Performance of chemically synthesized Mn3O4/rGO nanocomposite for electrochemical supercapacitor: a cost-effective high-performance electrode.

The manganese oxide graphene oxide (Mn3O4/rGO) composite heterojunction with copper oxide is useful for the production of an electrochemical supercapacitor. The graphene oxide and manganese oxide composite have been synthesized by adopting a method of co-precipitation. The composite of Mn3O4/rGO was synthesized with different concentrations of Mn3O4 and rGO. The structural, morphological, electrochemical and supercapacitive properties of Mn3O4/rGO composite have been examined. The electrochemical and supercapacitive properties have been studied with regard to different substrates. The Mn3O4/rGO composite was deposited on different substrates such as steel, copper and brass. The CuO/Mn3O4/rGO shows relatively better specific capacitance (856 F g-1) and better stability (82% retention after 2000 cycles) than other substrates used. The present work describes the development of cost-effective and high-performance CuO/Mn3O4/rGO-based nanomaterials for supercapacitors. The CuO/Mn3O4/rGO composite can be used as a flexible supercapacitor device.

Novel approach to synthesize NiCo2S4 composite for high-performance supercapacitor application with different molar ratio of Ni and Co.

Here, we developed a new approach to synthesize NiCo2S4 thin films for supercapacitor application using the successive ionic layer adsorption and reaction (SILAR) method on Ni mesh with different molar ratios of Ni and Co precursors. The five different NiCo2S4 electrodes affect the electrochemical performance of the supercapacitor. The NiCo2S4 thin films demonstrate superior supercapacitance performance with a significantly higher specific capacitance of 1427 F g-1 at a scan rate of 20 mV s-1. These results indicate that ternary NiCo2S4 thin films are more effective electrodes compared to binary metal oxides and metal sulfides.

Nanorods to hexagonal nanosheets of CuO-doped manganese oxide nanostructures for higher electrochemical supercapacitor performance.

In this work, the extraordinary properties of CuO addition on the morphology and supercapacitive performance of Mn2O3 electrodes were demonstrated. Concisely, CuO/Mn2O3 thin films were prepared by an easy and inexpensive successive ionic layer adsorption and reaction (SILAR) method. The prepared thin films were characterized by various sophisticated physiochemical systems. The results demonstrated formation of Mn2O3 thin films with noteworthy morphological alteration upon introduction of CuO. Furthermore, a significant effect of CuO introduction was observed on the electrocatalytic properties of the nanostructured Mn2O3 electrodes. At 3% CuO doping, the Mn2O3 electrodes displayed the maximum specific capacitance owing to formation of nanoplate-like structures. The enhanced specific capacitance attained for 3% CuO doping in the Mn2O3 electrode was 500 F/g at 5 mV/s in a 3 M KOH electrolyte. All results confirmed the plausible potential of the CuO/Mn2O3 electrode for supercapacitor applications.

Using chemical bath deposition to create nanosheet-like CuO electrodes for supercapacitor applications.

We report the effect of ionic liquids on chemically synthesized hierarchical-like copper oxide (CuO) thin films for supercapacitor applications. Concisely, the CuO thin films were deposited via chemical bath deposition (CBD) using 2-dimethylimidazolium chloride [HPDMIM(C1)], 1-(2',3'-dihydroxypropyl)-3-methylimidazolium chloride [DHPMIM(C1)], and N-(3-methyl-2-oxopropyl)pyridine chloride [MOCPP(C1)] ionic liquid solvents. The effects of the ionic liquid solvents on the morphological evolution of the as-prepared films were analyzed, and electrochemical properties were investigated. The highest specific capacitance was achieved for the electrode with a nanosheet-like structure produced by functionalization with the HPDMIM(C1) ionic liquid. The maximum specific capacitance achieved for the HPDMIM(C1):CuO hybrid electrode was 464 F g-1 at 5 mV s-1 in a 1 M Na2SO4 electrolyte. Thus, our findings, in addition to the stability of the HPDMIM(C1):CuO, indicate that it is a candidate for energy-storage applications.

Effect of electron beam irradiation on chemically synthesized nanoflake-like CdS electrodes for photoelectrochemical applications.

In this paper, we chemically synthesized interconnected nanoflake-like CdS thin films for photoelectrochemical solar cell applications and subsequently irradiated them with electron beam irradiation at various doses of irradiation. The as-synthesized and irradiated samples were characterized by means of X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), and electrochemical measurements. XRD and XPS results confirmed the formation of CdS with a hexagonal crystal structure. FE-SEM and HR-TEM studies confirmed the photoelectrochemical performance, which was dependent on the surface morphology. The calculated values for efficiency demonstrated an outstanding photoelectrochemical performance with a fill factor of 0.38 and efficiency of 3.06% at 30 kGy. The high photoelectrochemical performance may be due to the interconnected nanoflake-like nanostructure and higher active surface area of the CdS samples. These results show that the electron beam irradiation is capable as an electrode for photoelectrochemical solar cells.

Morphological enhancement to CuO nanostructures by electron beam irradiation for biocompatibility and electrochemical performance.

This paper reports the effect of electron beam irradiation on CuO thin films synthesized by the successive ionic layer adsorption and reaction (SILAR) method on copper foil for supercapacitor and biocompatibility application. Pristine and irradiated samples were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, and electrochemical study. Pristine and irradiated CuO films were pure monoclinic phase, with uniform nanostructures over the whole copper foil. After irradiation, CuO samples had formed innovative nanostructures. Biocompatibility of pristine and irradiated CuO samples suggest that CuO sample is non-toxic and ecofriendly. The specific capacitance of pristine and irradiated CuO strongly depends on surface morphology, and CuO electrodes after irradiation showed superior performance than pristine CuO. The highest specific capacitance of the 20kGy irradiated CuO nanoflowers exceeded 511Fg-1 at 10mVs-1 in 1M KOH electrolyte. Irradiated CuO samples also showed lower ESR, and were superior to other report electrical energy storage materials.

Chemical synthesis of hierarchical NiCo2S4 nanosheets like nanostructure on flexible foil for a high performance supercapacitor.

In this study, hierarchical interconnected nickel cobalt sulfide (NiCo2S4) nanosheets were effectively deposited on a flexible stainless steel foil by the chemical bath deposition method (CBD) for high-performance supercapacitor applications. The resulting NiCo2S4 sample was characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), and electrochemical measurements. XRD and X-ray photoelectron spectroscopy (XPS) results confirmed the formation of the ternary NiCo2S4 sample with a pure cubic phase. FE-SEM and HR-TEM revealed that the entire foil surface was fully covered with the interconnected nanosheets like surface morphology. The NiCo2S4 nanosheets demonstrated impressive electrochemical characteristics with a specific capacitance of 1155 F g-1 at 10 mV s-1 and superior cycling stability (95% capacity after 2000 cycles). These electrochemical characteristics could be attributed to the higher active area and higher conductivity of the sample. The results demonstrated that the interconnected NiCo2S4 nanosheets are promising as electrodes for supercapacitor and energy storage applications.

Chemical synthesis of flower-like hybrid Cu(OH)2/CuO electrode: Application of polyvinyl alcohol and triton X-100 to enhance supercapacitor performance.

In this research article, we report hybrid nanomaterials of copper hydroxide/copper oxide (Cu(OH)2/CuO). A thin films were prepared by using a facile and cost-effective successive ionic layer adsorption and reaction (SILAR) method. As-synthesized and hybrid Cu(OH)2/CuO with two different surfactants polyvinyl alcohol (PVA) and triton-X 100 (TRX-100) was prepared having distinct morphological, structural, and supercapacitor properties. The surface of the thin film samples were examined by scanning electron microscopy (SEM). A nanoflower-like morphology of the Cu(OH)2/CuO nanostructures arranged vertically was evidenced on the stainless steel substrate. The surface was well covered by nanoflake-like morphology and formed a uniform Cu(OH)2/CuO nanostructures after treating with surfactants. X-ray diffraction patterns were used to confirm the hybrid phase of Cu(OH)2/CuO materials. The electrochemical properties of the pristine Cu(OH)2/CuO, PVA:Cu(OH)2/CuO, TRX-100:Cu(OH)2/CuO films were observed by cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy technique. The electrochemical examination reveals that the Cu(OH)2/CuO electrode has excellent specific capacitance, 292, 533, and 443Fg-1 with pristine, PVA, and TRX-100, respectively in 1M Na2SO4 electrolyte solution. The cyclic voltammograms (CV) of Cu(OH)2/CuO electrode shows positive role of the PVA and TRX-100 to enhance supercapacitor performance.

Pear fruit extract-assisted room-temperature biosynthesis of gold nanoplates.

In this paper, a single-step room-temperature biosynthetic route for producing gold nanostructures using pear fruit is reported. The alkaline conditions of the pear fruit extract induced gold nanoparticles with plate-like morphologies. Successfully biosynthesized triangular and hexagonal nanoplates were observed, elegantly assembled with hexagonal gold nanoparticles. Nanostructure size, crystal nature, purity and morphologies were characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray diffraction (XRD), X-ray photoemission spectroscopy (XPS) and energy dispersive X-ray analysis (EDAX). The edge lengths of the nanostructures ranged from 200 to 500 nm. Using AFM analysis, the nanohexagons were observed to have a thickness ranging from 12 to 20 nm. The XRD patterns showed a (1 1 1) preferential orientation of the nanostructures. The XPS and EDAX analysis also confirmed the presence of pure-phase Au without any substantial impurities. The preparation of nanostructured gold particles using pear fruit provides an environmentally friendly option, as compared to currently available chemical and/or physical methods.

Degradation and detoxification of disperse dye Scarlet RR by Galactomyces geotrichum MTCC 1360.

Galactomyces geotrichum MTCC 1360 degraded the Scarlet RR (100 mg/l) dye within 18 h, under shaking conditions (150 rpm) in malt yeast medium. The optimum pH and the temperature for decolorization were pH 12 and 50 degrees , respectively. Enzymatic studies revealed an induction of the enzymes, including flavin reductase during the initial stage and lignin peroxidase after complete decolorization of the dye. Decolorization of the dye was induced by the addition of CaCO3 to the medium. EDTA had an inhibitory effect on the dye decolorization along with the laccase activity. The metabolites formed after complete decolorization were analyzed by UV-VIS, HPLC, and FTIR. The GC/MS identification of 3 H quinazolin-4- one, 2-ethylamino-acetamide, 1-chloro-4-nitro-benzene, N- (4-chloro-phenyl)-hydroxylamine, and 4-chloro-pheny-lamine as the final metabolites corroborated with the degradation pathway is suggested to understand the mechanism used by G.geotrichum and thereby aiding development of technologies for the application of this organism to the cleaning-up of aquatic and terrestrial environments.