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Design and fabrication of impressive and novel electrode materials for energy storage devices, especially supercapacitors, are of great importance. Herein, bimetallic CoSe2/FeSe2 hollow nanocuboid nanostructures derived from Co/Fe-Prussian Blue analogues (denoted as CoSe2/FeSe2 HNCs) are successfully designed and fabricated as a remarkable positive electrode material for high-performance supercapacitors. The bimetallic CoSe2/FeSe2 HNC nanostructures can have increased active sites and short electron-ion diffusion pathways. Bimetallic CoSe2/FeSe2 HNCs@NiF as a positive electrode showed efficient supercapacitive properties with a great specific capacity of 332.75 mA h g−1 (1197.90 C g−1) at 1 A g−1, retaining 80.61% of its initial capacity at 20 A g−1, considerable longevity (91.47% of its initial capacity after 10 000 cycles) and an excellent coulombic efficiency of 98.49%. Also, the designed and fabricated CoSe2/FeSe2 HNCs@NiF‖‖AC@NiF hybrid supercapacitor device using bimetallic CoSe2/FeSe2 HNCs@NiF (positive electrode) and activated carbon@NiF (AC, negative electrode) exhibited an efficient energy density of 63.62 W h kg−1 and a superior durability of 91.14% after 10 000 cycles. [ABSTRACT FROM AUTHOR]

Porous structures have attracted considerable attention as promising electrode designs for supercapacitor applications. Herein, we introduce a procedure towards the construction of nanoporous CuCoNi–P nanotube arrays (CCNP-NAs) by a metal–organic framework and hierarchical CoFe2Se4 nanosheet arrays (CFS-NAs) through a hydrothermal strategy, followed by selenization for the flexible asymmetric device. Due to the unique design of the electrode materials, the CCNP-NA and CFS-NA electrodes show exceptional specific capacities of ∼406.73 and 248.2 mA h g−1 at 2 A g−1, reasonable rate capabilities of 84.2 and 71.2% at 50 A g−1, and remarkable durability of 98.9% and 95.1%, respectively. Remarkably, an advanced flexible device was constructed using the CCNP-NA positive electrode and CFS-NA negative electrode. Our flexible device demonstrates tremendous energy density (∼153.5 W h kg−1 at 852.8 W kg−1), super-high durability of 96.2%, and considerable flexibility under bending conditions. This work proposes insight into the rational construction of porous nanostructures for next-generation electronic devices. [ABSTRACT FROM AUTHOR]

The present work describes a facile route for the synthesis of CdMn2O4 nanoplates. The nanoplates were synthesized by cathodic electrogeneration of base from mixed Cd/Mn nitrate solution (Cd/Mn ratio of 1:2) at a constant current density of 6 mA cm−2 and deposition time of 5 min followed by calcination at 900 °C for 45 min. X-ray powder diffraction (XRD), Fourier-transform infrared (FT-IR), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX), and Brunauer-Emmett-Teller (BET) surface area analysis were used to characterize the nanoplates. The charge storage ability and cycle stability of the obtained CdMn2O4 nanostructures were investigated by means of cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) in 1.0 M KOH. The as-prepared CdMn2O4 nanoplates exhibit high specific capacitance and good retention. The hierarchical CdMn2O4 nanoplates show the highest capacitance of 615.1 F g−1, and 98% of which can still be maintained after 5000 charge-discharge cycles. [ABSTRACT FROM AUTHOR]

Owing to the increased requirement for efficient energy storage systems (ESs), investigating favorable electrodes with porous nanoarchitecture for supercapacitors (SCs) is vital. Nonetheless, the development of these kinds of electrodes to obtain high energy density remains a difficult task. Low specific capacitances of positive (cathode) and negative (anode) electrode materials are a serious obstacle that limits the performance of asymmetric SCs (ASCs). Herein, we proposed the preparation of yolk–shell Cu–Co–P hollow nanospheres (Y-CCP HN) as a positive electrode using a metal–organic framework (MOF) and CuFeS2 nanosheet (CFS NS) arrays as a negative electrode via a low-cost and simple hydrothermal route for ASCs. The Y-CCP HN and CFS NS electrodes exhibited significant specific capacitances (∼2043.3 F g−1 (340.55 mA h g−1) and 654.3 F g−1 (218.1 mA h g−1), respectively), considerable rate performances (∼77.55% and 63.2%, respectively, even at 24 A g−1), and exceptional durability (96.7% and 95.3% after 8000 cycles, respectively). Most notably, the Y-CCP HN//CFS device delivers a wonderful energy density of 158.4 W h kg−1 at a power density of 900.3 W kg−1, a notable specific capacitance of 352.1 F g−1 (176.05 mA h g−1), and excellent cyclability (96.1% after 8000 cycles). This exploration demonstrates a good strategy for the construction of other metal phosphides and sulfides with porous nature, emphasizing considerable prospects for next-generation ESs. [ABSTRACT FROM AUTHOR]

Herein, we proposed a desirable strategy for the synthesis of graphene-wrapped NiCo2Se4 microspheres (positive electrode) and petal-like iron disulfide (FeS2) (negative electrode) on nickel foam substrates. The positive electrode represents a substantial specific capacitance of 2112.30 F g−1 and excellent durability (6.8% loss after 5000 cycles). Furthermore, the negative electrode reflects good electrochemical performance with a specific capacitance of 321.30 F g−1 and a satisfactory rate capability of 47% capacitance retention. Considering the notable properties of the electrodes, a flexible asymmetric all-solid-state device based on graphene-wrapped NiCo2Se4 microspheres (positive electrode) and petal-like iron disulfide (negative electrode) was assembled. Our flexible device exhibits the high specific capacitance of 221.30 F g−1, the significant energy density of 78.68 W h kg−1 and excellent flexibility. [ABSTRACT FROM AUTHOR]

The rational construction of advanced electrode materials with notable performances plays an essential role in the design of energy storage systems with excellent energy density and power density. In this study, for the first time, we offer a facile electrodeposition method for the synthesis of CoGa2O4 (CGO) as an advanced positive (cathode) electrode material supported on a nickel foam substrate to be used in an asymmetric supercapacitor (ASC). The CoGa2O4 (CGO)/nickel foam electrode created an efficacious and fast passageway for ion and electron transport in electrochemical process; for this reason, this electrode illustrated good electrochemical performance including excellent specific capacitance of 1379.16 F g−1 with a remarkable rate performance of 67.2% and excellent durability. Moreover, a pseudocapacitive negative electrode material of ZnFe2O4 (ZFO) was successfully deposited on a nickel foam substrate by a straightforward strategy. The as-constructed ZnFe2O4 (ZFO)/nickel foam electrode revealed a good specific capacitance of 300.5 F g−1 at 1 A g−1, satisfactory rate performance of 55.40% even at 50 A g−1 and significant durability after 6000 cycles. Due to the excellent electrochemical properties of the as-constructed pseudocapacitive electrodes, an asymmetric supercapacitor (ASC) was fabricated using CoGa2O4 (CGO)/nickel foam as an advanced positive (cathode) electrode and ZnFe2O4 (ZFO)/nickel foam as a negative (anode) electrode. The CoGa2O4 (CGO)/nickel foam//ZnFe2O4 (ZFO)/nickel foam device exhibited remarkable performance with good specific capacitance of 232.2 F g−1, excellent rate capability of 64% even at 50 A g−1, outstanding durability even after 6000 cycles and high energy density of 82.56 W h kg−1. Finally, the CoGa2O4 (CGO)/nickel foam//ZnFe2O4 (ZFO)/nickel foam device was employed to light up a blue light-emitting diode (LED), illustrating its significant potential as an advanced ASC device for the modern generation of electronic devices. [ABSTRACT FROM AUTHOR]

In this work, we investigate the application of Ni-Al LDH-rGO composite directly synthesized on nickel foam by a low cost and facile CV electrodeposition method as a new electrode for all-solid-state flexible supercapacitors. Due to the synergistic effects between the Ni-Al LDH and the graphene sheets, directly grown on the surface of Ni foam, the as prepared electrodes exhibit an ultrahigh specific capacitance of 2693.25 F g −1  at a current density of 2 A g −1 . When these electrodes are used in asymmetric (Ni-Al LDH-rGO//Fe 2 O 3 -rGO) and symmetric (Ni-Al LDH-rGO//Ni-Al LDH-rGO) all-solid-stat supercapacitors, the as-prepared devices show excellent flexibility with a maximum specific capacitance and energy density of 214.4 F g −1 and 76.23 Wh Kg −1 for asymmetric device, and 412.30 F g −1 and 36.65 Wh Kg −1 for symmetric device. [ABSTRACT FROM AUTHOR]

A facile synthetic route has been proposed to prepare cauliflower-like nanostructures of Cr doped Mn 2 O 3 . The synthesis was carried out by constant current cathodic electrodeposition from Mn 2+ nitrate solutions containing minor amounts of dichromate. It was found that the presence of Cr mediates the formation of cathodic MnO 2 which then reacts with the excess Mn 2+ species to form Mn 2 O 3 nanostructures. X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Differential Thermal Analysis (DTA) were used to characterize the nanostructures. The storage ability of the obtained nanostructures was investigated by cyclic voltammetry (CV) in 0.5 M Na 2 SO 4 solution. The results indicated that the Cr doped manganese oxide material shows better performance than the non-doped one, and the charge capacity (SC) of doped manganese oxide (218 F/g) was higher than pure manganese oxide (208 F/g). [ABSTRACT FROM AUTHOR]

In this work, a new solid-phase microextraction fiber was prepared based on nitrogen-doped graphene (N-doped G). Moreover, a new strategy was proposed to solve problems dealt in direct coating of N-doped G. For this purpose, first, Graphene oxide (GO) was coated on Pt wire by electrophoretic deposition method. Then, chemical reduction of coated GO to N-doped G was accomplished by hydrazine and NH 3 . The prepared fiber showed good mechanical and thermal stabilities. The obtained fiber was used in two different modes (conventional headspace solid-phase microextraction and cold-fiber headspace solid-phase microextraction (CF-HS-SPME)). Both modes were optimized and applied for the extraction of benzene and xylenes from different aqueous samples. All effective parameters including extraction time, salt content, stirring rate, and desorption time were optimized. The optimized CF-HS-SPME combined with GC-FID showed good limit of detections (LODs) (0.3–2.3 μg/L), limit of quantifications (LOQs) (1.0–7.0 μg/L) and linear ranges (1.0–5000 μg/L). The developed method was applied for the analysis of benzene and xylenes in rainwater and some wastewater samples. [ABSTRACT FROM AUTHOR]

The distribution of electric field vectors was first calculated for electromembrane extraction (EME) systems in classical and cylindrical electrode geometries. The results showed that supported liquid membrane (SLM) has a general field amplifying effect due to its lower dielectric constant in comparison with aqueous donor/acceptor solutions. The calculated norms of the electric field vector showed that a DC voltage of 50 V can create huge electric field strengths up to 64 kV m −1 and 111 kV m −1 in classical and cylindrical geometries respectively. In both cases, the electric field strength reached its peak value on the inner wall of the SLM. In the case of classical geometry, the field strength was a function of the polar position of the SLM whereas the field strength in cylindrical geometry was angularly uniform. In order to investigate the effect of the electrode geometry on the performance of real EME systems, the analysis was carried out in three different geometries including classical, helical and cylindrical arrangements using naproxen and sodium diclofenac as the model analytes. Despite higher field strength and extended cross sectional area, the helical and cylindrical geometries gave lower recoveries with respect to the classical EME. The observed decline of the signal was proved to be against the relations governing migration and diffusion processes, which means that a third driving force is involved in EME. The third driving force is the interaction between the radially inhomogeneous electric field and the analyte in its neutral form. [ABSTRACT FROM AUTHOR]

There are numerous published reports about dispersive liquid phase microextraction of the wide range of substances, however, till now no broadly accepted systematic and purpose oriented selection of extraction solvent has been proposed. Most works deal with the optimization of available solvents without adequate pre-consideration of properness. In this study, it is tried to compare the performances of low- and high-density solvents at the same conditions by means of novel type of extraction vessel with head and bottom conical shape. Extraction efficiencies of seven basic pharmaceutical compounds using eighteen common organic solvents were studied in this work. It was much easier to work with high-density solvents and they mostly showed better performances. This work shows that although exact predicting the performance of the solvents is multifaceted case but the pre-consideration of initial selection of solvents with attention to the physiochemical properties of the desired analytes is feasible and promising. Finally, the practicality of the method for extraction from urine and plasma samples was investigated. [ABSTRACT FROM AUTHOR]

Highlights: [•] A PEDOT/GO composite fiber coating was prepared electrochemically for SPME of PAHs. [•] Direct immersion, headspace and headspace cold fiber modes of SPME were compared. [•] Best extraction efficiencies for all PAHs were obtained by optimized HS-CF-SPME. [•] The method provides good recoveries for the analysis of PAHs in seawater samples. [ABSTRACT FROM AUTHOR]

In this study, a platinum wire coated with poly(3,4-ethylenedioxythiophen) was used as an electro-assisted solid-phase microextraction fiber for the quantification of tricyclic antidepressant drugs in biological samples by coupling to GC employing a flame ionization detector. In this study, an electric field increased the extraction rate and recovery. The fiber used as a solid phase was synthesized by the electropolymerization of 3,4-ethylenedioxythiophen monomers onto a platinum wire. The ability of this fiber to extract imipramine, desipramine, and clomipramine by using the electro-assisted solid-phase microextraction technique was evaluated. The effect of various parameters that influence the extraction efficiency, which include solution temperature, extraction time, stirring rate, ionic strength, time and temperature of desorption, and thickness of the fiber, was optimized. Under optimized conditions, the linear ranges and regression coefficients of calibration curves were in the range of 0.5-250 and 0.990-0.998 ng/mL, respectively. Detection limits were in the range of 0.15-0.45 ng/mL. Finally, this method was applied to the determination of drugs in urine and wastewater samples and recoveries were 4.8-108.9%. [ABSTRACT FROM AUTHOR]

Abstract: Electrochemical oxidation of catechol (1a) and 3-methyl-catechol (1b) has been studied in the presence of chloranilic acid (3) as a nucleophile in aqueous solution using cyclic voltammetry and controlled-potential coulometry. In this work, we proposed a novel mechanism for the electrode process and derived variety of products with good yield and purity using controlled-potential electrochemical oxidation at a graphite electrode in a two compartment cell. [Copyright &y& Elsevier]

Abstract: Electrochemical oxidation of 2,3-dimethylhydroquinone 1 has been studied in the presence of o-phenylenediamines 3a–c as nucleophiles in aqueous solution, using cyclic voltammetry and controlled potential coulometry. The results indicate that the quinone 2 derived from 2,3-dimethylhydroquinone participates in Michael addition and imine condensation reactions with o-phenylenediamine via an ECECC mechanism, and is converted to the corresponding phenazine derivatives 7a–c and 7′b. The electrochemical synthesis of compounds 7a–c and 7′b has been performed successfully at a carbon rod electrode in an undivided cell with good yields and high purities. [Copyright &y& Elsevier]

The development of durable, beneficial, and highly active non-precious metal-based electrocatalysts for hydrogen generation is a vital concern. This study proposes an effective strategy for the construction of Fe doped CoP nanosheet arrays wrapped by graphene (F0.25CP-G) on nickel foam as an efficient electrocatalyst for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). In this design, the final catalyst possesses a combination of the high conductivity of graphene, great surface porosity, and the intrinsic electrocatalytic activity of the F0.25CP-G which results in high-performance electrocatalytic activity toward the HER and OER. Therefore, the as-synthesized F0.25CP-G catalyst can achieve overpotentials of 66 mV and 230 mV for the HER and OER, respectively, in KOH at 10 mA cm−2. Furthermore, a practical electrolyzer (F0.25CP-G‖‖F0.25CP-G) exhibits a current density of 10 mA cm−2 at 1.60 V along with good durability for 24 h. [ABSTRACT FROM AUTHOR]

Metal–organic framework (MOF) derived nanoarchitectures have special features, such as high surface area (SA), abundant active sites, exclusive porous networks, and remarkable supercapacitive performance when compared to traditional nanoarchitectures. Herein, we propose a viable strategy for the synthesis of hollow manganese nickel selenide spheres comprising nanosheets supported on the nickel foam (denoted as MNSe@NF) from the MOF. The MNSe nanostructures can demonstrate enriched active sites, and shorten the ion-electron diffusion pathways. When the MNSe@NF electrode is used as a cathode electrode for a hybrid supercapacitor, the electrode reflected impressive supercapacitive properties with a high capacity of 325.6 mA h g−1 (1172.16 C g−1) at 2 A g−1, an exceptional rate performance of 86.6% at 60 A g−1, and remarkable longevity (3.2% capacity decline after 15 000 cycles). Also, the assembled MNSe@NF∥AC@NF hybrid supercapacitors employing activated carbon on the nickel foam (AC@NF, anode electrode) and MNSe@NF (cathode electrode) revealed an impressive energy density of 66.1 W h kg−1 at 858.45 W kg−1 and an excellent durability of 94.1% after 15 000 cycles. [ABSTRACT FROM AUTHOR]

Herein, electromembrane extraction was combined with ultraviolet spectrophotometry using a customized manifold for preconcentration and simultaneous determination of morphine, codeine, and papaverine in water and human urine samples. Absorption spectra of the extracts were recorded inside the lumen of the hollow fiber using two fiber optics connected to a miniature spectrophotometer. Partial least squares regression was applied to resolve the overlapped spectra of the analytes. Performance of the model was validated by an independent test set. Central composite design was applied to optimize the extraction parameters. The optimized extraction conditions are as follows; supporting liquid membrane: 2‐nitrophenyl octyl ether containing 15% v/v bis(2‐ethylhexyl) phosphate, applied voltage: 80 V, donor pH: 3.0, acceptor pH: 1.0, extraction time: 20 min. Finally, the optimized extraction method was validated for determination of the mentioned alkaloids in human urine samples. The method showed good linearity (R2 > 0.995) for all of the mentioned alkaloids. The limits of detection for morphine, codeine, and papaverine in diluted human urine were found to be 0.6, 1.1, and 0.6 ng/mL, respectively with acceptable relative standard deviations. Enrichment factors of 104, 108, and 102 were achieved for morphine, codeine, and papaverine, respectively. [ABSTRACT FROM AUTHOR]

A one step electrospinning approach was utilized for the preparation of polyaniline (PANI) modified titanium dioxide/polyacrylonitrile (PAN) composite nanofiber using a mixture of dimethylformamde (DMF) and N -methyl-2-pyrrolidone (NMP) as solvents. Several techniques were carried out to characterize the resulting electrospun fibers including SEM, FTIR, XRD, TGA and DRUV-Vis absorption spectroscopy. The later method showed an optical band gap shifting for polyaniline modified titanium dioxide/polyacrylonitrile composites in comparison to unmodified one. Due to these optical absorptions, the fibers can be considered promising candidates as visible light photocatalysts to generate more electron-hole pairs. Photodegradation was accomplished using methyl orange (MO) as a model organic pollutant. The degradation of MO, extremely increased using photocatalysts which contained PANI and decolorization in the presence of visible light achieved up to 90% in less than 60 min in comparison with the neat nanofibers (about 10%). This advantage promises a bright future for these fibers as useful photocatalysts. The effect of reaction parameters such as photocatalyst dose, concentration of the starting substrate solution and pH were studied and photocatalytic kinetics was investigated. The stability of photocatalyst was also investigated. The photocatalyst retained 87% of its initial activity after 10 replicate uses. [ABSTRACT FROM AUTHOR]

Abstract: This study has performed on electromembrane extraction (EME) of some zwitterionic compounds based on their acidic and basic properties. High performance liquid chromatography (HPLC) equipped with UV detection was used for determination of model compounds. Cetirizine (CTZ) and mesalazine (MS) were chosen as model compounds, and each of them was extracted from acidic (as a cation) and basic (as an anion) sample solutions, separately. 1-Octanol and 2-nitrophenyl octylether (NPOE) were used as the common supported liquid membrane (SLM) solvents. EME parameters, such as extraction time, extraction voltage and pH of donor and acceptor solutions were studied in details for cationic and anionic forms of each model compound and obtained results for two ionic forms (cationic and anionic) of each compound were compared together. Results showed that zwitterionic compounds could be extracted in both cationic and anionic forms. Moreover, it was found that the extraction of anionic form of each model compound could be done in low voltages when 1-octanol was used as the SLM solvent. Results showed that charge type was not highly effective on the extraction efficiency of model compounds whereas the position of charge within the molecule was the key parameter. In optimized conditions, enrichment factors (EF) of 27–60 that corresponded to recoveries ranging from 39 to 86% were achieved. [Copyright &y& Elsevier]

Abstract: Electrochemical oxidation of 3,4-dihydroxybenzoic acid (1a) has been studied in the presence of 4-hydroxy-1-methyl-2(1H)-quinolone (3) as a nucleophile in aqueous solution using cyclic voltammetry and controlled-potential coulometry. The results indicate that 1a via a 1,4-(Michael) addition reaction under electro-decarboxylation reaction converts to benzofuran (or isochromeno[4,3-c]quinoline) derivative (6a). The electrochemical synthesis of 6a has been successfully performed in an undivided cell in good yield and purity. The oxidation mechanism was deduced from voltammetric data and by coulometry at controlled-potential. The product has been characterized after purification by IR, 1H NMR, 13C NMR and MS. [Copyright &y& Elsevier]

Agarose gel as a green membrane has been proposed for use in electromembrane extraction of five hypothalamic-related peptides without an ionic carrier. Octreotide, goserelin, triptorelin, cetrorelix, and somatostatin were extracted from 5.0 mL of sample solution (adjusted to pH 5.0) into a microvolume acceptor solution (HCl, 100 mM) under the applied voltage of 30 V in 15 min. The pH of the agarose gel 3.0% (w/v) was adjusted to 4.0 to facilitate the movement of peptides through the membrane. Quantification was performed using an HPLC-UV system on a C18 column. Quantification and detection limits were found to be in the range of 15.0–20.0 ng mL−1 and 4.5–6.0 ng mL−1, respectively. Dynamic linear ranges were found to be in the range of 15.0–1000 ng mL−1 (R 2 > 0.995) and recoveries were in the range of 62.3–77.6%. The optimized method was applied to spiked human plasma samples. The method showed relative recoveries in the range of 44.8–66.0%. Finally, the proposed method was compared with and shown to have higher recoveries than, the conventional electromembrane extraction method for the peptides under study. Image 1 • An agarose gel was applied as the membrane in EME for relatively high molecular weight peptides. • Aqueous nature of the agarose gel makes it possible to transfer the peptides through the membrane in their ionized form. • The EME of peptides was performed in the absence of any ionic carrier in the membrane. • Recoveries of the peptides was investigated as a function of their net charge. • Higher recoveries compared to the conventional electromembrane extraction was confirmed. [ABSTRACT FROM AUTHOR]

Designing advanced electrode materials with porous structures and prominent electrochemical activity could be a novel approach toward improving the energy density of supercapacitors (SCs). Herein, the construction of hollow MnCo 2 S 4 nanowires decorated with NiFeLDH nanosheets (MCS@NFLDH) as a promising binder-free electrode for SCs using the effective sulfurization and hydrothermal procedures is introduced. Furthermore, the MCS@NFLDH electrode texture wrapped by graphene (rGO) sheets would take the benefit of superior structural properties and amazing electrochemical performances. The MCS@NFLDH@rGO electrode reflects a considerable capacity of ≈327.3 mAh/g, a substantial rate capability of 73.2% at 20 A/g, and superior robustness. With the well-constructed nanostructures, a corresponding asymmetric supercapacitor (ASC) device based on MCS@NFLDH@rGO (positive electrode) and active carbon (AC) (negative electrode) was assembled and tested. Most importantly, the device reflects a satisfactory energy density of ≈47.98 Wh/kg and an exceptional robustness. Accordingly, this work opens up the opportunities for the well-design of binder-free electrodes for utilization in SCs and other energy storage devices (ESDs). Hierarchical MnCo 2 S 4 nanowires/NiFeLDH nanosheets/graphene nanostructures are constructed by a hydrothermal strategy for asymmetric supercapacitor. Image 1 [ABSTRACT FROM AUTHOR]

We are introducing mercapto-mesoporous carbon modified carbon paste electrode (mercapto-MP-C-CPE) as a new sensor for trace determination of omeprazole (OM) in biological samples. The synthesized modifier was characterized by thermogravimetry analysis (TGA), differential thermal analysis (DTA), transmission electron microscopy (TEM), Fourier transform infrared spectrometry (FT-IR), X-ray diffraction (XRD), elemental analysis (CHN) and N 2 adsorption surface area measurement (BET). The electrochemical response characteristic of the modified-CPE toward OM was investigated by cyclic and differential pulse voltammetry (CV and DPV). The proposed sensor displayed a good electrooxidation response to the OM, its linear range is 0.25 nM to 25 μM with a detection limit of 0.04 nM under the optimized conditions. The prepared modified electrode shows several advantages such as high sensitivity, long-time stability, wide linear range, ease of preparation and regeneration of the electrode surface by simple polishing and excellent reproducibility. [ABSTRACT FROM AUTHOR]

Abstract: Computational studies have been carried out at the DFT-B3LYP/6-31G(d) level of theory on the structural and spectroscopic properties of 2-(1-oxo-1 H-inden-3-yl)-2H-indene-1,3-dione (OID). Experimental studies were conducted on these parameters, including X-ray, FT-IR and 13C NMR spectroscopy. The optimized geometries of OID and its bonding characteristics as well as IR and NMR spectra have been calculated and analyzed. It was observed that the bond lengths and angles in the molecule, obtained by X-ray, IR and NMR at the level of theory, were in a good agreement with those of the experiment. The correlation between the theoretical and the experimental vibrational frequencies and the chemical shifts of the OID molecule were 0.994 and 0.991, respectively. The agreement mutually verified the accuracy of the experimental method and the validity of the applied mathematical model. [Copyright &y& Elsevier]

Owing to the high demands for fascinating energy storage devices, exploring cost-effective electrodes with exclusive architectures for supercapacitors is crucial; however, the advent of such electrodes to achieve the industrial necessities remains a challenging task. Herein the design and characterization of roselike nanoporous ZnGa2S4 hollow spheres (RN-ZGSHS) are described. This structure with the surface area of 71.7 m2 g−1 can provide a capacity of 358.4 mAh g−1 at 2 A g−1 and capacity of 260.2 mAh g−1 at 50 A g−1, as well as significant robustness of 98.4%. To achieve higher energy density in the asymmetric energy storage device, a yolk-shell nanoporous iron phosphide hollow spheres (YS–FePHS) as a negative electrode is also designed. The designed anode electrode with a quasi-rectangular-like character can deliver a capacity of 117.5 mAh g−1 at 1 A g−1 and maintains a high capacity of 65.8 mAh g−1 at 25 A g−1, with satisfactory robustness of 89.9%. Ultimately, the constructed asymmetric device (RN-ZGSHS//YS-FePHS) depicts the ED of 72.78 W h kg−1 at a power density (PD) of 800 W kg−1, while keeps a high energy density of 49.13 W h kg−1 at a power density of 64148.53 W kg−1. Image 1 • Rose-like nanoporous ZnGa 2 S 4 hollow spheres are synthesized as cathode electrode. • Yolk-shell nanoporous iron phosphide hollow spheres are prepared as anode electrode. • Cathode and anode electrodes exhibit high electrochemical performance. • An asymmetric supercapacitor is assembled based on cathode and anode electrodes. • The asymmetric supercapacitor illustrates excellent energy density. [ABSTRACT FROM AUTHOR]