Fabrication of MnS/GO/PANI nanocomposites on a highly conducting graphite electrode for supercapacitor application

We demonstrate a high surface area of manganese sulfide (MnS) nanoparticles via a simple solution method and investigated its morphology, physicochemical, and electrochemical studies. For the first time, we attempted to exploit the polymerization of aniline without adding HCl, as it is corrosive to the metal sulfide. Instead, the acidic group present on the graphene oxide surface plays a significant role to some extent as an acidic dopant in the polymerization process. This in-situ polymerization results in the uniform coverage of granular PANI on the entire MnS/GO nanocomposite, which enhances the interfacial interactions between PANI and MnS/GO nanoparticles. The introduction of graphene oxide (GO) to pristine MnS improved the specific capacitance, surface area, and average pore size. And incorporating PANI to MnS/GO leads to an increase in the interfacial interaction between the different pore sized nanoparticles giving enhanced specific capacitance. The specific capacitance for MnS/GO/PANI nanocomposite as measured by galvanostatic charge-discharge measurements was found to be 773 F/g at 1 A/g current density, and even at higher current density, it showed a specific capacitance of 484 F/g at 3.8 A/g. The specific capacitance obtained for MnS/GO/PANI nanocomposite from CV shows 822 F/g at 10 mV/s and 315 F/g at 200 mV/s. The combinatorial effects without destroying the metal sulfide nanostructure can provide an alternate route to design, promising electroactive nanocomposites is an ideal choice as a cost-effective, next-generation high-performance supercapacitor application.     

石墨烯/还原氧化石墨烯/聚苯胺复合材料的制备及在超级电容器中的应用

本研究以低成本、易规模化的亲水性石墨烯/氧化石墨烯为前驱体,通过原位聚合的方法制备石墨烯/氧化石墨烯/聚苯胺复合材料,经过化学还原后制备得到石墨烯/还原氧化石墨烯/聚苯胺复合材料.采用扫描电子显微镜(SEM)、透射电子显微镜(TEM)和傅里叶红外变化光谱仪(FT-IR)对制备的材料进行了结构和形貌的表征.运用循环伏安法...     

One-step electrochemical synthesis of MoS2/graphene composite for supercapacitor application

Journal of Solid State Electrochemistry - In this study, an MoS2/graphene composite is fabricated from bulk MoS2 and graphite rod via a facile electrochemical exfoliation method. The as-prepared...     

Transition metal complexes of acetamidomalondihydroxamate: synthesis,spectral, thermal and electrochemical studies

Acetamidomalondihydroxamate (K₂AcAMDH) and its manganese(II), iron(II), cobalt(II), nickel(II), copper(II) and zinc(II) complexes were synthesized and characterized by elemental analysis, UV–VIS, IR and magnetic susceptibility. The pK _a1 and pK _a2 values of the dihydroxamic acid in aqueous solution were found to be 8.0?±?0.1 and 9.7?±?0.1. The dihydroxamate anion AcAMDH behaves as a tetradentate bridging ligand through both hydroxamate groups, forming complexes with a metal to ligand ratio of 1?:?1 in the solid state. The FTIR spectra and thermal decompositions of the ligand and its metal complexes were recorded. The redox behavior of the complexes was investigated in aqueous solution by square wave voltammetry and cyclic voltammetry at neutral pH. In contrast to the solid state, in solution the copper(II) and zinc(II) ions form stable complex species with a metal to ligand ratio of 1?:?2. The iron(II) and nickel(II) complexes show a two-electron irreversible reduction behavior, while the copper(II) and zinc(II) complexes undergo reversible electrode reactions. The stability constants of the complexes were determined by square wave voltammetry.     

Ultrasonic route synthesis,characterization and electrochemical study of graphene oxide and reduced graphene oxide

Research on Chemical Intermediates - In this study, an efficient route for graphene oxide (GO) and reduced GO (RGO) synthesis was developed by using an ultrasonic probe and bath alternatively. RGO...     

氧化石墨烯浓度对还原氧化石墨烯/ZnS电化学性能的影响

以氧化石墨烯(GO)、乙酸锌(Zn(CH₃COO)₂)和硫脲为原料,采用水热法成功制备了还原氧化石墨烯/ZnS(rGO/ZnS)复合材料,并将该材料用作锂离子电池负极。高导电性的 rGO可以为锂离子和电子的传输提供有效的路径,ZnS可以提供较高的理论比容量。rGO/ZnS复合材料在rGO与纳米级高度分散的类球形ZnS颗粒协同作用下展现了较好的嵌锂容量和循环性能。当GO质量浓度为2 mg·mL^-1时制备的rGO/ZnS复合材料的倍率性能最好,循环稳定性最佳。     

氧化石墨烯浓度对还原氧化石墨烯/ZnS电化学性能的影响

以氧化石墨烯(GO)、乙酸锌(Zn(CH₃COO)₂)和硫脲为原料,采用水热法成功制备了还原氧化石墨烯/ZnS(rGO/ZnS)复合材料,并将该材料用作锂离子电池负极。高导电性的 rGO可以为锂离子和电子的传输提供有效的路径,ZnS可以提供较高的理论比容量。rGO/ZnS复合材料在rGO与纳米级高度分散的类球形ZnS颗粒协同作用下展现了较好的嵌锂容量和循环性能。当GO质量浓度为2 mg·mL^-1时制备的rGO/ZnS复合材料的倍率性能最好,循环稳定性最佳。     

Facile synthesis of nickel cobalt sulfide nano flowers for high performance supercapacitor applications

A facile synthesis of nickel cobalt sulfide (NCS) nanoflowers have been deposited successfully onto binder free 3D nickel foam electrodes using simple successive ionic layer adsorption and reaction (SILAR) method for supercapacitor applications. The obtained NCS nanoflowers manifest ultrahigh specific capacitance of 1899 F g^?1 at a scan rate of 5 mV s^?1. The NCS nanoflowers exhibit a prominent energy density of 55.16 Wh kg^?1 at power density of 495 W kg^?1 and superior cyclic stability of 94% after 10000 cycles. In addition, the asymmetric supercapacitor (ASC) device is fabricated using NCS nanoflower as positive and reduced graphene oxide (rGO) as negative electrodes, respectively. The ASC (NCS//rGO) delivered good capacity with excellent energy and power densities within 1.6 V wider potential window. Hence, NCS nanoflowers are an outstanding material for energy storage applications in near future.     

Synthesis of ruthenium/reduced graphene oxide composites and application for the selective hydrogenation of halonitroaromatics

Reduced graphene oxide （RGO） supported ruthenium （Ru） catalyst was prepared by an impregnation method using RuCI3 as a precursor and RGO as a support. The catalyst Ru/RGO was used for the selective hydrogenation ofp-chloronitrobenzene （p-CNB） to p-chloroaniline （p-CAN）, showing a selectivity of 96% at complete conversion of p-CNB at 60 ℃ and 3.0 MPa H2. The Ru/RGO catalyst was extremely active for the hydrogenation of a series of nitroarenes, which can be attributed to the small sized and the fine dispersity of the Ru nanoparticles on the RGO sheets characterized by TEM. Moreover, the catalyst also can be recycled five times without the loss of activity.     

Characterizations of nickel mesh and nickel foam current collectors for supercapacitor application

Nickel (Ni) current collectors having a three-dimensional and porous structure are considered attractive contestants for high-efficiency supercapacitors. Therefore, Ni current collectors have a unique architecture and outstanding electrochemical properties. This study reports the effect of electrochemical characterizations on the electrochemical behavior and physical properties of Ni mesh and Ni foam. Cyclic voltammetry (CV) and galvanostatic charge discharge (GCD) are used to examine the electrochemical properties and life span of the Ni mesh and Ni foam as a current collector in a supercapacitor application. Structural and microstructural characterizations are performed to verify the formation of an oxide layer after 1000 cycles of CV analysis. Results show that Ni foam can increase the yield electrochemical performance of the supercapacitor. Ni foam present better efficiency (35 F g⁻¹) compared to the Ni mesh (12 F g⁻¹) at 10 mV s⁻¹ scan rate by using 2 mg imaginary mass of active material. This result shows that Ni foam has good electrochemical performance and reversibility, higher pseudocapacitance, weaker polarization, and enhance rotating performance as to Ni mesh. The porous structure of Ni foam is in control for improving of the electrochemical properties, therefore, the electrochemical region was increased and shortened ion diffusion. Structural analysis shows that Ni mesh and Ni foam are oxidized after the electrochemical analysis and transformed to nickel oxide hydroxide (NiOOH). Higher specific surface area between the electrode and electrolyte leads to excellent electrochemical and pseudocapacitive performance of the Ni foam compared to the Ni mesh, even if the materials of current collectors are the same. Hence, the physical structure of the current collectors have a critical part in improving the energy density of the supercapacitor.     

Design and tailoring of a three-dimensional reduced graphene oxide/helical carbon nanotube composite for electrochemical biosensing application

Journal of Solid State Electrochemistry - Herein, three-dimensional reduced graphene oxide/helical carbon nanotubes (RGO/HCNTs) nanocomposites were synthesized by a combined solution-based method...     

Facile synthesis of cobalt oxide/reduced graphene oxide composites for electrochemical capacitor and sensor applications

Reduced graphene oxide sheets decorated with cobalt oxide nanoparticles (Co₃O₄/rGO) were produced using a hydrothermal method without surfactants. Both the reduction of GO and the formation of Co₃O₄ nanoparticles occurred simultaneously under this condition. At the same current density of 0.5 A g⁻¹, the Co₃O₄/rGO nanocomposites exhibited much a higher specific capacitance (545 F g⁻¹) than that of bare Co₃O₄ (100 F g⁻¹). On the other hand, for the detection of H₂O₂, the peak current of Co₃O₄/rGO was 4 times higher than that of Co₃O₄. Moreover, the resulting composite displayed a low detection limit of 0.62 μM and a high sensitivity of 28,500 μA mM⁻¹cm⁻² for the H₂O₂ sensor. These results suggest that the Co₃O₄/rGO nanocomposite is a promising material for both supercapacitor and non-enzymatic H₂O₂ sensor applications.     

Synthesis,electrochemical and anti-microbial study of 2,5-diamino benzoquinones

Fifteen symmetric and unsymmetric 2,5-diamino benzoquinones have been synthesized and their electrochemical activity was studied by cyclic voltammetry. Presence of electron donating substituent like amino group found to shift the half wave potential towards more negative value which is more prominent in benzyl amino substituted amino benzoquinones (ABQs). All the compounds were checked for their anti-bacterial and anti-fungal activity by agar well diffusion technique. The more negative E_1/2 values of benzyl amino substituted ABQs make them more active towards various bacterial and fungal speciesas is evident from MIC values.     

Synthesis, spectroscopic and electrochemical property of an unsymmetrical porphyrin and its Zn compound

<正>In this article,a new 5-(p-maleicaminophenyl)-10,15,20-triphenylporphyrin(H_2P) and relative zinc compound(ZnP) were synthesized and characterized by means of elemental analyses,UV-vis,IR,MS and ~1H NMR spectroscopies.Furthermore,we have investigated the fluorescence spectroscopy of these compounds.The oxidation and reduction properties of the compounds were studied by the cyclic voltarnmetry,the oxidation-reduction potentials were obtained.     

Synthesis and characterization of a nanocomposite of goethite nanorods and reduced graphene oxide for electrochemical capacitors

We report a one-step synthesis of a nanocomposite of goethite (α-FeOOH) nanorods and reduced graphene oxide (RGO) using a solution method in which ferrous cations serve as a reducing agent of graphite oxide (GO) to graphene and a precursor to grow goethite nanorods. As-prepared goethite nanorods have an average length of 200 nm and a diameter of 30 nm and are densely attached on both sides of the RGO sheets. The electrochemical properties of the nanocomposite were characterized by cyclic voltammetry (CV) and chronopotentiometry (CP) charge–discharge tests. The results showed that goethite/RGO composites have a high electrochemical capacitance of 165.5 F g^?1 with an excellent recycling capability making the material promising for electrochemical capacitors.     

Synthesis of new ethynylbipyridine-linked mono- and bis-tetrathiafulvalenes: electrochemical, spectroscopic, and Ru(II)-binding studies

Two new ethynylbipyridine-linked mono- and bis-tetrathiafulvalene (TTF) derivatives, together with a Ru(II) complex, were synthesized using Sonogashira coupling reactions and characterized by UV/vis spectroscopy and cyclic voltammetry. They display a clear electrochemically amphoteric behavior consisting of two reversible single-electron oxidation waves (typical for TTF derivatives) and one reversible single-electron reduction wave (bpy) and act as donor-acceptor (D-A) systems. Furthermore, for the Ru(II) complex, a quite intense fluorescence originating from the ³MLCT state is observed.     

Synthesis and electrochemical characterization of biphenyl-malonic ester substituted cobalt,copper, and palladium phthalocyanines

Phthalocyanines with four biphenyl-malonic ester groups on the periphery were synthesized by cyclotetramerization of 4-(1,1-dicarbethoxy-2-(4-biphenyl)-ethyl)-phthalonitrile. The new compounds were characterized by elemental analyses, FT-IR, ¹H NMR, ¹³C NMR, UV–Vis, and MASS spectral data. Electrochemical behaviors of novel Co(II), Cu(II), and Pd(II) phthalocyanines were investigated by cyclic voltammetry, potential differential pulse voltammetry, and applied potential chronocoulometry techniques. While Cu(II) and Pd(II) phthalocyanines give up to four common phthalocyanine ring reductions, Co(II) phthalocyanine gave two ligand-centered and two metal-centered redox processes. HOMO–LUMO gap of the complexes are comparable with the reported MPc papers.     

Synthesis of reduced graphene oxide/Co3O4 nanocomposite electrode material for sensor application

Research on Chemical Intermediates - A sensitive electrochemical sensor has been developed based on reduced graphene oxide/Co3O4 (rGO/Co3O4) nanocomposites (NCs) synthesized by a facile...     

Synthesis, structure and electrochemical behaviour of 2,2-diferrocenylpropane-substituted dihydropyrazole derivatives

The reaction of α,β-unsaturated ketones of 2,2-diferrocenylpropane with hydrazine led to the formation of 2,2-diferrocenylpropane-substituted dihydropyrazole. The further reaction of dihydropyrazole with p-pyridinecarboxylic acid chloride or benzoyl chloride resulted in the isolation of two novel 2,2-diferrocenylpropane-substituted acyl dihydropyrazole derivatives. All of these compounds were analyzed by MS, IR and ¹H NMR spectra. The crystal structure of representative compound, 1-p-pyridine acyl-3-ferrocenyl-5-(2,2-diferrocenylpropane)-4,5-dihydropyrazole (5a) has been elucidated by X-ray diffraction. The electrochemical behaviours of all the compounds have been examined.