Nickel Sulphide Nanoparticles Research Articles

Effective OER activity of rhombohedral nickel sulphide nanoparticles supported via reduced graphene oxide

Excessive utilization of fossil fuels is causing significant environmental contamination and energy loss, which has become a major problem today. Thus, there is a growing demand for green energy storage sources, such as water splitting, to address these energy concerns. Hydrogen gas is an economical and environmentally friendly energy source. It is produced from water and is known for being carbon-free. However, in current years, metal sulfides have gained significant interest as an efficient alternative to noble-metal-catalysts due to their capability to contribute to the oxygen evolution reaction (OER). The current work uses a hydrothermal approach to produce NiS/rGO nanocomposite, which is advantageous for commercial applications. It showed higher catalytic efficiency, low cost and convenient accessibility, which improves OER. The efficient fabrication and use of NiS/rGO nanocomposite material were confirmed and evaluated via several analysis approaches, such as XRD, SEM and BET, which showed unique structure, morphology and increased surface area. Furthermore, higher active regions provide a synergistic effect and the composite showed a significantly decreased over-potential (162 mV) at (10 mA/cm2) current-density (j) possessing a Tafel plot (32 mV/dec) for OER in 1 M KOH. The composite showed more active regions and more significant surface area potential for charge transfers due to its distinct structure, which makes the material more stable (40 h). By integrating carbon-based reduced graphene oxide (rGO) into oxygen-deficient NiS, the poor conductivity of the material may be enhanced. This improvement is shown by the low Rct (0.07 Ω) value measured via electrochemical impedance spectroscopy (EIS). The greater surface area (2852.5 cm2) at different scan rates (10–40 mV/s), is evidenced by ECSA measurement. Therefore, research indicates that combining a specific metal sulphide and reduced graphene oxide (rGO) can potentially improve electrocatalyst functionality and make it a feasible choice for OER applications in future due to its cost-effectiveness.

Phase transition in nickel sulphide nanoparticles

ABSTRACT The NiS nanoparticles were synthesised by the microwave-assisted chemical precipitation method. The XRD pattern shows that the prepared NiS nanoparticles have an orthorhombic structure. The SEM image of NiS nanoparticles confirms the nanostructure. The energy-dispersive X-ray analysis confirms the existence of Nickel and Sulphur in a proper ratio. The D.C. electrical resistances were measured in the temperature range 300 K–500 K. Oscillations were found in the temperature resistance curve of Nickel Sulphide nanoparticles on repeated heating and cooling due to phase transition. The XRD pattern of the powdered form of the NiS pellet used for the resistance measurement also confirms this phase transition. The two forms of UV and PL spectra of NiS nanoparticles were studied.

Facile One-Step Synthesis of Nickel Sulphide Nanoparticles Decorated Poly (Acrylic Acid) Coated Multi-Walled Carbon Nanotube for Detection of Tenofovir in Human Urine

Facile One-Step Synthesis of Nickel Sulphide Nanoparticles Decorated Poly (Acrylic Acid) Coated Multi-Walled Carbon Nanotube for Detection of Tenofovir in Human Urine

Roles of TOPO Coordinating Solvent on Prepared Nano-Flower/Star and Nano-Rods Nickel Sulphides for Solar Cells Applications.

The present study describes a cheap, safe, and stable chemical process for the formation of nickel sulphide (NiS) with the use of mixed and single molecular precursors. The production pathway is uncomplicated, energy-efficient, quick, and toxic-free, with large-scale commercialization potential. The obtained results show the effect of tri-N-octylphosphine oxide (TOPO) as a coordinating solvent on the reaction chemistry, size distributions, morphology, and optical properties of both precursors. Ni[N,N-benz-N-p-anisldtc] as NiSa, Ni[N,N-benzldtc] as NiSb, and Ni[N-p-anisldtc] as NiSc thermally decompose in a single step at 333–334 °C. The X-ray diffraction peaks for NiSa, NiSb, and NiSc matched well with the cubic NiS nanoparticles and corresponded to planes of (111), (220), and (311). The extrapolated linear part from the Tauc plots reveals band gap values of 3.12 eV, 2.95 eV, and 2.5 eV, which confirms the three samples as potential materials for solar cell applications. The transmission electron microscopy (TEM) technique affirmed the quantum dot size distribution at 19.69–28.19 nm for NISa, 9.08–16.63 nm for NISb, and 9.37–10.49 nm for NISc, respectively. NiSa and NiSc show a clearly distinguishable flower/star like morphology, while NiSb displays a compact nano-rod shape. To the best of the authors’ knowledge, very few studies have been reported on the flower/star like and nano-rod shapes, but none with the dithiocarbamate molecular precursor for NiS nanoparticles.

Impact of iron doping on structural and optical properties of nickel sulphide nanoparticles

Transition metal sulphides exhibit excellent optical, photo electrical and thermoelectric properties. These materials have attracted much attention because of its applications in the field of electroluminescence devices, light emitting displays, cathode material for rechargeable lithium battery, magnetic devices, dye degradation and optical sensors. In the present work, iron doped Nickel sulphide nanoparticles are synthesized using chemical precipitation method. Nickel chloride and Ferric chloride are used as precursors and sodium sulphide as a stabilizing agent. The performance of the synthesized nanoparticles are analysed by varying the molarity of the iron chloride from 0.01 M to 0.05 M. The synthesized nanoparticles are characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Ultraviolet Visible spectroscopy (UV–Vis) and Photoluminescence (PL) studies. FT-IR spectral analysis shows the band at 630 cm−1 corresponds to the bending vibration of metal sulphur bond (Ni-S) and the bands observed around 585 cm−1 and 456 cm−1 are ascribed to Fe–O stretching vibrations of tetrahedral and octahedral lattice sites respectively. The XRD analysis shows the crystalline nature of nanoparticles and the average nano-crystallite size is found to be 18 nm − 26 nm. The crystallite size increases with increase in the concentration of iron. The morphology of the samples is analyzed using scanning electron microscope and is found to be spherical in shape. The optical properties are characterized using UV–Vis spectral analysis and PL study. UV–Visible absorption spectra show absorption peaks of iron doped nickel sulphide nanoparticles and the band exhibits a blue shift, indicates quantum size effect. Electrochemical studies revealed two oxidation peaks at a potential about −0.3 V and 0.7 V for pure nickel sulphide nanoparticles and in addition to it, a redox peak is observed at a potential about −0.5 V due to the doping of iron into the nickel sulphide nanoparticles. The synthesized nanoparticles may be used as high-performance electrode materials for supercapacitor applications.

Electrochemical studies of synthesized nickel sulphide nano-particles

Ni7S6 has been synthesised using solvo-thermal route, ethylene diamine (C2H4(NH2)2) and ethylene glycol ((CH2OH)2) were used as solvent. Structural and morphological properties of the prepared sample were studied by X-ray diffractometer (XRD) and Field emission scanning electron microscope (FESEM).Crystallite size of the synthesised sample is 26 nm. Energy band gap of the Ni7S6 is 2.93 eV which was calculated from the ultraviolet–visible spectrometer technique. Electro-chemical properties of the synthesized Ni7S6 were studied by Nqyuist plot and cyclic Voltammetry technique. The measured parameters of the synthesized Ni7S6 indicates that Ni7S6 is the promising electrode material for energy conversion and storage devices.

Fabrication of electrospun nickel sulphide nanoparticles onto carbon nanofibers for efficient urea electro-oxidation in alkaline medium

To design and synthesize a noble-metal free electrocatalyst with increased efficiency and stability during urea electro-oxidation in alkaline solution is still an important challenge in the electrocatalytic field. In this work, carbon nanofibers were decorated with nickel sulphide nanoparticles [NiS@CNFs] through the electrospinning technique with subsequent heating into an argon atmosphere at 900 °C for 2 h. This formed nanomaterial was extensively characterized through X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), Raman spectroscopy and N2 adsorption-desorption measurements. A conductive network of intertwined CNFs was clearly detected by FE-SEM analysis technique with varied diameters in the range of 0.6–1 μm. A highly porous nature could be suggested after incorporating NiS nanospecies resulting in increased specific surface area and valuable electrocatalytic activity for urea molecules electro-oxidation. The pore size distribution curves showed a decreased average pore diameter for NiS@CNFs nanocomposite by 2.53 folds when compared to that at CNFs. The electroactivity of NiS@CNFs nanomaterial for catalyzing urea electro-oxidation was investigated using cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy measurements. Increased activity of this nanocatalyst was registered when urea molecules were added in increased concentrations into KOH solution. Lowered resistance values were also obtained describing the charge transfer process to confirm the feasibility of the studied reaction at NiS@CNFs surface. Moreover, its drawn chronoamperogram showed a stable performance during operation for long periods revealing a lowered catalytic decay. Accordingly, the aforementioned results of our fabricated nanomaterial could provide a good guide for fabricating suitable electrocatalysts for various electrocatalytic purposes.

Synthesis, characterization, and cyclic voltammetry of nickel sulphide and nickel oxide nanoparticles obtained from Ni(II) dithiocarbamate

Nickel sulphides and nickel oxides nanoparticles have been synthesized from Ni(II) bis (N-alkyl-N-ethanoldithiocarbamate), represented as NiL12 (L1, with methyl group) and NiL22 (L2, with ethyl group). Both complexes were characterized using Fourier transform infra-red (FTIR), nuclear magnetic resonance spectroscopy and elemental analysis. The sulphides were prepared by solvothermal route in hexadecylamine, and X-ray diffraction analyses revealed that Heazlewoodite Ni3S2 and hexagonal α-NiS1.19 were the phases obtained from compounds NiL12 and NiL22 respectively. The nickel oxides nanoparticles were synthesized via calcination process in air, and presented as NiO1 and NiO2 of which both oxides are Bunsenite phase. The optical and morphology of the nanoparticles were studied using UV–visible spectroscopy and transmission emission microscopy (TEM) techniques. Cyclic voltammetry (CV) and impedance spectroscopy were used for their electrochemical evaluation in 1 M NaOH solution. The Au/NiO2 modified electrode was more electroactive and displayed faster electron transport at the electrode surface than the bare Au and Au/NiO1 electrodes. The modified Au/NiS electrode, showed poor voltammogram which could be due to the poor interaction between the nanoparticles and the electrolyte solution, while the CV of uncapped NiS showed redox peak with oxidation peak potential at 0.36 V and the reduction peak potential at 0.30 V.

Trisodium citrate assisted morphology controlled synthesis of nickel sulphide nanoparticles with enhanced cyclic stability as carbonaceous free electrode material

Facile hydrothermal route is used for the synthesis of β-NiS nano-particles under the influence of trisodium citrate and ammonia. Trisodium citrate anions act as shape modifier for controlling the growth of β-NiS nano-particles and ammonia acts as reducing agent,which eliminates the different phase of nickel sulphide such as, α-NiS, NiS2, Ni3S2, Ni7S6, etc. Rietveld refinement of the XRD data affirms the single phase formation of β-NiS and its crystal structure is Rhombohedral. Morphology of β-NiS nanoparticles strongly depends upon the concentration of trisodium citrate. Pompon like structure was observed only when the molar ratio of nickel nitrate and trisodium citrate taken was 1:0.5. Increase in concentration of trisodium citrate results in formation of different morphologies which are observed in FESEM images. Growth mechanism of 3-D pompon like structure and its growth mechanism are discussed in detail. Morphology of the synthesized β-NiS nanoparticles influences the electrochemical properties. Electrochemical properties had been studied using Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS), cyclic stability. Carbonaceous material was not used during the fabrication of working electrode for electrochemical characterization. Pompon β-NiS showed 88% capacitive retention over 1000 CV cycles with charge transfer (Rct) resistance 4.32 Ω. Pompon like β-NiS offers the extra conductive paths, increase electron transport rate, specific direction for electron carriers. It helps to provide easy path for electrolyte ions as well as large active surface area with more Faradaic sites which enhance the diffusion rate, during redox process. Textural properties were studied by FTIR and BET. BET analysis revealed that synthesized β-NiS is mesoporous material. These results manifest that synthesized β-NiS nanoparticles, are potential for electrode for electrochemical devices such as, lithium ions batteries, pseudocapacitors, etc.

Enhanced dielectric properties of green synthesized Nickel Sulphide (NiS) nanoparticles integrated polyvinylalcohol nanocomposites**This work was presented at the 2nd International Conference on Nanoscience and Nanotechnology (ICNAN’19)’ at VIT University, Vellore (India) from 29th Nov–1st Dec. 2019. Chairman: Prof. A. Nirmala Grace.

A green synthesis approach has been adopted to prepare nickel sulphide nanoparticles (NiS NPs) using banana peel extract (BPE) as a reducing and capping agent. Polyvinyl alcohol (PVA)/NiS nanocomposite films were fabricated using a cost-effective solution casting technique by dispersing different contents of NiS NPs (0–3 wt%) in the PVA matrix. Various characterization techniques were employed to analyze the structural, thermal and morphological properties of the PVA/NiS nanocomposite films. Further, the dielectric behaviour of these nanocomposite films was investigated at frequency range 50 Hz–20 MHz and in the temperature range 40 °C–140 °C. Also, there exists a significant interaction between the polymer matrix and the nanofiller as evident from the notable improvement in the dielectric properties of the nanocomposites. The dielectric constant (ε) value of PVA/NiS nanocomposite film with 3 wt % NiS NPs loading was found to be 154.55 at 50 Hz and at 140 °C which is 22 times greater than the dielectric constant value of neat PVA (6.90). These results suggest that NiS NPs were dispersed homogeneously in the PVA matrix.

Nickel sulphide nano-composite assisted hole transport in thin film polymer solar cells

Nickel sulphide (NiS) nano-composite were synthesized and used as dopant in the hole transport layer of the thin film organic solar cell (TFOSC). The nano-particles are intended to assist in the charge transport processes at the interface between the active layer and the anode. Thin film solar cells were fabricated using photo-active layer composed of poly-3-hexylthiophene (P3HT) and (6-6) phenyl-C61-butyric acid methyl ester (PCBM) blend. The solar cells employed NiS doped PEDOT:PSS hole transport layer (HTL) which are investigated in terms of changes in optical and electrical properties of the films. The electrical properties of the newly fabricated solar cells showed significant improvement in photo-generated current as the result of reduced charge carrier recombination and enhanced charge transport processes at the interface. This in turn boost the power conversion efficiency (PCE) of the devices by 95% compared to the devices without NiS doped HTL. The observed PCE enhancement is attributable to the excitation of the localized surface plasmon resonance exhibited by the presence of NiS in hole transport layer. It is noted in the investigation that the performance of the solar cell is dependant on the concentration of NiS nano-particles in PEDOT:PSS layer. As consequence, the highest recorded PCE in this study was 6.03% at 0.1% NiS by weight, which is encouraging result for device fabrication in ambient laboratory condition.

A full-spectrum-absorption from nickel sulphide nanoparticles for efficient NIR-II window photothermal therapy.

Near-infrared (NIR) light has been widely applied in the field of photothermal therapy (PTT). Recent advances in the light wavelength for efficient cancer PTT have gradually shifted from the first NIR (NIR-I) biowindow (700-1000 nm) to the second NIR (NIR-II) biowindow (1000-1350 nm) owing to its intrinsic deeper tissue penetration ability and a higher maximum permissible exposure (MPE) value. Herein, we have prepared nickel sulphide (Ni9S8) nanoparticles (NPs) with a full-spectrum-absorption (400 nm-1100 nm) in the NIR region. By a fair comparison, it is found that the PTT using the NPs upon irradiation from an NIR-II (i.e., 1064 nm) laser is more efficient than that from an NIR-I (i.e., 808, 915, and 976 nm) laser. The large mass extinction coefficient value (22.18 L g-1 cm-1) and high photothermal conversion efficiency (46%) at 1064 nm make these NPs promising candidates for NIR-II photo-thermal therapy. This study will benefit future exploration and optimization of nickel-based photoabsorbers utilizing NIR-II light for photothermal applications.

Nickel Sulfide Nanoparticles Incorporated Poly(methyl methacrylate)-Zirconia Membranes for Ultra Deep Desulfurization of Dibenzothiophene

AbstractUltra deep desulfurization of liquid fuels such as gasoline/diesel has attracted considerable attention of modern clean fuel research due to strict environmental regulations. Apart from that, SOx produced during combustion, poison the catalytic converter and exhaust emission system. Comparing to conventional catalytic and hydrodesulfurization techniques, adsorptive method for removal of sulfur bearing compounds e.g. thiophene derivatives is a promising approach which does not require hydrogen gas and high temperature. In this study, we used nickel sulfide nanoparticles incorporated poly(methyl methacrylate)-zirconia membranes as potential affinity material for adsorptive extraction of dibenzothiophene from n-hexane. The functionality and surface morphology of synthesized material was examined by Fourier transformation infrared (FTIR) spectroscopy and atomic force microscopy (AFM) images, respectively. The quantitative data regarding adsorptive removal of dibenzothiophene was determined by monitoring the shift in absorbance values of standard solutions before and after treating with synthesized material under ambient conditions. Nickel sulphide nanoparticles exhibited suitable rebinding response for removal of dibenzothiophene down to 1 ppm due to affinity interactions which is useful concerning ultra deep desulfurization. Finally, nickel sulphide nanoparticles were incorporated in poly(methyl methacrylate)-zirconia membrane which showed potential application for adsorptive desulfurization of dibenzothiophene at ambient conditions.

Nickel sulphide-carbon composite hole transporting material for (CH3NH3PbI3) planar heterojunction perovskite solar cell

The present work reports about the low-cost inorganic nickel sulphide-carbon composite synthesized using the simple chemical method and to be used as hybrid hole extraction and as a counter electrode material for perovskite (CH3NH3PbI3)-based solar cells (PSCs). The structural analysis confirms the existence of nickel sulphide (NiS) crystalline phase composed of small-sized crystallites. The optimal bandgap values of the prepared perovskite (1.51 eV) and NiS (3.71 eV) materials found to be favorable in achieving the active absorbing and hole extraction properties in PSCs. The surface morphology of the nickel sulphide materials is found to be highly dependent on the NiS-carbon composition. The current density-voltage (J-V) results of the fabricated perovskite solar cells with nickel sulphide-carbon composite hole transporting layer (HTL) suggests that incorporation of commercial carbon paste into the nickel sulphide nanoparticles tends to promote the charge carrier transporting ability and resulted in yielding high power conversion efficiency (PCE) of 5.20%, when compared to that of the bare NiS (1.87%). The results show that this nickel sulphide-carbon composite can serve as an efficient dual role as an HTL to transport holes and as a conductive counter electrode for the planar heterojunction PSCs with the structure FTO/compact-TiO2/porous-TiO2/perovskite/NiS-carbon. So, nickel sulphide-carbon composite can be considered as an efficient replacement for the other unstable HTMs and high-cost metal counter electrodes used in PSCs.

Synthesis and characterization of homoleptic group 10 dithiocarbamate complexes and heteroleptic Ni(II) complexes, and the use of the homoleptic Ni(II) for the preparation of nickel sulphide nanoparticles

A series of new dithiocarbamate complexes of Ni(II), Pd(II) and Pt(II) of the form [NiL2], [PdL2] and [PtL2] (where L = N-ethyl-N-ethanoldithiocarbamate) have been synthesized and characterized by elemental analysis, FTIR, and 1H and 13C NMR spectroscopy. The nickel complex was utilized to prepare heteroleptic complexes bearing triphenylphosphino (PPh3) and isothiocyanate (NCS) or isocyanide (NC) molecules. Furthermore, the structures of the palladium complex and the heteroleptic nickel with PPh3 and NC molecules have been confirmed by X-ray diffraction. The Pd(II) complex indicated a trans arrangement with a distorted square planar geometry around the Pd atom, while the Ni(II) complex revealed a highly distorted geometry with another molecule of triphenylphosphine moiety, held by hydrogen bonding, within the crystal structure. The thermal stability studies of all the complexes conducted by using thermogravimetric analyser (TGA) showed they all have good stability above 200 °C. The nanoparticles synthesized using the homoleptic nickel complex yielded platelets of pure Heazlewoodite phase of Ni3S2 with average size of 7.60 nm. The optical properties of the nanoparticles studied by using UV–vis spectroscopy showed band gap energy of 4.0 eV (355 nm), which was a blue shift of 1.90 eV compared to the bulk and a consequence of quantum confinement effect.

Syntheses and characterization of nickel(II) dithiocarbamate complexes containing NiS4 and NiS2PN moieties: Nickel sulphide nanoparticles from a single source precursor

In this study, ammonium N-benzyldithiocarbamate was synthesized and used to prepare homoleptic Ni(II) bis(N-benzyldithiocarbamate) (1) and heteroleptic Ni(II) complexes involving isocyanate (2) and cyanide (3) ions. The complexes were characterized by elemental analysis, Fourier transform infra-red (FTIR), and NMR (1H and 13C) spectroscopic techniques. Complex 2 was further characterized by single crystal X-ray diffraction analysis. The FTIR showed bidentate co-ordination for all the complexes as the v(CN) stretching frequency were in the 980–1050cm−1 region without any splitting. Thermal decomposition profile of the complexes showed decomposition resulting in the formation of nickel sulphides. The homoleptic complex 1 was utilized as single source precursor (SSP) to prepare Nickel sulphide nanoparticles. The synthesis of the nanoparticles was conducted using different capping molecules (with various alkyl chain lengths), and at different reaction temperature and time. Pure phase Heazlewoodite (Ni3S2) nanoparticles were obtained from the X-ray diffraction study. The TEM analysis showed that the type of capping agent, reaction temperature, and time of reaction have significant effect on the morphology and size of the nanoparticles. The optical properties of the nanoparticles were studied using absorption and fluorescence spectroscopies, and they displayed evidence of quantum confinement effect.

Synthesis of Tunable Band Gap Semiconductor Nickel Sulphide Nanoparticles: Rapid and Round the Clock Degradation of Organic Dyes.

Controlled shape and size with tuneable band gap (1.92–2.41 eV), nickel sulphide NPs was achieved in presence of thiourea or thioacetamide as sulphur sources with the variations of temperature and capping agents. Synthesized NPs were fully characterized by powder XRD, IR, UV-vis, DRS, FE-SEM, TEM, EDX, XPS, TGA and BET. Capping agent, temperature and sulphur sources have significant role in controlling the band gaps, morphology and surface area of NPs. The catalytic activities of NPs were tested for round the clock (light and dark) decomposition of crystal violet (CV), rhodamine B (RhB), methylene blue (MB), nile blue (NB) and eriochrome black T (EBT). Agitation speed, temperature, pH and ionic strength have significant role on its catalytic activities. The catalyst was found to generate reactive oxygen species (ROS) both in presence and absence of light which is responsible for the decomposition of dyes into small fractions, identified with ESI-mass spectra.

Novel Method to Synthesize Conducting Polyaniline/nickle Sulphide Nanocomposite Films and the Study of their Structural and Electrical Properties

Different methodologies and routes have been adopted to enhance compatibility and applications of conjugated polymers since two decades. In this project we have adopted a novel method to synthesize polyaniline nanocomposite films with different weight percentages of nickel sulphide nanoparticles. These nanocomposite films were than subjected to various characterizations such as X-ray diffraction analysis, scanning electron microscopy (SEM), and standard four probe method to study the effect of various weight percentages of nanoparticles on structural and electrical properties.