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[Display omitted] • Polyaniline (PANi) and Ni particles modified composite electrode was prepared electrochemically on fluorine-doped tin oxide (FTO) • The FTO/PANi-Ni hybrid electrode exhibits high durability and low poisoning effect. • High performance, low cost and easy fabrication make this electrode a promising anode for DMFCs. A metal–organic composite thin film composed of polyaniline (PANI) and Ni was prepared and characterized for methanol electrooxidation reaction. First, PANI thin films were electrodeposited on a fluorine-doped tin oxide (FTO) coated glass support in an aqueous acidic solution. Subsequently, the polymer film was modified with Ni particles (FTO/PANI-Ni) by chronoamperometric (CA) technique. The composite film was characterized by structural, morphological and electrocatalytic analyses. X-ray diffraction (XRD) results confirmed the crystallization of Ni according to the cubic structure. Scanning electron microscopy (SEM) images showed that the Ni nanoparticles were uniformly dispersed on the PANI surface. The electrocatalytic performance of the FTO/PANI-Ni composite electrode for the methanol electrooxidation reaction was investigated in 0.5 M KOH solution containing methanol using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and chronoamperometry (CA) techniques. The effects of temperature and methanol concentration on the methanol electrooxidation performance were also studied. The modified composite catalyst exhibited an electrochemically active surface area of 0.5235 cm2. The presence of Ni nanoparticles on the polymer surface promoted the adsorption of methanol molecules and facilitated the oxidation process, leading to higher current densities and better overall performance. The maximum current density was 14 mA cm-2 and the electrode maintain 68 % of its initial activity even after 200 cycles, indicating that the FTO/PANI-Ni electrode exhibited good stability. The high methanol oxidation performance of the composite electrode was associated with large real surface area, a possible synergistic effect between the polymer moleucles and Ni particles as well as high intrinsic activity of Ni for this process. [ABSTRACT FROM AUTHOR]

Solvothermal synthesis offers an important approach to prepare nickel particles with high crystallinity and low agglomeration. In this study, submicron nickel particles are prepared by a solvothermal approach involving alcohol reduction with the assistance of different types of organic bases. The influences of the types of organic bases and solvents, and the amount of organic bases on the particle size and morphology of nickel are studied. It is found that an organic base with a stronger alkalinity is able to generate nickel particles with smaller size. Smaller nickel particles are also prone to be obtained from solvents with a stronger reducing ability. Moreover, the formation mechanism of nickel particles is investigated. It is found that the nickel precursor and OH− form nickel layered hydroxide salts at the initial stage, and then the nickel layered hydroxide salts gradually dissolve to form nickel particles. Magnetic measurement reveals the morphology-dependent magnetic properties. Although the sample which has the smallest size exhibits a relatively high coercivity, samples which have a rather large particle size but consist of smaller primary nanoparticles also show relatively high coercivity values. [Display omitted] • Nickel submicron particles are synthesized via a solvothermal approach in alcohols. • Organic bases with stronger alkalinity are found to generate smaller particles. • Nickel particles with a narrow size distribution (182 ± 18 nm) are obtained. • The formation mechanism of nickel particles in solvothermal conditions is revealed. • Morphology-dependent magnetic properties are observed. [ABSTRACT FROM AUTHOR]

5wt% of Ni supported on activated carbon, Al 2 O 3 and Carbon covered Al 2 O 3 (C-Al 2 O 3 ) prepared by impregnation technique have been subjected to nitrobenzene hydrogenation at atmospheric pressure in vapour phase conditions. The catalysts were characterized by XRD, BET surface area, TPR and H 2 -Pulse chemisorption. Among the catalysts, Ni/C-Al 2 O 3 catalyst exhibited excellent and steady activity in the nitrobenzene hydrogenation at 498 K which can be attributed to the presence of smaller Ni particles with proper metal support interaction. [ABSTRACT FROM AUTHOR]

The effect of the high order structure of an isotactic polypropylene (PP) composite on the resistivity of composites containing magnetically aligned Ni particles was studied. Only a small amount of particles needed to be added for the composite material to become conducting after heating while in a magnetic field. The Ni columns formed on applying the field were distorted by the formation of large PP spherulites. Changes to the crystallization process due to the addition of a nucleating agent gave rise to changes in the columnar structure, resulting in large changes in the resistivity of the composite material. Controlling the high order structure of the polymer matrix including its morphology is very important in order to be able to control the magnetically aligned Ni structure. [ABSTRACT FROM AUTHOR]

Abstract: Epidemiological studies show that exposure to nickel (Ni) compounds is associated with a variety of pulmonary adverse health effects, such as lung inflammation, fibrosis, emphysema and tumours. However, the mechanisms leading to pulmonary toxicity are not yet fully elucidated. In the current study we used Calu-3, a well differentiated human bronchial cell line, to investigate in vitro the effect of Ni in soluble form (NiCl2) and in the form of micro-sized Ni particles on the airway epithelium. For this purpose, we evaluated the effect of Ni compounds on the epithelial barrier integrity by monitoring the transepithelial electrical resistance (TEER) and on oxidative stress pathways by measuring reactive oxygen species (ROS) formation and induction of stress-inducible genes. Our results showed that exposure to NiCl2 and Ni particles resulted in a disruption of the epithelial barrier function observed by alterations in TEER, which occurred prior to the decrease in cell viability. Moreover, Ni compounds induced oxidative stress associated with ROS formation and up-regulation of the stress-inducible genes, Metallothionein 1X (MT1X), Heat shock protein 70 (HSP70), Heme oxygenase-1 (HMOX-1), and gamma-glutamylcysteine synthetase (γGCS). Furthermore, we have demonstrated that the induced effects by Ni compounds can be partially attributed to the increase in Ni ions (Ni2+) intracellular levels. [Copyright &y& Elsevier]

Abstract: This study forms composite solders by adding 0.5–3wt% of Ni particles in situ to Sn–3.5wt%Ag lead-free solder. Cu/solder/Cu specimens are prepared by dipping two Cu rods into a solder bath to produce a solder joint. Some of the joint specimens are retained in the as-soldered condition, while the others are aged at 150°C for 100, 200, 400, or 500h, respectively. The experimental results reveal that the addition of Ni to the molten Sn–Ag solder leads to the formation of in situ Ni3Sn4 dispersoids. The adhesive strength of the joint is found to increase with increasing Ni content in the as-soldered specimens. In general, the strength of the thermally processed specimens reduces as the thermal storage time increases. The Sn–Ag–0.5wt%Ni joints show a mixture of ductile and brittle fracture, whereas the joints containing more than 1wt% of Ni show mainly brittle fracture with solder residue at the exposed (Cu,Ni)6Sn5 IMC layer. [Copyright &y& Elsevier]

Abstract: Polypyrrole films modified with Ni Particles were eletrodeposited using a constant potential on a Pt/quartz crystal electrode with the aim to investigate the changes in the voltammetric and mass profiles compared with pure polypyrrole. The electrochemical behavior of the polypyrrole with Ni showed a new cathodic peak at −0.73V associated to Ni2+ reduction. Besides, it was characterized that there is a redox-pair of the polymer and Ni and a model was proposed to explain the phenomenon considering the eletroneutrality principle. The transport of the ion into (or outside) the polymer is opposite to the expected direction. This occurs due to the redox-pair between the PPy chain and Ni species which can be explained by a loss of anions during Ni oxidation and the gain of anions during the Ni reduction. [Copyright &y& Elsevier]