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1.
Recent research has focused on the search for new electrode materials to improve the specific capacitance of supercapacitors. Conductive polymers and metal oxides have been extensively tested as electrode materials for supercapacitors. Incorporating both conductive polymers and metal oxides into a composite provides excellent results for the electrochemical performance of supercapacitors. In this present work, we have fabricated the nanoscale α-NiMoO4 particles that enwrapped on electronically conducting polymer nanocomposites (PNCs) based on Polyvinyl alcohol (PVA)/Poly(vinyl) pyrrolidone (PVP) for supercapacitor applications. The different concentrations of PVA/PVP with α-NiMoO4 loaded polymer nanocomposites were developed by using a solution casting method. All the polymer nanocomposites have been subjected to Scanning Electron Microscopy (SEM), Fourier Transforms Infrared (FTIR), X-ray diffraction (XRD), and electrochemical studies. The prepared PNCs surface morphology has been acquired as a non-uniform rod-like structure. The electrochemical performances of the prepared PNCs have been investigated and the resultant value of the maximum specific capacitance is 15.56 F g−1 for 1 wt % of α-NiMoO4 nanoparticles(NPs) loaded polymer blended electrode at a scan rate of 5 mVs−1. The prepared PNCs exhibit 97.12% of columbic efficiency studied by using two electrode systems at room temperature in an aqueous electrolyte solution of 3 M KOH. From these investigation, it has been revealed that the PVA/PVP/α-NiMoO4 composites could be portable and flexible electrodes for energy storage applications.  相似文献   

2.
Hydrogen evolution reaction (HER) and electrochemical analysis are two important fields of electrochemical research at present. We found that both HER and some electrochemical analytical reactions relied on the concentration of hydrogen ions (H+) in solution, so we intended to develop an electrode material that is sensitive to H+ and can be used for both HER and some electrochemical analyses. In this work, we synthesized Ni3Mo3N coupled with nitrogen-rich carbon microspheres (Ni3Mo3N@NC MSs) as highly efficient electrode material for HER and detection of Hydrogen peroxide (H2O2), which plays an important role in physiological processes. Here the aniline was used as the nitrogen and carbon sources to synthesize Ni3Mo3N@NC. The Ni3Mo3N@NC MSs showed high performance for HER in 1 M KOH solution with a small overpotential of 51 mV at 10 mA cm?2 and superior stability. For H2O2 detection, a detection limit of 1 μM (S/N = 3), sensitivity of 120.3 μA·mM?1 cm?2 and linear range of 5 μM–40 mM can be achieved, respectively. This work will open up a low-cost and easy avenue to synthesize transition metal nitrides coupled with N-doped carbon as bifunctional electrode material for HER and electrochemical detection.  相似文献   

3.
Programmable design of nanocomposites of Li4Ti5O12 (LTO) conducted through hydrothermal route in the presence of ethylenediamine as basic and capping agent. In this work, effect of ZnO and Graphene on the Li4Ti5O12 based nanocomposites as anode materials investigated for Li-Ion battery performances. The full cells battery assembled with LTO based nanocomposites on Cu foil as the anode electrode and commercial LMO (LiMn2O4) on aluminum foil as cathode electrode. X-Ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDS), Fourier-transform infrared spectroscopy (FT-IR), along with Field Emission Scanning Electron Microscopy (FE-SEM) and Transmission electron microscopy (TEM) images was applied for study the composition and structure of as-prepared samples. The electrochemical lithium storage capacity of prepared nanocomposites was compared with pristine LTO via chronopotentiometry charge-discharge techniques at 1.5–4.0 V and current rate of 100 mA/g. As a result, the electrode which is provided by LTO/TiO2/ZnO and LTO/TiO2/graphene nanocomposites provided 765 and 670 mAh/g discharge capacity compared with pristine LTO/TiO2 (550 mAh/g) after 15 cycles. Based on the obtained results, fabricated nanocomposites can be promising compounds to improve the electrochemical performance of lithium storage.  相似文献   

4.
Coupling metallic and Mo2C phases uniformly on conductive matrix at nanoscale is a promising route to solve the poor electrical conductivity and aggregation problems of nano-Mo2C. In this work, a 3D self-supporting carbonized wood (CW) electrode encapsulation with mosaic structure Mo:Mo2C for hydrogen evolution reaction was fabricated successfully by a facile annealing treatment and a gas-solid reaction. The presence of Mo phase accelerated the transfer rate of electrons and provided heterogeneous interface. The obtained electrode shows abundant catalytic active sites and low electrochemical impedance, thus improving the catalytic process of splitting water for HER. The Mo:Mo2C-775 electrode requires an overpotential of 73.5 mV and 117 mV to achieve the current density of 10 mA cm?2 in 0.5 M H2SO4 and 1.0 M KOH, respectively. Moreover, Mo:Mo2C-775 electrode displayed excellent stability performance, which almost maintained a constant current density for 12 h (at ?100 mV vs RHE) in 0.5 M H2SO4 and 1.0 M KOH, respectively. This study provides a new idea for preparation of efficient 3D self-supporting electro-catalyst for HER.  相似文献   

5.
Developing a bi-functional material which can meet both electrochemical water splitting and supercapacitors (SCs) is a hot spot in current research. In this study, hierarchical zigzag-like phosphorus doped CuCo2O4 nanosheets based 3D electrode materials were successfully synthesized via a hydrothermal method and followed by thermal treatment. Since the unique morphology of 2D nanosheets with zigzag-like edges could provide more reactive sites, which is not only conducive to the hydrogen evolution reaction (HER), but also conducive to the electrochemical energy storage. Meanwhile, the doping of phosphorus was adopted to improve the conductivity, which would further enhance the electrochemical properties of CuCo2O4. Thereafter, its performance for HER and SCs in 1 M KOH were systematically investigated. As an electrode for HER, it only required a low overpotential of 152 mV to reach 10 mA cm?2 with a Tafel slope of 115.7 mV dec?1. Furthermore, I-t test result showed an excellent stability. As an electrode for SCs, it exhibited a high specific capacity of 896.9C g?1 at 1 A g?1 in three-electrode system. All in all, the obtained hierarchical zigzag-like phosphorus doped CuCo2O4 nanosheets provided a feasible route for the design of bi-functional electrode materials both for energy conversion and storage.  相似文献   

6.
The self-standing Co decorated Cu2O/CuS-based porous electrocatalyst was prepared with the help of simple electrodeposition and hydrothermal method. The structural characterizations of fabricated samples were performed with X-Ray diffraction spectroscopy and X-Ray photoelectron spectroscopy, while the morphology of catalysts was studied with the help of Field-Emission Spectroscopy and Transmission Electron Spectroscopy. The electrochemical performance of the hydrogen evolution reaction was checked in a basic electrolyte. The gradual increment in the electrochemical performance of Cu2O was observed when it underwent sulfurization without and with Co precursor respectively. The best electrochemical performance for hydrogen evolution reaction with an overpotential of 150.29 mV to achieve a geometric current density of 10 mA/cm2 was observed for the Cu2O sample sulfurized with Co precursor. The results of different characterizations suggested that the improved electrochemical performance could be attributed to the increased intrinsic activity and surface porosity of the electrocatalyst after sulfurization.  相似文献   

7.
In the context of constant research for the improvement of alkaline water electrolysis process using advanced electrocatalytic materials for the hydrogen evolution reaction (HER), various nickel particle based electrode materials were prepared and characterized. The synthesis of nickel hydroxide nanoparticles was performed in water in presence of three different stabilizers (CTAB, PVP and KBr). A thermal treatment at 400 °C under 5% H2/Ar atmosphere led to nickel nanoparticles. Mechanically milled commercial micrometric particles and nanoparticles synthesised by a polyol route completed a series of Ni powders showing broad ranges of size (5 nm–73 μm) and strain (6 ppm–0.7%). The electrocatalytic activity of the resulting electrode materials was evaluated versus powder morphology. Their apparent and intrinsic activity and the mechanism of the HER were studied by electrochemical impedance spectroscopy (EIS) and steady-state polarisation. A change in the HER mechanism is observed depending on particle size. This first systematic study demonstrates that the smaller the size and the more defective the particles, the greater the electrocatalytic activity. As a matter of fact, appreciable cathodic current densities of 100 mA cm−2 at ∼ −300 mV of overpotential were obtained for nickel nanoparticles with 5 nm size and 0.7% strain.  相似文献   

8.
The stability of La2Mo2O9−δ oxide-ion conductor was studied under Ar–H2 and controlled oxygen partial pressure (pO2) atmospheres within the range 608 ≤ T ≤ 1000 °C, by thermogravimetry (TG), X-ray Diffraction (XRD), Temperature Controlled X-ray Diffraction (TCXRD) and Scanning Electron Microscopy (SEM).  相似文献   

9.
Cu2FeSnS4 (CFTS) particles are synthesized using different surfactants such as thioglycolic acid (TGA), polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA) via the solution process. The effect of surfactants on crystal structure, morphology, elemental composition, and electrocatalytic properties of CFTS particles are investigated. CFTS particles with a better crystalline phase are obtained in PVP (surfactant), while impurity phases are observed in TGA and PVA (surfactants). The morphology of CFTS is significantly changed when a different surfactant is used in the synthesis process. The mixture of aggregate and porous (1 μm) particles is observed when PVA is used as a surfactant to synthesize CFTS particles. At the same time, highly porous particles having nanosheets and nanoparticles at the surface are obtained in the case of PVP. In the TGA case, spherical particles with 1 μm size are observed. The electrocatalytic ability of all CFTS particles toward hydrogen evolution reactions (HER) is studied in 0.5 M H2SO4 electrolyte. The overpotential of PVP-based CFTS particles is the lowest as ƞ = 421 mV at 10 mA/cm2 compared to the other two samples. CFTS particles synthesized using PVP exhibit enhanced electro-catalytic performance due to higher surface area.  相似文献   

10.
K2NiF4-type structure oxides La2Cu1−xCoxO4 (x = 0.1, 0.2, 0.3) are synthesized and evaluated as cathode materials for intermediate temperature solid oxide fuel cells (IT-SOFCs). The materials are characterized by XRD, SEM and electrochemical impedance spectrum (EIS), respectively. The results show that no reaction occurs between La2Cu1−xCoxO4 electrode and Ce0.9Gd0.1O1.95 (CGO) electrolyte at 1000 °C. The electrode forms good contact with the electrolyte after sintering at 800 °C for 4 h in air. The electrode properties of La2Cu1−xCoxO4 are studied under various temperatures and oxygen partial pressures. The optimum composition of La2Cu0.8Co0.2O4 results in 0.51 Ω cm2 polarization resistance (Rp) at 700 °C in air. The rate limiting step for oxygen reduction reaction (ORR) is the charge transfer process. La2Cu0.8Co0.2O4 cathode exhibits the lowest overpotential of about 50 mV at a current density of 48 mA cm−2 at 700 °C in air.  相似文献   

11.
Due to over depletion of fossil fuels, researchers started to find hydrogen energy to compete with the energy demands. Bi2WO6 and Ni (5% and 10%) doped Bi2WO6 were prepared via hydrothermal route. Structural confirmation of undoped and doped Bi2WO6 nanostructures was estimated by using standard characterization studies. The nanoflake and nanoneedle like morphology of undoped and Ni doped Bi2WO6 was confirmed in nanoscale range. The highest OER activity was achieved for 10% Ni doped Bi2WO6 nanostructure electrode with the excellent current density of 272 mA/g with overpotential of 242 mV in the fabricated three electrode half cell set up. The higher electron transport offered by Ni ions to Bi2WO6 host has been reported with the electrochemical mechanism. Hence, the unusual robust electrodes for electrochemical potential applications by tuning its property via suitable foreign ion dopant could be the great beginning of this recent year research. In such a way, this work would be the better way of swapping of nobel metal catalysts for electrochemical OER activity.  相似文献   

12.
Ternary Fe-Mo-R (R = Rare Earth metal) crystalline alloys, Fe75Mo20Gd5, Fe75Mo20Dy5, Fe75Mo20Er5 and Fe75Mo20MM5 (MM = mischmetal: 50.2% Ce, 26.3% La, 17.5% Nd, 6.0% Pr, atomic %) have been characterized by means of microstructural and electrochemical techniques in view of their possible applications as electrocatalytic materials for hydrogen evolution reaction (HER). The microstructure of the alloys was examined by scanning electron microscopy coupled with electron probe microanalysis; XRD measurements were also performed. The electrochemical efficiency of the electrodes has been studied on the basis of electrochemical data obtained from steady-state polarization and electrochemical impedance spectroscopy (EIS) techniques in 1 M NaOH solution at 298 K. The results were compared with those obtained on a binary Fe-Mo commercial alloy (Fe80Mo20, atomic %). Moreover, literature data concerning the electrocatalytic activity of the Ni75Mo25 and Co75Mo25 crystalline alloys, which are considered good electrocatalyst materials for the HER, were also reported for comparison. The microstructural features play a fundamental role in determining the electrocatalytic activity of the investigated alloys. The overall experimental data indicate that interesting electrocatalytic performances are displayed by the Fe75Mo20MM5 electrode, which exhibits the highest activity towards the HER.  相似文献   

13.
Cu2CoSnS4, Cu2SnS3, Cu2CoS4, Co2SnS3, Cu2S, CoS2, and SnS2 were synthesized using a one-step solvent-free solid-phase approach. The surface structure, morphology, and composition were characterized using an X-ray diffractometer (XRD), Fourier-Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), and X-ray Photoelectron Spectroscopy (XPS). The characterizations reveal pure phase formation and porous morphology. Further, the Hydrogen evolution reaction was performed using Cu2CoSnS4, Cu2SnS3, Cu2CoS4, Co2SnS3, Cu2S, CoS2, and SnS2-based electrodes. Amid all electrocatalysts, Cu2CoSnS4 shows an excellent hydrogen evolution reaction with a low overpotential of ?192.1 mV at ?10 mA/cm2 in 0.5 M H2SO4. And higher current density. Cu2CoSnS4 also shows a lower Tafel slope of 98.6 mV/dec and charge transfer resistance than mono and bimetallic chalcogenide-based electrodes. The Cu2CoSnS4 exhibit very good stability for ~22 h at ?10 mA/cm2 current density in 0.5 M H2SO4.  相似文献   

14.
Development of electrocatalysts composed of low cost and abundant elements that exhibit catalytic activity comparable to noble metals is important for water splitting. As such, in this study, a catalyst material with a ginger-like morphology consisting of Co6W6C is synthesized via a hydrothermal reaction and pyrolysis treatment. The Co6W6C catalyst exhibits satisfactory electrochemical properties towards both hydrogen and oxygen evolution reactions in an alkaline electrolyte, with a low overpotential, low Tafel slope, and durable stability. Co6W6C possesses a high activity for the hydrogen evolution reaction in alkaline conditions, with an onset potential and overpotential of −0.024 V and 101 mV, respectively, and low Tafel slope of 80.5 mV dec−1 at a current density of 10 mA cm−2. In addition, Co6W6C achieves a current density of 10 mA cm−2 for the oxygen evolution reaction at an overpotential of only 343 mV. Furthermore, electrochemical stability tests indicate that the Co6W6C catalyst maintains 91% of the original current after 60,000 s for the hydrogen evolution reaction and 95% of the original current after 45,000 s for the oxygen evolution reaction. Moreover, electrochemical splitting of water via a two-electrode system employing this catalyst can hold 89% of the initial current after 40,000 s in 1 M KOH.  相似文献   

15.
Catalytic processes are contemplated as break point in generating alternative and sustainable energy platforms. The cathodic oxygen reduction reaction (ORR) is an important catalytic system, mainly finding practice in fuel cell and metal-air battery technologies. This work presents the synthesis, structural characterization and electrocatalytic properties of three different Cu2Mo6S8 structures as alternative ORR electrocatalysts. The effect of different carbon additives during synthesis was studied and no positive influence of the carbon addition was indicated. Our findings show that only the bare Cu2Mo6S8 enhances the ORR electro-performance to class with the state-of-the-art ORR catalysts. Excellent stability of 10,000 consecutive ORR cycles, a superior onset potential of 0.894 V and half-wave (E1/2) potential of 0.641 V vs. reversible hydrogen electrode (RHE) increase the noteworthiness of the Cu2Mo6S8 electrodes. Aside from experimental investigations, density functional theory calculations deliver profound knowledge on the structural and electronic properties (electronic band structure, partial density of states and electron density) of Cu2Mo6S8.  相似文献   

16.
Reversible solid oxide cells (RSOCs) using identical material as both fuel electrode and air electrode have received extensive attentions due to their simplified fabrication process, increased compatibility between electrolyte and electrode. In this work, Molybdenum doped La0.5Sr0.5Fe0.9Mo0.1O3-δ (LSFMo) symmetric electrode based on RSOCs is firstly designed and synthesized via sol-gel method. The effect of Molybdenum substitution at Fe-site on crystal structure, chemical stability, conductivity and electrochemical performance of La0.5Sr0.5FeO3-δ oxide is thoroughly investigated. The structural stability of La0.5Sr0.5FeO3-δ (LSF) in reducing condition is significantly enhanced after the incorporation of Mo5+/6+ and the conductivity in 5% H2 for LSFMo is ~7 times higher than that of undoped LSF. In addition, the polarization resistance value at 850 °C based on LSFMo/LSGM/LSFMo is 0.08 and 0.09 Ω cm2 in air and wet H2, respectively. At 850 °C and 20%H2O–H2, a peak power density of 640 mW cm−2 is obtained in fuel cell mode, while a current density of −1000 mA cm−2 is attained at 1.3 V in electrolysis mode. Finally, the symmetric cell exhibits an excellent cycling reversible operation in both SOFCs mode and SOECs mode without detectable degradation.  相似文献   

17.
Low cost non-noble metal electrocatalysts are highly desirable for the sustainable production of hydrogen as a renewable energy source. Molybdenum carbide (Mo2C) has been considered as the promising non-noble metal electrocatalyst for the hydrogen production via hydrogen evolution reaction (HER) through water splitting. The nanostructured nitrogen (N) incorporated carbon (C) coupled with Mo2C is the potential candidate to boost the HER activity and electrode material for the energy conversion applications. In this work, nitrogen incorporated carbon coated Mo2C (Mo2C@C/N) has been synthesized in an eco-friendly way using waste plastic as the carbon source. The pure phase Mo2C@C/N has been synthesized at 700 and 800 °C for 10 h. The relatively higher temperature synthesized phase shows enhanced HER activity with lower Tafel slope (72.9 mVdec−1) and overpotential of 186.6 mV to drive current density of 10 mAcm−2. It also exhibits stability up to 2000 cyclic voltammetry (CV) cycles and retains the current density with negligible loss for 10 h. The higher temperature synthesized phase exhibits higher electrochemical active surface area (ECSA) and enhanced HER kinetics.  相似文献   

18.
La-doped Sr2-xLaxFe1.5Mo0.5O6-δ perovskite oxides are synthesized and used as a symmetric electrode to evaluate the effect of La on the crystal structure, conductivity, and catalytic activity for O2 reduction and H2 oxidation reaction. The electronic doping effect dominates the oversize effect in Sr2-xLaxFe1.5Mo0.5O6-δ oxide, resulting in unit cell volume expansion and decreased conductivity in air. In addition, the introduction of La increases the chemical structural stability of Sr2Fe1.5Mo0.5O6-δ in reducing condition due to the higher La–O bond compared with Sr–O bond, leading to high catalytic activity for the H2 oxidation reaction. At 800 °C, the Rp values of Sr1.9La0.1Fe1.5Mo0.5O6-δ symmetric cell in air and wet H2 are as low as 0.075 and 0.21 Ω cm2, respectively. Moreover, the peak power densities of 769, 561, 439, and 653 mW cm?2 at 850 °C are obtained when wet H2, CO, CH4, and C3H8 are used as fuels on Sr1.9La0.1Fe1.5Mo0.5O6-δ/LSGM/Sr1.9La0.1Fe1.5Mo0.5O6-δ cell. The symmetric cell also shows excellent stability (>100 h) in wet H2/air, implying Sr1.9La0.1Fe1.5Mo0.5O6-δ oxide is a promising symmetric electrode material.  相似文献   

19.
CexCu1-xO1.9 (x = 0.3, 0.5, 0.8 and 0.9) catalysts were synthesized by solid state method, using ball mill apparatus, and evaluated in medium temperature shift (MTS), as well as oxygen assisted MTS (OMTS) reactions at temperature range of 300–390 °C. Catalysts were characterized by X-Ray Diffraction (XRD), Temperature Programmed Reduction (TPR), Scanning Electron Microscopy (SEM), and N2 adsorption-desorption (BET) analysis. Ce0.9Cu0.1O1.9 sample showed the best catalytic activity and structural properties. Decrease in proportion of Cu to Ce, leads to increase in the Cu-Ce mixed oxide formation (according to TPR analysis), significant increase in BET surface area (from 18 m2/g for Ce0.3Cu0.7O1.9–48 m2/g for Ce0.9Cu0.1O1.9), and decrease in CuO crystalline size (XRD). Moreover, the effect of oxygen addition to the feed (O2/CO ratio = 0, 0.3, 0.5, 0.7 and 1), on the catalytic performance was evaluated. CO conversion was increased by enhancing the amount of oxygen (from 60% to 80% at 360 °C). CO and H2 oxidations are occurring as competitive parallel reactions in which CO oxidation is dominant at low O2/CO ratios (<0.5) and H2 oxidation (undesirable for MTS reaction) at high O2/CO ratios (>0.5). Furthermore, molar ratios of steam to CO at ranges of 2–4 were compared in OMTS reaction. According to the obtained results, the magnitudes of O2/CO ratio and S/C ratio which were 0.5 and 4, respectively, were selected as the best values for OMTS reaction.  相似文献   

20.
In this study, nickel cobalt oxide (NiCo2O4) microspheres were prepared by using facile hydrothermal route. The structural confirmation of bimetal oxide formation was acquired by X-ray powder diffraction and Raman studies. The formation of microspheres combined via irregular nanosheets was confirmed by scanning electron microscopy. Highly oriented NiCo2O4 microspheres yielded a high current density (258 mA/g) at 10 mV/s and low overpotential (224 V). The highly active electrode showed efficient electron transportation towards oxygen evolution reaction. Long-term stability over 16 h was achieved by the fabricated high-performance NiCo2O4 electrode. It is recommended that NiCo2O4 microspheres obtained from 3:1 stoichiometry ratio of Ni and Co would lead to new electrocatalysts that give best performance than expensive catalysts used currently in the water oxidation process.  相似文献   

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