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We propose a 0-D model describing processes in a system comprising an atmospheric pressure DC discharge and aqueous nickel nitrate solution. The model is represented as two coupled subsystems: plasma and solution. Characteristics of the discharge plasma have been determined by jointly solving the Boltzmann equation for electrons; equations of vibrational kinetics for the ground states of N2, O2, NO, H2, and H2O molecules; and equations of chemical kinetics (328 reactions, 34 components). In doing so, use was made of experimentally determined reduced electric field strength and vibrational and gas temperatures. The kinetics of the processes in the solution included 121 reactions and 34 components. The calculation results agree with experimental data on the vibrational temperatures of N2(X) molecules, the kinetics of the decrease in Ni2+ concentration, and the variation in solution pH. We have determined the degree of Ni2+ conversion and the energy yield of conversion and identified the mechanisms that determine the concentration of the major solution components. [ABSTRACT FROM AUTHOR]

Carbon foam is a material with wide application, whereas it is still a challenge whether the catalytic graphitization process of carbon foam can enhance the performance of the final carbon foam material while reducing energy consumption. In this study, a comparative evaluation was performed on the catalytic effects of nickel, iron, and boron catalysts on the graphitization of carbon foam. Subsequently, the influence of different catalyst loading levels and graphitization temperatures on the thermal conductivity of graphitized carbon foam was investigated. The carbon foam materials were analyzed using X-ray Diffraction (XRD) and Raman spectroscopy, while their thermal conductivity properties were characterized using a thermal conductivity meter. The oil yield from the pyrolysis of rich oil shale was also used to evaluate the thermal performance of carbon foam materials. The results revealed that, compared to Fe and Be, Ni was found to be more suitable for graphitization among the tested catalysts. Furthermore, the optimal conditions for achieving the best graphitization effect on carbon foam material were determined to be a nickel nitrate (Ni(NO3)2·6H2O) concentration of 2 mol/L and a graphitization temperature of 1000 °C. The thermal conductivity of the graphitized carbon foam material prepared under this condition was increased by 25.3% from 0.2016 W·m−1·K−1 to 0.2526 W·m−1·K−1, and the tar yield was increased by 46.4% when it was applied to oil-rich coal pyrolysis. This preparation process not only saves energy but also yields graphitized carbon materials with excellent thermal conductivity, holding promising prospects for a wide range of applications. [ABSTRACT FROM AUTHOR]

A series of Ni/SiO2–Al-x catalysts (x is the initial mass ratio of SiO2 to Al(NO3)3) with different aluminum contents was prepared by impregnation method using nickel nitrate as the Ni source. The prepared Ni/SiO2–Al-x catalysts were characterized by XRD, BET, TPR, TEM, XPS, NH3-TPD, and Py-FTIR methods. Taking m-cresol as a model compound, the effects of aluminum content and reaction conditions on the HDO performance were investigated. Results showed that addition of appropriate amount of aluminum can generate acid sites and improve the metal Ni dispersion by increasing the surface area of catalyst. Furthermore, the selectivity to deoxygenated methyl-cyclohexane product over aluminum modified Ni/SiO2–Al-x catalysts increased significantly as compared to that of Ni/SiO2, which confirmed the importance of aluminum addition on the dehydration of 3-methyl-cyclohexanol to methyl-cyclohexane. Among the prepared Ni/SiO2–Al-x catalysts, the Ni/SiO2–Al-5 catalyst exhibits the best HDO performance. A 100% m-cresol conversion with the selectivity to MCH of 100% was achieved under the conditions of T = 250°C, p = 2 MPa, t = 75 min with catalyst (mg)/m-cresol solution = 2. [ABSTRACT FROM AUTHOR]

Lead (Pb) and nickel (Ni) are serious soil pollutants that adversely affect plant growth and development and need to be removed through phytoremediation. The present study aimed to assess the morphological indices of Albizia lebbeck (L.) (Benth.) in relation to anatomical modifications for survival under both Pb and Ni stress. The seedlings of A. lebbeck were established and then subjected to four different concentrations, viz. 0 mM, 25 mM, 50 mM and 75 mM, of Pb and Ni for 14 days in two phases. Morphological traits such as shoot length (70.93%), fresh weight (79.27%), dry weight (83.9%), number of root hairs (65.7%), number of leaves per plant (67.4%) and number of leaflets per plant greatly reduced under Pb or Ni stress. Surprisingly, root length increased rather than decreased with the increase in Pb or Ni concentrations, along with an increase in leaflet width, leaflet length and leaflet area. Moreover, root cortical cell area, metaxylem area and phloem area decreased at 75 mM of Pb and Ni while epidermal thickness and cell area increased. Stem epidermal thickness, cell area and phloem area significantly decreased with the consistent increase in metaxylem area and cortical region thickness under both Pb and Ni stress. Leaf anatomical traits such as midrib thickness, abaxial epidermal thickness and stomatal density and adaxial epidermal thickness and stomatal area significantly increased with increasing Pb or Ni stress. Correlation analysis revealed close relations among morphological and anatomical traits (such as root length with cortical region thickness) for better plant survival under Pb or Ni stress, and a PCA-biplot further verified these correlation analyses. Cluster analyses demonstrated the associations among the morphological and anatomical traits based on different stress levels. Furthermore, we found that the longer exposure (from phase 1 to phase 2) of heavy metals stress is more dangerous for plant survival and can ultimately lead to plant death. Moreover, our results also confirmed that Ni is more harmful or dangerous to plants than Pb at high and moderate concentrations. The anatomical modifications ensured the survival of A. lebbeck in extreme heavy metals stress and therefore unlocked its potential to be used as a natural source of phytoremediation. We also recommend that the genetic potential of A. lebbeck associated with its survival under heavy metal stress be investigated. [ABSTRACT FROM AUTHOR]

An alternative route to synthesize Ni2P–N/TiO2 in N2 atmosphere instead of H2 atmosphere by thermal treatment method was proposed, and the Ni2P–N/TiO2 catalyst was investigated in benzofuran hydrodeoxygenation (BF HDO) performance. X-ray diffraction (XRD), transmission electron microscope (TEM), N2-adsorption specific surface area measurements, CO uptake and X-ray photoelectron spectroscopy (XPS) were used to characterize the catalysts. The results showed that, the Ni2P–N/TiO2 catalyst possessed a smaller and highly dispersed Ni2P particles on the catalysts showed a higher benzofuran hydrodeoxygenation conversion (91.9%) and ethylcyclohexane selectivity (70.4%). [ABSTRACT FROM AUTHOR]

Hybrid carbons/metals/metal (metalloid) oxides composites could be effective adsorbents for low– and high– molecular weight compounds, polar and nonpolar, gaseous and liquid. The presence of metal nanocrystallites and carbon nanostructures could provide catalytic properties in redox reactions. For more effective use of hybrid composites, their morphological, structural, textural, and adsorption characteristics should be appropriate for target applications and, therefore, well controlled. Therefore, the aim of this study was to synthesize carbon/metal/silica nanostructured composites with varied content of metal (Ni) to control the mentioned characteristics. Precipitated silica Sipernat 50 was selected as a substrate. Potato starch was used as a carbon precursor. Nickel nitrate (Ni(NO3)2∙6H2O) of varied amounts was used as a precursor of Ni nanoparticles reduced upon the starch carbonization. After the starch carbonization and Ni reduction, a set of C/Ni/silica samples was studied using atomic force microscopy, X–ray diffraction, X–ray fluorescence spectroscopy, nitrogen and p-nitrophenol adsorption, thermogravimetry, and Raman spectroscopy. The presence of nickel phase results in the formation of smaller but denser packed char nanoparticles. Estimation of possible contribution of pores accessible for nitrogen molecules in silica globules and outer surface of carbon/Ni particles suggests that the carbon phase is porous that provides a significant part of the specific surface area of the composites. Amorphous silica and char phases are characterized by the presence of certain nuclei of radius (R) < 1 nm and 2 nm < R < 10 nm estimated from the XRD patterns using full peak profile analysis with a self–consistent regularization procedure. Ni crystallites are of several sizes, since particle size distributions include two–three peaks in the range of 3–13 nm in radius. The Raman spectra show that the main changes with increasing Ni content are characteristic to sp³ carbon structures (D line) in contrast to the sp² structures (G line). The pore size distributions (both differential and incremental) demonstrate complex changes in a broad size range due to increasing Ni content in composites. As a whole, changes in the Ni content in nanostructured C/Ni/silica composites allow one to control the morphological, structural, and textural characteristics of the whole materials. [ABSTRACT FROM AUTHOR]

Nickel nitrate is a heavy metal known as an environmental contaminant due to its toxicity, long environmental half-lives, and capacity for bioaccumulation. This study aims to determine chromosomal aberration, nuclear alteration, and cell death in Allium cepa var. aggregatum L. root caused by different nickel concentrations. Roots of Allium cepa var. aggregatum were induced by soaking bulbs in water, then transferred to a solution containing nickel (Ni) at a concentration of 20 ppm, 30 ppm, and 40 ppm for 72 hours. Root tip mitotic chromosome preparations were done by the squash method. The chromosome was stained with aceto-orcein and chromosomal damages were observed under a microscope. The results showed that the mitotic index decreased from 5.025% at control to 3.144%, 2.467%, and 2.181% at immersion with 20 ppm, 30 ppm 40 ppm nickel nitrate, respectively. Anaphase and telophase indexes in roots with Ni treatments were lower than in control, suggesting that nickel inhibits cell division. Nickel nitrate induced chromosomal damages and nuclear abnormalities, such as sticky chromosome, fragmented chromosome, chromosome bridge and chromosome laggard, micronuclei, binucleate and nuclear budding. The percentage of chromosomal damage increases with a higher concentration of Ni. In situ cell visualization showed that the higher the nickel concentration, the more coloured the root tips indicating high levels of cell death. [ABSTRACT FROM AUTHOR]

Water electrolysis for energy-efficient H2 production coupled with hydrazine oxidation reaction (HzOR) is prevailing, while the sluggish electrocatalysts are strongly hindering its scalable application. Herein, we schemed a novel porous Ce-doped Ni3N nanosheet arrays grown on nickel foam (Ce-Ni3N/NF) as a remarkable bifunctional catalyst for both hydrogen evolution reaction and HzOR. Significantly, the overall hydrazine splitting system can achieve low cell voltages of 0.156 and 0.671 V at 10 and 400 mA·cm−2, and the system is remarkably stable to operate over 100 h continuous test at the high-current-density of 400 mA·cm−2. Various characterizations prove that the porous nanosheet arrays expose more active sites, and more excellent diffusion kinetics and lower charge-transfer resistance, therefore boosting catalytic performance. Furthermore, density functional theory calculation reveals that the incorporation of Ce can effectively optimize the free energy of hydrogen adsorption and promote intrinsic catalytic activity of Ni3N. [ABSTRACT FROM AUTHOR]

Nickel hydroxides are widely used as electrochemically active substances in alkaline batteries and hybrid supercapacitors; they can be used for electrocatalysis, in electrochemical sensors, and as pigments. Knowledge of the formation mechanism of nickel hydroxides is necessary for developing and optimizing targeted synthesis methods. The thermal effects of processes in the formation of nickel hydroxide from nitrate were studied by the calorimetry method. The mechanism of precipitate formation was investigated by the method of simultaneous potentiometric (with a glass universal electrode) and conductometric titration. The nickel content in the samples obtained at the determined NaOH/Ni2+ ratios was investigated by the chemical method of trilonometry after preliminary dissolution. Calorimetric investigations showed that the reaction of nickel nitrate with NaOH was exothermic with ΔНreaction=‒28328.5 J/mol. The exothermic nature of the NaOH dilution process was revealed with ΔНdilution =‒2454 J/mol. According to the results of potentiometric titration, the formation of a basic salt of the NiOHNO3 type was not detected. Analysis of the results of conductometric titration revealed a two-stage chemical mechanism for the formation of nickel hydroxide from nitrate. At the first stage, which had a high rate, due to the liquid-phase reaction of the nickel cation with the hydroxyl anion, a primary precipitate of the composition Ni(OH)1.87(NO3)0.13 was formed. In the second stage, as a result of a slow topochemical reaction of the primary precipitate with hydroxyl anions, nitrate ions were displaced from the precipitate to form nickel hydroxide. These data are confirmed by the analysis of precipitate obtained at NaOH/Ni2+ ratios of 1.87 and 2.2: the Ni content was 52.95 % and 55.63 %, corresponding to the formulas Ni(OH)1.87(NO3)0.13∙0.68H2O and Ni(OH)2∙0.71H2O. This clearly indicated that the primary precipitate was nitratedoped α-Ni(OH)2 and the final precipitate corresponded to the α-modification of nickel hydroxide. [ABSTRACT FROM AUTHOR]

In this paper, the spectrophotometric properties of a colored Nickel-based solution complex (Nickel nitrate hexahydrate and Methyl Orange (MO)) were investigated as a stable chemical dosimeter with a simple synthesis and low cost for use in radiation processing. The maximum absorbance for the solution was observed at 460 nm. This solution was irradiated at three different concentrations of Ni(No3)2.6H2O and MO by Co-60 gamma-ray. The results showed the solution absorbance decreases with an increase in doses, and this solution can be used as a routine dosimeter and has a linear response in the 50 to 1500 Gy range with acceptable repeatability and stability in environmental conditions up to 40 days before and after irradiation. [ABSTRACT FROM AUTHOR]

Lead (Pb) and nickel (Ni) are serious soil pollutants that adversely affect plant growth and development and need to be removed through phytoremediation. The present study aimed to assess the morphological indices of Albizia lebbeck (L.) (Benth.) in relation to anatomical modifications for survival under both Pb and Ni stress. The seedlings of A. lebbeck were established and then subjected to four different concentrations, viz. 0 mM, 25 mM, 50 mM and 75 mM, of Pb and Ni for 14 days in two phases. Morphological traits such as shoot length (70.93%), fresh weight (79.27%), dry weight (83.9%), number of root hairs (65.7%), number of leaves per plant (67.4%) and number of leaflets per plant greatly reduced under Pb or Ni stress. Surprisingly, root length increased rather than decreased with the increase in Pb or Ni concentrations, along with an increase in leaflet width, leaflet length and leaflet area. Moreover, root cortical cell area, metaxylem area and phloem area decreased at 75 mM of Pb and Ni while epidermal thickness and cell area increased. Stem epidermal thickness, cell area and phloem area significantly decreased with the consistent increase in metaxylem area and cortical region thickness under both Pb and Ni stress. Leaf anatomical traits such as midrib thickness, abaxial epidermal thickness and stomatal density and adaxial epidermal thickness and stomatal area significantly increased with increasing Pb or Ni stress. Correlation analysis revealed close relations among morphological and anatomical traits (such as root length with cortical region thickness) for better plant survival under Pb or Ni stress, and a PCA-biplot further verified these correlation analyses. Cluster analyses demonstrated the associations among the morphological and anatomical traits based on different stress levels. Furthermore, we found that the longer exposure (from phase 1 to phase 2) of heavy metals stress is more dangerous for plant survival and can ultimately lead to plant death. Moreover, our results also confirmed that Ni is more harmful or dangerous to plants than Pb at high and moderate concentrations. The anatomical modifications ensured the survival of A. lebbeck in extreme heavy metals stress and therefore unlocked its potential to be used as a natural source of phytoremediation. We also recommend that the genetic potential of A. lebbeck associated with its survival under heavy metal stress be investigated.

Hydrogen peroxide (H2O2) 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 H2O2 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 H2O2 under Xenon lamp irradiation.

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]

Although catalytic dry reforming of methane has recently attracted considerable attention from both environmental and economical points of view, due to the simultaneous utilization of two greenhouses with a high environmental impact, CO2 and CH4, and to the production of syngas (CO and H2 mixtures), a building block used for the synthesis of valuable chemicals and synthetic fuels, it has not yet been commercialized. Low-cost Ni-based catalysts with high activity have been developed. However, due to their major drawbacks (such as carbon formation and Ni particles sintering at high temperatures, which is required by the endothermic reaction), their industrial applicability is limited. What is more, access to advanced characterization techniques is needed to monitor coke deposition and to assess the efficiency of the dry reforming process, access which can be challenging for small and on-site laboratories. The focus of this current study is on the development and testing of a simple carbon deposition prediction method, which is easily accessible, based on the comparison of the gas composition measured at the exit of the reactor with the theoretical one, and calculated based on the process thermodynamics. Trustworthy results, confirmed by SEM and TGA/DSC measurements, were obtained when the method was applied for the monometallic, Ni/SBA-15, prepared by wet impregnation, and bimetallic, Ni-Co/SBA-15, and Ni-La/SBA-15 samples, prepared by both impregnation and co-impregnation, with different metal loading. The dry reforming process was performed at four temperatures: 550, 600, 650, and 700°C.

Introduction Contamination of soils with heavy metals is often resulted from human activities and phytoremediation is an effective and economic strategy to remove toxic metals from soils. Heavy metals are significant environmental pollutants, and their toxicity is a problem of increasing significance for ecological, evolutionary, nutritional and environmental reasons. The term ‘‘heavy metals’’ refers to any metallic element that has a relatively high density greater than 4 g/cm3, or 5 times or more, greater than water and is toxic or poisonous even at low concentration. However, chemical properties of the heavy metals are the most influencing factors compared to their density. Heavy metals include lead (Pb), cadmium (Cd), nickel (Ni), cobalt (Co), iron (Fe), zinc (Zn), chromium (Cr), iron (Fe), arsenic (As), silver (Ag) and the platinum group elements. Plants experience oxidative stress upon exposure to heavy metals that leads to cellular damage. In addition, plants accumulate metal ions that disturb cellular ionic homeostasis. To minimize the detrimental effects of heavy metal exposure and their accumulation, plants have evolved detoxification mechanisms. Such mechanisms are mainly based on chelation and subcellular compartmentalization. Chelation of heavy metals is a ubiquitous detoxification strategy described in wide variety of plants. The aim of this study was to investigate the effect of different compounds to reduce the toxicity and accumulation of heavy metals in the planting bed is pinto beans. Materials & Methods In order to evaluate the effects of different growing substrates on reducing toxicity and phytoremediation bean (cv. Sadri) under heavy metals, a greenhouse experiment was conducted as a factorial for four heavy metals (Cd(NO3)2, Pb(NO3)2, Ni(NO3)2 and CuSO4) seperately, based on CRD design with three replications in Yasouj University, 2013. The first factor included of four levels of different growing substrates (control, compost, vermicompost and Populus sawdust) and the second factor included of two levels of heavy metals (heavy metals with 50 mg kg-1 soil concentration and control). Results & Discussion Analysis of variance showed that the effect of organic compounds and cadmium nitrate in the soil and their interactions on amounts of cadmium accumulation in roots, shoot and grain was statistically significant. Compost and vermicompost significantly increased cadmium. Vermicompost can be used to remove metals from contaminated soils used because it is linked with metals and increases nutrient uptake by providing. A cadmium concentration in shoot tissue was more than adequate at all levels of the leveas (0.2-0.05 mg/kg dry weight). Lead levels in the tissues of roots, shoots and seeds in all treatments were the detection limit. It seems that due to the low accumulation of lead in beans can be attributed to the low mobility of lead in soil and plant. Means comparison showed the highest accumulation of nickel in the root of the control (normal soil) with an average of 14.45 mg/kg dry weight of roots and the lowest value of this attribute in use of poplar sawdust with an average of 11.42 mg/kg root dry weight that using compost and vermicompost was not significantly different. Analysis of variance showed that the effect of organic compounds in soil, copper sulfate and their interactions on the amount of copper metal roots was significant. When the low copper concentration in soil, compost and vermicompost with the stabilization of copper available and disabling decrease copper absorption and accumulation by the plants, but the high concentration of copper in the soil, add compost, vermicompost and poplar sawdust will not be enough to stabilize all accessible copper. In this study, the use of poplar sawdust to accumulate the highest amount of copper in copper sulphate roots in levels zero and 50 mg per kg dry weight soil. Conclusion The results showed that the use of compost and vermicompost increased amounts of cadmium accumulation in shoot and root. On the other side, compost and Populus sawdust decreases the amount of nickel in the bean shoot and root. Also, the highest accumulation of copper in roots of beans was achived by application of the Populus sawdust and compost. Accumulation of heavy metals in roots far more than shoots and seeds. In general, the results of this study showed that due to low accumulation of heavy metals in the seed of bean and high absorption by the root and shoot, this plant is suitable for cultivation in contaminated areas and if possible leaving the roots and shoots is also appropriate for the purification.

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]

Summary: The fabrication of flexible supercapacitors was achieved by employing the novel redox‐activated polymer electrolytes comprising poly(vinylphosphonic acid) (PVPA) and nickel nitrate Ni(NO3)2, Ni. The hydrogels, PVPA/NiX, were produced in various contents, in which X denotes the doping fraction of Ni in PVPA. The structure, thermal, and morphology of the materials were characterized, and then they were applied for construction of supercapacitors. The performance evaluations of the fabricated devices were carried out by electrochemical impedance spectroscopy, galvanostatic charge‐discharge, and cyclic voltammetry experiments. Flexible supercapacitor devices assembled with activated carbon (AC) electrodes and PVPA/NiX hydrogels produced 793 F g−1 specific capacitance with 30 times enhanced capacitance compared with Ni‐free system. The energy density of 103.1 Wh kg−1 was yielded from the device at a power density of 500 W kg−1. The supercapacitor demonstrated an excellent performance during 5.000 charge‐discharge cycles, while preserving 84% of its initial capacitance. The supercapacitor constructed of 1 × 5 cm dimension, successfully operates the LED after charging at 3 V. [ABSTRACT FROM AUTHOR]

Single crystalline Ni nanowires (with a controlled diameter of ∼14 nm) have been fabricated by electrochemical deposition in etched ion-track polycarbonate templates. The exchange bias effect in these nanowires has been studied at 10 K under a cooling field of 10 kOe applied parallel to the wire axis for different time intervals starting from the as-fabricated to ∼2 yr old samples. A continuous drop in the saturation magnetization has been observed with time due the formation of an antiferromagnetic oxide layer at the periphery of nanowires. A model for the drop of magnetization has been used to calculate the thickness of the oxide layer in nickel nanowires. The observed variation in exchange bias and saturation magnetization has been explained by taking into account the exchange interactions at the Ni-NiO interface and the development of antiferromagnetic NiO at the expense of metallic Ni. [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]

In this work, carbon nanotubes (CNTs) were synthesized by catalytic pyrolysis from waste polyethylene in Ar using an in-situ catalyst derived from ferric nitrate and nickel nitrate precursors. The influence factors (such as temperature, catalyst content and Fe/Ni molar ratio) on the formation of CNTs were investigated. The results showed that with the temperature increasing from 773 to 1073 K, the carbon yield gradually increased whereas the aspect (length-diameter) ratio of CNTs initially increased and then decreased. The optimal growth temperature of CNTs was 973 K. With increasing the Fe/Ni molar ratio in an FeNi bimetallic catalyst, the yield of CNTs gradually increased, whereas their aspect ratio first increased and then decreased. The optimal usage of the catalyst precursor (Fe/Ni molar ratio was 5:5) was 0.50 wt% with respect to the mass of polyethylene. In this case, the yield of CNTs reached as high as 20 wt%, and their diameter and length were respectively 20–30 nm, and a few tens of micrometers. The simple low-cost method developed in this work could be used to address the environmental concerns about plastic waste, and synthesize high value-added CNTs for a range of future applications.

We have completed a series of small-scale cook-off experiments of ammonium nitrate (AN) prills in our Sandia Instrumented Thermal Ignition test at nominal packing densities of about 0.8 g/cm3. We increased the boundary temperature of our aluminum confinement cylinder from room temperature to a prescribed set-point temperature in 10 min. Our set-point temperature ranged from 508 to 538 K. The external temperature of the confining cylinder was held at the set-point temperature until ignition. We used type K thermocouples to measure temperatures associated with several polymorphic phase changes as well as melting and boiling. As the AN boiled, our thermocouples were destroyed by corrosion, which may have been caused by reaction of hot nitric acid (HNO3) with nickel to form nickel nitrate, Ni(NO3)2. Videos of the corroding thermocouples showed a green solution that was similar to the color of Ni(NO3)2. We found that ignition was imminent as the AN boiling point was exceeded. Ignition of the AN prills was modeled by solving the energy equation with an energy source due to desorption of moisture and decomposition of AN to form equilibrium products. A Boussinesq approximation was used in conjunction with the momentum equation to model flow of the liquid AN. We found that the prediction of ignition was not sensitive to small perturbations in the latent enthalpies. [ABSTRACT FROM AUTHOR]

High Ni2+ levels are toxic to plant growth; however, being a micro-nutrient, its application and/or presence in low concentration may improve plant growth. Present study investigated the effects of exogenous Ni application on morpho-physiological attributes of two rice cultivars in China i.e., Yuxiangyouzhan and Meixiangzhan 2. Nickel was applied exogenously to 11 days old seedlings as Ni(NO3)2 in a solution form in the following concentrations: 0.1 mM (Ni1), 0.2 mM (Ni2) and 0.5 mM (Ni3). The seedlings without Ni2+ application were taken as control. Results showed that exogenous Ni2+ application improved the early growth of seedlings in terms of seedling length, basal diameter, biomass accumulation and seedling index. Substantial improvements were also observed regarding chl a, chl b, total chl contents and carotenoids in plants under Ni2+ application compared to CK. Furthermore, all Ni2+ treatments decreased the content of Malondialdehyde (MDA). Among all applied concentrations, Ni2 proved better regarding its promotive effects, however further research is needed to explore the molecular basis of Ni-induced modulations in seedlings of both rice cultivars. [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]

A novel metal-amino acid assembly is successfully prepared using the simplest amino acid structure – glycine – and nickel nitrate hexahydrate. Two-dimensional porous Ni-Glycine coordination complex [Ni(NH 2 CH 2 COO) 2 ](H 2 O) (CQU-Chen-Gly-Ni-2-1) sheets with 3D nanoflake array structures have been prepared by a facile and cost-effective method. As electrode materials for supercapacitors, the Ni-Glycine coordination complexes display a high specific capacitance of 2.34 F·cm −2 at 1.08 mA·cm −2 (2171.71F·g −1 at a current density of 1 A·g −1 ), outstanding rate performance (80.77% capacity retention from 1.08 to 10.8 mA·cm −2 ) and superior cycling performance (2.4% loss after 5000 cycles at 10.8 mA·cm −2 ). In addition, the optimized asymmetric supercapacitor could be cycled reversibly in the high-voltage region of 0–1.8 V. Furthermore, excellent asymmetric supercapacitors of Ni-Glycine//activated carbon were also fabricated, and exhibited high energy densities of 35.05 and 16.75 Wh·kg −1 at power densities of 900 and 9000 W·kg −1 , respectively. These fascinating performances can be attributed to the high capacitances and positive synergistic effects of the two electrodes. The impressive results presented here may pave the way for promising applications in high energy density storage systems. [ABSTRACT FROM AUTHOR]

Following an initial, brief, review of the environmental problems associated with the use of lead based primers, and also some of their potential replacements, this study investigated the preparation of the promising, lead free, energetic material nickel hydrazine nitrate by different methods. All three methods trialed produced the same, analytically indistinguishable, compound but with minor changes in visual appearance. The solution properties governing the precipitation process were investigated in a controlled pH titration experiment. Product solubility in a number of common solvents was investigated. Aqueous ammonia and hydrazine hydrate proved the best "non‐destructive solvents" for the solid. UV spectroscopy and conductivity of the solutions obtained was used as an indicator of the processes involved in the solubility. Using the critical pH conditions for precipitation from aqueous solutions of hydrazine and nickel nitrate the formation constant for the tris hydrazine complex was determined. Also using the solubility of the tris‐hydrazine complex in concentrated hydrazine hydrate an equilibrium constant for the formation of the soluble hexa‐hydrazine complex from insoluble tris hydrazine complex was determined. These values were compared with similar values for nickel hydrazine complexes with other anions. The origins of these differences were discussed. Further work on controlling and measuring the particle size of the NiHN produced should be considered. [ABSTRACT FROM AUTHOR]

Calcined Cu-based metal–organic frameworks impregnated with nickel nitrate catalysts (CuNi@C) were synthesised. X-Ray diffraction, scanning electronic microscopy, energy dispersive X-ray spectrometry, and X-ray photoelectron spectroscopy techniques were applied for the characterisation of the synthesised catalyst, which revealed an octahedral particle shape, rough surface, and metallic copper (Cu, CuO) and nickel (Ni, NiO) particles. CuNi@C was fabricated as a novel peroxymonosulfate (PMS) activator for the oxidative degradation of Acid Orange 7 (AO7) in aqueous media. Results showed that the CuNi@C/PMS system can efficiently degrade nearly 100 % of 0.02 mmol L−1 AO7 within 60 min. In addition, the trapping experiments confirmed the participation of sulfate radicals (SO4•−) and hydroxyl radicals (HO•) as reactive species in the system. Furthermore, the effects of parameters including catalyst and PMS dosages, initial concentration of AO7, and pH were studied. Results showed that the decolourisation efficiency increased with the increase of catalyst dosage, but decreased with the increase of AO7 concentration. The optimal PMS concentration was 0.675 mmol L−1, and initial pH showed no significant effect on the degradation of AO7. Moreover, the CuNi@C could be reused four times with good activity and reusability. Findings revealed that the CuNi@C/PMS system shows potential for degrading contaminants in the environment, due to its catalytic activity and non-negligible adsorption. Metal–organic frameworks have been increasingly proposed as heterogeneous catalysts for advanced oxidation processes. CuNi-MOFs were synthesised for the activation of peroxymonosulfate to degrade Acid Orange 7 and showed good catalytic activity and non-negligible adsorption. Findings revealed that the CuNi-MOFs/PMS system shows potential for degrading contaminants in the environment. [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]

A systematic study of the solid-liquid equilibria of the H 2 O-Co(NO 3 ) 2 -Ni(NO 3 ) 2 ternary system enabled to define the liquidus and the solidus curves of the isotherms at 287.15 K and 313.5 K. Two widespread solid solutions, Co (1-σ) Ni σ (NO 3 ) 2 .6H 2 O and Ni (1-ω) Co ω (NO 3 ) 2 .6H 2 O, were observed. They were formed by the substitution of Co 2+ cations by Ni 2+ cations in the monoclinic structure of the cobalt nitrate hexahydrate and the substitution of Ni 2+ by Co 2+ in the triclinic structure of the nickel nitrate hexahydrate. Two series of tie-lines for each crystallographic structure of these hexahydrates were obtained. The analyses of these tie-lines and those of the previous studies at 258.15 K and 303.15 K enabled a thermodynamic modelling of the solid-liquid equilibria within a temperature range from 258.15 K to 313.15 K. The simple equation system obtained allows to calculate the accurate composition of the mother solution, at a defined temperature, to reach the appropriate cationic ratio in the crystallised solid solution. [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]

Freestanding two dimensional (2D) porous nanostructures have great potential in electrical energy storage. In the present work, we reported the first synthesis of two-dimensional (2D) β-Ni(OH) 2 thin sheets (CQU-Chen-Ni-O-H-1) assembled by 3D nanoflake array as basic building units under acid condition by direct hydrothermal decomposition of the mixed solution of nickel nitrate (Ni(NO 3 ) 2 ) and acetic acid (CH 3 COOH, AA). The unique 3D nanoflake array assembled mesoporous 2D structures endow the thin sheets with a high specific capacitance of 1.78 F cm −2 (1747.5 F g −1 ) at the current density of 1.02 mA cm −2 and good rate capability of 67.4% retain from 1.02 to 10.2 mA cm −2 . The corresponding assembled asymmetric supercapacitor (ASC) achieves (CQU-Chen-Ni-O-H-1//active carbon (AC)) a high voltage of 1.8 V and an energy density of 23.45 W h kg −1 with a maximum power density of 9 kW kg −1 , as well as cycability with 93.6% capacitance retention after 10,000 cycles. These results show the mesoporous thin sheets have great potential for SCs and other energy storage devices. [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]

It is of great importance to design and exploit high-efficiency low-cost electrocatalysts for the oxygen evolution reaction (OER) under mild conditions for applications. In this Article, we propose that formation of a thin amorphous Ni carbonate layer on Ni 3 N nanoarray supported on carbon cloth (Ni 3 N NA/CC) is an effective strategy to boost its OER activity in at near-neutral pH. When used as a 3D non-noble-metal OER electrocatalyst, the resulting core–shell Ni 3 N@Ni-Ci NA/CC displays superior catalytic activity with extremely small overpotential of 400 mV for 20 mA cm −2 in 1.0 M KHCO 3 (bulk pH: 8.3). Moreover, it also exhibits considerable long-term electrochemical durability with its activity being preserved for at least 12 h. Conductive Ni 3 N nanoarray not only provides as the Ni source for in-situ electrochemical derivation of 3D Ni-Ci catalyst with high surface area, more exposed active sites and facilitated mass diffusion, but effectively prompts the electron transport from Ni-Ci shell to CC, enabling more efficient water oxidation electrocatalysis. [ABSTRACT FROM AUTHOR]

By using catalysts of $$\hbox {Co/Mg}_{1-\mathrm{x}}\hbox {Ni}_{\mathrm{x}}\hbox {O}$$ (x= 0, 0.03, 0.07, 0.15; 1 wt% Co each), we performed the dry reforming of methane. The catalysts were prepared by $$\hbox {K}_{2}\hbox {CO}_{3}$$ co-precipitation from aqueous nickel nitrate hexahydrate and magnesium nitrate hexahydrate. Impregnation of cobalt(II)acetylacetonate onto MgO-NiO was then conducted. TEM, XRD, FTIR, XRF, XPS, and BET characterizations of the catalysts were carried out. Results showed that the catalysts were reduced at $$700\, ^{\circ }\hbox {C}$$ by $$\hbox {H}_{2}$$ prior to each reaction. $$\hbox {CH}_{4}$$ and $$\hbox {CO}_{2}$$ conversions at $$900\, ^{\circ }\hbox {C}$$ of the catalysts after being tested for 200 h decreased in the arrange $$\hbox {Co/Mg}_{0.85}\hbox {Ni}_{0.15}\hbox {O}$$ , $$\hbox {Co/Mg}_{0.93}\hbox {Ni}_{0.07}\hbox {O}$$ , $$\hbox {Co/Mg}_{0.97}\hbox {Ni}_{0.03}\hbox {O}$$ , and Co/MgO. The highest $$\hbox {H}_{2}$$ and CO selectivities were observed at a 1:1 $$\hbox {CH}_{4}{:}\hbox {CO}_{2}$$ mole ratio. We further performed a dry reforming in the presence of low-concentration oxygen flow (1.25 Vol %) and found an increased $$\hbox {CH}_{4}$$ conversion. Graphical Abstract : SYNOPSIS. Dry reforming of methane (DRM) with catalyst $$\hbox {Co/Mg}_{1-X}\hbox {Ni}_{X}\hbox {O}$$ was investigated. Methane molecule adsorbed on Co metal and released $$\hbox {H}_{2 (g)}$$ . Carbon deposits were observed on the surface of Co metal, and the MgO surface adsorbed $$\hbox {CO}_{2}$$ to release CO and O atoms. Subsequently, oxygen atoms transferred onto the Ni and combination with carbon deposits on the metal catalyst enabled CO production [ABSTRACT FROM AUTHOR]

Nanoparticles (NPs) such as nickel (Ni) are widely used in several applications. Nevertheless, the environmental effects of Ni NPs are still poorly understood. In the present study, the toxicity of Ni NPs and nickel nitrate (NiNO3) was assessed using the standard test species in soil ecotoxicology, Enchytraeus crypticus (Oligochaeta), in a full life cycle test, adding the endpoints hatching, growth, and time to reach maturity, besides survival and reproduction as in the standard Organisation for Economic Co-operation and Development Guideline 220 and/or International Organization for Standardization 16387. For Ni NPs, the Ni in soil and in soil solution was concentration- and time-dependent, with a relatively higher soil solution content in the lower and shorter exposure concentrations and times. Overall, NiNO3 was more toxic than Ni NPs, and toxicity seemed to occur via different mechanisms. The former caused reduced hatching (50% effect concentration [EC50] = 39 mg Ni/kg soil), and the negative effects remained throughout the life cycle, in all measured endpoints (growth, maturation, survival, and reproduction). For Ni NPs, hatching was the most sensitive endpoint (EC50 = 870 mg Ni/kg soil), although the organisms recovered; that is, additional endpoints across the life cycle showed that this effect corresponded to a delay in hatching because organisms survived and reproduced at concentrations up to 1800 mg Ni/kg soil. On the other hand, the lowest tested concentration of Ni NPs (100 mg Ni/kg soil) caused reproduction effects similar to those at higher concentrations (1000 and 1800 mg Ni/kg soil). The present results show that the potential implications of a nonmonotonic dose response should be considered when assessing the risks of Ni NP exposure in soil. Environ Toxicol Chem 2017;36:2934-2941. © 2017 SETAC [ABSTRACT FROM AUTHOR]

Solvent engineering for the electrochemical preparation of porous, thick, and adherent nickel oxide layers is investigated. The deposition of this oxide is studied in pure aprotic dimethyl sulfoxide (DMSO) medium and in DMSO/water mixtures through the cathodic reduction of a nickel nitrate precursor. In pure DMSO, the as-grown layers were a mixture of directly obtained NiO and metallic nickel. On the other hand, in the presence of water, β-Ni(OH)2 and Ni° mixed layers were formed. In the absence of water or at low water contents, we show that the solvent is included in the layer. After annealing at a sufficient temperature to eliminate DMSO, pores are released and mesoporous films are formed. These solvent-templated electrodeposited layers have been applied in p-type dye-sensitized solar cells (p-DSSCs) after sensitization by the P1 dye. For high water content (25 vol.%), the electrodeposited layers were non-porous and were consequently unsuitable for p-DSSC application. [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]