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A gold surface is functionalized by chemisorption of the enantiopure N,N′-bis-[2,2′;5′,2″]tert-thiophene-5-yl methylcyclohexane-1,2-diamine (2T3N), a chiral oligothiophene derivative, via overnight incubation in a 2T3N ethanol solution. The Au|2T3N interface is characterized by x-ray photoelectron circular dichroism and comparing x-ray photoemission spectroscopy and electro-desorption results. Charge transmission at the Au|2T3N| solution interface is characterized by recording the cyclic voltammetry of the Fe(III)/Fe(II) reversible redox couple, finding a charge transfer rate constant, k°, variation from 1 × 10−1 to 3.3 × 10−2 cm s−1, when comparing the bare Au and the Au|2T3N interfaces, respectively. The "anomalous" high value of k° found for the chiral Au|2T3N interface can be rationalized on the basis of the chiral-induced spin selectivity effect, as further proved by magnetic–conductive atomic force microscopy measurements at room temperature. A spin polarization of about 30% is found. [ABSTRACT FROM AUTHOR]

[2.2]Paracyclophanes ([2.2]PCs) with substituents at specific positions possesses planar chirality and stands as a promising building unit for the development of chiroptical materials associated with polarized light. However, one of the easily accessible starting materials, bromo‐substituted [2.2]PC, shows low reactivity, and effective methods for π‐extension of planar chiral [2.2]PC are limited. Herein, an effective π‐extension method has established for chiral [2.2]PC with four substitutions from 4,7,12,15‐tetrabromo[2.2]PC. This has led to tetrakis(trimethylsilylphenyl)‐[2.2]PC that serves as a versatile building resource for radial‐type chiral π‐conjugated compounds with a [2.2]PC core. In this study, synthesizing compounds are further succeeded with the introduction of carbazole (Cbz4‐[2.2]PC and tBuCbz4‐[2.2]PC) and investigated their chiroptical properties and chiral induction ability in achiral π‐conjugated polymers. A thin film of [Poly[9,9‐dioctylfluorenyl‐2,7‐diyl)‐alt‐(benzo[2,1,3]thiadiazol‐4,7‐diyl)]] (F8BT) with 3wt% Cbz4‐[2.2]PC prepared by spin‐coating exhibits circularly polarized luminescence (CPL) properties with a high dissymmetry factor (|glum| = 0.01), which is much higher than that of Cbz4‐[2.2]PC in CH2Cl2 solution. By contrast, the doped film of F8BT with 3wt% tBuCbz4‐[2.2]PC exhibited only weak CPL properties. In addition, these chiral compounds show facile redox properties owing to the presence of carbazole units. Furthermore, Cbz4‐[2.2]PC undergoes electropolymerization to produce an insoluble thin film on the electrode. [ABSTRACT FROM AUTHOR]

A diprotic bis(β-thioketoimine) ligand precursor featuring a flexible 4,4'-methylbis(aniline) linker, H22, was synthesised via treatment of the corresponding bis(β-ketoimine) with Lawesson's reagent. Lithiation of H22 and coordination with one equivalent of d-block metal(II) chlorides MCl2(THF)x (M = Fe, Co and Zn) yielded a corresponding series of homoleptic dinuclear complexes, [M2(μ-2)2]. X-ray diffraction analysis reveals a tetrahedral geometry for the two metals and a double-stranded helicate structure arising from inter-strand face-face π-stacking. These interactions create a helical 'twist' of ca. 70°. Utilising a bulky mononucleating β-thioketoiminate ligand, [3]-, the analogous series of homoleptic monometallic complexes, [M(3)2] (M = Fe, Co and Zn), were prepared and characterised by spectroscopic and analytical techniques. A comprehensive DFT study of all complexes reveals a stronger M-S bonding compared to M-N due to a higher degree of covalency. Solution magnetic studies and natural bonding orbital calculations on the mono- and dinuclear iron and cobalt complexes are consistent with high-spin tetrahedral Fe(II) and Co(II) centres, and cyclic voltammetry reveals both oxidation and reduction processes are accessible. [ABSTRACT FROM AUTHOR]

The increasing demand in healthcare for accessible and cost-effective analytical tools is driving the development of reliable platforms to the customization of therapy according to individual patient drug serum levels, e.g. of anti-psychotics in schizophrenia. A modifier-free microfluidic paper-based electroanalytical device (μPED) holds promise as a portable, sensitive, and affordable solution. While many studies focus on the working electrode catalysts, improvements by engineering aspects e.g. of the electrode arrangement are less reported. In our study, we demonstrate the enhanced capabilities of the 3D electrode layout of μPED compared to 2D μPED arrangements. We especially show that screen printing can be employed to prepare 3D μPEDs. We conducted a comparison of different 2D and 3D electrode arrangements utilizing cyclic voltammetry in [Fe(CN)6]3−/4−, along with square-wave voltammetry for clozapine (CLZ) sensing. Our findings reveal that the utilization of the 3D μPED leads to an increase in both the electrochemically active surface area and the electron transfer rate. Consequently, this enhancement contributes to improve sensitivity in the CLZ sensing. The 3D μPED clearly outperforms the 2D μPED arrangement in terms of signal strength. With the 3D μPED under the optimized conditions, a linear dose–response for a concentration range from 7.0 to 100 μM was achieved. The limit of detection and sensitivity was determined to be 1.47 μM and 1.69 μA μM−1 cm−2, respectively. This evaluation is conducted in the context of detection and determination of CLZ in a human blood serum sample. These findings underscore the potential of the 3D μPED for future applications in pharmacokinetic analyses and clinical tests to personalize the management of schizophrenia. [ABSTRACT FROM AUTHOR]

Metal complexes based on mono(arylhydrazino)acenaphthenones (Ar-mhan) are extremely rare. In this work, synthetic routes for previously unknown rhodium complexes containing 2-(pyridin-2-yl)hydrazino acenaphthene-1-one (Py-mhan) are proposed. The interaction of RhCl3·3H2O with Py-mhan, depending on the conditions, led to two anionic complexes: (HPy-mhan)+[Rh(Py-mhan)Cl3] (1) and (NBu4)[Rh(Py-mhan)Cl3] (2). The complexes were characterized using X-ray diffraction analysis, elemental analysis, and IR- and 1H NMR-spectroscopies. The electrochemical properties of complex 2 were investigated using cyclic voltammetry. Complex 2 demonstrated irreversible reduction at −0.69 V (vs. Ag/AgCl), which is accompanied by the elimination of chloride ligands to give a Rh(I) complex namely [Rh(Py-mhan)(CH3CN)] (3). Complex 3 was isolated by electroreduction of complex 2 on a carbon glass electrode and characterized by EDS analysis, CHN analysis, 1H NMR spectroscopy and cyclic voltammetry. For complexes 2 and 3, reversible reduction processes localized on Py-mhan were found. To confirm the nature of electrochemical transformations for complexes 2 and 3 in solution, quantum chemical calculations were performed. [ABSTRACT FROM AUTHOR]

Supercapacitors, as promising energy storage devices, have gained significant attention due to their ability to deliver high power and efficient charge storage mechanisms. In this work, we report the synthesis and electrochemical characterization of pristine NiO and Ni 1-x Ce x O (x = 0.01, 0.02, 0.03) nanoparticles using a single-step auto ignition combustion method. Preliminary investigations indicate that Ni 1-x Ce x O (x = 0.02) nanoparticles (2 % Ce doping) exhibit superior specific capacitance compared to other compositions. Therefore, we focused on structural, morphological, and vibrational studies on pristine and 2 % Ce-doped NiO. XPS and BET techniques were explored to assess the electronic state and porosity of the samples. Subsequent electrochemical performance evaluations included Cyclic Voltammetry (CV) at various scan rates, Galvanostatic Charge-Discharge (GCD), and Electrochemical Impedance Spectroscopic (EIS) techniques. From CV at a scan rate of 5 mVs−1, specific capacitance values of 419 Fg-1 and 604 Fg-1 were obtained for pristine and 2 % Ce-doped NiO, respectively. GCD studies revealed a specific capacitance of 381 Fg-1 for 2 % Ce-doped NiO at a current density of 1 Ag-1 and demonstrated capacitance retention of 95.1 % over 3000 GCD cycles for a current density of 4 Ag-1. The symmetric two-electrode supercapacitor cell demonstrates exceptional electrochemical performance, exhibiting a high specific capacitance of 122 Fg-1, an impressive energy density of 8.17 WhKg−1, a power density of 700 WKg-1 at 1 Ag-1, and a remarkable 88 % capacitance retention after 5000 GCD cycles. DFT calculations suggest that Ce doping significantly alters pristine NiO's electronic and structural features due to lattice strain. Our work highlights the enhanced electrochemical performance of 2 % Ce-doped NiO and its potential as a good-quality supercapacitor material. [ABSTRACT FROM AUTHOR]

Electrode fabrication in microfluidic devices is often avoided due to the smaller footprint of the platform, associated complexity in the process, and absence of a well-established method. In this article a glass microchip with chemically modified and vapor deposited gold internal electrode was fabricated and used for biomolecule immobilization and electrochemical applications. The silanol (-OH) on glass surface of the microdevice was modified with (3-mercaptopropyl)trimethoxysilane prior to gold deposition to achieve a strong attachment of the metal film using the gold-thiol binding. The practical utility of the microdevice with gold surface was demonstrated by performing quantitative enzyme linked immunosorbent assay (ELISA) of human interferon gamma (IFN-γ) antigen, yielding a limit of detection (LOD) of 0.15 pg/mL compared to 4 pg/mL in the microplate assay. Additionally, the functionality of the internal electrode was established by performing cyclic voltammetry (CV) and linear sweep voltammetry (LSV) of potassium ferricyanide (III) in potassium chloride (KCl) solution using the proposed gold patterned electrode in the microchip, offering limits of detection of 0.14 and 0.11 mM for CV and LSV respectively. Both the ELISA and electrochemical assays were validated by generating calibration curves and using a control sample for the electroanalytical sensing applications. The measurements yielded experimental results that agreed with control concentration with 7% relative standard deviation (RSD). The promising reproducibility of the electrode in fabrication with no/minimum failure rate and its outstanding performance in immunosensor applications as well as an electron exchange surface makes our technique of gold electrode fabrication in microchips a state of the art. [ABSTRACT FROM AUTHOR]

L-Cysteine is a semi-essential and proteinogenic amino acid, with the formula HO2CCH (NH2) CH2SH. L-cysteine is mostly found in protein-rich foods. In this study, catalysts consisting of cobalt (Co) supported on carbon nanotubes (CNTs) were prepared using the sodium borohydride (NaBH4) reduction method. These catalysts were characterized by means of energy-dispersive x-ray (EDX) with scanning electron microscopy (SEM), temperature-programmed reduction (TPR), and temperature-programmed oxidation (TPO) techniques. Characterization results confirmed the successful preparation of the desired catalyst. After preparing the Co/CNT catalysts, a highly efficient and sensitive electrochemical sensor was developed using a glassy carbon electrode (GCE) modified with the Co/CNT catalysts. The electrochemical behavior of the bare GCE and Co/CNT-modified GCE electrodes was investigated using cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS) in 0.1 M phosphate buffer solution (PBS) + L-cysteine. Electrochemical results showed that the Co/CNT-modified GCE electrode exhibited high sensitivity and selectivity compared to the bare GCE, with sensitivity of 0.0046 µA/µM, limit of detection of 0.2 µM, and limit of quantification of 0.6 µM. Furthermore, this electrode showed higher sensitivity values than those reported in the literature. Further interference studies were performed using CV and EIS to investigate interfering species in the serum environment, such as D-glucose, uric acid, L-tyrosine, and L-tryptophan. In conclusion, the results suggest that the Co/CNT-modified GCE electrode is a promising catalyst for the sensitive detection of L-cysteine. [ABSTRACT FROM AUTHOR]

Conjugated polymers with delocalized polarons and near‐infrared (IR) absorption properties are promising materials for applications in electrochemical devices. However, the poor stability of low bandgap polymers in electrochemical redox conditions limits the realization of such devices. Herein, a new family of near‐IR absorbing conjugated polymers based on diketopyrrolopyrrole (DPP) derivatives with methoxy substituents to achieve reversible p‐type electrochemical doping with bistable near‐IR electrochromism is designed. The extent of volumetric doping in various electrolytes using cyclic voltammetry and spectroelectrochemistry for optimal electrochemical kinetics and near‐IR contrast is systematically investigated. Further, the spray‐coated films of polymers display high open circuit memory as the methoxylation is increased on the polymer backbone. The contrasting electrochromic memory and kinetics observed for these polymers are mainly ascribed to two factors; i) the effect of backbone structure on the spatial extent of polaron delocalization, and ii) the ionization energy of the polymers. The utility of DPP‐based polymers as energy‐efficient electrochromic optical attenuators (EVOAs) with high near‐IR coloration efficiencies, and an optical attenuation value of 5.1 dB at 1.3 and 1.5 µm wavelengths is demonstrated. Furthermore, the experimental findings are corroborated with theoretical studies to establish that the polaron delocalization length is central to the performance of the device. [ABSTRACT FROM AUTHOR]

Parkinson's disease (PD) is a progressive, neurodegenerative disease characterized by motor dysfunction and dopamine deficits. The MitoPark (MP) mouse model of PD recapitulates several facets of Parkinson's disease, including gradual development of motor deficits, which enables the study of potential therapeutic interventions. One therapeutic strategy involves decreasing the mitochondrial metabolic load by inducing ketosis and providing an alternative energy source for neurons, leading to decreased neuronal oxidative stress. Thus, we hypothesized that administration of a ketone ester–enriched diet (KEED) would improve motor and dopamine release deficits in MP mice. Motor function (rotarod and open field tests), dopamine release (fast‐scan cyclic voltammetry), tissue dopamine levels (gas chromatography–mass spectrometry) and dopamine neurons and axons (immunofluorescence) were assessed in MP, and control mice fed either the standard or a KEED. When started on the ketone diet before motor dysfunction onset, MP mice had improved motor function relative to standard diet (SD) MP mice. While the KEED did not preserve dopamine neurons or striatal dopamine axons, dopamine release in ketone diet MP mice was greater than SD MP mice but less than control mice. In a follow‐up experiment, we began the ketone diet after motor dysfunction onset and observed a modest preservation of motor function in ketone diet MP mice relative to SD MP mice. The improvement in motor dysfunction indicates that a KEED or ketone supplement may have a beneficial effect on delaying motor deficit progression in Parkinson's disease. [ABSTRACT FROM AUTHOR]

This study aims to investigate the effect of Mn doping on the performance of polyvinyl alcohol/borax‐structured (PMB) supercapacitor electrodes for high‐capacity, flexible, and self‐healing supercapacitor electrodes. The PMB electrodes were characterized by x‐ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy (SEM). Electrochemical characterization was conducted using cyclic voltammetry (CV), which revealed that redox reactions, which are evident at low scan rates, enhance capacitive performance. However, high scan rates introduce limitations owing to the increased vibrations of the PVA chains and incomplete electrolyte polarization. The PMB electrodes exhibited remarkable electrochemical properties and capacitive performances, which were significantly affected by the MnO₂ structure. The electrodes exhibited self‐healing properties and demonstrated flexibility to stretch by up to 40%. In addition, the results indicate that the electrode capacity of the PVA/borax system increased by 2.03 times after 1000 cycles with manganese doping. The solid electrolyte interface (SEI) layer formed on the electrode surface plays a critical role in stabilizing the capacity loss during prolonged charge–discharge cycles. The study concluded that PMB supercapacitors offer higher capacitance in 0‐2 V applications compared to other PVA/borax combination hydrogels. Moreover, the incorporation of metal‐based additives, particularly manganese, enhanced the capacitive performance, and operating voltage levels. [ABSTRACT FROM AUTHOR]

The behaviour and compatibility of monoclinic sodium manganite, α‐NaMnO2, cathodes at the interface with electrolytes based on the 1‐ethyl‐3‐methylimidazolium bis(fluorosulfonyl)imide (EMIFSI) and N‐trimethyl‐N‐butylammonium bis(fluorosulfonyl)imide (N1114FSI) ionic liquids is presented and discussed. The Na+ insertion process was analysed through cyclic voltammetry tests combined with impedance spectroscopy measurements and the cell performance was tested by charge‐discharge cycles. XPS and FIB‐SEM measurements allowed analysis of the surface composition and the morphology of post‐mortem cathodes. Overall, the α‐NaMnO2 cathode showed high reversibility in N1114FSI‐based electrolyte, delivering 60 % of the initial capacity after 1200 cycles in conjunction with a Coulombic efficiency above 99 %. To our knowledge, these very promising results are the best result obtained till now for monolithic α‐NaMnO2 cathodes, are ascribable to the formation of a stable passive layer onto the electrode surface, as confirmed by spectroscopic analysis. [ABSTRACT FROM AUTHOR]

A widely used method to obtain tetrazoles is through the azide and nitrile [3+2] cycloaddition. However, this process often involves using non‐recyclable transition metals or Lewis acid catalysts and stoichiometric amounts of oxidants and additives, which reduces atom efficiency. We have discovered a convergent paired electrochemical reaction to perform this cycloaddition reaction, without the need for metal catalysts or oxidants. This tetrazolation strategy uses azidotrimethylsilane (TMSN3) and N‐heterocycles in an undivided cell at a constant current. We use a mixture of CH3CN and equivalent amounts of H2O as co‐solvent at room temperature. It is crucial to produce a stoichiometric amount of active hydroxyl ions through the cathodic reduction of water. Cyclic voltammetry (CV) studies and control experiments confirm that the cycloaddition reaction is specific to the electrode electron transfer process, eliminating the need for a mediator to shuttle electrons. This metal‐ and oxidant‐free strategy is highly compatible with different functional groups and produces products with moderate to good yields. We have successfully tetrazolated bioactive compounds at a late stage, scaled up batches efficiently, and synthesized free amino‐containing N‐heterocycles via denitrogenation of tetrazoles. [ABSTRACT FROM AUTHOR]

NASICON electrode materials exhibit a broad spectrum of electrochemical potentials, robust ionic conductivity, and structural and thermal stabilities. Using solid state reaction method, Li2Cu2(MoO4)3 was synthesized, a member of NASICON family of compounds based on molybdenum. Various analytical techniques employed to assess structural and morphological properties of synthesized nanomaterial. X‐ray diffraction (XRD) pattern indicated that generated Li2Cu2(MoO4)3 nanomaterial exhibited orthorhombic crystalline structure, with crystallite size of approximately 48 nm. The nanomaterial morphology was evaluated using field emission scanning electron microscopy (FESEM), showing columnar‐ or fiber‐like morphology composed of some conductivity points. The elemental composition of Li2Cu2(MoO4)3 was analyzed by EDAX analysis, confirming the presence of elements lithium, copper, molybdenum, and oxygen. The optical properties and band gap of Li2Cu2(MoO4)3 were analyzed by ultraviolet visible diffuse reflectance spectroscopy (UVDRS). Elemental composition of surface along with electronic states and oxidation states of component present in the nanomaterial Li2Cu2(MoO4)3 were investigated from X‐ray photoelectron spectroscopy (XPS). Electrochemical evaluation using cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopic (EIS) showed a specific capacitance of 250 F g−1 at 3.5 A g−1 with the high retention rate of 95.82% after 3000 cycles, indicating its potential for high performance supercapacitors. [ABSTRACT FROM AUTHOR]

CuCo2O4 nanoparticles were synthesized via facile hydrothermal route using oxalic as a precipitant, thermal decomposition of CuCo2O4 precursor at 400∘C. The structural studies from X-ray diffraction (XRD), Fourier transform infrared spectrometer, Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) disclose the predominant spinel crystal phase for copper cobaltite. The optical absorption spectra reveal two band gaps of 3.8eV and 4.4eV in the CuCo2O4 nanoparticles. The cyclic voltammetry (CV) was used to assess the electrochemical characteristics of the resulting product in an organic electrolyte at −1.5–1.5V under ambient conditions. On 22.4nm CuCo2O4 nanoparticles, a greater capacitance of 920F/g at a scan rate of 5mV/s was achieved. [ABSTRACT FROM AUTHOR]

Morphine, as one of the most important narcotic drugs, significantly affects the nervous system and increases euphoria, which raises the likelihood of its misuse. Therefore, its measurement is of great importance. In this work, a new electrochemical sensor based on a nanocomposite of CuS/g-C3N5/AgNPs was developed for modifying Screen printed carbon electrodes (SPCEs) and used for the measurement of morphine through cyclic voltammetry and differential pulse voltammetry. Various analytical methods initially characterized the nanocomposite. The prepared sensor, which also has an extensive surface area, achieved a detection limit of 0.01 µM for morphine in a concentration range of 0.05–100 µM at pH 7. Besides its excellent capability in measuring morphine in real samples, the sensor exhibits good stability, reproducibility, and repeatability. The presence of CuS, due to its excellent high surface area alongside silver nanoparticles, leads to an increase in the conductivity of the g-C3N5 modified electrode, resulting in an increased oxidative current of morphine at the surface of the prepared sensor. Therefore, measuring low concentrations of morphine with this sensor was made possible. Additionally, measuring morphine without interference from various species is a strong point of the electrochemical sensor for morphine detection, and combined with the simplicity and ease of the method, it allows for morphine measurements to be conducted in the shortest possible time. [ABSTRACT FROM AUTHOR]

This study presents the electrochemical reduction of graphene oxide (GO) to reduced graphene oxide (rGO) directly onto flexible interdigitated gold electrodes and its application as a strain sensor. GO reduction is achieved using cyclic voltammetry (CV). Remarkably, only a single CV cycle transformed GO into rGO to obtain low‐resistance (≈100 Ω) devices. The reduction of GO is confirmed using Raman spectroscopy and electrical measurements. rGO on flexible interdigitated gold electrodes exhibits graphene‐like characteristics when used as electrolyte‐gated field‐effect transistors. The fabricated devices display a gauge factor (GF) of ≈3.7 in the 0–794 με range. This value represents a substantial improvement, ≈60% higher than traditional metallic strain sensors, which have a GF of ≈2.1. Most importantly, the rGO strain sensor exhibits fast response (1.1 s) and recovery (0.92 s) times. The rGO sensor is mounted on a clamp with an adjustable diameter, which reveals exceptional flexibility and bendability without damage or degradation. These results highlight the potential of rGO for advancing strain‐sensing applications, offering promising opportunities for the future of this technology. [ABSTRACT FROM AUTHOR]

We report on dual, light‐responsive and redox‐active foldamers that demonstrate reversible and robust stimuli‐induced behaviour. Herein, UV/Vis, 1H NMR and circular dichroism (CD) spectroscopy and cyclic voltammetry have been used to establish the reversibility and highly robust nature of the light‐ and redox‐driven behaviour of these new foldamers with minimal levels of fatigue observed even upon multiple cyclic treatments with irradiative/non‐irradiative and oxidative/reductive conditions. This proof‐of‐concept work paves the way towards the creation of novel stimuli‐responsive foldamers of increasing sophistication capable of demonstrating reversible and robust responses to multiple distinct stimuli. [ABSTRACT FROM AUTHOR]

A Rh(III)-catalyzed additive-controlled regioselective [4 + 1] and [4 + 2] cyclization of benzoic acids with alkynyl esters/amides under electrochemical conditions has been developed for the synthesis of phthalides and isocoumarins. The selectivity for the product formation was attained by merely changing the additive. Employment of NaOAc in the reaction produces isocoumarins whereas AcOH favors phthalides. Cyclic voltammetry and control experiments reveal the mechanistic pathway of the reaction. [ABSTRACT FROM AUTHOR]

N-(1,3-Dimethylbutyl)-N′-phenyl-1,4-benzenediamine (6PPD) is a common additive in tires. 6PPD protects rubber from oxidative damage by ozone. Leaching of 6PPD in the environment leads to the formation of harmful byproducts such as 6PPD quinone. In this work we provide the fundamental basis for the detection of 6PPD by electrochemical techniques. We use cyclic voltammetry to study the adsorption of 6PPD on glassy carbon. We show that adsorbed 6PPD can be reversibly oxidized and reduced without disturbing the adsorption process. This result enables repeated electrochemical titrations. We determine, in neutral condition at 22 °C, an adsorption constant of Kads = 1.2 ± 0.5 μM−1 and kinetics of adsorption kads∈[0.74–5.60] × 104 L mol−1 s−1. Based on this knowledge we demonstrate the lowest concentration of 6PPD ever detected electrochemically, 10 nM. We also identify current challenges for electrochemical sensing of 6PPD. Multiple layers are formed at concentrations above 4.6 μM and the slow kinetics of adsorption requires long (hour) measurement time to reach maximum sensitivity. [ABSTRACT FROM AUTHOR]

The design of electrochemical sensors is crucial considering important factors such as efficiency, low cost, biocompatibility, and availability. Manganese oxides are readily available, low-cost, and biocompatible materials, but their low conductivity limits their efficiency as sensors. Today, morphology engineering of manganese oxide has been one of the most common research topics, because manganese oxides' electrochemical properties are highly dependent on their morphologies. In this study, a method for reducing the charge transfer resistance (Rct) of MnO2-based electrodes was established by the cyclic voltammetry technique accompanied by step-by-step heat treatment to electrodeposition MnO2 nanofilm, which remarkably improved the Rct. Next, the sensing performance of MnO2/FTO for two separate measurements was examined, one for the simultaneous measurement of paracetamol (PAR) and 4-aminophenol (4-APh), and the other for the measurement of 4-nitrophenol (4-NP). Under the optimum conditions, the linear ranges of 4-APh, PAR, and 4-NP, were 0.8 to 22.0 µM, 2.0 to 55.0 µM, and 0.1–250 µM, with limits of detection (LOD) of 0.19 µM, 0.60 µM, and 0.01 µM, respectively. It also was unaffected by a 200-fold excess of interferences. In addition, the designed sensor was successfully applied to the analysis of real samples. [ABSTRACT FROM AUTHOR]

Hydrogen is a renewable and environmentally friendly energy carrier and is considered a viable alternative to fossil fuels. Consequently, developing electrodes with excellent hydrogen evolution electrocatalysis is a top priority in research. However, the use of flat electrodes as cathode substrates by most researchers limits the electrocatalytic active area of the prepared electrode. To address this issue, it is essential to prepare a micro-nano structure on a cathode substrate before electrodeposition. This study introduced a novel Ni nanocone/Grid electrode, obtained through a combined laser-electrodeposition process to investigate its electrocatalytic activity and stability for the hydrogen evolution reaction (HER). Various techniques, including linear sweep voltammetry (LSV), electrochemical impedance spectra (EIS), cyclic voltammetry (CV), and chronopotentiometry (CP) in 1 M KOH solution, were employed to assess the HER electrocatalytic performance of the Ni nanocone/Grid electrodes. The experimental results demonstrated that the electrodes could achieve current densities of -10, -20, and -100 mA/cm2 with corresponding overpotentials of -281, -308, and -390 mV, respectively. Additionally, the Tafel slope of these electrodes was found to be only -82.05 mV/dec. The enhanced catalytic performance of the electrode was attributed to the synergistic effect of the grid-like and nanocone structures, which significantly increased the electrocatalytically active area and improved surface hydrophilicity, thereby boosting electrocatalytic performance. The simplicity of the preparation method and the exceptional performance of the electrode provide a promising new avenue for future research on HER electrocatalysts. • A new laser-electrodeposition combined process was proposed to prepare the catalytic electrode for hydrogen evolution. • Ni nanocone/Grid showed low overpotential and Tafel slope for hydrogen evolution. • The combination of grid structure and nanocone can significantly increase the ECSA of the electrode. • The electrode shows excellent hydrophilicity and extraordinary durability. [ABSTRACT FROM AUTHOR]

The utilization of magnetoelectric composites, particularly core-shell configurations, enhances their versatile applications in various sectors such as medicine and data storage. Among these composites, the perovskite-spinel combination is distinguished by its significant potential. A series of (1-x) BiFeO 3 -(x) CoFe 2 O 4 (where x = 0.0, 0.2, 0.5, and 1.0) nano core-shell structures were synthesized using a sol-gel auto-combustion method to explore their multifunctional capabilities. Structural analyses identified peaks corresponding to both perovskite and spinel phases. Field Emission Scanning Electron Microscopy revealed a reduction in average particle size with an increase in CoFe 2 O 4 content.The particle size in the BFO80-CFO20 sample has been reduced from 243 nm to 34 nm. Additionally, Transmission Electron Microscopy images of the BFO80-CFO20 sample highlighted the evolution of core-shell structures. Our findings indicate that higher CFO concentrations significantly affect the dielectric, ferroelectric, and optical properties. The bandgaps of the nanocomposites BFO80-CFO20 and BFO50-CFO50 were estimated to be 1.43 eV and 1.39 eV, respectively. Magnetic analysis showed increases in both saturation magnetization and remanent magnetization with increased CFO content, while the coercive field followed a different trend. The saturation magnetization values for the samples BFO, BFO80-CFO20, BFO50-CFO50, and CFO were calculated as 0.205, 14.612, 28.374, and 74.105 (e m u g r) , respectively. The measured values for the same samples were 0.08, 5.07, 11.34, and 34.01 (e m u g r) , respectively. Further, the electrochemical properties were thoroughly investigated using cyclic voltammetry, linear sweep voltammetry, and electrochemical impedance spectroscopy. [ABSTRACT FROM AUTHOR]

Compared with traditional ferroelectric materials sintered by two steps, CaCu 3 Ti 4 O 12 is regarded as a promising dielectric material attributed to its huge dielectric constant, temperature stability, and more easily sintered by only one step through solid-state reaction. However, the origin of the giant dielectric constant remains controversial due to the complexity of the interface and the lack of effective tools to reveal defects and boundary effects. In this work, CaCu 3 Ti 4 O 12 ceramics with different oxygen concentrations were prepared and the influence of defects on their electrical properties was studied by cyclic voltammetry method. It was found that the resistance of CaCu 3 Ti 4 O 12 decreases with increasing the number of cyclic voltammetry conditioning and after certain cycles, the voltampere (CV) characteristics change dramatically from nonlinear to linear. In addition, the resistance transition is strongly dependent on the oxygen concentration, and samples sintered in a vacuum with more oxygen vacancies are more easily induced. A filamentary mechanism of oxidation-reduction reaction was proposed to explain the resistive transition of CaCu 3 Ti 4 O 12. [ABSTRACT FROM AUTHOR]

The current work reports a novel approach for the development of an electrochemical sensor based on Ni and Mg-co-doped ZnO nanoparticles (ZNMO) to detect and quantify cysteamine (CA). The chemical co-precipitation strategy was used to synthesize zinc oxide co-doped with magnesium and nickel which can be used as a catalyst material. FTIR, XRD, XPS, BET and SEM-EDX examinations were used to confirm the produced material. The surface of the glassy carbon electrode (GCE) was modified with ZNMO nanoparticles, resulting in a remarkable improvement in the surface area of the electrodes which in turn improved the response for CA compared to previously reported studies. This enhancement can be attributed to the superior catalytic activity of the material in electro-oxidizing CA. The electrochemical studies were carried out using the analytical techniques like cyclic voltammetry and differential pulse voltammetry using 0.1 M phosphate buffer saline as a supporting medium. This fabricated sensor, ZNMO nanoparticles modified GCE (ZNMO/GCE) has shown superior sensing characteristics, including high selectivity, sensitivity, stability, and repeatability, for the identification and quantification of CA. The sensor successfully confirmed the diffusion-controlled electrode technique. It exhibited the widest linear range, spanning from 1 nM to 2500 μM, which is the most impressive result ever reported. The limit of detection (LOD) was determined to be 0.75 nM. Additionally, at the developed sensor, a real-sample analysis was conducted using biological fluids. Hence, the fabricated ZNMO/GCE showed excellent electrocatalytic performance for CA sensing, making it suitable for real-time monitoring. [Display omitted] [ABSTRACT FROM AUTHOR]

A novel molecularly imprinted electrochemical sensor (MIECS) was constructed for the specific detection of sulfadiazine (SDZ) in food. Niobium carbide (Nb2CTx) as a typical two-dimensional lamellar nanomaterial has good electrical conductivity and unique structure, which was assembled with one-dimensional silver nanowires (AgNWs) to form quasi-three-dimensional composite nanomaterials (Nb2CTx/AgNWs). As spacer material, AgNWs prevented the aggregation of Nb2CTx and the collapse of Nb2CTx layers. At the same time, a fast electron transport channel was constructed through the synergistic effect between nanomaterials the two. The Nb2CTx/AgNWs realized the enhancement of electrical signals. Molecularly imprinted polymers (MIPs) endowed the sensor with selectivity, achieving the specific detection of sulfadiazine. Under the optimal experimental conditions, the method has a wide linear range (1 × 10−8–1 × 10−4 mol L−1) and a low limit of detection (1.30 × 10−9 mol L−1). The sensor was used to detect sulfadiazine in pork, chicken, and feed samples, and the recovery was 82.61–94.87%. The results were in good agreement with the HPLC results, which proved the accuracy and practicability of the method. [ABSTRACT FROM AUTHOR]

A novel electrochemical sensor–based glassy carbon electrode (GCE) was fabricated and applied to simultaneous detection and degradation of tebuconazole (TBZ) for the first time. The GCE was consecutively modified by multi-walled carbon nanotubes (MWCNTs), bismuth oxybromide (BiOBr), ꞵ-cyclodextrin (ꞵ-CD), and in situ addition of tetrabutylammonium bromide (TBABr). The detection was based on the decreasing of Bi signal at its anodic potential (Epa) of 0.05 V. Under the optimum conditions, the modified electrode exhibited a linear response to TBZ in the concentration range 1–100 μg L−1 with a detection limit of 0.9 μg L−1. TBZ was firstly adsorbed on the surface of the modified electrode through host–guest molecule interactions of the ꞵ-CD. The adsorption was further enhanced by the large surface area of BiOBr and MWCNTs. The adsorbed TBZ on the electrode surface hindered the electron transfer of Bi, thus decreasing the oxidation of Bi. In addition, the in situ addition of tetrabutylammonium bromide (TBABr) enriched TBZ via electrostatic interactions, increasing its detection sensitivity. The fabricated electrochemical sensor was applied to determine TBZ in water and soil samples from rice fields with recoveries of 80.5–100.5% and 87.6–112%, respectively. Furthermore, the degradation of TBZ on the modified electrode was studied under a solar light simulator. The degradation percentage (100%) of TBZ (50 µg L−1) was achieved in 5 min owing to the excellent photocatalytic properties of BiOBr. [ABSTRACT FROM AUTHOR]

Copper is efficient, has a high conductivity (5.8 × 107 S/m), and is cost-effective. The use of copper-based catalysts is promising for the electrocatalytic reduction of nitrates. This work aims to grow and characterize copper micro-crystals on Screen-Printed Electrodes (SPEs) for NO3− reduction in water. Copper micro-crystals were grown by cyclic voltammetry. Different cycles (2, 5, 7, 10, 12, 15) of copper electrodeposition were investigated (potential ranges from −1.0 V to 0.0 V, scan rate of 0.1 V s−1). Electrodeposition generated different morphologies of copper crystals on the electrodes, as a function of the number of cycles, with various performances. The presence of numerous edges and defects in the copper micro-crystal structures creates highly reactive active sites, thus favoring nitrate reduction. The manufactured material can be successfully employed for environmental applications. [ABSTRACT FROM AUTHOR]

The Co3O4 nanowire@NiCo2O4 nanosheet hierarchical array was constructed on Ni foam using hydrothermal and annealing approaches in turn, from which a NiCo2O4 nanosheet could self-assemble on the Co3O4 nanowire. The structure and morphology of the Co3O4 nanowire@NiCo2O4 nanosheet hierarchical array were characterized via XRD, EDS, SEM, and FESEM, respectively. The electrochemical performance of the composite array was measured via a cyclic voltammetry curve, galvanostatic current charge–discharge, charge–discharge cycle, and electrochemical impedance and then compared with the Co3O4 nanowire. The results show that the Co3O4 nanowire@NiCo2O4 nanosheet hierarchical array could reach a high value of 2034 F g−1 at a current density of 2.5 A g−1. After 5000 galvanostatic charge–discharge cycles, the specific capacitance of the Co3O4 nanowire@NiCo2O4 nanosheet hierarchical array could still maintain 94.7% of the original value. Therefore, the Co3O4 nanowire@NiCo2O4 nanosheet hierarchical array would be a desirable electrode material for a high-performance supercapacitor. [ABSTRACT FROM AUTHOR]

This study investigates the preparation of nickel nanostructured electrodes for the enhancement of supercapacitor performance. The nanostructured electrodes are synthesized using nanoporous anodic alumina (NAA) as a template via the pulsed electrodeposition method. Structural properties are examined using field‐emission scanning electron microscopy, while electrochemical characterization is conducted through cyclic voltammetry (CV) and electrochemical impedance spectroscopy. The results reveal that Ni nanorod arrays can be obtained embedded in the NAA matrix and with electrical contact with the aluminum substrate. On average, the rods are spaced 90 nm apart, with a diameter of 70 nm and a length of 2 μm. The Ni@NAA electrode exhibits an enlarged active area and exceptional electrochemical performance, demonstrating remarkable stability over 5000 cycles of CV at a scan rate of 50 mV s−1. Specific capacitance values exceeding 100 mF cm−2 and maximum charging times of less than 10 min are reported, highlighting its suitability for high‐power energy devices requiring pseudo‐supercapacitance. The study underscores the significance of nanostructured electrodes in advancing energy storage technologies and presents promising prospects for practical applications. [ABSTRACT FROM AUTHOR]

This work reports the electrochemical fabrication of thin films comprising polyaniline nanofibers (PANI) in conjunction with graphene oxide (GO) and reduced graphene oxide (rGO) on ITO substrate, along with examining the electrochemical properties, with a focus on the influence of the substrate and electrolyte in the electrodeposition methods. The study explores the electrochemical characteristics of these thin films and establishes a flexible framework for their application in diverse sectors such as sensors, supercapacitors, and electronic devices. It analyzes the impact of the substrate and electrolyte in electrodeposition techniques. The effects were studied using techniques such as cyclic voltammetry and chronoamperometry. The fabrication process of PANI/GO and PANI/rGO thin films involved the integration of rGO within PANI via electropolymerization, conducted under sulfuric acid. GO was synthesized by modifying the well-known Hummers' method and characterized by X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). SEM showed the diameters of the formed PANI were between 40 and 150 nm, which helped to intertwine the rGO nanosheets with PANI nanofibers to form thin films. The electrochemical behavior of the PANI/rGO thin films was examined using cyclic voltammetry (CV) and chronoamperometry in different electrolytes, including sulfuric acid (H₂SO₄) and potassium nitrate (KNO₃). The CV profiles exhibited distinct oxidation and reduction peaks, with variations in the voltammogram morphology attributed to the nature of the electrolyte and the substrate employed during the electrodeposition process. These results highlight the critical role of both the substrate and electrolyte in governing the electrochemical performance of PANI/rGO thin films. The findings from this study demonstrate a versatile approach for the fabrication of PANI/graphene-based thin films with tunable electrochemical properties, and such a strategy has great application to fabricating other thin film composites for supercapacitors or other control source frameworks requiring enhanced charge storage and electrochemical responsiveness. [ABSTRACT FROM AUTHOR]

A simple, economical, and safe method for the synthesis of mesoionic 1,3-diaryltetrazolium derivatives bearing a para -substituted phenyl group at the 1- or 3-position via thiosemicarbazides was established. Such compounds were directly obtained from the corresponding para -substituted anilines instead of aryl isothiocyanates and arylhydrazines. The newly synthesized mesoionic compounds were successfully converted into the corresponding nitrosotetrazolium salts, which were utilized as catalysts for oxidation of an aliphatic alcohol and analyzed by cyclic voltammetry to determine the correlation between the catalytic efficiencies and redox potentials. The proposed method can be widely applied and is valuable for investigating the substituent effects in mesoionic and related compounds. [ABSTRACT FROM AUTHOR]

The stability of the all-solid-state electrode (ASSE) is influenced by its fabrication procedure, which has been insufficiently investigated. In this study, we report that by applying direct annealing of solid contact (polypyrrole-carbon black [PPy-CB]), and slow-drying the membrane during fabrication, electrode capacitance is improved which determines the stability of the ASSE-based astringent taste sensor. The deposition of the PPy-CB by direct annealing accelerated the sensor fabrication time and improved the capacitance. The slow-drying method led to a thinner and denser membrane, which consequently reduced bulk and charge-transfer resistance and improved the electrode capacitance. In synergy with the annealed PPy-CB, the proposed sensor exhibited an areal capacitance of 9090 μF/cm2. In addition, the sensor maintained its linear response to the standard astringent substance (tannic acid), selectivity against various interfering taste substances, and retained repeatable measurements for at least 27 d. [ABSTRACT FROM AUTHOR]

The paper production industry annually produces approximately 50 million tons of lignin, an intermediate product. While lignin has the potential for producing valuable chemicals and energy materials, an effective method for its conversion is yet to be developed. This study aims to establish a sustainable and environmentally friendly approach for electrochemically synthesizing valuable compounds from lignin with using natural deep eutectic solvents as electrolytes. The study used cyclic voltammetry (CV) for the electrochemical depolymerization of Kraft lignin, examining the effects of different scan numbers on depolymerization and the resulting lignin derivatives. Observed changes in the depolymerization peak current of lignin were reported as the number of scans increased. Choline chloride: Lactic acid (CC:LA), Choline chloride: Ethylene glycol (CC:EG), and Lactic acid:1,2-propanediol (LA:PR) were used as green electrolytes. Syringaldehyde was found to be the major compound obtained by this method. As a result of statistical analysis performed using The Grey Relations Analysis method, it was determined that the conditions that utilized Kraft lignin with the highest added value involved performing five cycles of CV scans with the CC:LA electrolyte. CV scans in DES environments increased the yield of lignin-derived phenolic compounds. [ABSTRACT FROM AUTHOR]

A new electrochemical sensor for the highly sensitive and selective determination of dopamine was developed, based on the use of a glassy carbon electrode modified with cobalt(II) polymer. Both electrochemical and morphological characterizations were investigated. Square wave voltammetry (SWV) was used for the determination of dopamine. From the SWV results obtained on the modified electrode under the optimized conditions, the successive addition of dopamine increased the anodic peak current. The results obtained show a linear response of the electrode modified with Co(II) polymer in a wide concentration range. Each concentration decade is characterized by a new calibration plot with a corresponding mathematical expression. The highest sensitivity (13.182) was obtained for the lowest concentration range, and the detection limit of 0.03 µM, calculated based on the 3 × sb/m criterion, indicates a very high sensitivity and great application potential. When analyzing a real sample, the modified electrode showed good electroanalytical activities in terms of oxidation of dopamine, good anti-interference ability, stability, reproducibility, and potential applicability in commercial pharmaceutical samples. [ABSTRACT FROM AUTHOR]

We report the comparison of multiple acetylene black (AB) rigid carbon composites for electrochemical purposes exploring several binders, including one (polyurethane) from a renewable source of castor oil. The acetylene black–based composites presented less roughness and increased surface homogeneity evinced by AFM and SEM images within the micrometer range. Contact angle analysis and Raman spectra confirmed a high degree of surface functionalization associated with structural defects on AB even when the base conductive material is associated with a non-conductive binder. The acetylene black-castor oil electrode presented superior performance (lower resistance to charge transfer and increased peak currents) when compared to its graphite counterparts regardless of the mechanical activation. The proposed electrode presented an excellent electrochemical performance in analyzing contaminants of emerging concern when compared to glassy carbon electrodes. The sustainable aspect of this work is evinced considering the room temperature synthesis, low cost of the AB, and renewable castor oil binder source. [ABSTRACT FROM AUTHOR]

The supercapacitive properties of the polythiophene (PTh) and its composites with iron dust synthesized by chemical oxidative polymerization are investigated. The UV–Vis, FTIR, TGA, XRD, SEM, and EDX were used to characterize the composites. Iron (Fe) dust is inserted into PTh matrix as confirmed by FTIR, UV–Vis, EDX, and XRD analysis. The TGA shows that composites have higher thermal stability than pure PTh. The SEM reveals highly porous and packed morphology of the composites as compared to pure PTh. Cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS) show that a 1:1 ratio by mass of PTh and Fe composite displayed greater specific capacitance than pure PTh. The high specific capacitance of the composite material (428.46 F/g at 1 A/g) suggested that the material is suitable for supercapacitor electrode. Cyclic stability is also tested for 1000 cycles at a current density of 1 A/g with excellent retention of 88.89%. [ABSTRACT FROM AUTHOR]

The electrochemical performance of gold electrode in sulfuric acid was studied with addition of different concentrations of dissolved fullerenol-d with C60(OH)24 chemical formula. Based on the cyclic voltammetry data, the conclusion of surface complexation of Au(III) with fullerenol was made. The scheme was suggested to describe the electrode process, based on catalysis of anodic Au dissolution by fullerenol molecules. The technique was suggested to detect fullerenol-d (C60(OH)24) in concentration range from 2.6·10–9 M to 2.0·10–7 M by means of cyclic voltammetry of gold in aqueous sulfuric acid solution. [ABSTRACT FROM AUTHOR]

Fuel cell technologies constitute a clean, reliable, highly efficient, and eco‐friendly source of alternative energy generation. However, they still require a reliable and robust catalytic system showing comparative electrochemical activity to precious metal Pt with less cost. In this work, Mn@ZnO NPs were synthesized using a hydrothermal‐assisted simple method. Several techniques including SEM, TGA, and XRD were used to confirm the material synthesis. Electrochemical properties were analyzed by using linear sweep voltammetry, chronoamperometry, and cyclic voltammetry. A higher ORR activity in terms of mass activity and current density was observed 133.9 mA/mg as compared to Pt/C (96 mA/mg) and Pd/C (67 mA/mg) under otherwise identical conditions. Mn@ZnO also exhibited excellent current density (1.913 mA cm−2), comparable to Pt/C (1.55 mA cm−2). Chronoamperometry shows stability for up to 800 s. Comparative studies were conducted in both acidic and basic mediums, with observed higher ORR activity in acidic media. [ABSTRACT FROM AUTHOR]

Activated carbon derived from biomass offers several advantages, including high surface area, customizable pore sizes, abundance, resilience across temperatures, and cost-effectiveness. This study focuses on exploring the potential of palm shell as a renewable alternative for supercapacitor electrode materials. Specifically, it investigates the utilization of a gel composed of NaOH and PVA for activating carbon. Here, palm shell undergoes chemical activation, and its resulting activated carbon's structural and physicochemical properties are comprehensively examined using XRD, FTIR, and BET measurements. The investigation delves into the electrochemical properties using cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy of electrodes fabricated from chemically activated carbon derived from palm shells. The activated carbon enhanced a surface area of 216.062 m2 g−1 and a pore volume of 0.1468 cm3 g−1, and it is produced through the innovative approach of gel-based activation. This research highlights the potential of palm shell-derived activated carbon as a viable, sustainable, and efficient material for supercapacitor electrodes. [ABSTRACT FROM AUTHOR]

A novel approach was employed to craft innovative carbon-paste electrodes using cerium(IV) oxide (CeO2)-doped clay, aiming to modify graphite electrodes. The introduction of Ce involved the adsorption of Ce3+ ions onto an activated carbon (AC) clay mixture, showcasing an impressive adsorption capacity of 40.0 mg g−1, which surpasses that of clay alone. This step was undertaken to enhance the conductivity of raw clay and increase its electrochemical surface area. Sintering clay-CeO2 at 1000 °C resulted in the maximum electrochemical area when utilized as a 10 wt% dopant for graphite electrodes. Heavy metal ion analysis (HMI) involving Cd2+, Pb2+, Cu2+, and Hg2+ was conducted using five electrochemical techniques: Cyclic Voltammetry (CV), Square Wave Voltammetry (SWV), Normal Pulse Voltammetry (NPV), Differential Pulse Voltammetry (DPV), and Linear Sweep Voltammetry (LSV). SWV emerged as the optimal technique and was termed SWAdSV after the stripping process, displaying peak current responses for Cd2+ (74.7 µA), Pb2+ (42.4 µA), Cu2+ (36.0 µA), and Hg2+ (22.8 µA). Calibration curves were utilized to determine the Limit of Detection (LOD) and Limit of Quantification (LOQ) values for Cd2+, Pb2+, Cu2+, and Hg2+. The repeatability, expressed as %RSD, for the same electrode was found to be 1.70%, 2.04%, 1.14%, and 3.61% for Cd2+, Pb2+, Cu2+, and Hg2+. While the reproducibility, also expressed as %RSD, for different electrodes was determined to be 1.98%, 2.31%, 1.52%, and 1.89% for Cd2+, Pb2+, Cu2+, and Hg2+, respectively. [ABSTRACT FROM AUTHOR]

To ensure the green and sustainable advancement of hydrogen energy, there is a critical need for the development of a cost-effective catalyst to address the sluggish kinetics of water electrolysis under alkaline conditions. An approach to achieve this is by constructing ultrathin Pt shell-structured catalysts that offer enhanced electrocatalytic hydrogen evolution reaction performance through modulation of the inner core while minimizing costs. Herein, an ultrathin Pt shell catalyst with an inner core consisting of a PtNi face-centered cubic and hexagonal-close-packed mixed-phase interface (named PtNi-mix) is synthesized through a pre-synthesis method followed by post-acid etching process. Encouragingly, the PtNi-mix catalyst only requires 12.9 mV overpotential to achieve a current density of 10 mA·cm-2 in 1 M KOH, which is much lower than that of the commercial 20 wt.% Pt/C catalyst (71.2 mV). Also, it possesses a high mass activity (7.2 A·mg-1) at an overpotential of 70 mV, which is 9 times higher than that of the commercial 20 wt.% Pt/C catalyst. Additionally, the performance of the PtNi-mix catalyst remains almost unchanged after 10,000 cyclic voltammetry tests, indicating that the catalyst exhibits excellent stability. [ABSTRACT FROM AUTHOR]

A novel electrochemical molecularly imprinted composite (MIC)-based sensor for detection of triclosan was developed. MIC was synthesized from o-phenylenediamine (o–PD), -COOH functionalized multiwalled carbon nanotube (cf-MWCNT), and triclosan by cyclic voltammetry on molybdenum nanoparticle (Mo-NP) embedded cf-MWCNT (Mo-cf-MWCNT) coated glassy carbon (GC) electrode, following removal of surface triclosan to form MIC/Mo-cf-MWCNT/GC. In our earlier work, two novel electrodes MIC/cf-MWCNT/GC and MIC/GC were fabricated. The presence of cf-MWCNT coating substrate on GC in MIC/cf-MWCNT/GC had improved the sensing performance than MIC/GC since presence of this substrate had decreased the electrochemical band gap (Eg) and increased Debye length (λd), Gibb's free energy of adsorption (− ΔGads), electrochemical surface area (Ae), and surface redox site concentration (C*). Therefore, further improvement in sensing performance can be carried out by utilizing Mo-NP in the cf-MWCNT coating substrate using MIC to be the sensing material. This novel electrode (MIC/Mo-cf-MWCNT/GC) provided a limit of detection (LOD) of 900 ppt of triclosan, which was lower than the LOD achieved by using MIC/cf-MWCNT/GC (10 ppb) and MIC/GC (40 ppb). Adsorption isotherm was constructed for MIC/Mo-cf-MWCNT/GC delivering − ΔGads value of 59.049 kJ/mol indicating stronger chemisorption. To understand the role of Mo-cf-MWCNT in detection of triclosan, cyclic voltammetry, electrochemical impedance spectroscopy, and electrochemical band gap studies were conducted. This MIC/Mo-cf-MWCNT/GC showed good selectivity towards triclosan in presence of interfering ions. [ABSTRACT FROM AUTHOR]

The properties of lithium‐ion battery (LIB) anodes fabricated from nanoscale silicon Si and polyaniline (PANI) as a binder are reported. PANI is prepared by in situ polymerization of aniline in the presence of phytic acid, which serves both as dopant and as a gel‐forming agent. PANI pellets obtained by dry compression are used to investigate the morphology and to measure the resistivity of PANI and Si/PANI composites. The anodes are fabricated using the slurry technique. Their properties as a function of precursor ratio are studied in the half‐cell cells by charge–discharge characteristics, cyclic voltammetry, electrochemical impedance spectroscopy and cyclic lifetime. It is shown that stable cycling (>350 cycles at a current of 300 mA g−1) is inherent only to thin Si/PANI layers with composite loading <0.7 mg cm−2. The discharge capacity in this case is as high as 500–800 mAh g−1. [ABSTRACT FROM AUTHOR]

The Cu2+ complexes of three [1 + 1] azacyclophane macrocycles having the 1H-pyrazole ring as the spacer and the pentaamine 1,5,8,11,15-pentaazadecane (L1) or hexaamines 1,5,8,12,15,19-hexaazanonadecane (L2) and 1,5,9,13,17,21-hexaazaheneicosane (L3) as bridges show endo- coordination of the pyrazolate bridge giving rise to discrete monomeric species. Previously reported pyrazolacyclophanes evidenced, however, exo-coordination with the formation of dimeric species of 2 : 2, 3 : 2 or even 4 : 2 Cu2+ : L stoichiometry. The complexes have been characterized in solution using potentiometric studies, UV-Vis spectroscopy, paramagnetic NMR, cyclic voltammetry and mass spectrometry. The measurements show that all three ligands have as many protonation steps in water as secondary amines are in the bridge, while they are able to form both mono- and binuclear Cu2+ species. The crystal structures of the complexes [Cu(HL1)Br]Br(1+x)(ClO4)(1−x)·yH2O (1) and [Cu2(H−1L2)Cl(ClO4)](ClO4)·H2O·C2H5OH (2) have been solved by X-ray diffraction studies. In 1 the metal ion lies at one side of the macrocyclic cavity being coordinated by one nitrogen of the pyrazolate moiety and the three consecutive nitrogen atoms of the polyamine bridge. The other nitrogen of the pyrazole ring is hydrogen-bonded to an amine group. In 2 the two metal ions are interconnected by a pyrazolate bis(monodentate) moiety and complete their coordination spheres with three amines and either a bromide or a perchlorate anion, which occupy the axial positions of distorted square pyramid geometries. Paramagnetic NMR studies of the binuclear complexes confirm the coordination pattern observed in the crystal structures. Cyclic voltamperommetry data show potentials within the adequate range to exhibit superoxide dismutase (SOD) activity. The IC50 values calculated by McCord–Fridovich enzymatic assays show that the binuclear Cu2+ complexes of L2 and L3 have SOD activities that rank amongst the highest ones reported so far. [ABSTRACT FROM AUTHOR]

Morphology engineering and elemental doping proved to be an efficient way to enhance the capacitive performance of electroactive materials. To investigate the tuning of morphology via doping here, pure α-Fe 2 O 3 and Ni 1-x Mn x FeO 3+δ (x = 0,0.3,0.5,0.7,1) was synthesized via the hydrothermal method and investigated the impact of Ni and Mn doping on the structural, morphological, and electrochemical properties of α-Fe 2 O 3. The XRD and Raman spectra confirmed the single-phase hematite's rhombohedral crystal structure of pure α-Fe 2 O 3 with no extra peaks confirming the Ni and Mn doping without impurities. SEM analysis demonstrated a shift in the morphology of nanostructures, from spherical to nano-rod structures with increasing the concentration of Mn doping. Cyclic voltammetry results unveiled the battery-type behavior of Ni 1-x Mn x FeO 3+δ nanoparticles while GCD results indicated an escalation in specific capacity from 380 Cg-1 (706 Fg-1) to 751 Cg-1 (1251 Fg-1) with higher Mn content. This increase culminated in the highest specific capacity of 751 Cg-1 (1251 Fg-1) for α-MnFeO 3 +δ nanoparticles at the current density of 1 Ag-1 which is higher than α-Fe 2 O 3 (380 Cg-1), NiFeO 3+δ (425 Cg-1), Ni 0.7 Mn 0.3 FeO 3+δ (470 Cg-1), Ni 0.5 Mn 0.5 FeO 3+δ (530 Cg-1), and Ni 0.3 Mn 0.7 FeO 3+δ (590 Cg-1). In addition, α-MnFeO 3+δ exhibited a remarkable charge capacity retention (96%), and 100% coulomb efficiency after 10,000 consecutive GCD cycles. The noteworthy specific capacity and robust stability of the α-MnFeO 3+δ nanorods suggest their suitability as potential candidates for battery type supercapacitors. Morphological transition in α-Ni 1-x Mn x FeO 3+δ (x = 0, 0.3, 0.5, 0.7, 1) with increasing Mn dopant for energy storage applications. [Display omitted] • Mn and Ni co-doped α-Fe 2 O 3 lattice is developed with high BET surface area. • Mn doping in α-Ni 1-x Mn x FeO 3 , transforms its morphology from macro spherical size to nano rods. • Ni 1-x Mn x FeO 3 (x = 0, 0.3, 0.5, 0.7, 1) show their potential as battery as well as psuedo-supercapacitive type electrode • Mn induces tuning of morphology and excellent energy storage capacity in α-Ni 1-x Mn x FeO 3. [ABSTRACT FROM AUTHOR]

Renewable energy sources, such as hydrogen play a crucial role in developing sustainable technologies. Hydrogen is one of the best candidates for future energy transition. Today, hydrogen storage techniques have become an important and debated issue in many countries. This study represents the first attempt to prepare CuCr 2 O 4 nanoparticles using two different methods (sol-gel and green) and compare their performance as an electrocatalyst in electrochemical hydrogen storage. The tetragonal crystal structure, spherical shape, purity, and mesoporous features of the sample were studied using X-ray diffraction (XRD), Fourier transform infrared (FT-IR), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDS), and Brunauer-Emmett-Teller (BET) techniques. Additionally, the hydrogen storage performance of CuCr 2 O 4 nanoparticles was investigated using cyclic voltammetry (CV), and charge-discharge chronopotentiometry (CP) in a 3 M KOH alkaline medium. The result revealed that the specific capacitance values of CuCr 2 O 4 nanoparticles in sol-gel and green methods were obtained to be 2427 and 1503 Fg-1, respectively. The discharge capacities of CuCr 2 O 4 nanoparticles in sol-gel and green methods after 11 cycles were calculated to be 4304 and 3011 mAh/g, respectively. The superior hydrogen storage capability of CuCr 2 O 4 nanoparticles in the sol-gel method can be attributed to its high porosity. [Display omitted] • CuCr 2 O 4 nanoparticles were synthesized using the sol-gel and green methods. • Study of crystal structure, morphological, and electrochemical properties of the samples. • CuCr 2 O 4 showed excellent hydrogen storage capacity of 4304 and 3011mAh/g in the sol-gel and green methods, respectively. • A promising material for hydrogen storage applications. [ABSTRACT FROM AUTHOR]

The spirocyclic framework is found in many natural products, some of which are biologically active. However, It remains a challenge to develop environmentally friendly and atom‐economic synthetic methods. Herein, we report an intramolecular dearomatization reaction of benzene derivatives enabled by electrochemistry‐mediated two successive single‐electron‐transfer (SET) processes, providing an alternative method for the rapid construction of spirocyclic skeletons without using sacrificial reagents. A series of cyclohexadiene products were obtained in 25–81% yields. Furthermore, a proposed mechanism involving a sequential electron transfer event was supported by cyclic voltammetry experiments. This strategy features transition‐metal‐free conditions and easy handling, which will greatly enhance its practical utility. [ABSTRACT FROM AUTHOR]

Organic compounds with potential antioxidant activity have attracted special attention of researchers and they have been widely studied in several areas, including pharmacology and medicinal chemistry. In this context, electrochemistry through cyclic voltammetry becomes a fast and efficient tool for the characterization of the antioxidant potential of these compounds. Herein, a study was carried out on the electrochemical behavior of seleno‐dihydropyrimidinones and chloro‐dihydropyrimidinones via cyclic voltammetry in the presence of acetonitrile. By employing this approach, the characterization of the oxidation processes and the determination of antioxidant activities of the target molecules was disclosed. It was also proposed a comparison of the results obtained with the antioxidant activity of the 2,2‐diphenyl‐1‐picrylhydrazyl radical. Among the evaluated compounds, four molecules exhibited significant antioxidant capacities which were efficiently detected by 2,2‐diphenyl‐1‐picrylhydrazyl radical assay and by cyclic voltammetry when measuring the charges transferred until 0.9 V vs Fc+/Fc. [ABSTRACT FROM AUTHOR]

휋‐Conjugated polymers, including those based on acetylenic repeating units, are an exciting class of materials that offer narrow optical band gaps and tunable frontier orbital energies that lead to their use in organic electronics. This work expands the knowledge of structure‐property relationships of acetylenic polymers through the synthesis and characterization of a series of Glaser‐Hay‐coupled model compounds and random copolymers comprised of BF2 formazanate, fluorene, and/or bis(alkoxy)benzene units. The model compounds and copolymers synthesized exhibit redox activity associated with the reversible reduction of the BF2 formazanate units and the irreversible reduction of the fluorene and bis(alkoxy)benzene units. The copolymers exhibit absorption profiles characteristic or intermediate of their respective models and homopolymers, leading to broad absorption of UV–vis light. The alkyne linkages of the model compounds and copolymers are reacted with [Co2(CO)8] to convert the alkyne functional groups into cobalt carbonyl clusters. This transformation leads to blue‐shifted absorption profiles due to a decrease in π‐conjugation, demonstrating the ability to tune the properties of these materials through post‐polymerization functionalization. The redox activity and broad absorption bands of the polymers reported make them excellent candidates for use in photovoltaics and other light‐harvesting applications. [ABSTRACT FROM AUTHOR]