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Herein, the synthesis of three nickel(II) dithiophosphonate complexes of the type [Ni{S2 P(OR)(4-C6 H4 OMe)}2 ] [R=H (1), C3 H7 (2)] and [Ni{S2 P(OR)(4-C6 H4 OEt}2 ] [R=(C6 H5 )2 CH (3)] is described; their structures were confirmed by single-crystal X-ray studies. These complexes were subjected to surfactant/solvent reactions at 300 °C for one hour as flexible molecular precursors to prepare either nickel sulfide or nickel phosphide particles. The decomposition of complex 2 in tri-octylphosphine oxide/1-octadecene (TOPO/ODE), TOPO/tri-n-octylphosphine (TOP), hexadecylamine (HDA)/TOP, and HDA/ODE yielded hexagonal NiS, Ni2 P, Ni5 P4 , and rhombohedral NiS, respectively. Similarly, the decomposition of complex 1 in TOPO/TOP and HDA/TOP yielded hexagonal Ni2 P and Ni5 P4 , respectively, and that of complex 3 in similar solvents led to hexagonal Ni5 P4 , with TOP as the likely phosphorus provider. Hexagonal NiS was prepared from the solvent-less decomposition of complexes 1 and 2 at 400 °C. NiS (rhom) had the best specific supercapacitance of 2304 F g-1 at a scan rate of 2 mV s-1 followed by 1672 F g-1 of Ni2 P (hex). Similarly, NiS (rhom) and Ni2 P (hex) showed the highest power and energy densities of 7.4 kW kg-1 and 54.16 W kg-1 as well as 6.3 kW kg-1 and 44.7 W kg-1 , respectively. Ni5 P4 (hex) had the lowest recorded overpotential of 350 mV at a current density of 50 mA cm-2 among the samples tested for the oxygen evolution reaction (OER). NiS (hex) and Ni5 P4 (hex) had the lowest overpotentials of 231 and 235 mV to achieve a current density of 50 mA cm-2 , respectively, in hydrogen evolution reaction (HER) examinations.

Nonprecious water oxidation electrocatalysts that perform well at high current densities are among the key enabling drivers of renewable energy technologies. Herein, we report a novel strategy to produce 3D ultrasmall zero‐valent iron‐coupled nickel sulfides nanosheets (Fe0−NixSy) hybrid on self‐supported conductive Ni foam (denoted as Fe0−NixSy/NF) through a robust single‐step gas–solid reaction. In this 3D hybrid, the Fe0−NixSy nanosheets with a length of approximately 400 nm and an average thickness of 33 nm are uniformly grown on the Ni foam. Benefiting from the unique 3D hierarchical structure and synergistic effect between Fe0 and NixSy, the 3D Fe0−NixSy/NF hybrid shows an excellent electrocatalytic activity towards oxygen evolution reaction (OER) at extremely high current densities in basic media. The current densities of 1000 and 1500 mA cm−2 are achieved at low potentials of 1.57 and 1.60 V, respectively, thus meeting the expected OER standards for industrial applications. These overpotentials of the 3D Fe0−NixSy/NF hybrid are the lowest among all previously reported nickel‐sulfide‐based electrocatalysts, and are even superior compared to state‐of‐the‐art Ir/C catalysts. We further demonstrate that the integration of the 3D Fe0−NixSy/NF electrocatalyst as both anode and cathode with a silicon photovoltaic cell enables highly active and sustainable solar‐driven overall water splitting.

Photocatalytic cellulose reformation is regarded as a potential and affordable route for sustainable H2 evolution. However, direct photoreformation still suffers from challenges such as the limited solubility of cellulose and the dependence on the catalytic activity of noble metals. Herein, we report a new photoreformation of cellulose into H2 over TiO2 that is modified with nickel sulfide (Nix Sy ) and chemisorbed sulfate species (SO42- ) by a one-pot approach. A significant elevation in the photocatalytic hydrogen evolution rate is achieved with a maximal value of 3.02 mmol g-1 h-1 during the first 3 h, which is almost 76-fold higher than that of P25 and comparable to that of Pt-P25. Aided by systematic investigation, it is proposed that nickel sulfide and sulfate modification contribute synergistically to the remarkably increased efficiency of biomass transformation. Specifically, Nix Sy acts as a cocatalyst for photocatalytic H2 production, and we infer that SO42- ions promote cellulose hydrolysis and the consequent accessibility of the biomass to catalysts. Further, the accumulated formate intermediates have a poisoning effect on the catalysts, the desorption of which can be controlled by tuning the aqueous alkalinity. Overall, our strategy for the modification of TiO2 with SO42- and Nix Sy provides a new perspective for the concurrent acceleration of cellulose hydrolysis and increase of the number of hydrogen evolution sites for the efficient photocatalytic reformation of cellulose into H2 .

It remains challenging to develop alternatives, based on widely abundant elements, to highly active Pt catalysts for the hydrogen evolution reaction. Metal sulfide nanoparticles (NPs) are potential candidates for such catalysts because of their metallic features and intrinsic high surface area; however, their poor electrocatalytic activity, owing to the presence of surface ligands, is an obstacle to practical use. Here we report the selective synthesis of oleylamine (OAm)-stabilized Ni₃S₄ (Ni₃S₄/OAm) NPs. The insulating ligands were exchanged with S²¯ and loaded on electrodes by a layer-by-layer (LbL) assembly method with metal cation linkers. The enhanced catalytic properties were confirmed by electrochemical measurements. A LbL assembled film with Ni²+ as a linker (11 cycles) showed an overpotential of 555 mV@-4 mA/cm² at pH 6.8 and a stable current density for 12 h. In addition, when this LbL assembly method was applied to a CdS/Cu(In,Ga)Se₂ photocatalyst electrode, the resulting photoelectrode showed an enhanced photocurrent compared with that of the Ni₃S₄/OAm NPs-spin coated and bare photoelectrodes. These results indicate the versatility of LbL assembly for fabrication of ligand-free NP electrocatalyst films.

Polymer electrolyte membranes employed in contemporary fuel cells severely limit device design and restrict catalyst choice, but are essential for preventing short‐circuiting reactions at unselective anode and cathode catalysts. Herein, we report that nickel sulfide Ni[subscript 3]S[subscript 2] is a highly selective catalyst for the oxygen reduction reaction in the presence of 1.0 m formate. We combine this selective cathode with a carbon‐supported palladium (Pd/C) anode to establish a membrane‐free, room‐temperature formate fuel cell that operates under benign neutral pH conditions. Proof‐of‐concept cells display open circuit voltages of approximately 0.7 V and peak power values greater than 1 mW cm[superscript −2], significantly outperforming the identical device employing an unselective platinum (Pt) cathode. The work establishes the power of selective catalysis to enable versatile membrane‐free fuel cells., National Science Foundation (U.S.) (Award CHE-­1454060)

Saturates, aromatics, resin, and C7 asphaltene (SARA) fractions of feedstock were analyzed systematically, and molecular models were constructed. The Monte Carlo method was utilized to investigate the intermolecular interactions between SARA fractions and the ligands absorbed on nickel sulfide nanocatalysts. Additionally, the structural characteristics of the hydrocracked products were analyzed by using elemental analysis, 1H NMR spectroscopy, and FTIR spectroscopy to study the effect of surface modification on the catalytic performances of nickel sulfide nanocatalysts. Simulation results reveal that oleic acid and 1-dodecanethiol have a better miscibility with aromatic fractions of residue than cetyltrimethyl ammonium bromide and that oleic acid has a high affinity and selectivity to C7 asphaltene. Adsorption experiments show that nickel sulfide nanocatalysts modified with oleic acid and 1-dodecanethiol present a certain “core affinity” in the diffusion of residue colloid, which leads to a higher catalyst concentration in C7 asphaltene than the average value in the feedstock. Subsequently, experimental data demonstrate that surface modification with oleic acid and 1-dodecanethiol enhances the catalytic activity of nickel sulfide nanocatalysts, which also facilitates the hydrogenation of C7 asphaltene. Furthermore, nickel sulfide nanocatalysts modified with oleic acid show the best hydrogenation and anticoke activity because of the affinity between oleic acid and C7 asphaltene.

In this report, based on the concept of nanoconfinement a synthetic strategy is developed to construct an ultrathin carbon film coated nickel sulfide anchored on carbon nanotubes (CNTs) (CNT@NiS/C). The synthesis involves direct growth of nickel hydroxide on the CNTs followed by dehydration, sulfidation, and carbon coating. When used as an anode material in sodium-ion batteries (SIBs), the nickel sulfide-based anode shows a high utilization rate of active material and a favorable reversible capacity of 390 mAh g-1. The excellent performance of the nickel sulfide-based anode in SIBs demonstrates the potential of nickel sulfide to be used as the anode material in SIBs when it is engineered in a nanoconfinement environment to overcome its structural constraints. In principle, this strategy can be conveniently adapted to engineer other transition metal-based materials for applications in energy storage.

Sodium-ion batteries (SIBs) are considered as promising alternatives to lithium-ion batteries (LIBs) for energy storage due to the abundance of sodium, especially for grid distribution systems. The practical implementation of SIBs, however, is severely hindered by their low energy density and poor cycling stability due to the poor electrochemical performance of the existing electrodes. Here, to achieve high-capacity and durable sodium storage with good rate capability, hierarchical hollow NiS spheres with porous shells composed of nanoparticles are designed and synthesized by tuning the reaction parameters. The formation mechanism of this unique structure is systematically investigated, which is clearly revealed to be Ostwald ripening mechanism on the basis of the time-dependent morphology evolution. The hierarchical hollow structure provides sufficient electrode/electrolyte contact, shortened Na+ diffusion pathways, and high strain-tolerance capability. The hollow NiS spheres deliver high reversible capacity (683.8 mAh g−1 at 0.1 A g−1), excellent rate capability (337.4 mAh g−1 at 5 A g−1), and good cycling stability (499.9 mAh g−1 with 73% retention after 50 cycles at 0.1 A g−1).

Making highly efficient catalysts for an overall ​water splitting reaction is vitally important to bring solar/electrical-to-hydrogen energy conversion processes into reality. Herein, the synthesis of ultrathin nanosheet-based, hollow MoOx/Ni3S2 composite microsphere catalysts on nickel foam, using ammonium molybdate as a precursor and the triblock copolymer pluronic P123 as a structure-directing agent is reported. It is also shown that the resulting materials can serve as bifunctional, non-noble metal electrocatalysts with high activity and stability for the hydrogen evolution reaction (HER) as well as the oxygen evolution reaction (OER). Thanks to their unique structural features, the materials give an impressive water-splitting current density of 10 mA cm−2 at ≈1.45 V with remarkable durability for >100 h when used as catalysts both at the cathode and the anode sides of an alkaline electrolyzer. This performance for an overall water splitting reaction is better than even those obtained with an electrolyzer consisting of noble metal-based Pt/C and IrOx/C catalytic couple—the benchmark catalysts for HER and OER, respectively.

Ultra-small nickel sulfide nanoparticles (NSNPs) of 5–8 nm are prepared by a reverse microemulsion route and then modified by oleic acid and 1-dodecanethiol to replace the adsorbed surfactant. Experimental results reveal that the particle size and crystal structure of the NSNPs did not change significantly during the modification process. Different from the adsorption by the electrostatic attraction between the surfactant and NSNPs, oleic acid and 1-dodecanethiol are adsorbed firmly on the NSNPs through chemisorption. Catalytic hydrocracking tests demonstrate that the surface modification enhances the hydrocracking activity of the NSNPs. The surfactant-coated NSNPs disperse in toluene-insoluble products in as agglomerates of 20–30 nm, whereas the modified NSNPs mainly disperse as their original size. The results prove that the chemisorption of oleic acid and 1-dodecanethiol on NSNPs remains steady and maintains the stable dispersion of NSNPs under high temperature and pressure.

Addition of sub-stoichiometric quantities of PEt3 and diphenyl disulfide to a solution of [Ni(1,5-cod)2 ] generates a mixture of [Ni3 (SPh)4 (PEt3 )3 ] (1), unreacted [Ni(1,5-cod)2 ], and [(1,5-cod)Ni(PEt3 )2 ], according to 1 H and 31 P{1 H} NMR spectroscopic monitoring of the in situ reaction mixture. On standing, complex 1 converts into [Ni4 (S)(Ph)(SPh)3 (PEt3 )3 ] (2), via formal addition of a "Ni(0)" equivalent, coupled with a CS oxidative addition step, which simultaneously generates the Ni-bound phenyl ligand and the μ3 -sulfide ligand. Upon gentle heating, complex 2 converts into a mixture of [Ni5 (S)2 (SPh)2 (PEt3 )5 ] (3) and [Ni8 (S)5 (PEt3 )7 ] (4), via further addition of "Ni(0)" equivalents, in combination with a series of C-S oxidative addition and CC reductive elimination steps, which serve to convert thiophenolate ligands into sulfide ligands and biphenyl. The presence of 1-4 in the reaction mixture is confirmed by their independent syntheses and subsequent spectroscopic characterization. Overall, this work provides an unprecedented level of detail of the early stages of Ni nanocluster growth and highlights the fundamental reaction steps (i.e., metal atom addition, CS oxidative addition, and CC reductive elimination) that are required to grow an individual cluster.

Electrochemical water splitting for hydrogen production is currently hindered by the sluggish kinetic of anodic oxygen evolution reaction (OER). By integrating photothermal materials into electrocatalytic network and thus allowing solar energy to work as additional driving force, the OER is expected to be boosted. However, the rational design of such electrochemical system still remains a challenge due to the spatial inconsistency between photothermal component and electrocatalytic component. Herein, it is reported that multifunctional nickel sulfide (Ni3 S2 ) nanosheet arrays show both photothermal and electrocatalytic properties for solar-intensified electrocatalytic system, which well eliminates the spatial inconsistency between the aforementioned two types of functional components by using one bifunctional material. The deliberate design of nanoarray architecture formed by the interconnected Ni3 S2 nanosheets endows larger surface area and higher surface roughness, thus enhancing light absorption by suppressing diffuse reflection and facilitating electron transfer in electrocatalytic reactions. Therefore, the OER activity is significantly improved. Under light illumination, the current density of Ni3 S2 nanosheets could reach 492.2 mA cm-2 at 1.55 V, about 2.5-fold that in dark conditions, with a Tafel slope of as low as 60 dec-1 . The solar-intensified electrochemical system based on multifunctional material presents prospective potential in electrochemical water splitting for efficient hydrogen production.

Nanostructured NiS thin film was prepared by a one-step electrodeposition method and the structural, morphological characteristics of the as-prepared films were analyzed by X-ray diffractometry (XRD), field emission scanning electron microscopy (FESEM) and energy dispersive X-ray analysis (EDAX). The electrocatalytic activity of NiS thin film towards glucose oxidation was investigated by fabricating a non-enzymatic glucose sensor and the sensor performance was studied by cyclic voltammetry (CV) and amperometry. The fabricated sensor showed excellent sensitivity and low detection limit with values of 7.43 μA μM(-1) cm(-2) and 0.32 μM, respectively, and a response time of

Metal sulfide electrodes were compared to a conventional platinum (Pt) counter electrode (CE) in quantum-dot-sensitized solar cells (QDSSCs), in which they were used to improve the short circuit current, fill factor, and conversion efficiency (η). We deposited optimal-temperature-based nickel sulfide (NiS) thin films on a fluorine-doped tin oxide (FTO) substrate by a facile chemical bath deposition method and successfully employed them as a highly efficient CE for QDSSCs. The obtained NiS thin-film nanoparticles exhibit high electrocatalytic performance and fast mass transfer rates toward the polysulfide electrolyte. Under the illumination of one sun (100 mW cm–2), the QDSSC with a NiS CE produces a higher η of 3.30 %, which is much higher than that of a Pt CE (1.89 %). Cyclic voltammetry, electrochemical impedance spectroscopy, and Tafel polarization measurements were performed to investigate the electrocatalytic activity of the NiS CE toward polysulfide electrolyte.

White-fungus-like NiSx microspheres have been synthesized on a large scale by using a simple hydrothermal method. The influence of the reaction time and the surfactant on the final products was investigated, and the formation mechanism was discussed. The synthesized white-fungus-like NiSx microspheres were used firstly as fillers in the fabrication of NiSx /polyvinylidene fluoride (PVDF) composites. Relationships between the loadings of the NiSx and wave-absorption properties of the composites were analyzed. The loss mechanisms of NiSx /PVDF with different loadings were also discussed according to their dielectric and magnetic behaviors.

An effective, nondestructive, and universal strategy to homogeneously modify freestanding carbon nanotube (CNT) films with various active species is essential to achieve functional electrodes for flexible electrochemical energy storage, which is challenging and has attracted considerable research interest. In this work, a generalizable concept, to utilize silicon oxide as the intermediate to uniformly decorate various metal sulfide nanostructures throughout CNT films is reported. Taking nickel sulfide nanosheet/CNT (NS/CNT) films, in which the NS nanosheets are homogeneously attached on the intact few-walled CNTs, as an example, the sheet-like NS provides sufficient active sites for redox reactions and the CNT network acts as an efficient electron highway, maintaining the structural integrity of the composite and also buffering volume changes. These merits enable NS/CNT films to meet the requirements of versatile energy storage applications. When used for supercapacitors, a high specific capacitance (2699.7 F g-1 /10 A g-1 ), outstanding rate performance at extremely high rates (1527 F g-1 /250 A g-1 ), remarkable cycling stability, and excellent flexibility can be achieved, among the best performance so far. Moreover, it also delivers excellent performance in the storage of Li and Na ions, meaning it is also potentially suitable for Li/Na ion batteries.

Electrically conductive adhesive (ECA) was prepared with cyanate ester resin and bismaleimide resin formed bismaleimide-triazine resin as the matrix, a γ-glycidoxy propyl trimethoxy silane (KH-560) as the coupling agent, and the carbon microcoils (CMCs) as the conducting filler. CMCs were synthesized by the catalytic decomposition of acetylene using nickel sulfide particles as the catalyst, which prepared by solvothermal method. The morphology and microstructure of CMCs were examined by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. The electrical conductivity of the ECA increased to 3.16 × 10−2 S/cm. When the content of CMCs was 1.5 wt %, the shear strength between 25 and 200°C remained at a high value of 22.8 and 21.4 MPa, respectively. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Highly (001)-textured, photoactive WS2 films, which could be deposited before only on insulating substrates, have been prepared on polycrystalline metal layers, which can be used as back contacts for electronic WS2 devices, for instance for thin film solar cells. The WS2 films were prepared by the amorphous-solid-liquid-crystalline-solid (aSLcS) crystallization process from a Ni–S eutectic. However, normal polycrystalline metallic films can not be used as back contact layers, caused by the diffusion of the thin metal promoter (Ni) into the back contact layer, before a nickel–sulfur eutectic can be formed. Preventing the diffusion of the metal promoter into the back contact allows using the well-known metal-promoter assisted crystallization to grow photoactive films on different back contacts, like TiN:O. Additionally, WS2 films on tungsten layers could be grown by Ni-induced sulfidation of W films. Based on these experiments the model of the rapid nickel sulfide induced crystallization was modified: Ni assists the growth of WS2 crystallites already at temperatures between 500 and 600 °C leading to WS2 films with differently oriented crystallites. At temperatures above the Ni–S eutectic temperature (637 °C) liquid NiSx droplets induce, as reported earlier, a rapid recrystallization, which leads to WS2 films with strong (001) orientation.

Highly symmetrical, isotropic nickel disulfide (NiS2) nanocubes have been synthesised via a Physical Vapour Transport (PVT) method in which sulfur vapour generated in situ is reacted with nickel-coated silica substrates. Systematic studies demonstrate the effect of the reactant ratio, substrate, metal layer thickness, and reaction temperature on the synthesis and growth process. The evolution of structure and composition has been followed by diffraction and electron microscopy techniques, and the size of the NiS2 cubes can be varied from below 200 nm to 1–2 μm across. Magnetic properties of the disulfide nanomaterials have been determined using SQUID magnetometry. Initial experiments also demonstrate that related Chemical Vapour Transport (CVT) techniques can be exploited to produce alternative compositions in the Ni–S system with varying morphologies that can be controlled via chemical and physical reaction parameters.

Peapodlike Ni/Ni3S2 chains of about 30 nm in outer diameter, with Ni cores of 10–15 nm, can be synthesized by a sacrificial template route. The Ni3S2 shell exhibits paramagnetic properties with a mass susceptibility of χ ≈ 5 × 10−5 emu (gOe)−1, while the ferromagnetic Ni cores show a superparamagnetic behavior with a blocking temperature of TB ≈ 130 K. The shape anisotropy of the chainlike structure is determined as 5.0 × 104 J·m−3, which is larger than the bulk magnetocrystalline anisotropy by one order of magnitude. The demagnetization factor is determined as ΔN = 0.29. The sample provides an ideal structure for studying the magnetization reversal property by the chain-of-sphere model. The observations on the formation of the peapod structure verify a growth mechanism of the nanoscale Kirkendall effect. Based on the preparation of peapod chains, a series of nickel sulfide hollow chains with average diameters of 25, 50, and 100 nm are fabricated. In addition, the phase transition for hollow chains from Ni3S2 to NiS is studied.

A series of unsupported sulfide catalysts containing nickel and molybdenum (with variable atomic ratio a Ni/Ni + Mo) was prepared using a variant of the H.S.P. method which promotes an “intimate contact” between the metallic ions. These catalysts show good activities in the dibenzothiophene hydrodesulfurization (under atmospheric or high pressure) and in the biphenyl hydrogenation. For the two reactions, the maximum of synergy is observed for a about 0.7. X-ray diffraction shows that for a < 0.3, only the MoS2 type phase is detected (before and after catalytic test). For higher values of a, nickel sulfide initially present under the NiS2 and NiSβ phases form, is converted into the Ni3S2 phase by catalytic working. The variations, in terms of a, of the specific area, of the stoichiometric ratio S/Ni + Mo' of the c parameter of the MoS2 type phase, of the TPR spectra shape, show the existence of a mixed phase “Mo - Ni - S” of the same crystallo-graphic type than MoS2. The presence of this phase would induce an increase of the HDS and hydrogenation properties of the catalyst without explaining the position of the synergy maximum.

A series of unsupported NiMo catalysts, containing 30% Ni atoms, were prepared by the homogeneous sulfide precipitation method (HSP) and sulfided at different temperatures in the range 673-1073 K. XPS, XRD, microelectrophoresis and BET surface area measurements were used to characterize the samples. The catalytic activity of the various catalysts for the hydrodesulfurization of thiophene and the hydrogenation of cyclohexene in a mixture containing both compounds was measured in mild conditions (573 K, 3 MPa). Both the evolution of the ''NiMoS phase'' during catalytic reaction and the influence of the sulfidation temperature on the properties of the unsupported NiMo catalysts were investigated. The sample sulfided at 673 K gave all the characteristic signals of the ''NiMoS phase''. As the sulfidation temperature increases, larger amounts of nickel segregate from ''NiMoS phase'' to form nickel sulfide. The ''NiMoS phase'' was found unstable under reaction conditions. The maximum catalytic activity for both HDS and HYD reactions was obtained when both ''NiMoS phase'' and bulk Ni3S2 were present in the catalyst. It thus appears as a precursor of a very active mixture of phases rather than of the stable catalyst itself. These results are discussed in relation to some models attempting to explain the synergy in the NiMo catalysts. They are compatible with the remote control mechanism.

High temperature sulfidic corrosion has caused safety and reliability issues in refinery units for decades. The objective of the work was to investigate the kinetics of sulfidation under refinery conditions and to characterize, at the nanometer scale, the sulfide layers formed on different steels. The experiments were performed in an autoclave filled with a refinery high-sulfur crude oil at 300°C on XC18 carbon steel (Fe-0.18%C), P5 alloy steel (Fe-5% Cr-0.5%Mo) and 304L stainless steel (Fe-18% Cr-8%Ni). The duration of the test ranged from a few hours to a few days. The combination of X-ray diffraction and transmission electronic microscopy showed the presence of pyrrhotite (Fe 1-x S) on XC18, PS and 304L samples. For all alloys, the S 2p core level decomposition (X-ray photoelectron spectroscopy) proved the presence offive sulfur species on the surface: sulfide (main species), disulfide, elemental sulfur, sulfite and sulfate. On 304L, the presence of chromium oxide and nickel sulfide was revealed by XPS, whereas chromium sulfide was hardly detected. The macroscopic kinetics of sulfidation was followed by mass loss. The results showed that a parabolic law can fit the kinetics of sulfidation of XC18 and P5 steels. The kinetics of sulfidation of the adherent sulfide layer formed on 304L steel, determined from XPS measurements, follows a logarithmic law.

Most of the sulfide nickel deposits in China occur on the margins of platforms and their outer mobile belts. The ore- bearing basic- ultrabasic rock bodies were formed in the Proterozoic and Variscan. The types of metallogenic rock bodies include ultrabasic- basic complexes related to volcanism in eugeosynclines and ultrabasic rock bodies, ultrabasic-basic complexes and basic rock bodies related to deep fractures. On the basis of ore-forming processes and modes, nickel sulfide deposits of China may be divided into two major types: in- situ magmatic liquid unmixing deposits and deep- seated magmatic liquid unmixing injection deposits. The latter may by subdivided into four types: single injection deposits, multiple injection deposits, and pulsatory injection depositis, and late injection deposits which may inject into either comagmatic rocks or other kinds of country rocks. Two metallogenic models for nickel sulfide deposits are proposed in this paper.

A mercury sulfide layer was prepared at the surface of a mercury electrode by an anodic reaction (+0.1 V vs. Ag|AgCl|KCl(3 M)) in the presence of thiourea at the micromolar concentration level. Electrochemical reactions of mercury sulfide were investigated by a subsequent cathodic scan at near-neutral pH values and in the absence/presence of a second metal ion. Two different forms of mercury sulfide were evidenced by characteristic cathodic peaks; the first one (in the form of adsorbed molecules) undergoing a reversible reduction at about −0.6 V, whereas the second one (probably as nanoaggregates) being reduced in an irreversible process at −0.9 V. A detailed analysis of the first process was performed by adapting the already existing theoretical approaches. It was proven that the HgS layer prepared by mercury anodization in the presence of thiourea is similar to that prepared by anodization in the presence of sulfide ion. Other metal sulfides were prepared via the exchange reaction of mercury in HgS with a metal ion in solution; namely, Zn2+, Ni2+, and Cd2+; reactions of the latter proceeding in a fair agreement with the theoretical model used (the rapid exchange leading to the single CdS form with no soluble cadmium sulfide species). Evident deviations from this model have occurred with both Ni2+ and Zn2+ due to a sluggish exchange reaction, formation of soluble species, and occurrence of various metal sulfide forms. Two different forms of nickel sulfide were detected by characteristic cathodic reactions, namely i) adsorbed free molecules that are reduced at −1.0 V and are able to take part in a catalytic (EC′) reduction of Ni2+; and ii) an aggregated form that is irreversibly reduced at negative potentials beyond −1.2 V and acts as a catalyst for hydrogen evolution. The method presented herein allows one electrochemical preparation and investigation of metal sulfides with no difficulty due to hydrogen sulfide volatility at pH

Although several fundamental physico-chemical aspects of nickel sulfides have been studied in detail, particularly for millerite (nickel(II) monosulfide), the most common nickel sulfide mineral, no satisfactory investigation of optical vibrational modes has been reported previously. In this paper, we provide a definitive assignment of the optical phonons in millerite, investigated by polarized Raman spectroscopy on an oriented single crystal. The impact of the power of the incident laser beam on the spectra has also been investigated, revealing evidence for degradation in the quality of the spectra at sufficiently high laser power. Copyright © 2008 John Wiley & Sons, Ltd.

Thin films of nickel sulfide (NiS 1.03 , NiS 2 ,α-Ni 7 S 6 , or mixtures thereof) and palladium sulfide (PdS, Pd 16 S 7 , Pd 4 S, or mixtures thereof) have been prepared by aerosol-assisted (AA)CVD using dithiocarbamate precursors of the type M(S 2 CNRR') 2 (M = Ni, Pd; RR' = Et 2 , MeEt, Me n Bu, or Me n Hex). The solid-state structure of Ni(S 2 CNMe n Bu) 2 , was determined by X-ray single-crystal diffraction and is characteristic of known nickel dithiocarbamates. Films were grown on glass substrates at temperatures of 400-525 °C and characterized by X-ray diffraction (XRD), energy dispersive analysis of X-rays (EDAX), and scanning electron microscopy (SEM).