Synthesis,characterization, and evaluation of unsupported porous NiS submicrometer spheres as a cathode material for lithium batteries

Synthesis of a nanostructured pure phase nickel sulfide in a single step is a challenge. In this work, a new method for direct synthesis of uniform NiS–SiO₂ submicrospheres was developed by ultrasonic spray pyrolysis. Colloidal silica was used as a sacrificial template to create the porous structure. After silica removal, hollow, porous pure phase NiS nanospheres were obtained. The product was characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, transmission electron microscopy, and N₂ adsorption/desorption isotherm. The results confirmed the formation of single phase millerite NiS porous nanospheres with a high surface area of 312 m² g^?1. The NiS spheres were tested as cathode for lithium batteries. A discharge capacity of 340 mAh g^?1 with good capacity retention during multiple cycles was obtained.     

MWCNTs-TiO<Subscript>2</Subscript> core-shell nanoassemblies for fabrication of poly(vinylidene fluoride) based composites with high breakdown strength and discharged energy density

Dielectric polymer composites with high breakdown strength and discharged energy density have potential applications in modern electric power systems. In this study, composites comprising MWCNTs-TiO₂ core-shell nanoparticles and poly(vinylidene fluoride) (PVDF) were fabricated by a solution casting method, followed by a melting and quenching process. The obtained composites are γ-phase PVDF dominated and present a dense structure. By the incorporation of MWCNTs-TiO₂ core-shell nanoparticles, the dielectric constant of composites can be significantly enhanced while the dielectric loss of composites remains low. Because of the core-shell structure of well-dispersed MWCNTs-TiO₂ and their strong interactions with matrix, high breakdown strength above 175 V/μm can be achieved in the composites. Additionally, the composites exhibit enhanced discharged energy density, which can be as high as 6.4 J/cm³ at 250 V/μm, while the maximum discharged energy density obtained in pure PVDF is only 2.6 J/cm³ (270 V/μm).     

Use of Nickel Sulphide–PMMA Composite Beads for Removal of 106Ru from Alkaline Radioactive Liquid Waste

Abstract

Use of NiS coprecipitation was found to be very effective at a concentration level of 2500 ppm of Ni⁺² and 1300 ppm of S^?2 for the effective removal of ¹⁰⁶Ru from the effluent stream. However, the NiS precipitate increases the sludge volume. Efforts were made to form the composite material of NiS in combination with Poly methyl metha acrylate (PMMA) polymer beads. The NiS–PMMA composite beads were loaded in a column and its ruthenium uptake behavior was studied. The NiS–PMMA beads were found to be functioning satisfactorily in alkaline conditions. It has shown a K_d value of about 8000–9000. The NiS–PMMA composite material has also shown the potential for the uptake of ¹²⁵Sb. The effect of salt concentration on the K_d value is negligible. The equilibrium conditions are achieved in around 25–30 min in batch mode of operation. The composite material can be suitably used in the column mode of operation.     

Highly efficient photocatalytic degradation of methylene blue using carbonaceous WO<Subscript>3</Subscript>/TiO<Subscript>2</Subscript> composites

Recent improvements in the performance of photocatalysts made it possible to tackle pollution through environment friendly methods. This study investigates the modification of the photocatalytic activity of TiO₂ by employing WO₃ and conductive polymers, namely, polyaniline (Pani) and polypyrrole (Ppy). Basing on our previous improvement of TiO₂ using a conductive polymer and activated carbon (AC), this study determines the activated carbon forms of TiO₂. The prepared composites are characterized using X-ray powder diffraction, transmission electron microscopy, Fourier transform infrared, thermogravimetric analysis, Brunauer–Emmet–Teller, and UV–Vis spectroscopy. The specific surface area of the mesoporous composites is as follows: WO₃/TiO₂·AC (Pani) > WO₃/TiO₂·AC (Ppy) > WO₃/TiO₂·Pani > WO₃/TiO₂·Ppy (127 > 98 > 68 > 44 m² g^?1), which exhibited a similar trend to the photocatalytic performances (100 > 95 > 91 > 72 % conversion rate). This result could be attributed to higher porosity, surge of charge separation, and photo-responding range extension induced by the synergistic effect of WO₃, conducting polymers, and TiO₂ in the samples.     

Construction of NiPx/MoS2/NiS/CdS composite to promote photocatalytic H2 production from glucose solution

Constructing multi-component photocatalyst is an efficient method to achieve high photocatalytic efficiency. In this work, CdS nanorods modified with NiS nanoparticles are first prepared to improve the photocatalytic performance, as no H₂ generates on single NiS or CdS catalyst from glucose solution. MoS₂ and NiP_x, as the cocatalysts for H₂ production, are loaded on the surface of NiS/CdS composite. With step-by-step solvothermal synthesis, four components (CdS, NiS, Mo₂S, and NiP_x) are fully combined in the NiP_x/MoS₂/NiS/CdS nanorods, generating many intimate contact interfaces. Moreover the optimized NiP_x/MoS₂/NiS/CdS performs a significantly increased photocatalytic activity, with H₂ production rate at 297 µmol h^–1 g^–1. The synergistic effects of heterostructure (NiS/CdS) and cocatalysts (MoS₂ and NiP_x) are the main reasons in enhancing photocatalytic performance, which facilitate the separation of charge carriers and prolong their lifetimes. This work provides an effective strategy to design photocatalysts with multiple components and fast charge separation for highly efficient H₂ production.     

Polyaniline‐functionalized magnetic mesoporous nanocomposite: A smart material for the immobilization of lipase

Magnetically separable mesoporous silica nanocomposites with polyoaniline functionalization (Pani‐MS@Fe₃O₄) were synthesized for the immobilization of lipase via electrostatic adsorption. The as‐prepared Pani‐MS@Fe₃O₄ nanocomposites as well as immobilized lipase were characterized by FTIR, XRD, HRTEM, FESEM, BET, and TGA techniques. The BET surface area was calculated to be 779.27 m²/g, 425 m²/g, and 230.45 m²/g for magnetic mesoporous nanoparticle (MS@Fe₃O₄), Pani‐MS@Fe₃O₄ nanocomposite, and lipase immobilized Pani‐MS@Fe₃O₄ nanocomposite respectively. The comparison experiments verified that the immobilized lipase exhibited slightly higher optimal pH and temperature value with a wider pH‐activity and temperature stability in comparison with the free lipase. From Michaelis–Menten kinetic study, the lower K_m value (0.25 mM) and higher V_max value (0.0341 mM/min) for the immobilized lipase revealed the higher affinity of immobilized lipase toward the substrate. Further, reusability studies of the immobilized lipase indicated that up to 70% of the original activity was retained after having been recycled seven times. POLYM. COMPOS. 37:1152–1160, 2016. © 2014 Society of Plastics Engineers     

New semiconductor core-shell based on nano-rods core materials

ABSTRACT

The present work describes a remarkable synthetic interest of semiconducting core-shell nanocomposites (CSNCs) contained aluminum oxide. Al₂O₃@terpoly(aniline, anthranilic acid, and o-phenylenediamine) (Al₂O₃/PANI-AA-o-PDA) CSNCs were fabricated by the fivefold molar ratio of the appropriate moieties with various quantities of γ-Al₂O₃ by oxidative polymerization. The formation of the Al₂O₃/PANI-AA-o-PDA CSNCs was confirmed by spectral characteristics. The feature of CSNCs is core-shell nano-rods structure with sizes 19–39 nm. The recorded σ_dc is 8.8 × 10^?9-4.8 × 10^?8 Ω^?1 m^?1 being in the range of semiconductor materials at room temperature and increases with increasing temperature. The newly fabricated materials were investigated as antimicrobial agents. The setup presents a facile, cheap, novel and beneficial methodology to develop novel CSNCs acquiring the required numerous functionality.     

Synthesis and Characterization of Poly(Acrylonitrile-co-Vinylacetate)/Fe2O3@PEDOT Core-Shell Nanocapsules and Nanofibers

P(AN-co-VAc)/Fe₂O₃ core-shell nanocapsules were synthesized by miniemulsion polymerization and P(AN-co-VAc)/Fe₂O₃@PEDOT core-shell structure was constituted by oxidative polymerization. Homogeneous nanofibers were obtained from the core-shell nanocapsules. Characterizations were performed by XRD, GPC, UV-vis, and FTIR-ATR. SEM, AFM, and TEM. Molecular weight and Tg of the nanocapsules were effected by the increase in γ-Fe₂O₃ NPs. Nanofiber resistance (Rnfb) drastically decreased from 2700 to 110 kΩ.cm² by the inclusion of γ-Fe₂O₃ NPs into the nanocapsules 8.3 kΩ.cm² obtained after coating with PEDOT. The electrochemical Impedance results were fitted to models of [R (Q(R (CR)))] and [R (Q(R (QR)))], respectively.     

Conductive polyaniline–polychloroprene blends

The electrical conductivity of polychloroprene (CR)/polyaniline (Pani) blends prepared by bulk and solution processes were investigated. Pani doped with HCl (Pani · HCl) and p-toluenesulfonic acid (Pani · TSA) were employed in vulcanized blends obtained by the bulk process. These blends showed an increase in the conductivity only for blend composition of CR/Pani = 50:50 wt %. At this composition, blends with Pani · HCl and Pani · pTSA presented conductivity values of 10⁻⁹ and 10⁻¹⁰ S · cm⁻¹, respectively. CR/Pani · HCl blend films prepared by the solution process displayed surface conductivity values of 10⁻⁴ S · cm⁻¹ with as low as 10–15 wt % of PAni · HCl. Surface analysis of these blends by X-ray photoelectron spectroscopy indicated no traces of the conductive additive. The surface composition was found to be exclusively constituted of CR. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 1543–1549, 1998     

Low temperature atomic layer deposition of nickel sulfide and nickel oxide thin films using Ni(dmamb)2 as Ni precursor

Nickel(II) 1-dimethylamino-2-methyl-2-butoxide (Ni(dmamb)₂) with water and hydrogen sulfide as oxygen and sulfur sources was employed in atomic layer deposition (ALD) of nickel oxide (NiO) and nickel sulfide (NiS) thin films. Both NiO and NiS thin films demonstrate temperature-independent growth rates per cycle of 0.128?nm/cycle and 0.0765?nm/cycle, at 130–150?°C and 80–160?°C, respectively. Comparison of two nickel-based thin film materials demonstrates dissimilar deposition features depending on the reactivity of the Ni precursor, i.e., Ni(dmamb)₂ with anion sources provided by the water and hydrogen sulfide reactants. Difference in reactivity observed for NiO and NiS ALD processes is further investigated by density functional theory (DFT) simulations of surface reactions, which indicated that H₂S demonstrate higher reactivity with surface-adsorbed Ni precursor than H₂O. The material properties of ALD NiO and NiS thin films including stoichiometry, crystallinity, band structure, and electronic properties were analyzed by multiple experimental techniques, showing potential of ALD NiS as electrode or catalyst for energy-oriented devices.     

High electrical conductive polymethylmethacrylate/graphite composites obtained via a novel pickering emulsion route

In this work, high electrically conductive Polymethylmethacrylate/graphite (PMMA/G) composites with a specific core-shell structure were synthesized via Pickering emulsion (solid-stabilized emulsion) route. The electrical conductivity of the core-shell composites was measured by a four-point probe resistivity determiner and a very high value of 9.8?×?10^?3 S/cm (10¹³ times higher than virgin PMMA) was obtained at 30 wt% graphite. However, the electrical conductivity of the PMMA/G composites gained through traditional blend process was relatively lower and the value only reached 9.4?×?10^?9 S/cm at same graphite loading fraction. Contact angle measurement was applied to determine the surface free energy of the modified graphite which was cladded by Al(OH)₃. The morphology of the core-shell composites was observed by SEM and optical microscopy. Dynamic rheology analysis was employed to study the structural change by the interconnection of the graphite flakes and the formation of the networks in the composites. The interconnected networks of the core-shell composites were more easily constructed when compared with the composites obtained by the traditional blending process.     

Improved photocatalytic oxidation of ciprofloxacin by NiS-coupled WO3 nanorods synthesized by solvothermal method under visible light

Photocatalytic oxidation of antibiotics over semiconducting nanostructured photocatalysts is stared as a capable procedure for preventing possible antimicrobial resistance. Accordingly, plenteous research suggestions for photocatalyst design and trials are investigated to realize this approach. Moreover, photostability and reusability are important factors for sustainable utilization. Herein, tungsten trioxide (WO₃) nanorods were grown by a solvothermal route in the presence of double soft templates, followed by incorporating nickel sulfide (NiS) nanoparticles on their surface to have NiS/WO₃ nanocomposite photocatalysts. These formed heterojunctions were analyzed via several tools. The NiS incorporation has widened the visible-light harvesting owing to the bandgap reduction from 2.82 eV for pure WO₃ to 2.40 eV at 9 wt% of NiS. The mesoporous surface has not been meaningfully impacted by incorporating NiS with a value of the surface area between 163 and 189 m² g^-1. The photooxidation of ciprofloxacin (CiP) over the formed photocatalysts were done under visible-light irradiation. The 2.0 g L^-1 of 9% NiS/WO₃ has completely oxidized 30.2 μmol CiP at a 1.38 μmol min⁻¹. This progressive NiS/WO₃ p-n heterojunction has also implied reusability for five repetitive cycles. This excellent photoactivity is ascribed to the charge transfer by the S-scheme mechanism and the synergistic upshot of a particular NiS expanse.     

Boron nitride based polyaniline nanocomposite: Preparation,property, and application

In this study, we report first time the electrical properties and photocatalytic activity of HCl doped polyaniline (Pani) and Pani/boron nitride (Pani/BN) nanocomposite prepared by in situ polymerization of aniline using potassium persulfate (K₂S₂O₈) in the presence of hexagonal boron nitride (h‐BN). The prepared Pani and Pani/BN nanocomposite were characterized by Fourier transform infrared, X‐ray diffraction, Thermogravimetric analysis, Scanning electron microscope, and Transmission electron microscope. The stability of the Pani/BN nanocomposite in comparison of Pani in terms of the DC electrical conductivity retention was investigated under isothermal and cyclic aging conditions. The Pani/BN nanocomposite in terms of DC electrical conductivity was observed to be comparatively more thermally stable than Pani. The degradation of Methylene blue (MB) and Rhodamine B (RhB) under UV‐light irradiation were 50 and 56.4%, respectively, over Pani and 65.7 and 71.6%, respectively, over Pani/BN. The results indicated that the extent of degradation of MB and RhB was greater over nanocomposite material than Pani, which may result due to high electron–hole pairs charge separation under UV light. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43989.     

Dodecylbenzenesulfonic acid micelles assisted in situ preparation and enhanced thermoelectric performance of semiconducting polyaniline–zirconium oxide nanocomposites

Herein, we report in situ preparation of dodecylbenzenesulfonic acid (DBSA) micelles assisted polyaniline (Pani)/zirconium oxide (ZrO₂) nanocomposites (Pani/ZrO₂) by using K₂S₂O₈ as an oxidizing agent. Thus prepared nanocomposites were characterized by SEM, FTIR, XRD and UV–vis spectrophotometry. DBSA acted as dopant/surfactant, and the incorporation of ZrO₂ nanoparticles improved the stability, electrical and thermal properties of nanocomposites. From the results of UV–vis absorbance it was observed that Pani/ZrO₂ nanocomposite was more stabilized under UV light than Pani. DC electrical conductivity retention was studied by isothermal and cyclic ageing techniques and was observed to be better than Pani under ambient environmental conditions.     

Poly(BMA-co-NVP)/NiS core-shell hybrid materials via Interfacial-initiated miniemulsion copolymerization and gamma-irradiation

In this work, N-butyl methacrylate (BMA)/N-vinyl-2-pyrrilidone (NVP) amphiphilic core-shell nanoparticles were successfully prepared via miniemulsion copolymerization, the emulsion was initiated by the redox initiation couple of cumene hydroperoxide (CHPO) and ferrous sulfate hydrate (FS). The synthetic waterborne polyurethane (WPU) was used as surfactant and hexadecane (HD) as co-stabilizer, respectively. FTIR and XPS were used to confirm the occurrence of copolymerization between two monomers. TEM and DLS were used to observe the particle morphology and determine the particle size and its polydispersity index (PDI). It was found that the core-shell poly(BMA-co-NVP) nanoparticles prepared via interfacial-initiated miniemulsion copolymerization (IMEP) had relatively small diameters (40–120 nm) and narrowly particle size distribution (0.066–0.243). Only about 2 wt% surfactants based on the solution was enough to prepare a stable miniemulsion. The results demonstrated that IMEP prompted the copolymerization of water-soluble NVP monomer with oil-soluble BMA monomer to form core-shell nanoparticles. The effects of surfactant and co-stabilizer affect on the miniemulsion copolymerization were discussed. All the results indicate that the fabrication amphiphilic core-shell nanoparticles via IMEP were successful. Then the poly(BMA-co-NVP)/NiS hybrid materials were fabricate via the reaction of NiSO₄ and CH₃CSNH₂ on the copolymers surface under ⁶⁰Co γ-irradiation at room temperature and ambient pressure. The hybrid materials were characterized by FESEM.     

Hydroxy Acid-Assisted Synthesis of Highly Dispersed Ni-NiS on CdS as Effective Photocatalyst for Hydrogen Evolution

To achieve the well-dispersed Ni–NiS dual-cocatalysts anchored CdS, the samples have been successfully constructed by a cheap and convenient method of hydroxy acid assisted hydrothermal method. Based on the coordination and reduction effects of hydroxy acids, Ni²⁺ can be facilely transformed into the high dispersed dual-function sites of Ni⁰ electrons trap and NiS holes reservoir. The highly dispersed Ni–NiS dual-cocatalysts not only provide more dual-function active sites but also present distinctly enhanced visible light absorption, effectively separated electron hole pairs and quickly migrated charge carriers. The optimized Ni–NiS/CdS–CA presented an excellent photocatalytic H₂ generation rate of 57.88 mmol·h^?1·g^?1, which is about 15.35 times higher than that of NiS/CdS. Moreover, the stability can be distinctly increased by modulating the surface cover of Ni–NiS with a suitable Ni/(Ni?+?Cd) atomic ratio. This work would provide a unique strategy to design the high effective photocatalysts with high dispersed bi-function dual cocatalysts.

Graphic Abstract

The well-dispersed Ni-NiS dual-cocatalysts anchored CdS in situ have been successfully constructed via the coordination and reduction effects of hydroxy acid assisted hydrothermal method. Ni-NiS/CdS-CA not only presents dual-function active sites but also exhibits distinctly enhanced visible light absorption, effectively separated electron hole pairs and quickly migrated charge carriers, resulting in a remarkable enhancement in photocatalytic H2 evolution activity.

     

Honeycomb-like NiCo2O4@Ni(OH)2 supported on 3D N−doped graphene/carbon nanotubes sponge as an high performance electrode for Supercapacitor

In order to increase the energy density of supercapacitor, a new kind electrode material with excellent structure and outstanding electrochemical performance is highly desired. In this article, a new type of three-dimensional (3D) nitrogen-doped single-wall carbon nanotubes (SWNTs)/graphene elastic sponge (TRGN?CNTs?S) with low density of 0.8 mg cm^?3 has been successfully prepared by pyrolyzing SWNTs and GO coated commercial polyurethane (PU) sponge. In addition, high performance electrode of the honeycomb-like NiCo₂O₄@Ni(OH)₂/TRGN-CNTs-S with core-shell structure has been successfully fabricated through hydrothermal method and then by annealing treatment and electrochemical deposition method, respectively. Benefited from 3D structural feature, the compressed NiCo₂O₄@Ni(OH)₂/TRGN-CNTs-S electrode exhibits high gravimetric and volumetric capacitance of 1810 F g^?1, 847.7 F cm^?3 at 1 A g^?1. The high rate performance and long-term stability was also obtained. Furthermore, an asymmetric supercapacitor using NiCo₂O₄@Ni(OH)₂/TRGN-CNTs-S cathode and NGN/CNTs anode delivered high gravimetric and volumetric energy density of 54 W h kg^?1 at 799.9 W kg^?1 and 37 W h L^?1 at 561.5 W L^?1. In summary, an excellent electrochemical electrode with new elastic 3D SWNTs/graphene supports and binder free pseudocapacitive materials was introduced.     

Synthesis and Characterization of Low-Cost Electroactive Hybrid Composites Derived From Polyaniline and NiS

The synthesis and characterization of conducting polyaniline (PANI) salt and nickel sulfide (NiS) hybrid composites are reported in this study. The PANI-NiS hybrid composites showed nearly two orders of magnitude higher than that of pure PANI. The specific conductivities of PANI and PANI-NiS hybrid composites (2% and 20% by weight) were found to be 5.1 × 10^?4, 1.6 × 10^?2, and 3.8 × 10^?2 S/cm. The polarity of Hall voltage of the hybrid composite was found to be negative indicating that the PANI-NiS composite is an n-type semiconductor. The composites pellets were characterized by XRD, SEM and FTIR and the results were compared.     

Synthesis and enhanced supercapacitor performance of carbon self-doping graphitic carbon nitride/NiS electrode material

The thermal oxidation carbon self-doped graphitic carbon nitride/NiS (TC-g-C₃N₄/NiS) composites with high electrochemical performance were synthesized by combining nickel sulfide with carbon self-doping carbon nitride through a hydrothermal method. The graphitic carbon nitride (g-C₃N₄) could improve charge fluidity by carbon self-doping process, and be etched by further heat treatment, which provides conditions for the introduction of NiS particles. NiS particles uniformly adhered to the layers of g-C₃N₄, thus avoiding particle aggregation. The as-prepared active composite maintains high specific capacitance (1162 F/g at the current density of 1 A·g⁻¹) and shows great cycle stability (capacitance retention rate of 82.0% after 8000 cycles). The conductivity of active composite has also been improved. Moreover, the assembled TC-g-C₃N₄/NiS//AC exhibit a relatively high-energy density of 27 Wh/kg and exhibits excellent cycling performance with a capacity retention rate of 87.9% after 8000 cycles. Hence one can see that TC-g-C₃N₄/NiS composites have broad application prospects in the field of supercapacitors.