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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]

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]

Construction of porous nanosheet arrays of transition‐metal sulfides (TMSs) holds great potential for energy storage. Herein, a one‐step hydrothermal process is employed for the construction of porous Ni1.43Fe.5Co.5S.97 nanosheet arrays (NFCS‐NS) on the nickel foam as a proper positive electrode for hybrid supercapacitor. Owing to the appealing structural features, the NFCS‐NS depicts a high capacity of 1156 C g−1 at 2 A g−1, desirable rate capability of 81.1 %, and significant cyclability of 92.9 %. Also, a promising hybrid device (NFCS‐NS//AC) based on NFCS‐NS and activated carbon (AC) represents a reasonable energy density of 57.3 Wh kg−1 at 807.04 W kg−1 and a notable power density of 20000 W kg−1 at 40 Wh kg−1. Therefore, our current research can introduce an effective strategy for the fabrication of high‐performance electrodes with porous architectures. [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]

Abstract: Rational construction of electrode materials with exclusive structures and compositions are highly attractive for improving the electrochemical properties of supercapacitors (SCs). In the present study, we demonstrate the construction of unique core–shell Ni−Mn−Co−S@Co(OH)2 nanoarrays on nickel foam (denoted as NMCS@COH/NF) as an attractive battery‐type electrode material for SCs through the hydrothermal and electrodeposition strategies, in which the Ni−Mn−Co−S nanowires are well wrapped in the Co(OH)2 shells. Benefiting from the attractive structural properties, the NMCS@COH/NF electrode exhibits considerable electrochemical properties in the aspects of reasonable rate performance (80.3 % up to 24 A g−1), long‐term cyclability (retention rate of 93.3 % undergoing 10 000 cycles), and exceptional capacity (284.85 mAh g−1 at 2 A g−1). Subsequently, the NMCS@COH electrode is assembled into a hybrid supercapacitor, which delivers a good energy density of 51.1 Wh kg−1 at 751.47 W kg−1 and a maximum power density of 18411.76 W kg−1 at 31.3 Wh kg−1. This work provides a straightforward route to rational construction of the electrode materials with promising structural and electrochemical properties for SC applications. [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]

Electrode materials with unique nanoarchitecture, great conductivities, and desirable mechanical stabilities are essential for developing nearly all energy storage devices (ESDs). Herein, a low‐cost route for the fabrication of double‐layer CuCo2S4@Ni−Mo−S (CCS@NMS) nanosheet arrays as an advanced binder‐free positive electrode for supercapattery is presented. The CCS@NMS porous nanoarchitecture has the advantages of good ion diffusion and excellent electronic transport. Accordingly, when employed as battery‐type electrode in supercapattery device, the CCS@NMS electrode reflects amazing capacity (Cs) of 446.3 mAh g−1 (3213.6 F g−1) at 1 A g−1 and 375.8 mAh g−1 (2705.85 F g−1) at 18 A g−1, and 98.2 % of the Cs was still maintained at 6 A g−1 after 5000 cycles, which are higher than that of CCS electrode. Most importantly, using the CCS@NMS electrode as the positive electrode and active carbon (AC) as the negative electrode, the device indicates notable Cs of 66.8 mAh g−1 (160.4 F g−1), the considerable specific energy of 50.125 Wh kg−1 at a specific power of 750.04 W kg−1 and outstanding robustness of 96.8 %. [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]

Herein, we present a new method to construct a graphene wrapped yolk–double shell NiGa2S4 hollow microsphere (GW@YDSNGSHM) as a cathode electrode and a graphene wrapped FeS2–FeSe2 core–shell cratered sphere (GW-FeS2–FeSe2-CSS) as an anode electrode to enhance the performance of asymmetric supercapacitors. The GW@YDSNGSHM electrode shows considerable improvement of electrochemical performance including small internal resistance, reversibility, rapid kinetics, exceptional durability, and a notable specific capacitance (SC) of 2868.4 F g−1. The advancement in the performance of the GW-FeS2–FeSe2-CSS includes a good SC of 634.6 F g−1 and preferable durability. An asymmetric supercapacitor composed of the GW@YDSNGSHM (cathode) and GW-FeS2–FeSe2-CSS (anode) was assembled and tested. The advanced device revealed a SC of 352.30 F g−1 and an energy density (ED) of 158.53 W h kg−1 at a power density (PD) of 2236.16 W kg−1. This improved performance is related to the structural properties of both electrodes which can ensure promising potential for future generations of electronic devices. [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]

A fast and facile electrochemical method called electrooxidation was used to prepare SnO2 nanoparticles. In this route, a sacrificial tin anode is dissolved in an electrolyte by applying a voltage to an electrochemical cell. We used different electrolyte environments, namely tetramethylammonium chloride and different counterions of tetrabutylammonium cation, viz. Br−, Cl−, and ClO4−. Characterization results showed that the size distribution was more uniform for the nanoparticles created with Br− and Cl− counterions. Furthermore, the particles in these samples were smaller than in the others. The amount of OH groups on the surface of the Br− and Cl− samples was higher than for the other samples, enhancing dye adsorption. Dye-sensitized solar cells (DSSCs) were fabricated from the produced SnO2 nanoparticles, and the influence of the different counterions on their performance was investigated. By varying the counterion in the electrolyte, samples with different hydrophilic nature and dye-loading ability were obtained. The dye adsorption and consequently the current density of the cell made from the Br− solution were higher than for the other samples, and the power conversion efficiency in this case reached 1.5%. [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]

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]

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]

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]

Design and fabrication of impressive and novel electrode materials for energy storage devices, especially supercapacitors, are of great importance. Herein, bimetallic CoSe 2 /FeSe 2 hollow nanocuboid nanostructures derived from Co/Fe-Prussian Blue analogues (denoted as CoSe 2 /FeSe 2 HNCs) are successfully designed and fabricated as a remarkable positive electrode material for high-performance supercapacitors. The bimetallic CoSe 2 /FeSe 2 HNC nanostructures can have increased active sites and short electron-ion diffusion pathways. Bimetallic CoSe 2 /FeSe 2 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 CoSe 2 /FeSe 2 HNCs@NiF||AC@NiF hybrid supercapacitor device using bimetallic CoSe 2 /FeSe 2 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.

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 (F 0.25 CP-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 F 0.25 CP-G which results in high-performance electrocatalytic activity toward the HER and OER. Therefore, the as-synthesized F 0.25 CP-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 (F 0.25 CP-G||F 0.25 CP-G) exhibits a current density of 10 mA cm -2 at 1.60 V along with good durability for 24 h.

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.