural analyses confirm the reduction of GO into rGO by forming crystalline Fe3O4 and Ag nanoparticles in the rGO matrix, with a crystalline size of 25.77 nm. Further, the FTIR, UV-Vis, and BET analyses confirmed the effective interaction between Fe3O4 and Ag nanoparticles in the rGO matrix, tunable bandgap, and a higher specific surface area. Various electrochemical techniques such as cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy have been performed in a 2 M KOH electrolyte to investigate its electrochemical performance. The synthesized ternary nanocomposite exhibits a specific capacitance of 493 Fg−1 at a current density of 1 Ag−1, with notable capacitive retention of 91.5% even after 10,000 cycles. This nontoxic technique provides a substitute pathway for the formation of graphene-based ternary nanocomposites with exceptional structural, morphological, optical, surface, and electrochemical properties. The ternary nanocomposite synthesized through this procedure displays an outstanding specific capacitance, cyclic stability, and corrosion resistance and hence the possibility of using nanocomposite as a promising electrode material can be explored for energy storage devices. [ABSTRACT FROM AUTHOR]

The high catalytic activity of arenediazonium, along with the ability of gold ions to form specific bonds with amikacin, has been used in the fabrication of an electrochemical sensor based on a glassy carbon electrode modified with a gold solution and arenediazonium tosylate (Ar/GGCE) for the detection and quantification of amikacin upon its release from implants. Atomic force microscopy, cyclic voltammetry, and square-wave voltammetry were used to demonstrate that the use of a gold solution and arenediazonium tosylate for the surface modification of a glassy carbon electrode significantly enhances the electrode characteristics. The determination of amikacin was achieved using square wave voltammetry, which enabled the detection of amikacin at the Ar/GGCE in the concentration range 0.2–60 μM and ensured a limit of detection of 0.058 μM for amikacin released from implants. [ABSTRACT FROM AUTHOR]

This work presents a comprehensive study of the UV–Visible and fluorescence properties, as well as the redox behavior of the [AuIII(Salen)]Cl complex in acetonitrile. The [AuIII(Salen)]+ complex exhibited intriguing fluorescence and phosphorescence characteristics on an indium tin oxide (ITO)-coated glass plate when excited at wavelength λexc ~ 260 nm, with fluorescence emission observed at λems ~ 437 nm and phosphorescence at λems ~ 520 nm. The origin of fluorescence emission was attributed to the intra-ligand charge transfer effect, commonly known as the "Push–Pull" effect. The electrochemical behavior of [AuIII(Salen)]+ on a glassy carbon electrode (GCE) revealed a remarkable one-step three-electron reduction process, leading to the reduction of [AuIII(Salen)]+ to Au(0). Furthermore, the reduction of [AuI(Salen)]− to Au(0) resulted in the removal of gold metal from the SalenH2 ligand. The electrochemical results suggested a mixed diffusion-adsorption redox process occurring at the GCE surface, indicating the involvement of both diffusion and adsorption during redox reactions. The cyclic voltammogram demonstrated the non-reversibility of the electrochemical redox reactions. Overall, the redox behavior of the [AuIII(Salen)]Cl complex proved to be intriguing, opening up avenues for further exploration and potential applications of this complex in various fields. [ABSTRACT FROM AUTHOR]

The technology for manufacturing electrodes for supercapacitors based on commercial carbon nanotubes with the specific surface area of 109.6 m2/g is optimized aimed at their further application as the carbon electrodes in self-charging supercapacitors. The electrochemical characteristics of electrodes of carbon nanotubes are studied in a symmetrical two-electrode cell using the methods of cyclic voltammetry, galvanostatic charge–discharge, and impedance spectroscopy. The specific capacitance of the electrode in the organic electrolyte consisting of 1-butyl-3-methylimidazolium trifluoromethanesulfonate/propylene carbonate (volume ratio 3 : 1) is shown to be 9.1 F/g. [ABSTRACT FROM AUTHOR]

Electrochemical properties of magnetite nanoparticles supported on carbon paste electrodes were investigated by means of cyclic voltammetry. The measurements were performed for bare and coated with citrate magnetite nanoparticles in aqueous solutions of various electrolytes: NaCl, NaClO4, and Na2HPO4. Cyclic voltammetry curves obtained on bare and citrate functionalized Fe3O4 nanoparticles are rather similar indicating that the electrochemical properties of the magnetite nanoparticles are not significantly affected by the citrate coating. Cyclic voltammetry scans reveal the formation of metallic iron below −1.2 V. The defective structure of the oxide phases formed by oxidation of metallic iron seems to play an important role in the chemisorption of chloride ions and their subsequent oxidation. [ABSTRACT FROM AUTHOR]

Facile synthesis of perovskite materials for the electrochemical sensing applications are remains challenging. In the current work, a simplified electrochemical sensor system based on an electrode modifier containing LaNiO3 was developed to detect catechol (CC). The surface micrograph of LaNiO3 was examined using X-ray diffraction pattern (XRD), X-ray photoelectron spectroscopy (XPS), and High-resolution transmission electron microscopy (HRTEM). Besides, the LaNiO3 reveals a remarkable electrooxidation response for the detection of catechol by cyclic voltammetry (CV) and amperometry techniques. The suggested sensor platform shows a broad linear range for catechol detection from 5 µM to 2000 µM with LOD and sensitivity of 0.6 µM and 54 µA cm−2 mM−1, respectively, under optimised conditions. Furthermore, LaNiO3 altered GCE was fruitfully implemented for the quantification of catechol in tap water sample. [ABSTRACT FROM AUTHOR]

Graphene is extremely sensitive to its surrounding environment. In fact, any modification on its surface, such as an adsorption of a molecule, can change its properties. The conductivity of graphene is a crucial parameter to be examined for potential graphene-based applications, especially biosensors. In this paper, we have investigated the effects of non-covalent functionalization based on π–π interaction, using 1-pyrenebutyric acid N-hydroxysuccinimide ester (PBASE), on the conductivity of graphene-based electrodes by electrochemical techniques. Graphene layers were obtained by chemical vapor deposition (CVD) and characterized by Raman spectroscopy, Scanning Electron Microscopy (SEM), and X-Ray Diffraction (XRD). The results demonstrate the synthesis of a high quality and continuous monolayer graphene with an I2D/IG ratio = 2.71 and ID = 0. After the functionalization of graphene-based electrode with PBASE, the electrochemical analyses confirmed a p-doping effect existence influencing the conductivity by increasing the charge transfer resistance Rct from 816.5 to 2213 Ω. Furthermore, increasing the concentration of PBASE from 5 mM to 10 mM did not affect the conductivity as the Rct did not change. Solvent adsorption was found to be the main cause of the decrease in conductivity during the functionalization process. This study highlights the effect of non-covalent π-π stacking of PBASE on graphene to tune the electrical properties of graphene through functionalization processes for a better performance for their use as biosensors. [ABSTRACT FROM AUTHOR]

A glassy carbon electrode (GCE) modified with electrochemically reduced graphene oxide (ErGO) and gold nanorods (AuNRs) (GCE/ErGO/AuNRs) was prepared for determining As(III) in bivalve mollusks samples (Mytilus chilensis). The modified electrode was characterized by cyclic voltammetry, scanning electron microscopy (SEM), and atomic force microscopy (AFM). Chemical and electrochemical parameters were optimized, observing that the presence of AuNRs provides selectivity, while the incorporation of ErGO improves the sensitivity of the modified electrode for the detection of As(III). Using square wave anodic stripping voltammetry (SWASV), a linear range of 2.0–60.0 µg L−1 with a detection limit (LOD) of 0.21 µg L−1 was obtained. The validation was made using water and mussel tissue-certified reference materials (TMDA-64.2 and ERM®-CE278k, respectively), showing good accuracy and reproducibility. The methodology allowed the determination of As(III) in real samples of marine resources, with excellent results (RSD < 2%). [ABSTRACT FROM AUTHOR]

This study presents the synthesis and electrocatalytic performance of the cobalt(III) complex [Co3(μ1,1,1‐O)(μ1,3‐CH3CO2)(L)3]2(DMF)3 (Cotri), featuring a double deprotonated (N,O)‐donor ligand (L2‐), where the protonated form of it (H2L) is 2,2′‐(hydrazine‐1,2‐diylidenebis(ethan‐1‐yl‐1‐ylidene))diphenol. The X‐ray structure reveals a trinuclear cobalt cluster formed with three cobalt(III) centers interlinking through oxido (μ1,1,1‐O) and acetato (μ1,3‐O2CCH3) bridges in coupling with bis‐congregator‐type chelating ligands. Cotri adopts cobalt centers of octahedral and trigonal bipyramidal coordination geometries and bears a dominant Co(2)...H(DMF) agostic interactions appraised by lattice dimethyl formamide (DMF) molecules. Further, Cotri shows promising heterogeneous electrocatalytic hydrogen evolution activity in 1 M KOH, with an overpotential of 441 mV to achieve 10 mA/cm2 current density. Tafel slope analysis suggests the Volmer–Heyrovsky step as the rate‐determining step. The number of active sites and TOF for Cotri were estimated at 4.010 × 10−8 mol and 0.2467 s−1, respectively, ensuring its excellent hydrogen generation activity. Stability assessments through controlled potential electrolysis (CPE) and cyclic voltammetry (CV) for multiple cycles addressed the transformation of Cotri to Co2O3 nanoparticles, which turned out to be a more active Co2O3 electrocatalyst. The morphology and particle size of the in situ developed Co2O3 active catalyst under the electrochemical conditions attributes to the superior hydrogen evolution activity. [ABSTRACT FROM AUTHOR]

Heavy metal poisoning is the most prevalent health hazard at hazardous waste sites, affecting a large population on daily basis, with arsenite poisoning ranking third in terms of prevalence and severity. Therefore, the main objective of this study is to develop a novel, highly efficient sensor for detecting trace amounts of arsenite (AsIII) in human serum by utilising reduced graphene oxide/gold nanoparticles (rGO/AuNPs) based nanocomposite structure. In this work, a screen-printed carbon electrode (SPE) was modified using rGO/AuNPs nanocomposite to detect AsIII in human serum. The detection data were recorded and analysed using Cyclic Voltammetry (CV) and Differential Pulse Voltammetry (DPV), whereas transmission electron microscope (TEM), scanning electron microscope (SEM) as well as Fourier transform infrared (FTIR) spectroscopy were used to determine the surface morphological features and the presence of significant elements/groups in the prepared nanocomposite structure. Under the optimised conditions, the linear regression coefficient (R2) for the DPV response of the fabricated electrode (rGO/AuNPs@SPE) was observed to be 0.98. The rGO/AuNPs@SPE demonstrated remarkable sensor response for AsIII with detection limits of 10 ppb via DPV in standard samples, due to the synergistic effect of rGO and AuNPs based nanocomposite. The sensitivity of the sensor was found to be 0.0142 Appb−1cm−2 for 100–1000 ppb concentration range of AsIII. The rGO/AuNPs@SPE sensor also displayed good stability and reproducibility when used in AsIII spiked human serum samples in which the limit of detection was observed at 100ppb. The porous structure of rGO on the sensing interface efficiently improves the electrode's adsorption and conductivity, while citrate capped AuNPs offer the functional groups required for maximum adsorption of AsIII. Hence, the developed electrochemical sensor (rGO/AuNPs@SPE) can be used very precisely and reliably in various applications for trace level detection of AsIII in human serum. [ABSTRACT FROM AUTHOR]

We report on the sensing of a hazardous pesticide alphacypermethrin (ACM) using electrochemical technique through a nanocomposite film modified electrode. The nanocomposite film comprising of octadecylamine, chitosan, polyvinyl alcohol-silver nanowires and haemoglobin, shortly (OCPAH), was prepared by Langmuir–Blodgett (LB) film deposition technique on various substrates and electrodes. The composite LB film was characterised by UV-visible spectroscopy and scanning electron microscopy, which confirms the stable and multilayer film. The LB film modified electrode was used for sensing ACM pesticide by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and square wave voltammetry (SWV) techniques. The achieved sensing parameters such as limit of detection as 14 nM, 5 nM and 10 nM; linear range as 10–100 nM, 10–40 nM and 50–100 nM/10–100 nM; and sensitivity as 0.418 µA/nM/cm2, 0.259 µA/nM/cm2 and 0.271 µA/nM/cm2 for CV, DPV and SWV techniques, respectively. The reported sensor is found to have stability of 74% upto 20 cycles, the relative standard deviation (RSD) value for metal ion/organic interference species as 2% and for real samples are within 1.4% using CV technique. The reported nanocomposite-based ACM pesticide sensor will open up new options for research on LB film nanocomposite-based sensing of different organophosphorus groups of pesticides. [ABSTRACT FROM AUTHOR]

Bio-carbon–manganese composites obtained from olive mill wastewater were successfully prepared using manganese acetate as the manganese source and olive wastewater as the carbon precursor. The samples were characterized chemically and texturally by N2 and CO2 adsorption at 77 K and 273 K, respectively, by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction. Electrochemical characterization was carried out by cyclic voltammetry (CV) and linear sweep voltammetry (LSV). The samples were evaluated in the electro-Fenton degradation of tetracycline in a typical three-electrode system under natural conditions of pH and temperature (6.5 and 25 °C). The results show that the catalysts have a high catalytic power capable of degrading tetracycline (about 70%) by a three-electron oxygen reduction pathway in which hydroxyl radicals are generated in situ, thus eliminating the need for two catalysts (ORR and Fenton). [ABSTRACT FROM AUTHOR]

Purpose: This paper aims to develop a simple and efficient plasma technology for the production of copper (I) oxide with the ability to control the morphology and size of Cu2O particles. To achieve this goal, the phase composition of the precipitate formed was estimated, the composition and size of the obtained particles were determined and Pourbaix diagrams were constructed. Design/methodology/approach: An integrated approach combining thermodynamic calculations and experimental research methods is used. The constructed Pourbaix diagram makes it possible to suggest the phase composition of the sediment. The use of cyclic voltammetry made it possible to establish the mechanism of deposit formation on the cathode during the treatment of the solution with contact nonequilibrium low-temperature plasma. The resulting product was examined using X-ray phase analysis and scanning electron microscopy. Findings: The article presents the results of theoretical and experimental studies on the synthesis of copper (II) oxide. The influence of the parameters of plasma-chemical synthesis on the shape and phase composition of the deposits formed has been studied. Originality/value: A plasma-chemical technology for obtaining copper oxide in the form of single crystals of a regular faceted shape is proposed. The mechanism of formation of copper oxide has been established by cyclic voltammetry. The constructed Pourbaix diagrams show the area of existence of the product. [ABSTRACT FROM AUTHOR]

An ultra-high sensitivity pH sensor based on vertical organic electrochemical transistors (vOECT) with extended gate was proposed. The vOECT, which exhibited high transconductance (gm), was for the first time used in the preparation of a pH sensor. The extended gate was modified by electrochemical deposition of polyaniline (PANI) using the cyclic voltammetry (CV) technique. Open circuit potential (OCP) measurements were used to optimize the scan rate, showing a super-Nernstian sensitivity at all scan rates. The pH sensor based on vOECT with extended gate was investigated at different pH levels, and it exhibited an ultra-high sensitivity of 3363.6 µA/pH in the pH range 5–9, which was about 36 times greater than the maximum current sensitivity (91 µA/pH) of other transistor-based pH sensors, to the best of our knowledge. This pH sensor performed excellently in terms of reversibility, long-term stability, and selectivity. To confirm the reliability of the pH sensor, we conducted measurements on real samples using this pH sensor and compared the results with those obtained from a standard pH meter. The ultra-high sensitivity pH sensor based on vOECT with extended gate offers a sensitive and promising alternative in environmental monitoring, food safety, chemistry, clinical diagnostics, and bio-sensing applications. [ABSTRACT FROM AUTHOR]

An electrochemical immunoassay system was developed to detect CA-125 using a glassy carbon electrode (GCE) modified with MXene, graphene quantum dots (GQDs), and gold nanoparticles (AuNPs). The combined MXene-GQD/AuNPs modification displayed advantageous electrochemical properties due to the synergistic effects of MXene, GQDs, and AuNPs. The MXene-GQD composite in the modified layer provided strong mechanical properties and a large specific surface area. Furthermore, the presence of AuNPs significantly improved conductivity and facilitated the binding of anti-CA-125 on the modified GCE, thereby enhancing sensitivity. Various analytical techniques such as FE-SEM and EDS were utilized to investigate the structural and morphological characteristics as well as the elemental composition. The performance of the developed immunosensor was assessed using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), square wave voltammetry (SWV), and differential pulse voltammetry (DPV). Under optimized conditions in a working potential range of −0.2 to 0.6 V (vs. Ag/AgCl), the sensitivity, linear range (LR), limit of detection (LOD), and correlation coefficient (R2) were determined to be 315.250 µA pU.mL−1/cm2, 0.1 to 1 nU/mL, 0.075 nU/mL, and 0.9855, respectively. The detection of CA-125 in real samples was investigated using the developed immunoassay platform, demonstrating satisfactory results including excellent selectivity and reproducibility. [ABSTRACT FROM AUTHOR]

The development of a portable analytical procedure is described for rapid sequential detection and quantification of the explosives 2,4,6-trinitrotoluene (TNT) and cyclotrimethylenetrinitramine (RDX) in forensic samples using a graphite sheet (GS). A single GS platform works as a collector of explosive residues and detector after its assembly into a 3D-printed cell. The detection strategy is based on cyclic square-wave stripping voltammetry. The cathodic scan from + 0.1 to −1.0 V with accumulation at 0.0 V enables the TNT detection (three reduction peaks), and the anodic scan from + 0.2 to + 1.55 V with accumulation at −0.9 V provides the RDX detection (two oxidation processes). Low detection limit values (0.1 µmol L−1 for TNT and 2.4 µmol L−1 for RDX) and wide linear ranges (from 1 to 150 µmol L−1 for TNT and from 20 to 300 µmol L−1 for RDX) were obtained. The sensor did not respond to pentaerythritol tetranitrate (PETN), which was evaluated as a potential interferent, because plastic explosives contain mixtures of TNT, RDX, and PETN. The GS electrode was also evaluated as a collector of TNT and RDX residues spread on different surfaces to simulate forensic scenarios. After swiping over different surfaces (metal, granite, wood, cloths, hands, money bills, and cellphone), the GS electrode was assembled in the 3D-printed cell ready to measure both explosives by the proposed method. In all cases, the presence of TNT and RDX was confirmed, attesting the reliability of the proposed device to act as collector and sensor. [ABSTRACT FROM AUTHOR]

The Ni-, Co-, and Mo-supported Ni foam (NiF–NiCoMo) was produced via galvanostatic method, and electrooxidation of methanol in alkaline medium was examined. The characterization was achieved using field emission scanning electron microscopy, energy-dispersive X-ray, and X-ray diffraction analysis. The electrochemical behavior was determined via cyclic voltammetry and chronoamperometry analysis. The contribution of each transition metal to electrocatalytic performance of NiF was monitored via mono, binary, and ternary modifications of each transition metal (Ni, Co, and Mo) for several amounts (5, 10, and 15 μg). Experiments were performed to determine the influence of catalyst amounts, methanol concentration, and scan rate parameters. The impacts of independent parameters on methanol electrooxidation were statistically investigated using Design-Expert software. The ability to analyze multiple parameters with a limited number of experimental performances is one of the method's key benefits. The developed model showed that 9.41 and 14.03 µg catalyst amounts were the appropriate values for NiF–NiMo and NiF–NiCoMo achieving optimal circumstances, respectively. [ABSTRACT FROM AUTHOR]

In this paper, the Cu/Cu2O and Cu/Cu2O/CuO electrodes were successfully fabricated from the copper layer of a printed circuit board using an electrical oxidation method. The physical properties of these samples were verified through X-Ray diffraction and scanning electron microscopy (SEM) measurements. The Cu/Cu2O and Cu/CuO/Cu2O electrodes were employed as non-enzyme sensors for the detection of glucose in the alkaline solution. The properties of electrodes were investigated using cyclic voltammetry and amperometry measurements with glucose solution. The results show that both types of electrodes can detect and quantify glucose concentrations. The Cu/Cu2O/CuO composite electrode demonstrated superior performance compared to the Cu/Cu2O electrode. The proposed sensor demonstrated a limit of detection of approximately 63.08 nM. Additionally, the proposed sensor was also investigated with various interfering substances, including ascorbic acid, urea, and table salt. The results revealed that the current intensity remained nearly unchanged for these substances, while it significantly increased from 0.3 to 2.5 mA/cm2 for glucose. With these achieved results, the developed system shows promise for application in glucose testing systems, benefiting diabetic patients in the future. [ABSTRACT FROM AUTHOR]

The Optical properties of the FBTC (1-((4-((5-chlorobenzo[d]oxazol-2-ylthio)methyl)-1H-1,2,3-triazol-1-yl)methyl)-3H-benzo[f]chromen-3-one) molecule were studied experimentally and theoretically. The spectra of absorption and fluorescence were recorded in various solvents to explore their Solvatochromic behavior and dipole moment at room temperature. To determine the ground and excited state of dipole moment experimentally and theoretically, we employed different Solvatochromic techniques, including microscopic solvent polarity functions developed by Lippert, Bakhshiev, Kawaski-Chamma-Viallet, and Reichardt's, as well as density functional theory (DFT) and time-dependent density functional theory (TD-DFT) methods. The stability of the excited state dipole moment in FBTC is higher. Using prime functional, FBTC was optimized in its ground state, and its HOMO (Highest Occupied Molecular Orbital) and LUMO (Lowest Unoccupied Molecular Orbital), energies were estimated. These values were then compared with those obtained through cyclic voltammetry. Based on the HOMO and LUMO values given, we calculated the global reactivity parameter and energy gap, which was found to be low at 3.77 eV. This study also includes an estimation of electron absorption energies and oscillator strength. Natural population analysis (NPA), Milliken atomic charge, and molecular electrostatic potential (MESP) map are correlated. In addition, FBTC exhibited exceptional physiological temperature sensing behaviour from 20 °C -65 °C with high relative sensitivity and firm stability. Hence these results confirm that FBTC is a potential candidate for photonic devices and it's also applicable in optical temperature sensing. [ABSTRACT FROM AUTHOR]

The novel rare earth (Lu) doped zinc ferrite nanoparticles, synthesized via a solution combustion approach, exhibit exceptional sensitivity to carbon monoxide (C.O.), a capability studied for the first time. The successful detection of C.O. by these nanoparticles underscores their potential as efficient gas sensors. Structural and morphological characterization confirmed the creation of single-phase zinc ferrite nanoparticles, utilizing various standard and advanced modern probes. To assess the gas sensing capabilities, the nanoparticles were exposed to carbon monoxide gas, revealing an outstanding gas response of 80 % at 300 °C, with a response against 20,000 parts per million by volume (PPMv) of carbon monoxide. These results indicate the promising applicability of Lu-doped zinc ferrite nanoparticles in C.O. gas sensing applications. Furthermore, the supercapacitance performance of the synthesized nanoparticles was investigated. Electrodes fabricated from Lu-doped zinc ferrite nanoparticles (Lu 0, 0.3, 0.5, and 0.7) were examined in a 3 M K.O.H. electrolyte using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (E.I.S.). The electrochemical properties of all nanoparticles exhibited good Faradaic behaviour, with the Lu 0.7 electrode achieving a high specific capacitance of 280 F/g at a current density of 0.25 A/g. This highlights the prominent electrochemical stability and potential applications of Lu-doped zinc ferrite nanoparticles in energy storage devices. Overall, the comprehensive investigation of the gas sensing and super capacitance performance of Lu-doped zinc ferrite nanoparticles demonstrates their versatility and potential for various technological applications, including gas sensing and energy storage. These findings pave the way for further research and development in utilizing rare earth-doped ferrite nanoparticles for advanced functional materials. [ABSTRACT FROM AUTHOR]

In recent years, the detection and determination of numerous drugs and pharmaceuticals in various media have become crucial aspects of modern healthcare and environmental management. Among the available sensing techniques, electrochemical methods, particularly those utilising screen-printed electrodes (SPEs) and different portable equipment have emerged as rapid, effective, sensitive, and inexpensive. This study focuses on the detection of the anti-inflammatory drug diclofenac in neutral media. Cyclic voltammetry measurements were conducted to identify diclofenac and determine the kinetics and electrochemical mechanism of its oxidation, along with assessing the surface characteristics of the employed SPEs. Graphene and modified graphene SPEs were explored as nanosensors for this purpose. The surface of the graphene SPE was modified using polyvinylidene fluoride, applied through a drop modification procedure. The morphology of the examined SPEs was observed by means of scanning electron microscope, while the electrolyte (0.1 g of diclofenac per litre of phosphate-buffered solution, pH = 7.4) was analysed using UV-Vis spectroscopy. The results indicate that the studied SPEs exhibit promising potential for the detection of diclofenac. [ABSTRACT FROM AUTHOR]

The energy transition and the implementation of new electrochemical technologies will result in an increased reliance on critical raw materials for electrodes. Their large‐scale application will ultimately mean working with lower grade materials. Here we study the influence of metal impurities on nickel foam electrocatalysts. We do this by electrodepositing known amounts of first‐row transition metals (Cu, Cr, Mn, Fe, Co and Ni) on nickel foam and studying their performance in the oxygen evolution reaction (OER) as a model reaction. The electrodes' performance is studied using cyclic voltammetry (CV), linear sweep voltammetry (LSV), Tafel analysis, stepwise chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS). Combining these results with microscopy analysis, we show that even small amounts of transition‐metal impurities have profound effects on the catalytic performance of nickel electrodes. The changes affect the OER onset potential (the energy that the system requires to convert OH– to O2) and the Tafel slope of each electrode (the electrode's initial activity in the OER onset region). Our results highlight the implications of such impurities on electrode design and future large‐scale application. [ABSTRACT FROM AUTHOR]

Despite many recent efforts, the field of organic electrosyn‐thesis faces important challenges due to the intricate nature of heterogeneous redox processes, the wide parameter space to be explored and the lack of standardized methods. To overcome these limitations, we developed a cost‐effective high‐throughput electrochemical (HTE) reactor capable of running 24 individually controlled parallel reactions. This system allows the rapid testing of electrochemical parameters on a given reaction, assessing not only yield but also reproducibility. Using the hypervalent iodine‐mediated dearomatization of phloretic acid as a demonstration of HTE capabilities, we ran more than 200 electrosyntheses in different experimental conditions and demonstrate the effect of parameters such as total charge transferred, current, electrode materials, electrolyte formulation and concentration, mediator formulation and concentration and electrochemical technique of oxidation. Notably, this report demonstrates that while catalytic amounts of iodine mediator can be used successfully, the reproducibility may be affected, which calls for a cautious approach when developing similar transformations. Using cyclic voltammetry, density functional theory, chronopotentiometry, and Raman spectroscopy, we shed light on the causes of this issue. [ABSTRACT FROM AUTHOR]

This research focused on harnessing amino‐functionalized montmorillonite (Mt) clay, achieved through the grafting of [3(2‐aminoethyl)amino]propyltrimethoxysilane (AEP‐TMS), as carbon paste electrode (CPE) modifier for the electroanalysis of ciprofloxacin (CF). The characterization of both Mt and the amino‐functionalized (Mt‐NH2) materials was carried out using various techniques including Fourier‐transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X‐ray diffraction (XRD). Afterwards, various CPEs modified using Mt and Mt‐NH2 were prepared and characterized employing SEM‐energy dispersive X‐ray (EDX), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). By EIS, Mt‐NH2‐CPE exhibited significantly faster electron transfer with lower charge‐transfer resistance (438.5 Ω) compared to Mt‐CPE (3572.1 Ω) and to the bare CPE (2066.1 Ω). Additionally, CV experiments performed by using redox probes demonstrated the excellent accumulation capability of [Fe(CN)6]3− ions on Mt‐NH2‐CPE surface. The Mt‐NH2‐CPE was subsequently applied using square wave voltammetry to determine CF in the presence of cetyltrimethylammonium bromide (CTAB), yielding an impressive linear range from 30 to 240 μM (R=0.999) and a low detection limit of 0.07 μM (23.2 μg L−1). The method exhibited stable and reproducible responses (RSD=3.25 %; n= 6) under optimized conditions. Following interference studies, the optimized method was effectively applied to quantify CF concentrations in pharmaceutical and water samples. [ABSTRACT FROM AUTHOR]

This study aims to investigate the photoelectrochemical behavior of the n-type 4H-SiC, focusing on aqueous, hydroxide-based electrolytes. Despite its high stability, this wide-bandgap semiconductor material undergoes electrochemical reactions, such as anodic oxidation or etching, under specific conditions. Since electrons are the majority charge carriers in n-type semiconductors, oxidation processes require above-bandgap illumination. Then, the reaction rate is influenced by the number of electron holes available for an oxidation process and the velocity of the transport of hydroxide ions to/from the surface. The goal is to focus on the essential reaction parameters (i.e., potential and electrolyte concentration) to clarify the reaction mechanism in aqueous (alkaline) electrolytes. Methods with controllable hydrodynamic conditions are required to investigate the transport processes in the electrolyte. Even though the rotating disk electrode (RDE) is a commonly used and powerful method, it is not well suited for our purpose. Photoelectrochemical etching of SiC is extraordinary because it involves both mass transfer phenomena and gas evolution but also needs high-intensity illumination from an appropriate light source. Hence, a new concept for an inverted rotating cell was developed and implemented. This setup was used to study the effect of the mass transport of hydroxide ions on the photoelectrochemical behavior of SiC in each potential region at varying rotation speeds. In order to interpret the experimental findings, a distinct electrical network model was formulated for simulating the results, aiding in unraveling the underlying reaction mechanism. Electrochemical measurements were complemented by surface-sensitive analytical techniques. XPS was the method of choice to investigate the composition of the sample surface before and after etching. SEM and AFM allow the characterization of the surface morphology in the initial stages of etching. The totality of this information provides a complete picture of the complex processes in the vicinity of the semiconductor electrode. [ABSTRACT FROM AUTHOR]

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Laser-inscribed graphene (LIG) is an emerging material for micro-electronic applications and is being used to develop supercapacitors, soft actuators, triboelectric generators, and sensors. The fabrication technique is simple, yet the batch-to-batch variation of LIG quality is not well documented in the literature. In this study, we conduct experiments to characterize batch-to-batch variation in the manufacturing of LIG electrodes for applications in electrochemical sensing. Numerous batches of 36 LIG electrodes were synthesized using a CO2 laser system on polyimide film. The LIG material was characterized using goniometry, stereomicroscopy, open circuit potentiometry, and cyclic voltammetry. Hydrophobicity and electrochemical screening (cyclic voltammetry) indicate that LIG electrode batch-to-batch variation is less than 5% when using a commercial reference and counter electrode. Metallization of LIG led to a significant increase in peak current and specific capacitance (area between anodic/cathodic curve). However, batch-to-batch variation increased to approximately 30%. Two different platinum electrodeposition techniques were studied, including galvanostatic and frequency-modulated electrodeposition. The study shows that formation of metallized LIG electrodes with high specific capacitance and peak current may come at the expense of high batch variability. This design tradeoff has not been discussed in the literature and is an important consideration if scaling sensor designs for mass use is desired. This study provides important insight into the variation of LIG material properties for scalable development of LIG sensors. Additional studies are needed to understand the underlying mechanism(s) of this variability so that strategies to improve the repeatability may be developed for improving quality control. The dataset from this study is available via an open access repository. [ABSTRACT FROM AUTHOR]

Graphite is a versatile material used in various fields, particularly in the power source manufacturing industry. Nowadays, graphite holds a unique position in materials for anode electrodes in lithium-ion batteries. With a carbon content of over 99% being a requirement for graphite to serve as an electrode material, the graphite refinement process plays a pivotal role in the research and development of anode materials for lithium-ion batteries. This study used three different processes to purify spherical graphite through wet chemical methods. The spherical graphite after the purification processes was analysed for carbon content by using energy-dispersive X-ray (EDX) spectroscopy and was evaluated for structural and morphological characteristics through X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer–Emmett–Teller (BET) analyses. The analyses results indicate that the three-step process via H2SO4–NaOH–HCl cleaning can elevate the carbon content from 90% to above 99.9% while still maintaining the graphite structure and spherical morphology, thus enhancing the surface area of the material for anode application. Furthermore, the spherical graphite was studied for electrochemical properties when used as an anode for Li-ion batteries using cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) measurements. The results demonstrated that the purification process significantly improves the material's capacity with a specific capacity of 350 mAh/g compared to the 280 mAh/g capacity of the anode made of spherical graphite without purification. [ABSTRACT FROM AUTHOR]

Currently, the development of oxygen-evolving anodes for eco-friendly technologies to produce important metals and alloys by electrolysis of molten salts seems to be an urgent task. To determine the degree of "inertness" of a particular anode material, data on the kinetics and mechanism of the anode process on an ideal material not subject to oxidation are required. In this connection, the anode process on gold in the low-temperature KF-AlF3-Al2O3 melt for electrolytic aluminum production was investigated in this work by cyclic and square-wave voltammetry methods. The influence of temperature (715 and 775°C) of the melt, the content of Al2O3 in it (from 0.1 to saturation), as well as the polarization rate (0.05–1 V s−1) on the kinetics and some features of the mechanism of the investigated process was determined. An assumption is made that oxygen release on gold without dissolution of the substrate takes place in the region of overvoltages from 0 to 0.8 V. It is shown that the process includes the stages of electrochemical adsorption and desorption of the intermediate product, the first of which is limited by the diffusion of electroactive anions to the anode. [ABSTRACT FROM AUTHOR]