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Six terpyridine‑nickel complexes 1 – 6 were formed by the coordination of 4′-(4- R -phenyl)-2,2′:6′,2″-terpyridine (R = hydroxyl (L 1 ), methoxyl (L 2 ), methylsulfonyl (L 3 ), fluoro (L 4 ), bromo (L 5 ), iodo (L 6 )) derivatives to nickel nitrate. The compositions and structures of these complexes were analyzed by Fourier Transform infrared spectroscopy (FT-IR), elemental analyses, electrospray ionization mass spectra (ESI-MS), solid-state ultraviolet-visible (UV–Vis) spectroscopy, and single crystal X-ray diffraction (1 , 2 and 4) studies. In vitro anticancer cell proliferation experiments against SiHa (human cervical squamous cancer cell line) cells, Bel-7402 (human hepatoma cancer cell line), Eca-109 (human esophageal cancer cell line) and HL-7702 (human normal hepatocyte cell line) indicate that they have more excellent anti-proliferation effects than the cis -platin against Siha cells, Bel-7402 cells and Eca-109 cells. Especially, complex 5 showed a rather outstanding inhibitory effect against the SiHa cell line and was less toxic than the other compounds to the HL-7702 cell line, implying an obvious specific inhibitory effect. Therefore, complex 5 has the potential value to be developed as an anticancer cell-specific drug against human cervical squamous carcinoma. Molecular docking simulation, UV–vis absorption spectroscopy and circular dichroism experiments show that they prefer to bind to DNA part in an embedded binding manner. Six Ni(II)-terpyridine complexes were fabricated and investigated with excellent anti-proliferative activity than commercial cisplatin, and their interaction with DNA has been experimental and computational studied. These complexes interact with the DNA through an embedded binding mode, thereby hindering the proliferation of cancer cells. [Display omitted] • In vitro cytotoxicity assay indicates that these complexes have higher antiproliferative activities than cisplatin against cancer cells. • One of them exhibited much higher antiproliferation to cancer SiHa cells than cisplatin while low toxicity to normal HL-7702 cells. • Spectroscopic characterization and computational simulation suggest that they tend to exert influence on cells by binding with DNA. [ABSTRACT FROM AUTHOR]

Hydrogen peroxide (H 2 O 2) is one of the most promising, green, and effective oxidants that can be used in different applications. In this study, zeolitic imidazolate frameworks (ZIFs), consisting of organic ligands and metal sites, were selectively prepared from zinc or nickel nitrate solutions for use in photocatalytic H 2 O 2 production. High concentrations of zinc nitrate solution provided more metal sites to coordinate with 2-methylimidazole, producing ZIF-8 with larger particle size, whereas low zinc nitrate concentrations resulted in more interconnected N–H⋯N hydrogen bonds, forming 2D-layered ZIF-L, with smaller particle size. Various concentrations of zinc and nickel nitrate solutions produced ZIFs that exhibited ZIF-8 or ZIF-L topology, with bandgap energies of 5.45 and 4.85 eV, respectively. These samples could serve as promising photocatalyst for the successful production of H 2 O 2 under Xenon lamp irradiation. [ABSTRACT FROM AUTHOR]

The catalytic graphitization of the phenolic resin was investigated in the presence of various amounts of nickel nitrate at 600–1200 °C in a reducing atmosphere for 3 h. For comparison, the effect of catalyzed phenolic resin versus none-catalyzed one was explored on the microstructure and mechanical properties of the Al 2 O 3 –C refractory specimens within a range of 800–1400 °C. The phase composition and microstructure evolution were investigated using X-ray diffraction and SEM, respectively. RAMAN spectroscopy was used to measure the graphitization level of phenolic resin. Results indicated that crystalline carbon (graphite) was achieved only from Ni-catalyzed phenolic resin at a high temperature (~ 1200 °C), while non-catalyzed resin led to the formation of amorphous carbon. Mechanical properties of the Al 2 O 3 –C specimens were improved due to the presence of catalyzed phenolic resin. SEM results illustrated that the enhancement was associated with the in-situ formation of the SiC phase in whisker shape in the microstructure of specimens containing Ni-catalyzed phenolic resin. [ABSTRACT FROM AUTHOR]

Abstract This work outlines the synthesis of pure CdO and Ni-CdO nanoparticles with different weight percentage (2, 4, 6, 8 and 10 wt%) of Ni2+ through microwave combustion route using cadmium nitrate and nickel nitrate as precursors and ethylene glycol as solvent. The morphological, optical and electrical properties of the material obtained after calcination was systematically characterized for various physicochemical properties and photoconductivity characteristics. The X-ray diffraction study of the synthesized and calcinated CdO and Ni-CdO nanoparticles confirms the existence of cubic phase with no impurity peaks (up to 4 wt%). The average crystalline size is found to be in the range of 41–47 nm based on Debye-Scherrer formula calculation. The scanning electron micrograph reveals that the synthesized samples are prismatic to spherical shaped and also it is observed that, the porosity enhances with increase in the concentration of Ni2+ ions. Energy dispersive X-ray micrographs show the existence of Ni2+ in the Ni-CdO samples. The optical bandgaps of synthesized samples are determined by Tauc's plot. Transmission electron microscope images are in accordance with the surface morphologies of scanning electron micrographs. The current-voltage characteristic (I–V) of CdO and Ni-CdO films shows that the photo current of CdO and Ni-CdO films is greater in UV-light as compared to dark. Highlights • Ni2+ ion doped CdO nanoparticle was prepared by microwave combustion method. • Variation of average crystalline size, lattice constant and micro-strain discussed Ni2+ doping consequences. • The band gap of CdO and Ni-CdO was analysed using UV-Visible absorption spectra. • Enhance the conductivity CdO with Ni2+ doping. [ABSTRACT FROM AUTHOR]

Nickel catalysts supported on silica microspheres were prepared by the application of porous resin beads (Amberlite XAD7HP) as hard template using different order of nickel nitrate and tetraethoxysilane (TEOS) introduction. Large nickel oxide nanoparticles distributed over silica microspheres were formed when nickel precursor was introduced directly to the polymer template prior to the silica framework development or added into the silica-polymer composites. On the other hand, an impregnation of as-prepared silica microspheres after template removal led to the formation of small nickel oxide nanoparticles. The catalysts showed hierarchical pore structure. Low-temperature nitrogen adsorption/desorption and photoacoustic Fourier-transform infrared spectroscopy studies revealed slight changes of porosity and surface properties of catalysts affected by the synthesis methods. X-ray diffraction, scanning and transmission electron microscopy, temperature-programmed reduction and hydrogen desorption studies were used for determination of the properties of metallic nickel nanoparticles. It was stated that the activity and selectivity of catalysts in the CO 2 methanation reaction was related to the active surface area and the size of nickel nanoparticles. An increase in CO 2 conversion and selectivity to methane at low temperatures (220–350 °C) with an increase in active surface area and decrease in nickel crystallite size was observed. [ABSTRACT FROM AUTHOR]

Nickel (II) nitrate hexahydrate (Ni) is a common heavy metal material in battery manufacturing, electroplating alloy parts and ceramic staining, therefore we frequently contact with Ni-related products in daily life. In this study, we aimed to investigate the effects of Ni on neutrophils extracellular traps (NETs) release by canine polymorphonuclear neutrophils (PMNs). The structure of Ni-induced NETs was observed by fluorescence confocal microscopy. Ni-triggered NETs release was quantified by Pico Green ® and fluorescence microplate reader. In addition, the inhibitors of NADPH oxidase, ERK1/2-, p38 - signaling pathways were used for preliminary inquiry into the potential mechanism of this process. The results showed that Ni markedly triggered the formation of NETs-like structures, and these structures were mainly consisted of DNA decorated with NE and MPO. Furthermore, quantification experiments showed that Ni significantly increased NETs formation compared to control groups. These results forcefully confirmed that nickel nitrate possesses the ability to induce NETs formation. However, inhibiting the NADPH oxidase, ERK1/2- and p38 MAPK-signaling pathways did not significantly change the quantitation of Ni-induced NETs release. To our knowledge, this study is the first report of Ni-triggered NETs release in vitro , which might provide an entirely new mechanism of several diseases and health issues induced by nickel overexposure. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Multi-Ni@Ni phyllosilicate@SiO 2 core shell hollow spheres have been designed. • They show high carbon resistance for DRM. • Strong metal support interaction and confinement effect prevent the growth of CNTs. • The facile synthesis method can be used to design other core shell hollow catalyst. Abstract Carbon dioxide reforming of methane (DRM) reaction has been widely explored since it is a sustainable process to transform carbon dioxide and methane which are the main greenhouse gases to value added synthesis gas. Herein, Ni@Ni phyllosilicate@SiO 2 core shell hollow spheres (Ni@NiPhy@SiO 2 HS) with high carbon resistance for DRM at 600 °C (10.4% weight loss after 50 h reaction) have been designed. Additionally, it also showed stable and high conversions (82.5% and 78.4% for carbon dioxide and methane respectively) and carbon resistance (5.5% weight loss) for DRM reaction at 700 °C within the testing time of 600 h. By contrast, for Ni@NiPhy without SiO 2 shell, tremendous carbon nanotubes (CNTs) formed for DRM at 600 °C, even though it is interesting to find that there is slight nickel sintering. TPO-MS, H 2 -TPR, XPS and TEM characterizations showed that the interactions between nickel nanoparticles and NiPhy materials were increased due to the coating of SiO 2 shell which also confined nickel and inhibited detaching of nickel from the surface of Ni@NiPhy@SiO 2 , which eliminates the accumulation of carbon to become CNTs. The synthesis method for core shell HS provides numerous opportunities to design other structured materials such as Ni-M (M = Co, Fe, Mg)@SiO 2 HS for the efficient utilization of greenhouse gases through environmentally sustainable processes. [ABSTRACT FROM AUTHOR]

Solution processed NiO x is one of the promising hole transport layer (HTL) for planar perovskite solar cells, which can replace hygroscopic poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT: PSS) HTL. In this study, we investigated effects of ethylenediamine (EDA) additive in NiO x precursor solution (nickel nitrate hexahydrate dissolved in ethyleneglycol) on optoelectronic and surface morphological properties of resultant solution processed NiO x films. By varying EDA content (0–10.0 v/v %) in the precursor, we could find out that adequate EDA additive (~5.0%) provide much reduced electrical resistivity and enhanced optical transmission compared with control NiO x film (No EDA) by suppressing formation of byproducts (i.e. nickel hydroxide). In addition, AFM surface topography showed much compact and dense deposition of NiO x film on ITO electrode. This contributed to improve charge transport properties and suppress charge recombination loss at ITO/perovskite interface, which provided strong enhancement in fill factor from 0.599 to 0.714 in the perovskite solar cells. As a result, a power conversion efficiency (PCE) was strongly increased from 13.9 (No EDA) to 16.7% (EDA 5.0%). This also outperformed the performance (14.3%) of device using PEDOT: PSS, which indicates that the adequate control of EDA additive for NiO x HTL could offer much promising photovoltaic performance. [ABSTRACT FROM AUTHOR]

Hydrothermal reaction of nickel nitrate, an adamantane-based dicarboxylic acid, and a hydrogen-bonding capable dipyridyl ligand generated six coordination polymers that were isolated and subsequently structurally characterized by single-crystal X-ray diffraction. {[Ni(adc)(ebin)(H 2 O)]·2H 2 O} n ( 1 , adc = 1,3-adamantanedicarboxylate, ebin =  N , N ′-ethylenediaminebis(isonicotinamide)) shows ABAB stacked (4,4) coordination polymer grids. In contrast, [Ni(ada)(ebin)] n ( 2 , ada = 1,3-adamantanediacetate) manifests a very rare self-penetrated layer with a 3,5-connected (4 2 6)(4 2 6 7 8) topology. {[Ni(adc)(pbin)]·2H 2 O} n ( 3 , pbin =  N , N ′-propyleneenediaminebis(isonicotinamide)) shows a dimer-based 4 12 6 3 pcu network, while {[Ni 5 (ada) 5 (pbin) 5 (H 2 O) 5 ]·8H 2 O} n ( 4 ) manifests looped layers with (4)(4.8 5 ) topology. {[Ni 2 (adc)(adcH) 2 (dpa) 2 ]·H 2 O} n ( 5 , dpa = 4,4′-dipyridylamine) possesses [Ni 2 (adc)(adcH) 2 ] linear fragments connected into an uncommon 3-connected 10 3 srs network. Concomitantly formed along with 5 , {[Ni(adc)(dpa)]·6.5H 2 O} n ( 6 ) is a stacked (4,4) grid phase but with a direct AAA stacking pattern. Embedded {Ni 2 (OCO) 2 } dimeric units in 2 and 3 exhibit antiferromagnetic coupling ( J  = −10.5(1) cm −1 ( 2 ), J  = −2.38(7) cm −1 ( 3 )). Thermal decomposition behavior of 1 – 6 was also investigated. [ABSTRACT FROM AUTHOR]

In this paper, nickel nitride (Ni 3 N) nanoparticles with spherical structure are successfully synthesized by urea glass route. The morphology and structure of the as-prepared nanoparticles are characterized by scanning electron microscopy and X-ray diffraction. The electrocatalytic properties of the synthesized Ni 3 N for ethanol and methanol oxidation in alkaline media were investigated using cyclic voltammetry and chronoamperometry. A peak current of about 200 µA for ethanol and 100 µA for methanol oxidation was recorded during ethanol and methanol oxidation under the test condition of adding 1.0 M alcohols in 0.1 M NaOH solution. The stability of the catalyst was investigated using steady state chronoamperometry for 1000 s. The results show that the nickel nitride exhibits excellent electrocatalytic activity that is very promising catalyst for fuel cell application. [ABSTRACT FROM AUTHOR]

This study used a solution cast process to prepare a PEO doped with (4, 8 and 12 wt%) NiNO 3 metal salt. Techniques including FTIR, optical microscope (OM), and UV–Visible-absorption spectrometry were employed to examine the structural, microscopic configuration and optical behaviors of the electrolyte. The FTIR bands indicated shifting and narrowing of PEO- O -H stretching bands by addition of 4w%NiNO 3 , suggesting a good interaction between the NiNO 3 and the polymer. The optical microscope images showed the dark regions ascribed to amorphous phases and it is more dominant in the doped films than in the pure films. According to the optical absorption measurements optimum absorption and transmission of UV–visible light were observed at 4 wt% filler loading. Absorbance and transmittance of PEO were amplified by integrating 4 wt%NiNO 3 , although concentration above 4 wt% had insignificant influence on the optical behavior of PEO. The PEO:4w% NiNO 3 films showed a higher value of refractive index and a greater optical conductivity in the UV wavelength which confirmed the presence of more charge carriers in the doped film. The regions attributed to band gap width and the different types of electron transitions were identified by using the Tauc's model in detail. The absorption edge shifting was distinguished for the 4 wt% doped PEO, and the optical band gap was reduced from 5.25 eV to 4.2 eV. • Preparation of PEO based electrolyte with improved optical properties. • Structural characterization through FTIR approach. • Crystalline and amorphous phase identification through Optical Microscope. • Optical band gap study through Taucs Model and Optical dielectric loss. • Band gap reduction from 5.5 eV to 4.3 eV were achieved. [ABSTRACT FROM AUTHOR]

We report the initiation mechanisms and subsequent chemical decompositions of energetic metal-organic frameworks (MOFs) nickel hydrazine nitrate (NHN) crystal at high temperatures and high temperatures coupled with high pressures by ab initio molecular dynamics simulations. The initial decomposition step is the collapse of the MOF cage at 518 K and 518 K coupled with 1, 2, and 3 GPa. But their cleavage steps are different. It is found that the pressure decelerates the initial decomposition of the NHN crystal. The decomposition mechanisms of the NHN crystal at 518 K coupled with 20.2 GPa are much different from those at 518 K coupled with low pressures. The results indicate that the temperature is the foremost factor that affected the decomposition of the NHN crystal. At 4000 K and 4000 K coupled with 20.2 GPa, the initial decomposition mechanisms of NHN are both the cage collapse by several Ni N bond breaking. The variation tends and the release times of H 2 O are similar at the two cases. In the early decomposition stage, NHN decomposed very fast and drastically. But the later decomposition was slow. During 1.0 ps, there are ten H 2 O released fast at the two extreme conditions. Then the population of H 2 O keeps nearly stable during the later decomposition stage. At 7.959 ps, last one H 2 O was formed. Our results may provide useful information for understanding the chemical decompositions of energetic metal-organic frameworks compounds. [ABSTRACT FROM AUTHOR]

Lithium sulfur batteries have been widely studied because of their high energy density. However, their commercialization has been impeded by several problems, such as the poor conductivity of the active material sulfur and its discharge products, the volume expansion and the shuttle effect caused by the polysulfide intermediates dissolving in organic electrolytes. To address these problems well, we have constructed high sulfur content spherical sulfur-carbon nanotube-polyethylene glycol-nickel nitrate hydroxide (SCNT-PEG-NNH) composite material by using a simple ball-milling method. The conductivity of the composite material gets improvement due to the spherical conductive frame constructed by CNT, while the shuttle effect of polysulfides is well inhibited by the wrapping of the PEG and the fixation of NNH. The results of electrochemical tests have shown that the performance of cathode made by the SCNT-PEG-NNH composite material is greatly improved. Therefore, the SCNT-PEG-NNH composite material can be a promising cathode material for lithium sulfur batteries. [ABSTRACT FROM AUTHOR]

Herein, a macroporous graphitic carbon foam (MGCF) electrode decorated with polydopamine (PDA) is used as a high-performance anode for microbial fuel cell (MFC) applications. The MGCF is facilely prepared by pyrolysis of a powder mixture comprising maltose, nickel nitrate, and ammonia chloride, without using solid porous template. The MGCF is coated with PDA by self-polymerization of dopamine in a basic solution. The MGCF can provide a large surface area for bacterial attachment, and PDA coated on the MGCF electrode can further promote bacterial adhesion resulting from the improved hydrophility, so the MGCF-PDA electrode as an anode in a MFC can show ultrahigh bacterial loading capacity. Moreover, the electrochemical oxidation of flavins at the MGCF-PDA electrode is greatly accelerated, so the extracellular electron transfer mediated by flavins is improved. As a result, the MFC equipped with a MGCF-PDA anode can show a maximum power density of 1735 mW cm −2 , which is 6.7 times that of a MFC equipped with a commercial carbon felt anode, indicating a promising anode for MFC applications. [ABSTRACT FROM AUTHOR]

The state-of-the-art and stable electrocatalysts with non-noble metal elements are exceedingly desirable for hydrogen/oxygen production from water splitting. Herein, three-dimensional (3D) iron-nickel nitride nanoparticles grown on carbon cloth (Ni 3 FeN-NPs) are developed as a flexible bifunctional electrocatalyst for overall water splitting. The as-prepared Ni 3 FeN-NPs show outstanding electrocatalytic activities toward both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in 1 M KOH solution, with low overpotentials of 238 and 241 mV at 10 mA/cm 2 , Tafel slopes of 46 and 59 mV/dec, respectively. Moreover, an advanced water electrolyzer based on the Ni 3 FeN-NPs electrodes as anode and cathode is assembled and could achieve overall water splitting with a cell voltage of 1.81 V at 10 mA/cm 2 . Also, the as-fabricated water electrolyzer exhibits stable electrocatalytic performance without decreasing in 1 M KOH after 130 h even at the foldable state. [ABSTRACT FROM AUTHOR]

A ditopic 18-membered N 2 O 2 S 2 -macrocycle ( L ) incorporating hard (NO 2 ) and soft (NS 2 ) binding sites in each side was employed and its three complexes ( 1 – 3 ) exhibiting different stoichiometries, geometries, and topologies have been prepared and structurally characterized. First, nickel(II) nitrate hexahydrate reacts with L to give a mononuclear complex [Ni( L )](NO 3 ) 2 ·2H 2 O ( 1 ) in which the metal center locates inside the macrocyclic cavity adopting a hexa-coordinated octahedral geometry shielded by the strongly bound macrocycle from the anion and solvent. While, silver(I) tetrafluoroborate afforded a one-dimensional coordination polymer {[Ag( L )]BF 4 } n ( 2 ) with an L -Ag- L -Ag pattern. In 2 , the silver(I) center is penta-coordinate with NO donors from one L and NS 2 donors from an adjacent L to form a sandwich-type adopting a distorted trigonal bipyramidal geometry. Mercury(II) chloride yielded a dinuclear complex [Hg 2 ( L )Cl 4 ] ( 3 ) in which two mercury(II) ions locate opposite side of L in a chair form. Each mercury(II) center in 3 is penta-coordinate, being bound to one pyridine N atom, two O(S) donors in the compositional disorder, and two chloride ions adopting a distorted square-pyramidal geometry. The comparative NMR studies show the preferential binding affinity of silver(I) over potassium(I) toward L . [ABSTRACT FROM AUTHOR]

Li-rich nickel cobalt manganese oxide (NCM) materials with partial substitution of lithium by magnesium is synthesized by the Pechini process. Different synthesized Li 100-2x Mg x -NCM materials ( x = 0, 1, 2.5, 5, and 10) are investigated by X-ray diffraction (XRD), neutron diffraction, and scanning electron microscopy to determine the role of Mg in the structure and its impact on the morphology and electrochemical properties. The chemical composition, crystal structure, and particle morphology are compared with those of the reference ( x = 0) material. Mg substitution has a significant impact on the electrochemical properties. In comparison with the reference sample, the x = 1 sample exhibits a mitigation of the voltage drop owing to more stable structure during cycling, leading to a specific discharge of 210 mAh g −1 after 100 cycles at C/10 rate. However, compositions with x ≥ 2.5 exhibit larger voltage drop in discharge, due to the faster formation of a spinel-like structure during cycling. [ABSTRACT FROM AUTHOR]

The main aim of this work is to study the respective contribution of the hard and soft blocks of a metal-ligand containing block copolymer to the self-healing behavior. To this aim, different block copolymers containing terpyridine were synthesized using reversible addition-fragmentation chain transfer (RAFT) polymerization. These block copolymers consisted of polystyrene as the hard block, n -butyl acrylate (BA) as soft block and terpyridine units as the ligand moiety placed at different locations in the soft block. These block copolymers were complexed with manganese(II) chloride to introduce transient crosslinks and, thus, self-healing behavior. Homopolymers with the hard and soft block only were also synthesized and tested. A quasi-irreversible crosslinking, i.e. by using nickel(II) nitrate, was performed in order to study the dynamics of the permanently (strongly) crosslinked network. Rheological master curves were generated enabling the determination of the terminal flow in these networks and the reversibility of the supramolecular interactions. Additionally, the macroscopic scratch healing behavior and the molecular mobility of the polymer chains in these supramolecular networks were investigated. A kinetic study of the scratch healing was performed to determine the similarities in temperature dependence for rheological relaxations and macroscopic scratch healing. In our previous work, we have explored the effect of strength of the reversible metal-ligand interaction and the effect of changing the ratio of hard to soft block. This work goes further in separating the individual contributions of the hard and soft blocks as well as the reversible interactions and to reveal their relative importance in the complex phenomenon of scratch healing. [ABSTRACT FROM AUTHOR]

Nanocomposite thin films with TiN dispersed in Ni matrix were deposited in an environment having Ar:N 2 = 1:2 on silicon (100) substrate with bias of − 60 V at 300 °C, 500 °C or 700 °C by co-sputtering of Ti and Ni targets used as RF and DC sources, respectively. The structure and properties of these films were compared with those deposited at ambient temperature and then annealed for 1 h in vacuum at above-mentioned temperatures. Whereas < 111 > is the preferred orientation of Ni, transition from < 100 > to < 111 > is observed for TiN at temperatures ≥ 500 °C, as confirmed by XRD analyses. The average grain sizes of Ni and TiN have been found to be in the ranges of 11–25 nm and 6–13 nm, respectively, using both XRD and TEM studies. Transition from compressive to tensile residual stress is observed with increase in substrate temperature for deposition or annealing. Hardness, elastic moduli and scratch-resistance of the films evaluated using a nanoindentor are found to possess the most optimum values on their growth at substrate temperature of 300 °C. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) graphene-like carbon frameworks (3DGLCFs) were facilely prepared via copyrolysis of polyaniline and nickel nitrate powder, followed by acid etching. The as-prepared 3DGLCFs possess graphene-like network structure, high specific surface area, and high content nitrogen dopant. Because these features enable large electrochemically active surface area, rapid electron transfer, and fast transport of analytes to electrode surface, the 3DGLCFs modified glassy carbon electrode (GCE) shows current response much higher than commercial graphene (CG) modified GCE towards the oxidation of ascorbic acid (AA), dopamine (DA) and uric acid (UA). The anodic peak separations at 3DGLCFs/GCE are 0.23 V between AA and DA, 0.13 V between DA and UA, and 0.36 V between AA and UA. For the simultaneous electrochemical determination of AA, DA and UA using differential pulse voltammetry, the 3DGLCFs/GCE shows linear response ranges of 1.25×10 −5 –4×10 −4 M for AA, 5×10 −8 –1.0×10 −5 M for DA, and 5×10 −8 –1.5×10 −5 M for UA, with low detection limits of 2×10 −6 M for AA, 1×10 −8 M for DA, and 1×10 −8 M for UA. The 3DGLCFs/GCE was also applied for the measurement of human serum, exhibiting satisfactory recoveries. [ABSTRACT FROM AUTHOR]

In the present contribution, a single step H 2 -reduction strategy was developed for the first time to fabricate nickel-based KIT-6 (Ni-KIT-6) for adsorptive desulfurization of fuels. As-synthesized KIT-6 was used as a support and nickel nitrate, nickel chloride and nickel acetate as a nickel precursor was directly introduced into as-synthesized KIT-6. Ni 0 -based KIT-6 was obtained by single-step H 2 -reduction strategy which not only remove template and decompose nickel precursors to NiO but also reduce NiO to Ni 0 . This strategy is much more convenient and facile than reported strategies for Ni-based mesoporous silica KIT-6. Characterization results show that Ni-KIT-6 with nickel content up to 30 wt.% was highly dispersed due to silanols and confined space in as-synthesized KIT-6. The percentage content (54%) of Ni 0 in the as-synthesized KIT-6 is higher than Ni-based calcined KIT-6 (38%). Interestingly, Ni-based as-synthesized KIT-6 prepared using nickel nitrate as a precursor exhibited stronger nickel-KIT-6 interaction, higher Ni 0 content and dispersion than those prepared with nickel chloride and nickel acetate precursors. We also demonstrate here that the shielding effect of capping anions and hydration degree of different nickel precursors significantly affect the dispersion of nickel species even using as-prepared KIT-6 as a support. As a result, Ni-KIT-6(NO 3 − ) captured 0.195 and 0.12 mmol g −1 of sulfur from model fuel and FCC gasoline, respectively. Thus, single step H 2 -reduction strategy may have potential applications to be applied for fabrication of other nickel based mesoporous silicas for adsorptive desulfurization technology. [ABSTRACT FROM AUTHOR]

Fluid Cracking Catalyst (FCC) and three different modified bio-chars were tested for their thermal degradation capability of acetic acid in a custom-made continuous-flow reactor operated at 450 °C under nitrogen flow. The tested modified bio-chars were: switchgrass bio-char (BC), bio-char impregnated with nickel nitrate solution (BCNi), and bio-char deposited with iron oxide (BCFe). The modified bio-chars showed acetic acid degradation capability comparable to the FCC catalyst as quantified by total conversion. The total conversions were 5.55%, 17.33%, 15.21%, and 12.41% for the blank (no catalyst), modified bio-chars (BC and BCNi), and FCC catalyst, respectively while modified bio-char BCFe showed the highest conversion of 40.66%. [ABSTRACT FROM AUTHOR]

The mechanical performance of low-carbon Al 2 O 3 -C refractories can be further enhanced using the in-situ formation approach of MWCNTs. Evidently, the nickel nitrate catalyst in the matrix benefit the improved mechanical properties of Al 2 O 3 -C refractories after coking at elevated temperatures. The in-situ formation of MWCNTs and SiC whiskers contributes to their higher cold modulus of rupture. Moreover, dispersing catalyst into the binder solution promotes a fabric-like structure interlaced through MWCNTs and SiC whiskers in the binder system and thus a better bonding strength can be achieved. Compared to the Al 2 O 3 -C refractories with a close starting carbon content fabricated by adding as-received MWCNTs or the combined carbon sources of nano carbon black and flake graphite, superior thermal shock resistances were attained with the approaches presented in this paper. Additionally, MWCNTs are more influential to the toughening and SiC whiskers are more responsible for the strengthening behaviors. [ABSTRACT FROM AUTHOR]

Undoped and Nickel nitrate (Ni 2+ ) doped Potassium acid phthalate (KAP C 8 H 5 KO 4 ) single crystals were grown by cost effective Slow Evaporation Solution Growth. The grown crystals were subjected to various characterization techniques. The structural and lattice parameters were analyzed by single crystal X-ray diffraction. The spectral properties were assessed by FTIR spectral analysis. Optical characters were analyzed by UV-Vis spectral studies. Mechanical properties of the doped and undoped crystals were evaluated by Vicker's Microhardness study. Thermal stability of the sample was assessed by TG/DTA analysis. EDX analysis confirms the incorporation of metal ion into the crystal lattice of the title compound. SHG studies confirm that Ni 2+ doped KAP crystal is a potential candidate for NLO applications. [ABSTRACT FROM AUTHOR]

Metal nanoparticles (NPs) were prepared from acrylamide complex of iron and nickel nitrates by controlled thermolysis at constant temperature in a self-generated atmosphere and used to fabricate epoxy resin nanocomposites. X-ray diffraction performed on the nanoparticles revealed a metal core/polymeric shell structure for the nanoparticles thermolysed at higher temperature as also confirmed by cross analysis of thermo-gravimetrical and vibrating magnetometer data. Optical microscopy was used to investigate the achieved dispersion of the nanoparticles within the uncured resin and transmission electronic microscopy was used to analyse the morphology and the average dimensions of the nanoparticles. Thermal stability of manufactured nanocomposites was studied by thermo-gravimetric analysis in inert and oxidative conditions, reporting that negligible variations are induced by the presence of nanofillers. A complete thermo-mechanical and fracture characterization was carried out to assess the effect of nanoparticles on final nanocomposite system. A slight increase of the modulus is recorded at room temperature whereas a significant variation is induced for higher temperature. The presence of nanoparticles induces a global increase in the fracture energy of nanocomposite associated to different failure mechanisms. Magnetic data indicate that iron particles based nanocomposites display room-temperature ferromagnetic behaviour with saturation magnetization and coercivity depending on the diameter of the metal core. [ABSTRACT FROM AUTHOR]

In this work, nickel–carbon (Ni/C) nanocomposites were prepared facilely as potential light-weight microwave absorbers via the calcination of nickel nitrate–polyacrylamide mixture in flowing ammonia. The electromagnetic properties of as-prepared Ni/C nanocomposites were investigated in relation to their composition and microstructure. Findings indicate that as-prepared Ni/C nanocomposites are of island-like morphology and consist of uniformly dispersed Ni nanoparticles and porous carbon medium. The electromagnetic properties of Ni/C nanocomposites are highly dependent on calcination temperature; and the Ni/C nanocomposite obtained at 600 °C exhibits excellent electromagnetic properties. This is attributed to the special porous structure and desired electromagnetic impedance matching of the carbon medium as well as the uniform dispersion of Ni nanoparticles in the carbon medium. Namely, the carbon medium is accessible to induced multi-dielectric polarization thereby improving the microwave absorbing properties of the Ni/C nanocomposites, and it also contributes to improving the thermal stability, chemical stability, and dielectric performance of the nanocomposites while the intrinsic magnetic properties of metallic Ni are retained. [ABSTRACT FROM AUTHOR]

Nickel-containing mesoporous silica, Ni-KIT-6, was prepared by directly grinding nickel nitrate into the as-synthesized KIT-6 occluded with template for adsorptive desulfurization of fuels. The obtained materials were well-characterized by N 2 adsorption, XRD, HRTEM, H 2 -TPR, FT-IR, XPS and TG/DTG. The results reveal that the abundant silanols, as well as the confined space between silica walls and template in as-synthesized KIT-6 are highly efficient in dispersing large amount of nickel oxide in the channels of mesoporous silica. Compared with the material synthesized using calcined KIT-6, Ni-KIT-6 demonstrates extremely smaller Ni particles on the support, stronger interaction of Ni with silica matrix and higher content of active Ni 0 in the KIT-6. As a result, the adsorptive desulfurization performance of Ni-KIT-6, both in commercial and model fuels was enhanced. The present strategy not only saves time and energy, but also allows template removal and precursor conversion in one step instead of repeated calcinations in conventional methods. After regeneration of spent sorbent, approximately 100% of adsorption capacity was recovered. [ABSTRACT FROM AUTHOR]

An electrochemically stable and cobalt-free cathode material is prepared by impregnating Li 2 MnO 3 with nickel nitrate and subsequent calcination at 650 °C. X-ray diffraction and scanning electron microscopy reveal a phase pure material with a homogenous distribution of nickel over the particle surface. Structural changes related to the treatment before and after cycling as well as electrochemical performance are investigated. The surface modified samples exhibit improved cycling stability and rate capability. In particular, the material with a nickel content of 5.7 wt% shows 173 mAh g −1 at rate C/10 and 104 mAh g −1 at rate 3C. Furthermore, a constant capacity of 155 mAh g −1 is obtained at rate C/5. Derivative plots of galvanostatic curves in combination with Raman spectroscopy depict a reduced transition from a layered to spinel-like structure compared with pristine Li 2 MnO 3 , while ICP measurements reveal a drastically decreased dissolution of manganese. [ABSTRACT FROM AUTHOR]

Denitration of the aqueous solution of nickel nitrate hexahydrate (Ni(NO 3 ) 2 ⋅6H 2 O) by a microwave heating method was investigated. Since Ni(NO 3 ) 2 ⋅6H 2 O aqueous solution cannot be heated to over 300 °C by microwave irradiation owing to the low microwave absorptivity of its intermediate, the final product of the denitration reaction (NiO) could not previously be obtained by microwave heating. We propose a novel NiO synthesis method that uses microwave heating without the risk of chemical contamination. In this technique, a NiO powder reagent (the same as the final product) was added to the solution of the raw material to function as a microwave acceptor. Moreover, the denitration efficiency to NiO could be improved by setting an adiabator around the reactor to increase the temperature homogeneity in the reactor, as well as raise the temperature at the periphery. Numerical simulations also reveal that the use of the adiabator results in remarkable changes in the electromagnetic field distribution in the reactor; consequently, temperature inhomogeneity decreases. Furthermore, the temperature dependence of the denitration efficiency to NiO, which is calculated from the simulated temperature distribution, approximately agrees with the experimental data. Accordingly, this indicates that the simulated results can estimate the progress of the denitration reaction to NiO using this microwave heating method. [ABSTRACT FROM AUTHOR]

Hydrothermal reaction of cobalt or nickel nitrate with 5- tert -butylisophthalic acid (H 2 tbip) and bis(4-pyridylformyl)piperazine (bpfp) under varying synthetic conditions afforded four coordination polymers that were subsequently structurally characterized via single-crystal X-ray diffraction. {[Co(Htbip) 2 (H 2 O) 2 (bpfp)]·H 2 O} n ( 1 ), prepared with a lower concentration of added base, exhibits a 1D sawtooth chain structure. {[Co 2 (tbip) 2 (H 2 O) 4 (bpfp)]·2H 2 O} n ( 2 ), prepared under higher base conditions, and its analog {[Ni 2 (tbip) 2 (H 2 O) 4 (bpfp)]·2H 2 O} n ( 3 ), show isostructural 1D ladder topologies. {[Ni(tbip)(H 2 O) 2 (bpfp)]·2.25H 2 O} n ( 4 ), prepared using a higher concentration of reactants than for 3 , manifests an extremely rare 6 5 8 4T10 4-connected self-penetrated topology and represents the first metal dicarboxylate coordination polymer to possess this network. Thermal decomposition behavior of these materials is also discussed. [ABSTRACT FROM AUTHOR]

The asymmetric YSZ hollow fibers have been prepared by a phase-inversion method, based on which, the integrated electrolyte/anode hollow fibers are fabricated via a vacuum-assisted impregnation of nickel nitrate. The content of NiO in the integrated hollow fibers enhances linearly from 0 to 42 wt.% with the impregnation cycles from 0 to 10. The porosity of the integrated electrolyte/anode hollow fibers decreases from 43% to 31% with the repeated impregnation and calcination of Ni catalyst. Its conductivity reaches up to 728 S cm −1 after 10 cycles of impregnation. And the mechanical strength of the integrated hollow fiber enhances from 128 to 156 MPa due to the increased NiO content. Based on the integrated electrolyte/anode hollow fibers, the prepared microtubular solid oxide fuel cells (MT-SOFCs) deliver a peak power density of 562 mW cm −2 after ten cycles of Ni impregnation. The cell stability has been verified in 40 thermal cycles with a steady OCV of 1.1 V and stable power density around 560 mW cm −2 operated at 800 °C. [ABSTRACT FROM AUTHOR]

The ferromagnetic tetranuclear nickel(II) complex [Ni4(L)4(CH3OH)2]·2MeOH·8H2O (1) has been synthesized by reacting nickel nitrate hexahydrate with the Schiff base ligand H2L (H2L= N-(2-hydroxyphenyl)-3-methoxy-salicylideneamine). Complex 1 was characterized by analytical, thermogravimetric, optical and magnetic techniques. The solid state structure of 1 was established by single crystal X-ray diffraction analysis. Crystal structure determination shows the formation of a distorted Ni4O4 cubane moiety encapsulated by four Schiff base ligands. Compound 1 crystallizes in the triclinic space group with a =12.7624(9)Å, b =15.0477(9)Å, c =16.8589(10)Å, α =94.732(2)°, β =94.308(2)°, γ =99.136(2)° and Z =2. The magnetic properties of complex 1 show a predominant ferromagnetic coupling inside the Ni4 cluster with g =2.240, J 1 =+0.88cm−1, J 2 =+0.84cm−1, J 3 =−0.014cm−1, J 4 =+1.22cm−1 and D =9.6cm−1. [ABSTRACT FROM AUTHOR]

Abstract: The effects of combinational additive on the DC-bias superposition characteristic of NiCuZn ferrite were investigated experimentally. The composite NiCuZn ferrite was prepared by a conventional ceramic method. The sharp decrease of the permeability can be avoided when the magnetic field is small. It is because the permeability is mainly attributed to the with fine grain size. Owing to the thicker nonmagnetic grain boundary, samples with good DC-bias superposition characteristic can be obtained by special combinational additions. Composite addition of Bi2O3, AlBSi glass, and SnO2 can both retard the grain growth and increase the thickness of the nonmagnetic grain boundary δ. Finally, an excellent performance sample was obtained. [Copyright &y& Elsevier]

Abstract: Two new mononuclear complexes, [Co(L−)2(H2O)2] (1) and [Ni(L−)2(H2O)2] (2) (HL=3-methyl-4-nitro-1-phenyl-5-pyrazolone), have been synthesized by the solvothermal reaction of Co(NO3)2 or Ni(NO3)2 with MPP (MPP=3-methyl-1-phenyl-5-pyrazolone) in acetonitrile solution, and the ligand HL was generated in-situ through the nitration of MPP mediated by cobalt or nickel nitrate rather than mixture acids. Single crystal X-ray diffraction of 1 reveals that 1 consists of one Co(II), two L− and two coordinated water molecules, and Co(II) adopts slightly octahedral geometry. Through intermolecular hydrogen bonding interactions, 1 presents two-dimensional network. Furthermore, the plausible nitration mechanism of MPP was also discussed. [Copyright &y& Elsevier]

Abstract: Nanostructured Co x Ni1−x (OH)2 (x = 0, 0.053, 0.068, 0.116, 0.192) composites are synthesized via a simple template-free growth process onto nickel foam by using a mixed aqueous solution of nickel nitrate, cobalt nitrate and ammonia. Their structure and surface morphology are characterized by X-ray diffraction, energy dispersive X-ray spectroscopy and scanning electron microscopy. The SEM images show changes in the microstructure of β-Ni(OH)2 by the doping of cobalt. The effects of cobalt content on the electrochemical behaviors of β-Ni(OH)2 are investigated by cyclic voltammetries, galvanostatic charge/discharge and electrochemical impedance spectroscopy. The results show that the Co0.116Ni0.884(OH)2 composite electrode exhibits a drastic improvement in the capacitive characteristics of β-Ni(OH)2 with a specific capacitance increase from 386.4 to 1082.6 F g−1 at a high discharging current density of 6 A g−1. This work suggests that the as-prepared Co0.116Ni0.884(OH)2 composite electrode has a promising future as higher charging/discharging rate materials for pseudo-supercapacitors. [Copyright &y& Elsevier]

Abstract: Titanium carbide (TiC) particles were coated with nickel (Ni) to increase their compatibility with a metal matrix, leading to an improvement in the dispersibility of TiC particles in the molten matrix. TiC particles were dispersed into a basic aqueous solution of pH 12, and then nickel nitrate (Ni(NO3)2), as a Ni precursor, was added to the TiC suspension. The interaction between the TiC particles and the Ni precursor is driven by the attractive force between the Ni cations and the TiC particles with negative charge. An inoculant (ferrosilicon), which has been used in the foundry industry to improve crystal growth of graphite, was used as a core particle. The Ni-treated TiC particles were coated onto the surface of the inoculant using an inorganic binder converted into its glass phase by sol–gel reactions. The reinforcement particles prepared through the dual-coating process were then injected into the molten matrix based on iron at 1500°C. The crystal phase of the graphite is more finely and shortly grown in the reinforced metal matrix than in that without the reinforcement particles. This means that the reinforcement particles are homogeneously and uniformly dispersed into the matrix without any aggregation of particles, implying that the mechanical properties of the reinforced matrix would be greater than those of a non-reinforced matrix. Consequently, metal matrix composites with reasonable properties can be fabricated successfully using the reinforcement particles prepared by the dual-coating process. [Copyright &y& Elsevier]

Abstract: Transparent thin films of nickel doped zinc oxide were deposited on to corning glass substrates via chemical spray pyrolysis using zinc acetate and nickel nitrate as precursors. Structural, morphological, optical, electrical, dielectrical and impedance properties of the films as a function of nickel doping concentration as well as inter-particle interactions by complex impedance spectroscopy were investigated. The deposited films are polycrystalline with a hexagonal (wurtzite) crystal structure along (002) preferential orientation. The films are highly transparent in the visible region with a transmittance higher than 86%, and have an optical band gap ranging from 3.23 to 3.19eV depending on the nickel doping concentration. The high electrical conductivity of doped films is explained on the basis of the presence of oxygen vacancies. Decrease of electrical conductivity due to nickel doping is explained on the basis of compensation of oxygen vacancies. The dielectric constant and loss tangent as a function of frequency are reported. Interparticle interactions in the deposited films are studied by complex impendence spectroscopy. [Copyright &y& Elsevier]

Abstract: In this study, we present the preparation of nickel oxide/carbon using sewage sludge as precursor and nickel nitrate as activating agent by one-step pyrolysis method. The nickel oxide could be self-assembled on the surface of sewage sludge based carbon materials. The surface modified carbon adsorbent was characterized by Brunauer–Emmett–Teller (BET) surface area, scanning electron microscopy (SEM), Fourier-transform infrared spectra (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and energy dispersive spectrum (EDS) to illustrate the successful deposition of nickel oxide on the carbon adsorbent. The effect of the surface activation treatment on the adsorption performance of the carbon adsorbents was investigated. The results indicated that the prepared nickel oxide/carbon adsorbents produced beneficial effects on sulfur dioxide adsorption performance due to the existence of nickel oxide and nickel particles. Furthermore, the Fourier-transform infrared spectra and thermogravimetric method are used to illustrate the possible adsorption mechanism. [Copyright &y& Elsevier]

Abstract: In the first part of this paper [1], we have discussed the effect of preparation method on the performance of Ni/Al2O3 catalysts for aqueous-phase reforming of ethanol (EtOH). One catalyst was synthesized using a sol–gel method (SG). The other was synthesized by adding nickel nitrate to a solution combustion synthesized alumina support (SCS). Based on the product distribution, we proposed the reaction pathway as a mixture of dehydrogenation of EtOH to acetaldehyde followed by C–C bond breaking to produce CO and CH4 and oxidation of acetaldehyde to acetic acid followed by decarbonylation to CO2 and CH4. CH4 (C2H6 and C3H8 also) can form via Fischer–Tropsch reactions of CO/CO2 with H2. The CH4 (C2H6 and C3H8) reacts to form hydrogen and carbon monoxide through steam reforming, while CO converts to CO2 mostly through the water-gas shift reaction (WGSR). The SG catalysts showed poorer WGSR activity than the SCS catalysts. The difference of the metal particle size distribution governed by preparation method appeared to be the key factor of controlling catalytic efficiency, but some contradictory results could not be explained. In this paper, we report the microstructural and phase compositional differences of the catalysts imposed by the variation of the preparation methods. The XRD analysis, TEM characterization, and H2-pulse chemisorptions showed that the SG samples sintered and metal particles grew during heat treatment and catalytic reaction, but for the SCS samples these changes are much less severe under similar conditions. N2 adsorption/desorption analysis showed that the used SCS(10%) catalyst contained a mesoporous structure of higher pore volume and the SG(%10) catalyst contained macro pores of smaller pore volume. The X-ray photoelectron spectroscopy (XPS) analysis of the used samples demonstrated less coke deposition and less bulk spinel formation on the SCS(10%) sample than that on the SG(10%) sample. These factors may be responsible for higher water gas shift activity in the SCS(10%) sample than that in the SG(%10) catalyst. For the CM(10%) sample, the large particle size and low dispersion of metal on the support were responsible for lower EtOH conversion, H2 & CO2 selectivity, and TOF values. Additionally, the XPS data showed that the SCS(2%) and SG(2%) catalysts have more bulk spinel than the 10% Ni samples and for SCS(2%) sample this is the highest. This diminishes the advantages of smaller Ni particle sizes and less C deposition for them, and explains the apparently anomalous kinetic results observed in the first part of the paper. [Copyright &y& Elsevier]

Abstract: Various magnetic nanocomposites with carbon-coated nickel structure (Ni@Cs) for selective adsorption of Pb2+ and Cu2+ have been prepared by a simple solid-state method, in which citric acid and nickel nitrate were selected as carbon resource and magnetic substance, respectively. Ni@C-1:5/1:10/1:20 were obtained with various mass ratios (nickel nitrate/citric acid) under the experimental conditions. FESEM and TEM results reveal that the nanocomposite particles exhibit relatively homogeneous distribution in shape/size, possessing mostly carbon-coated structure. Based on the analysis of N2 adsorption–desorption isotherm, the surface areas and pore volumes of the nanocomposites (Ni@C-1:5/1:10/1:20) are (183, 220, 149)m2 g−1 and (0.29, 0.22, 0.08)cm3 g−1, respectively. The saturation magnetization values for the Ni@Cs are as high as (11.82, 5.20 and 3.84)emug−1 obtained by the VSM. Following, the application of the Ni@Cs for the removal of heavy metal ions (Pb2+ and Cu2+) from wastewater as potential and effective adsorbents was investigated. The results reveal the adsorbents possess more accessible active sites and good dispersibility in water, exhibiting excellent performance for selectivity of Pb2+ than that of Cu2+. The results of adsorption behavior are followed the pseudo-second-order kinetics and Freundlich model between the adsorbents and the heavy metal ions. Furthermore, the adsorbents can be recovered easily with an external magnetic field, having a higher remove efficiency after several times. [Copyright &y& Elsevier]

Abstract: The process for synthesizing metallic oxide powders by the microwave denitration method was investigated using hexahydrated nickel nitrate and trihydrated copper nitrate aqueous solutions, and the electrical field and the temperature distributions in the reactor were numerically simulated. Although CuO powder can be obtained from a trihydrated copper nitrate aqueous solution by the microwave denitration method, a hexahydrated nickel nitrate aqueous solution cannot be heated up to over 270°C by microwave irradiation. It was also found that the reaction routes for microwave heating are the same as those for conventional external heating. This finding indicates that the success of producing oxide particles by microwave denitration depends not only on the microwave absorptivity of the intermediate and the metallic oxide, but also on the temperature difference between the completion of the conversion to the intermediate and the beginning of the significant conversion to metallic oxide. Furthermore, the simulation results suggest that the reactor has a radially inhomogeneous temperature distribution with the highest temperature at the center, which causes the denitration reaction to produce CuO powder to progress concentrically from the center of the reactor. [Copyright &y& Elsevier]

Abstract: Novel Ni–Mo/activated carbon (AC) hydrotreating catalysts were prepared and evaluated for upgrading heavy vacuum gas oil (HVGO). The AC supports were derived from Alberta oil sand petroleum coke, i.e. fluid coke and/or delayed coke, hereafter referred to as OSP coke, through a chemical process. The BET surface area was as high as 2194m2/g for the fluid coke derived AC and 2357m2/g for the delayed coke derived AC. Both ACs contained a large number of micropores with pore volume as high as 1.2cm3/g. Ni and Mo based active component precursors could be easily loaded on the activated carbon supports by chemical impregnation of nickel nitrate and ammonium molybdate followed by calcination in nitrogen at 773K without further modification or oxidation treatment to the activated carbons. Scanning electron microscopy (SEM) observation showed highly porous surface structure of the bare activated carbon supports and well dispersed metal (oxide) precursor nanoparticles of 30–50nm loaded on the AC supports. For comparison, two reference catalysts were also prepared by the same procedure but using commercial activated carbon and porous alumina as supports. After catalyst activation by sulfiding, the hydrotreating performance of the prepared catalysts was evaluated in a magnetically stirred autoclave with a HVGO feedstock to examine their hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) activities. Two commercial hydrotreating catalysts were also tested and compared under similar conditions with the same feed. The results showed that the catalysts based on the activated carbon supports prepared from OSP coke had better hydrotreating performance than the other catalysts. Scanning transmission electron microscopy (STEM) characterization of the catalysts after activation showed that small particles of nanostructure (2–5nm in size) were evenly embedded in the carbon matrix except for some bigger particles that were located on the catalyst surface. Energy dispersive X-ray (EDX) spectroscopy revealed that these particles were composed of Ni, Mo and S elements. The dispersed nanoparticles formed the active sites and were responsible for the observed high HDS and HDN activity. Elemental analysis and surface characterization of the spent catalysts showed that the formation of coke precursors was favored on the alumina supported catalyst, which resulted in catalyst deactivation. [Copyright &y& Elsevier]

Abstract: Nickel and copper nitrate complexes with 2,2′-bipyridine (bipy) as a N donor and nitrate and water as oxygen donor ligands of the general formula [M(NO3)(C10H8N2)(H2O)3](NO3), where M=Ni and Cu, have been obtained from the corresponding metal nitrate salts. These complexes were characterized by X-ray crystallography, FT-IR, and CHN analysis. Both the complexes have been found to be six coordinated. Their thermal decomposition behaviour was investigated by TG, DTA, and ignition delay measurements. TG–DTA examinations of these complexes revealed multistep thermal decomposition. The corresponding metal oxide residues obtained after thermolysis were identified from their X-ray diffraction patterns (XRD). Kinetics of isothermal decomposition of the complexes was established from both the model-fitting as well as isoconversional methods. [Copyright &y& Elsevier]

Abstract: Single crystals of hexakis(thiourea)nickel(II) nitrate [Ni(SC(NH2)2)6](NO3)2 are grown by slow evaporation of methanolic solution at room temperature. Structural analysis by single crystal X-ray diffraction analysis reveals that the crystal belongs to monoclinic system with space group C2/c and the cell parameters are a=22.046(2)Å, b=9.3325(4)Å, c=16.221(2)Å, Z=8. The metal is coordinated by six thiourea groups with Ni–S–C bond angles ranging from 114.81° to 116.85° and Ni–S bond lengths lying in the range 2.35 to 2.61Å in a distorted octahedral geometry. The interesting feature observed in this study is that although it crystallizes in centrosymmetric structure, contrary to expectations, it exhibits a positive second harmonic generation (SHG) result, quite likely due to the change in stereochemical arrangement. An Nd:YAG laser with a modulated radiation of 1064nm directed on the powdered sample leads to local noncentrosymmetry and this could be due to the loss of thiourea ligands resulting in tetrakis(thiourea)nickel(II) complex causing green light emission. The powder X-ray diffraction study reveals the crystallinity of the grown material. The vibrational patterns in FT-IR clearly evidence the complex formation. Thermogravimetric analysis (TG) reveals the purity of the sample and no decomposition is observed up to the melting point. The crystal is further characterized by diffused reflectance spectroscopy, dielectric studies and microhardness analysis. [Copyright &y& Elsevier]

Abstract: Al2O3 based grain-sintered filter element support was first impregnated with a fine, wet-milled suspension of a MgO–Al2O3 and successively with nickel nitrate hexahydrate. The catalytic filter candle was inserted in the freeboard of a 0.1m I.D. fluidized bed biomass gasifier, in order to obtain a very compact gasification and hot gas cleaning unit. Continuous catalytic steam gasification runs of almond shells have been performed in a temperature range of 808–813°C (maintained by means of an electric furnace), and the volume composition of the product gas has been analyzed by means of IR, UV and TCD facilities for online detection of CO, CO2, CH4, H2, NH3 and H2S. A 20h test has been performed with intermediate char burning steps. The measured gas yield was 2.09Nm3/kgdaf, meanwhile the gas composition in % by volume was H2 =56, CO=22, CO2 =20, and CH4 =2. NH3 and H2S in the dry gas were 60–80ppmv and 10–15ppmv, respectively. [Copyright &y& Elsevier]

Abstract: Hollow NiO–SnO2 nanospheres have been fabricated via a simple one-pot template-free method. The synthesis is based on solvothermal treatment of stannate and nickel nitrate as the precursor in a mixed solvent of heptane–ethanol. The hollow nanospheres show diameters of about 200–300nm with the wall thickness of about 50nm, and the shell consists of numerous small nanoparticles. The gas sensor based on hollow NiO–SnO2 nanospheres exhibits high response and quick response–recovery to NH3, which are much better compared with sensors based on solid NiO–SnO2 nanospheres. The enhanced sensor performances are attributed to the larger surface area and fast gas diffusion. [Copyright &y& Elsevier]

Abstract: Three identical hydrothermal self-assembly reactions in a mixture of nickel nitrate hexahydrate, nicotinic acid, sodium azide were carried out with the applied magnetic fields of 0, 0.15, 0.3T, respectively. It was found that [Ni1.5(N3)(nic)2(Hnic)] n can be obtained at 160°C for 48h without an applied magnetic field, while the final product totally changed into [Ni2(nic)4(H2O)] as a 0.3T weak magnetic field was employed in the reaction. Both of the two products show three-dimensional frameworks, however, they display two different coordination geometries with different ligands. We consider the mechanism base on changes of magnetic susceptibilities and structures of [Ni2(nic)4(H2O)], and propose a view that the magnetic field can reduce the activation energy of reaction pathways according to transition state theory. The possible reason of the decrease of activation energy is that a magnetic field can mediate coupling among the Ni2+ ions during the formation of [Ni2(nic)4(H2O)], which is indicated by the slight changes of microstructure of crystal, such as bond angle and length. [Copyright &y& Elsevier]

Abstract: Magnetic resonance imaging (MRI) was used to study the process of infiltration and solute transport in an undisturbed soil sample of coarse sandy loam. The sample was subjected to the recurrent ponded infiltration (RPI) experiment, which was carried out in order to assess the changes in the entrapped air volume and its impact on steady state flow rates and solute breakthrough. The main stages of the first and second experimental RPI runs were monitored using an MRI sequence that follows both water density and magnetic relaxation. In a steady state stage of each experimental run a nickel nitrate pulse was injected in order to visualize the solute breakthrough. Effluent from the sample was collected for chemical analysis and a breakthrough curve of the nickel was constructed. To obtain information about the soil structure and to reveal potential preferential pathways, the soil sample was scanned using computed tomography. The local nickel ion transport breakthrough was evaluated from MR images in a series of local observation points distributed along the selected preferential pathways. The preferential flow instability phenomenon with the emphasis on air bubble formation was shown by detecting a 60% decrease of the steady state infiltration rate. The detailed analyses of MRI measurements at observation points revealed air bubble formation, producing a flow rate decrease accompanied by redirection of nickel ion transport trajectories. By analyzing M0 maps it was found that the volumetric water content decrease was 2.2%. [Copyright &y& Elsevier]

Abstract: H2O+Ni(NO3)2 binary system were investigated in the temperature range from −25°C to 55°C. The solid–liquid equilibria of the ternary system H2O+Fe(NO3)3 +Ni(NO3)2 were studied using a synthetic method based on conductivity measurements. Tow isotherms were established at 0°C and 30°C, and the appearing stable solid phases are iron nitrate nonahydrate (Fe(NO3)3·9H2O), iron nitrate hexahydrate (Fe(NO3)3·6H2O), nickel nitrate hexahydrate (Ni(NO3)2·6H2O) and nickel nitrate tetrahydrate (Ni(NO3)2·4H2O). [Copyright &y& Elsevier]

Abstract: A series of Ni/Mg x Al catalysts with different Mg/Al molar ratios were prepared by impregnating Mg–Al mixed oxides with nickel nitrate aqueous solution and used for the pre-reforming of LPG in the temperature range of 400–500 °C. XRD and H2-TPR results showed that the Ni/Mg x Al catalysts calcined at 800 °C mainly consisted of γ-Al2O3, Mg(Ni)Al2O4 and Mg(Ni)O phases varying with Mg/Al molar ratio without free NiO species observed. The effects of Mg/Al molar ratio, S/C molar ratio and reaction temperature on the catalytic behavior of the Ni/Mg x Al catalysts were investigated in detail. The results revealed that the catalyst with Mg/Al molar ratio of 1.25 had the highest catalytic activity and stability. The increase in S/C molar ratio promoted both the steam reforming of LPG and the methanation of carbon oxides and hydrogen. The stability tests of 15%Ni/Mg1.25Al catalyst showed that the catalyst was stable for the pre-reforming of LPG, and the stability decreased with elevating the reaction temperature due to more coke deposition. [Copyright &y& Elsevier]