Nickel-based ethylene polymerization catalysts have unique features, being able to produce macromolecules with a variable content of branches, resulting in polymers ranging from semicrystalline plastics to elastomers to hyperbranched amorphous waxes and oils. In addition to Brookhart's α-diimine catalysts, iminopyridine Ni(II) complexes are among the most investigated systems. We report that Ni(II) complexes bearing aryliminopyridine ligands with bulky substituents both at the imino moiety and in the 6-position of pyridine afford either hyperbranched low molecular weight polyethylene oils or prevailingly linear crystalline polyethylenes or both depending on the ligand structure and the reaction conditions. The formation of multiple active species in situ is suggested by analysis of the post-polymerization catalyst residues, showing the partial reduction of the imino function. Some related arylaminopyridine Ni(II) complexes were also synthesized and tested, showing a peculiar behavior, i.e. the number of branches of the produced polyethylenes increases while ethylene pressure increases.

Metallic masters can be used as a metallic mold to replicate polymeric pieces with high resolution. Metallic masters with high resolution were created by photolithography technique and nickel electrodeposition technique. AZ 9260 photoresists and SPR 220-7.0 photoresists were used to coat metallic substrates and to compare results. Steel substrate and nickel substrate were used as the metallic substrate to compare results. Two different nickel electrodeposition protocols were used to compare results. In the conclusion section, was determined the best photoresist, metallic substrate, and nickel electrodeposition protocol to fabricate metallic masters.

In this scientific research, thermally stable nickel nanoparticles were synthesized and characterized. Nickel nanoparticles were synthesized using phenol –formaldehyde by chemical method followed by calcination. The polymer metal complex was confirmed by FTIR and NMR. The spherical morphology of nickel nanoparticles confirmed by SEM. The crystallographic structure is confirmed by XRD and size of cobalt nanoparticles is 24.0 nm. The TGA analysis was performed over a range of 29-600OC. The TGA thermograph predicts mass decomposition of 11%, for nickel phenol-formaldehyde nanocomposite. The decomposition rate of composites is very low 2% weight loss per 100OC increment in temperature.

Iron-containing nickel sulfides, selenides, and sulfoselenides were synthesized via a simple two-step hydrothermal reaction (temperature 160 °C) for their application as electrocatalysts in the oxygen evolution reaction (OER) in an alkaline solution (1 mol L–1 KOH). The study demonstrated that iron-containing nickel cobalt sulfides and selenides exhibit superior OER performance with lower overpotentials compared to iron-free nickel cobalt sulfide and selenide, which highlights the significant role of iron in enhancing OER nickel cobalt electrocatalysts: Fe0.1Ni1.4Co2.9(S0.87O0.13)4, η50 = 318 mV; Fe0.2Ni1.5Co2.8(S0.9O0.1)4, η50 = 310 mV; Fe0.3Ni1.2Co2.5(S0.9O0.1)4, η50 = 294 mV; Fe0.6Ni1.2Co2.5(S0.83O0.17)4, η50 = 294 mV, Fe0.4Ni0.7Co1.6(Se0.81O0.19)4, η50 = 306 mV compared to Ni1.0Co2.1(S0.9O0.1)4, η50 = 346 mV and Ni0.7Co1.4(Se0.85O0.15)4, η50 = 355 mV (all values at current densities η50 of 50 mA cm–2). Furthermore, the iron-containing nickel cobalt sulfoselenide Fe0.5Ni1.0Co2.0(S0.57Se0.25O0.18)4 displayed exceptional OER performance with η50 = 277 mV, surpassing the benchmark RuO2 electrode with η50 = 299 mV. The superior performance of the sulfoselenide was attributed to its low charge transfer resistance (Rct) of 0.8 Ω at 1.5 V vs. the reversible hydrogen electrode (RHE). Moreover, the sulfoselenide demonstrated remarkable stability, with only a minimal increase in overpotential (η50) from 277 mV to 279 mV after a 20 h chronopotentiometry test. These findings suggest that trimetallic iron, nickel and cobalt sulfide, selenide and especially sulfoselenide materials hold promise as high-performance, cost-effective, and durable electrocatalysts for sustainable OER reactions. This study provides a valuable approach for the development of efficient electrocatalytic materials, contributing to the advancement of renewable energy technologies.

Background: Gingival enlargement is defined as an abnormal overgrowth of gingival tissues. A case of a 34–year–old female presenting with maxillary chronic inflammatory gingival enlargement associated with a nickel wire allergy is reported here. Replacement of the wire, good oral hygiene therapy and surgical therapy was carried out to provide a good aesthetic outcome. Histopathological evaluation was done of the excised specimen. There is only one similar case reported in literature to the best of our knowledge and ours is the second case. Result: A Histopathological diagnosis of inflammatory fibrous hyperplasia was established. No recurrence was reported at the end of 1 year. Conclusion: The patient should be made aware of the allergy at the initial visit and oral hygiene instructions should be reinforced at every visit. The significance of patient compliance during and following therapy as an important factor in the success of treatment.

Anion exchange membrane (AEM) electrolysis is hampered by two main issues: stability and performance. Focusing on the latter, this work demonstrates a highly active NiMo cathode for hydrogen evolution in AEM electrolysis. We demonstrate an electrolyzer performance of 1 A cm⁻² at 1.9 V (total cell voltage) with a NiMo loading of 5 mg cm⁻² and an iridium black anode in 1 M KOH at 50 °C, that may be compared to 1.8 V for a similar cell with Pt at the cathode. The catalysts developed here will be significant in supporting the pursuit of cheap and environmentally friendly hydrogen fuel.

NiO nanoparticles have been synthetized by calcination of layered double hydroxides (LDHs) precursors prepared using dimethylamine (DMA) as a precipitating agent. The incorporation of Ce and La oxides to the structure was investigated. The samples were characterized by element chemical analysis, powder X-ray diffraction, FT-IR spectroscopy, thermal analysis and specific surface area analysis. Furthermore, the optical band gaps of the semiconductor samples were estimated by ultraviolet-visible diffuse reflectance spectroscopy. The results showed that it is possible to obtain Ni-LDHs precursor with good crystallinity and a small crystal size, which can be used as precursors of NiO nanoparticles with ≈3.7 nm of crystal size. The semiconductors obtained have good values of band gaps with rather large specific surface areas, which make them suitable for their use as photocatalysts.

The hydrogen evolution reaction (HER) has garnered attention to access sustainable energy generation with a pollutant-free combustion product in the form of H2 gas. Despite the utility of this pathway in the context of growing climate concerns, stable HER electrocatalysts which avoid the use of rare-earth platinum while retaining high catalytic performance and efficiency remains a challenge. In this work, we present the application of a binuclear nickel (II/III) Schiff base complex [Ni]2[L]2 2 for HER electrocatalysis. The design of the electrocatalyst provides optimal HER activity as the presence of electronegative heteroatoms in proximity to the metal centers augments proton affinity. As a result, the catalyst displays excellent HER activity with 100% faradaic efficiency (FE) at an onset potential of 0.4 V vs. reverse hydrogen electrode (RHE), sustained catalytic activity during prolonged electrolysis for greater than 17 hours, and provided a turn over number (TON) of 0.0006 s-1.

Urea, a prevalent component found in wastewater, shows great promise as an alternative substrate to water for energy-efficient hydrogen production by electrolysis. However, the sluggish kinetics of the anodic urea oxidation reaction (UOR) significantly hampers the overall reaction rate. To address this challenge, this article presents a comprehensive study focusing on the controlled fabrication of hierarchically structured nanomaterials as potential catalysts for UOR. The prepared MnO2@NiCo-LDH hybrid catalyst demonstrates remarkable improvements in reaction kinetics, benefiting from synergistic enhancements in charge transfer and efficient mass transport facilitated by its unique three-dimensional architecture. Notably, the catalyst exhibits an exceptionally low onset potential of 1.228 V and requires only 1.326 V to achieve an impressive current density of 100 mA cm-2, representing a state-of-the-art performance in UOR. These findings highlight the tremendous potential of this innovative material-designing strategy to drive advancements in electrocatalytic processes.

Abstract: Five patients with standard medical treatment-resistant symptoms of skin lesions, ear infections, allergic rhinitis, nasal congestion, asthma, heartburn, and failure to thrive were success- fully treated with an integrative medicine assessment and integrative medicine treatment approach. The integrative medicine assessment method of autonomic response testing enabled the identifica- tion of nickel sensitivity as a common element in these patients. It guided the use of the integrative medicine therapies of low dose immunotherapy, gamma linoleic acid supplementation, chelation, dietary nickel restriction, and removal of nickel containing dental and cosmetic appliances. A chart review of 151 patients indicated a strong association of nickel and the simultaneous presence of skin lesions.

Magnetoelectric sensors based on microelectromechanical cantilevers consisting of TiN / AlN / Ni are investigated using finite element simulations in regard of the anisotropy of the E effect and its impact on the sensor sensitivity. The E effect is derived from the anisotropic magnetostriction and magnetization of single crystalline Nickel. The magnetic hardening of Nickel in saturation is demonstrated for the (110) as well as the (111) orientation. It is shown further, that magnetostrictive bending of the cantilever has a negligible impact on the eigenfrequency and thus sensitivity. The intrinsic E effect of Nickel decreases in magnitude depending on the crystal orientation when integrated into the magnetoelectric sensor design. The transitions of the individual magnetic domain states are found to be the dominant influencing factor on the sensitivity for all crystal orientations. The peak sensitivity was determined to 41.3 T-1 for (110) in-plane orientated Nickel at a magnetic bias flux of 1.78 mT. It is found, that the transition from domain wall shift to domain rotation along the hard axes yields much higher sensitivity than the transition from domain rotation to magnetization reversal. The results achieved in this work show that Nickel as hard magnetic material is able to reach almost identical sensitivities as soft magnetic materials, such as FeCoSiB.

While there are extensive studies on the mineralogy and geochemistry of laterites worldwide, the temporal and spatial mineralogical development of a typical nickel laterite profile is still poorly constrained. In this study, we present a detailed mineralogical and geochemical characterization of samples systematically collected from a nickel laterite profile at the Sta. Cruz nickel laterite deposit, Zambales, Philippines, to describe the temporal and spatial development of the laterite profile. Wavelength-dispersive X-ray fluorescence spectroscopy (WDSXRF), mass balance-element mobility calculations, transmitted and reflected light microscopy, and previously reported results from coupled X-ray diffraction (XRD) and Rietveld refinement analyses, reveal that the laterite profile investigated is composed of two main horizons: the limonite and saprolite zones, separated by a thin transitional zone. The main zones are further subdivided into subzones based primarily on the mineral assemblage and major element chemistry: upper limonite, lower limonite, transitional zone, upper saprolite, and lower saprolite. Late-stage Ni-rich serpentine veins were observed cutting the upper and lower saprolite subzones. Investigation of the structure of goethite within the limonite zone via Rietveld refinement show that the crystallinity of goethite decreases with increasing Ni content and increasing crystallite size. This suggests that upwards through the limonite zone, as goethite ages, its crystallinity increases which possibly results in the removal of Ni from its crystal structure and eventual remobilization to the lower laterite zones. We propose a genetic model of the formation of the Sta. Cruz laterite consisting of four stages: (1) early-stage alteration, (2) continued serpentinization and volume expansion, (3) late stage serpentinization, dissolution, and incipient oxide formation, and (4) goethite ageing and Ni-rich serpentine vein formation. Overall, our results suggest that serpentinization is an important aspect of Ni laterite formation, both before and after the emplacement of the peridotite protolith.

In aqueous solution planar bis(1,2-dithiooxalato)nickelates(II), [Ni(dto)2]2- react with lanthanide ions (Ln3+) to form pentanuclear, hetero-bimetallic complexes of the general composition [{Ln(H2O)n}2{Ni(dto)2}3] · x H2O (n = 4 or 5; x = 9 - 12). Two complexes of this series, [{Pr(H2O)5}2{Ni(dto)2}3] · 11 H2O, Pr2Ni3 1 and [{Gd(H2O)5}2{Ni(dto)2}3] · 11 H2O, Gd2Ni3 2 were synthesized and characterized by single crystal X-ray structure analysis, X-ray powder diffraction, and IR spectroscopy. All Ln2Ni3 complexes crystallize as monoclinic crystals in the space group P21/c.

Nickel molybdate, NiMoO₄, nanoparticles were synthesized via calcination of an oxalate complex in static air at 500 °C. The oxalate complex was analyzed by thermal gravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR). The as-synthesized nickel molybdate was characterized by Brunauer–Emmett–Teller technique (BET), X-ray diffraction (XRD), and transmission electron microscopy (TEM) and its catalytic efficiency was tested in the reduction reaction of the three-nitrophenol isomers. The nickel molybdate displays a very high activity in the catalytic reduction of the nitro functional group to an amino. The reduction progress was controlled using UV-Vis absorption.

This study investigates the microstructural evolution and mechanical properties of high-nickel shipbuilding steel during thermal processing using High Temperature Confocal Laser Scanning Microscopy (HTCLSM). The in-situ observation of the heating and holding processes reveals critical insights into phase transformations, grain growth behavior, and the formation of precipitates. The experimental results demonstrate that austenitization begins at approximately 700°C, with significant grain boundary nucleation. At 900°C, the formation of black precipitates was observed, and their persistence up to temperatures exceeding 1000°C was confirmed. Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) analyses identified these precipitates as chromium carbides (Cr7C3), which significantly contribute to the material's strength. The comprehensive analysis using Transmission Electron Microscopy (TEM) confirmed the presence and distribution of Cr7C3 within the grains and along grain boundaries. These findings provide a deeper understanding of the microstructural dynamics in high-nickel steels, guiding the optimization of heat treatment processes to enhance mechanical properties for maritime applications.

Two interesting compounds such as quaternary ammonium lignin(QAL) and 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester (P507) were synthesized as ionic liquids(QP-ILs) for the extraction of metal ions. The extraction behavior of Co(II) and Ni(II) from chloride solution was compared between QP-ILs and P507. The results showed that the extraction rates of Co(II) and Ni(II) in the two solutions varied with the extraction conditions, but QP-ILs has stronger extractability for cobalt than P507, while Ni is on the contrary. Under the same conditions, the Co/Ni separation performance(βCo/Ni) in QP-ILs is superior to that in p507. At pH4.0, 55℃, concentration of 20%, extraction time of 10 minutes, the βCo/Ni of QP-ILs reached to 2703, while that of P507 was only 164. In conclusion, QP-ILs was more efficient than P507 for separating Co from mixed solutions.

The usage of biotechnological molecules and processes is an indispensable part of the resource technology research. The development of novel biomolecules therefore needs to be adapted to the existing applicational conditions and biological processes are to be examined. Novel biosorbents may not only contribute to future applications but can be of further used, e.g. to better understand the interaction of known metal- and metalloid-interacting biological molecules and materials. This review highlights biotechnological approaches published so far for bioremediation as well as metal recovery with a special spotlight on cobalt, nickel and arsenic.

Pt-coated Ni layer supported on Ni foam catalyst (denoted PtNi/Nifoam) was investigated for the oxidation of the formic acid (FAO) in acidic media. The prepared PtNi/Ni foam catalyst was studied as a function of the formic acid (FA) concentration at bare Pt and PtNi/Nifoam catalysts. The catalytic activity of the PtNi/Nifoam catalysts, studied on the basis of the ratio of the direct and indirect current peaks (jd)/(jnd) for the FAO reaction, showed values about 10 times higher compared to those on bare Pt, particularly at a low formic acid concentrations, reflecting the superiority of the former catalysts for the oxidation of FA to CO2. Ni foams provide a large surface area for the FOR while synergistic effects between Pt nanoparticles and Ni-oxy species layer on Ni foams contribute significantly to the enhanced oxidation of FA via the direct pathway, making it almost equal to the indirect pathway, particularly at low formic acid concentrations.

The Ni-laterite deposit at the San Felipe plateau, located 30 km northwest of Camagüey, in cen-tral Cuba, is the best example of a clay-type deposit in the Caribbean region. San Felipe resulted from weathering of mantle peridotites of the Cretaceous Camagüey ophiolites. In this study, a geochemical and mineralogical characterization of two profiles (83 and 84) from the San Felipe deposit has been performed by XRF, ICP-MS, quantitative XRPD, oriented aggregate mount XRD, SEM, FE-SEM and EMPA. Core 83 with a length of 23 m, and drilled in the central part of the plateau, presents a notable concentration of cryptocrystalline quartz fragments and a rather poor content in NiO, averaging 0.87% wt. Core 84, which is 12 m long, and drilled at the border of the plateau, lacks silica fragments and presents a higher NiO content, averaging 1.79 %wt. The smectite structural formulae reveal that they evolve from trioctahedral to dioctahedral towards the top of the laterite profiles. Quantitative XRD analyses indicate that smectite is a dominant Ni bearing phase, accompanied by serpentine and minor chlorite. Serpentine, as smectite, is en-riched in the less soluble elements Fe3+, Al and Ni towards the top of the profiles. Core 83 seems to have been affected by collapses, replenishments, whereas core 84 may have remained undis-turbed.

In this investigation, Cu-Ni alloys for possible fixed dental prostheses (FDPs), with different aluminum additions were produced using vacuum atmosphere. Annealed alloys (He atmosphere) with low aluminum concentration showed a coarse dendritic structure, while samples with high aluminum concentration showed a refined dendritic structure. Structural defects analyses have shown a relative low vacancy concentrations. Hardness value increases approximately five times for the alloyed samples compared with the as-cast and unalloyed samples. Compression test results have shown a noticeable strengthening improvement, mainly in samples heat treated with 10 at % Al, while samples with 5 at % Al presented also acceptable resistance. Results are discussed in terms of dislocation mobility and hardening precipitation mechanism.

Within the study, magnetic/polyetherimide-acrylonitrile composite nanofibers membrane with effective adsorption of nickel ions in aqueous solution were established, through a simple electrospinning method. Iron oxide nanoparticles were stirred and ultrasonically dispersed into polyetherimide-acrylonitrile solution for homogenous suspension. Afterwards, the polyetherimide-acrylonitrile solution with uniform suspension of iron nanoparticles was used in electrospinning machine to produce uniform and smooth nanofibers composite membrane. The confirmation of nanoparticles incorporation into polymeric membrane were characterized by SEM, EDX, FTIR, XRD and nanoparticles aqueous stability through leach out test. The high adsorption capability of the composite membranes on nickel ions was mainly attributed to the combination of magnetic nanoparticles, polyetherimide-acrylonitrile matrix and nano-sized structure of membrane. Membrane containing magnetic nanoparticles demonstrate the maximum adsorption capabilities (102 mg/g) for nickel ions from aqueous solution. Different kinetics and isotherm models were applied to understand the adsorption behavior during adsorption process, amongst them pseudo second order kinetic and Langmuir isotherm model were well fitted. Additionally, EDX, FTIR and XRD results confirmed the presence of nickel ions onto membrane after adsorption process. Polyetherimide-acrylonitrile composite nanofibers membranes containing magnetic nanoparticles may use as an environmentally-friendly and non-toxic adsorbent for the removal of nickel ions in aqueous medium due to its ease of preparation, easy to use and stability in aqueous medium by retaining the nanoparticles inside the nanofibers membranes.

Results are presented concerning the influence on the water splitting process of enantiopure tartaric acid present in bulk solution. Stainless steel and electrodeposited nickel are used as working electrode (WE) surface. The latter is obtained by electrodeposition on the two poles of a magnet. The influence and role played by the chiral compound in solution has been assessed by comparing the current values, in cyclic voltammetry (CV) experiments, recorded in the potential range at which oxygen evolution reaction (OER) occurs. In the case of tartaric acid and nickel WE a spin polarization of about 4 % is found. The use of the chiral environment (bulk solution) and ferromagnetic chiral Ni electrode allows for observing the OER at a more favourable potential: about 50 mV (i.e. a cathodic, less positive, shift of the potential at which the oxygen evolution is observed).

Metal matrix composite are used in such fields of technology, such as: aerospace, electronics, energy, industry, defense, automotive, aviation, shipbuilding, and more. Composite coatings of ceramic - metals is used primarily to enhance the durability of machine parts. Therefore, new materials are permanently looked for, what has resulted in the past in development of composite materials. The coatings dispersed are consisting of metallic matrix (metals and their alloys) and small non-metallic particles. The deposition of ceramic particles simultaneously with metallic matrix leads often to composite coatings possessing properties much better than those of metallic coating. The nickel and less often, other iron group elements are usually used as a matrix and Al2O3 as tough particles. The welding technology of applying alloy and composite coatings is widely used. The technology of infrasound thermal spraying of metal matrix composite coatings was presented. It is a simple technology and a very useful one in ship machinery regeneration during the cruise craft (e.g. internal combustion engines, torque pumps, separators). The metal matrix composite coatings must undergo finishing due to high surface roughness after application. In the article to used finishing by plastic working and machining of coatings nickel matrix composite was proposed.

The microstructure and solidification behavior of nickel based GTD222 superalloy at different cooling rates are studied. The solidification of the GTD222 superalloy proceeds as follows: L→L+γ, L→L+γ+MC, L→L+(γ/γ ′)-Eutectic and L→η phase. The temperature of liquidus of GTD222 superalloy is 1360 °C while the solidus is slightly lower at 1310 °C, which due to the alloying elements redistribution. It was found that the dendrite arm spacing of the alloy decreased with the increase of cooling rate (From 200 μm at 2.5 K/min to 100 μm at 20 K/min).

Herein, we report about the monometallic Ni and bimetallic Pd-Ni catalysts supported on CeO2-Al2O3 binary oxide, which were investigated in oxy-steam reforming of methanol (OSRM). Monometallic and bimetallic supported catalysts were prepared by wet aqueous impregnation and subsequent impregnation method, respectively. The physicochemical properties of the catalytic systems were investigated using various methods such as: BET, XRD, TPR-H2, TPD-NH3, XPS and SEM-EDS techniques. It has been proven that the addition of palladium to the nickel catalyst facilitates its reduction. The activity tests performed for all catalysts confirmed the promotion effect of palladium on catalytic activity of nickel catalyst and selectivity towards hydrogen production. Both nickel and bimetallic palladium-nickel supported catalysts showed excellent stability during the reaction. Such catalytic systems are valuable for the advance of the field of fuel cell technology.

The environmental paradigm emphasizes the importance of political-economic and socio-economic factors that can significantly affect environmental health. One of the above-mentioned factors in the EU's so-called Eastern bloc is also the issue of unresolved environmental burdens. Our case study sought answers to the questions: How and why was Niklová Huta (Nickel smelter) Sereď created? How is it possible that, despite the knowledge of nickel's harmfulness to the environment, production continued for so long? Why, even 30 years after the end of production, the solid leaching residue (lúženec) landfill was not disposed of? The main methods of data collection were a content analysis of secondary data, a self-constructed questionnaire and semi-structured interviews. The research group for the quantitative part of the case study consisted of 354 respondents, of which 274 (77.40%) were women and 80 were men (22.60%). The data obtained by the questionnaire are presented through descriptive statistics. 12 informants participated in the quantitative research through semi-structured interviews, of which 9 were men and 3 were women. The interviews lasted between 30-45 minutes, were transcribed and we used qualitative thematic analysis to process them. The result of our case study is the creation of a conceptual model that captures the key points in the process of the formation of a toxic landfill and its persistence in the environment during the last 30 years.

Nickel electrodeposition is a widely utilized method for creating thin films on various substrates with various desirable attributes. Recently, there has been a growing interest in developing nickel composite coatings that incorporate additional elements or particles into the nickel matrix to enhance their properties. These composite coatings offer superior wear resistance, corrosion resistance, hardness, and other functional benefits compared to pure nickel coatings. Some of the recent advancements in electrodeposited nickel composite coatings include improved wear resistance, enhanced mechanical properties and better corrosion resistance. Researchers have discovered that adding Al, Si, Zr, C, W, and Ti particles to nickel coatings can significantly enhance wear resistance. The uniform distribution of these particles within the nickel matrix acts as a barrier to wear and tear. Studies have also shown that nickel composite coatings with Al, Si, Zr, C, W, and Ti particles exhibit superior mechanical properties, including increased hardness. These particles refine the grain size of the nickel matrix and hinder defect movement, leading to greater mechanical strength. Moreover, nickel composite coatings offer improved protection against corrosion compared to pure nickel coatings. This review provides a detail discussion of nickel composite coatings with regard to their comparative advantaged compared to pure nickel coatings on different substrates.

This study explores the effects of tempering on the precipitation behavior and impact toughness of high-nickel steel. The specimens underwent double quenching at 870°C and 770°C, followed by tempering at various temperatures. Advanced characterization techniques including optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to elucidate precipitation phenomena. Additionally, electron backscatter diffraction (EBSD) was employed to assess the misorientation distribution after tempering. Charpy impact tests were performed on specimens tempered at different temperatures to evaluate their toughness. The findings reveal that with increasing tempering temperature, the fraction of low-angle grain boundaries decreases, which correlates positively with enhanced impact toughness. The impact toughness peaks at 580°C and then diminishes with further temperature increases.

Hybrid organic/inorganic conducting and magnetic composites of core–shell type have been prepared by in-situ coating of nickel microparticles with polypyrrole. Three series of syntheses have been made. In the first, pyrrole was oxidized with ammonium peroxydisulfate in water in the presence of various amounts of nickel and the composites contained up to 83 wt% of this metal. The similar syntheses in 0.1 M sulfuric acid followed. Finally, the composites with polypyrrole nanotubes were prepared in water in the presence of structure-guiding methyl orange dye. FTIR and Raman spectroscopies confirmed the formation of polypyrrole. The resistivity of composite powders of the order of tens to hundreds Ω cm was monitored as a function of pressure up to 10 MPa. The resistivity of composites slightly increased with increasing content of conducting nickel. This apparent paradox is explained by the coating of nickel particles, which prevents their contacts and generation of metallic conducting pathways. Electrical properties were practically independent of the way of composite preparation or nickel fraction and were controlled by polypyrrole phase. On the contrary, magnetic properties were determined exclusively by nickel content. The composites were used as a solid phase to prepare a magnetorheological fluid. The test showed better performance when compared with a different nickel system.

Acetaldehyde decomposition was performed under heating at the temperature range of 25-125oC and UV irradiation on TiO2 doped by the metallic Ni powder and TiO2 supported on the nickel foam. Process was carried out in high temperature reaction chamber “The Praying MantisTM”, with simultaneous in situ FTIR measurements and UV irradiation. Ni powder was added to TiO2 in the quantity of 0.5 to 5.0 wt%. Photothermal measurements of acetaldehyde decomposition indicated, that the highest yield of acetaldehyde conversion on TiO2 und UV irradiation was obtained at 75oC. Doping of nickel to TiO2 did not increase its photocatalytic activity. Contrary to that, application of nickel foam as a support for TiO2 appeared to be highly advantageous, because increased decomposition of acetaldehyde from 31 to 52% at 25oC and then to 85% at 100oC by comparison with TiO2 itself. At the same time mineralisation of acetaldehyde to CO2 increased two times at the presence of nickel foam. However, oxidised nickel foam used as support for TiO2 was detrimental. Most likely, different mechanisms of electrons transfer between Ni-TiO2 and NiO-TiO2 occurred. Application of nickel foam greatly enhanced separation of free carriers in TiO2. As a consequence, high yields of the photocatalytic reactions were obtained.

Current hydrogen production is based on the reforming process leading to the emission of pollutants; therefore, a substitute production method is imminently required. Water electrolysis is an ideal alternative for large-scale hydrogen production, as it does not produce any carbon-based pollutant byproducts. Production of green hydrogen from water electrolysis using intermittent sources (e.g., solar, eolic) would facilitate clean energy storage. However, the electrocatalysts currently required for water electrolysis are noble metals, making this potential option expensive and inaccessible for industrial applications. Therefore, there is a need to develop electrocatalysts based on earth-abundant and low-cost metals. Nickel-based electrocatalysts are a fitting alternative because they are economically accessible. Extensive research has focused on developing nickel-based electrocatalysts for hydrogen and oxygen evolution. Theoretical and experimental work have addressed the elucidation of these electrochemical processes and the role of heteroatoms, structure, and morphology. Even though some works tend to be contradictory, they have lit up the path for efficient nickel-based electrocatalysts. For these reasons, herein, a review of recent progress is presented.

In this study, vermiculite was explored as a support material for nickel catalysts in two key processes in syngas production through dry reforming of methane with CO2 and steam reforming of ethanol. The vermiculite was subjected to acid or base treatment, then, Ni catalysts were prepared through incipient wetness impregnation and characterized using various techniques, including X-ray, FTIR, temperature programmed reduction (H2-TPR). TG-TD analyses were performed to assess the formation of carbon deposits on spent catalysts. The Ni based catalysts were used in the reaction tests without a reduction pre-treatment. Initially, raw vermiculite-supported nickel showed limited catalytic activity, however after acid (Ni/VTA) or base (Ni/VTB) treatment, vermiculite became an effective support for nickel in dry methane reforming. The resulting catalysts (Ni/VTB and Ni/VTA) displayed outstanding performance, with high methane conversion and hydrogen yield. Acidic treatment improved the reduction of nickel species and reduced carbon deposition, outperforming alkali treatment. The prepared catalysts were also explored in ethanol steam reforming. The performance was investigated as a function of the temperature, water/ethanol ratio, and space velocity, with acid-treated catalysts performing as the best. The study emphasized the importance of contact time with the catalyst and addressed challenges related to carbon formation and sintering for long-term stability. In conclusion, acidic treatment of the vermiculite support, before Ni deposition, significantly enhanced the catalytic activity and stability of nickel catalysts in both dry methane reforming and ethanol steam reforming processes.

There is currently much interest in avoiding precious metals in Catalysis. The devel-opment of nickel catalysts to replace palladium in the Mizoroki-Heck reaction is a relevant case in this line of research since both elements share many chemical features. This contri-bution focuses on -Phenyl elimination in alkylnickel complexes. This is the microscopic reverse of olefin insertion (or carbometallation), a fundamental step of the Heck cycle that is usually considered irreversible and selectivity-determining. However, the potential reversibil-ity of carbometallation is generally concealed by the facile beta-hydrogen elimination that follows. Where -hydrogen elimination is hindered, beta-aryl elimination may ensue. We have previously shown that cationic 2-methyl-2-phenylpropyl (neophyl) palladium com-plexes supported by bidentate ligands experience -Ph elimination, which can be seen as an example of olefin de-insertion. In this contribution, we report that -phenyl elimination can also occur in their nickel analogs, in which case fast hydrolyses of the resulting phenyl product can follow the reaction. We investigated the mechanism of these processes and compared their feasibility for nickel and palladium catalysts using DFT calculations. These results are relevant information for the design of nickel-based catalysts for the Heck reac-tion.

In order to study the feasibility of copper-nickel smelting slag（CNSS） and palygorskite for large-scale consumption and utilization in the field of mine filling, gellable composite materials were prepared from copper-nickel smelting slag ,cement and palygorskite. The effects of palygorskite addition and curing time on the mechanical properties and microstructure of copper-nickel smelting slag-based cementitious materials were studied in detail. The results showed that the addition of palygorskite had a positive effect on the curing of the cemented filler of the non-ferrous smelting slag by promoting the early hydration reaction. palygorskite also affected the mechanical properties of the cementitious materials with different maintenance times and the ability to cure heavy metals. The strength of gellable composite materials reaches 23.05MPa when 1% palygorskite, 50% of copper-nickel smelting slag and 48% cement were used, which meet the standards requirements of filling materials for mine goaf. The addition of 1% palygorskite can improve the ability of cementitious materials to solidify heavy metals to realize the economic utilization of solid waste in mining areas.

This manuscript presents the result of utilizing cellulose as a template to prepare na-nosized WO3-NiWO4 and its application as co-catalysts in Pt/WO3-C and Pt/WO3-NiWO4-C for ethanol and glycerol electro-oxidation. Microcrystalline cellulose was hydrolyzed with phosphotungstic acid (H3PW12O40) to prepare the nanosized template of crystalline cellulose. Next, the template was impregnated with Ni(NO3)2, rendering a precursor mate-rial that is subsequently air-calcinated, removing the carbon-template material to obtain the nanometric WO3 and NiWO4. Elemental analysis confirmed the coexistence of nickel and tungsten, whereas the thermal analysis evidenced the high thermal stability of these materials. The X-ray diffractograms displayed crystal facets of WO3 and, when added Ni, of NiWO4. The transmission electron micrographs corroborated the formation of na-nosized particles with average particle sizes close to 50 nm. Finally, to apply this material, Pt/WO3-C and Pt/WO3-NiWO4-C were prepared and used in ethanol and glycerol electro-oxidation in alkaline medium, observing a promotional effect of the oxide and tungstate by reducing the onset potential and increasing the current density. These materials show great potential to produce clean electricity or green hydrogen contributing to energetic transition.

Photocatalytic decomposition of ethylene was performed under UV-Led irradiation at the presence of nanocrystalline TiO2 (anatase, 15 nm) supported on the porous nickel foam. Process was carried out in the high temperature chamber with regulated temperature from ambient to 125°C under flow of reacted gas (ethylene in a synthetic air, 50 ppm) with simultaneous FTIR measurements of sample surface. Ethylene was decomposed with higher efficiency in elevated temperatures with maximum of 28% at 100-125°C. The nickel foam used as support for TiO2 allowed to enhance the ethylene decomposition at the temperature of 50°C. However, at 50°C the stability of ethylene decomposition was not retained within the following reaction run, but it was at 100°C. Performed photocatalytic measurements at the presence of some radicals scavengers indicated that higher efficiency of ethylene decomposition was obtained due to the improved separation of charge carriers and increased formation of superoxide anionic radicals, which were formed at the interface of thermally activated nickel foam and TiO2.

There is a high iron content in the nickel slag that mainly exists in fayalite phase. Basic Oxide can destroy the stable structure of fayalite which is beneficial to the treatment and comprehensive utilization of nickel slag. The reseach was based on the composition of the raw nickel slag, taking CaO-SiO₂-FeO-MgO system as the object and CaO as a modifier. The effect of basicity on the melting characteristics, viscosity and structure of CaO-SiO₂-FeO-MgO system was studied. The relationship between the viscosity and structure of CaO-SiO₂-FeO-MgO system was also explored. The results show as follows. (1) When the basicity is 0.38~0.90, the phase of primary crystal is olivine at argon atmosphere, while it is monoxide at the basicity of 0.90~1.50. The liquidus temperature, softening temperature, hemispherical temperature, and flow temperature all reach the lowest value at the basicity of 0.90. (2) With the increase of basicity, critical viscosity temperature of CaO-SiO₂-FeO-MgO system decreases first and then increases. Critical viscosity temperature is the lowest at the basicity of 0.90, which is 1263 ℃. (3) When the slag system is heterogeneous, the viscosity of the molten slag increase rapidity because of the type and quantity of solid phase precipitated from CaO-SiO₂-FeO-MgO system. And critical viscosity temperature of the slag system is also significantly affected. (4) When the slag system is in a homogeneous liquid phase, the molar fraction of O0 decreases with the increase of basicity and the mole fraction of O^- and O^2- increases continuously at the basicity of 0.38~1.50. The silicate network structure is gradually depolymerized into simple monomers, resulting in the degree of polymerization is reduced and the viscosity is reduced, too.

Phenolic antioxidants such as tert-butylhydroquinone (TBHQ) are widely used by manufacturers to prevent deterioration and more stable preservation of cooking oils. Cooking oil is a necessary substance that everyone needs to consume every day, but the overuse of TBHQ will harm the quality of food and public health, and many countries have set up limited standards for the use of TBHQ, therefore, it is very necessary to research and design an efficient detection technology for TBHQ. In this work, we grew NiAl-LDH, a nickel-aluminium double hydroxide, on glucose carbon spheres (GC), and formed porous carbon nanomaterials (named NiAl-LDH@GC-800) after the pyrolysis process. The NiAl-LDH@GC-800 material was fabricated on GCEs for sensors with remarkable sensitivity to TBHQ, with a low limit of detection (LOD) of 8.2 nM and possessed excellent detection linear range (20 nM ~ 300 µM). The prepared electrochemical sensor successfully detected TBHQ detection in edible oils in life, including chilli oil, peanut oil, and canola oil.

Cathode materials play a key role in the development and application of lithium-ion batteries, but the unfavorable factors such as structural phase transformation and low conductivity in the cycling process restrict the further improvement of battery performance, so the development and modification of high-performance cathode materials is a current research hotspot. LiNixCoyMn1-x-yO2(x≥0.6), a high-nickel cathode material, has the advantages of high platform potential, high energy density and low cost, and is an ideal material to achieve the goal of 300 Wh kg-1 and above for batteries. However, its poor thermal stability, poor interface stability, safety and life cannot meet the requirements of current power batteries. In this paper, the research status of high-nickel cathode materials is introduced, including bulk doping and surface coating, and the modification method of doping and coating integration is also introduced. Finally, we put forward the prospect of the future development trend of high-nickel cathode materials.

Nickel is widely used in industrial processes and plays a crucial role in many applications. However, most of the nickel resource mainly exists as nickel oxide in laterite nickel ore with complex composition, resulting in difficulty in upgrading the nickel content using physical separation methods. In this study, high-grade ferronickel concentrates were obtained through a carbothermal reduction and magnetic separation using laterite nickel ore and anthracite as raw materials. The effects of different types of additives (CaF2, Na2SO4 and H3BO3), carbon ratio (nc/no in metal oxides) and grinding time on the recoveries and grades of ferronickel concentrates were experimentally investigated, along with the microstructure and chemical composition of the products. CaF2 was proved to be the primary active additive in the aggregation and growth of the ferronickel particles, and the improvement of the grade of the product. Under the optimal conditions of CaF2 addition of 12 wt.%, carbon ratio of 1.4, and grinding time of 240 s, high-grade magnetically separable ferronickel concentrate with nickel grade 8.93 wt.% and iron grade 63.96 wt.% was successfully prepared. This work presents a practical method for the highly efficient recovery and utilization of iron and nickel from low-grade laterite nickel ore, contributing to the development of strategies for the sustainable extraction and utilization of nickel resources.

Nickel-based superalloys are attractive to many industrial sectors (automotive, military, energy, aerospace etc.). However, their physical properties make them difficult to machining using traditional tools. Therefore, the new materials for the machining of Ni-based alloys are required. Ceramic-based composites could act as a tool to replace the current materials. The incentives for this paper are to provide an overview of existing ceramic composites and draw some conclusions that will help in solving the problem of choosing materials for processing of Ni-based superalloys. Despite the diversity of ceramic composites in this work the focus was on the SiAlON ceramic.

The Ni-Co-Cr-W-Mo system is critical for the design of nickel-based super-alloys. This system stabilizes different topologically close packed (TCP) phases in many of the commercially super-alloys with high W and Mo contents. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermodynamic calculations are applied to investigate the thermodynamics of the precipitates in two different W content Ni-Co-Cr-W-Mo super-alloys. Computational thermodynamics verified experimental observation of the f u phase formation as a function of temperature and alloy chemistry, but the kinetics for the precipitation of M6C phase do not agree with the experimental findings. The major precipitates of alloy 1 at temperatures 700 and 750 °C during long time exposure are M23C6, γ′ phase, and MC, and alloy 2 are M23C6, γ′ phase, MC, M6C and u phase. The W addition is found to promote the precipitation of M6C and u phase during exposure. The M6C has higher W and lower Ni content than that of u phase, meanwhile, M6C is an unstable phase would transform into M12C after 5000 h exposure at 750 °C. A great quantity of needle-like u phases precipitated after exposure at 750 °C for 5000h, which have no effect on the impact property of alloy 2.

This article reports the two-step synthesis of NiFeO_x nanomaterials, their characterisation and bifunctional electrocatalytic activity measurements in alkaline electrolyte for metal-air batteries. The samples were mostly in layered double hydroxide at the initial temperature, but upon heat treatment, they were converted to NiFe₂O₄ phases. The electrochemical behaviour of the different samples was studied by linear sweep voltammetry and cyclic voltammetry on the glassy carbon electrode. The OER catalyst activity was observed for low mass loadings (0.125 mg cm⁻²), whereas high catalyst loading exhibited the best performance on the ORR side. The sample heat treated at 250 °C delivered the highest bi-functional oxygen evolution and reduction reaction activity (OER/ORR) thanks to its thin-holey nanosheet like structure with higher nickel oxidation state at 250 °C. This work further helps to develop low-cost electrocatalyst development for metal-air batteries.

The laser melting process (DED-LB-p) is used for the production of large components due to the high deposition rates. The large number of process parameters and printing strategies makes it difficult to optimize this process to achieve the optimal properties. Intensive post-processing is still the main obstacle to the widespread use of this process. In this work, the relationship between different printing strategies, printing strategies and process parameters on the microstructural, and tensile mechanical performance at room temperature is investigated. The porosity was measured in both printing directions. Grain orientation and size were analyzed by EBSD. A very low porosity of less than 0.4% was found in all printed samples. The samples printed with the optimized offset printing strategy show a significant improvement in tensile strength of 1000 MPa without heat treatment compared to other processing routes.

The paper presents the numerical and experimental results of research aimed at determining the influence of hardness in the range of 50-90 Shore A of layered tools made of elastomeric materials on the possibility of forming Inconel 625 nickel-based alloy sheets. A stamping die made of 90MnCrV8 steel (hardness 60HRC) was designed for forming embosses in drawpieces, ensuring various stress states on the cross-section of the formed element. The principle of operating the stamping die was based on the Guerin method. Finite element-based numerical modelling of the forming process for various configurations of polyurethane inserts was also carried out. The drawpieces obtained by sheet forming were subjected to geometry tests using optical 3D scanning. The results confirm that in the case of forming difficult-to-deform Inconel 625 Ni-based alloy sheets, the hardness of the polyurethane inserts significantly affects the geometric quality of the obtained drawpieces. The assumptions made in numerical simulations were verified in experimental studies. Based on the test results, it was concluded that the selection of polyurethane hardness should be determined by the shape of the formed element. Significant non-uniform sheet metal deformation was also found, which may pose a problem in the process of designing forming tools and technology of plastic forming of Inconel 625 Ni-based alloy sheets.

Various methods including electrochemical purification, chemical precipitation, solvent extraction, and ion-exchange resins, have maturely been used for removal of copper from nickel anolyte. Interestingly, these approaches of copper removal from nickel anolyte by precipitation are well used as the primary industrial method in nickel production again. However, these methods suffer from several severe drawbacks in industrial practices. One is that a small amount of nickel precipitates with copper in slags，resulting in slag treatment difficulties. Second, this process requires an extremely high activity of the sulfide-based copper removal agents which results in high production costs; the short storage period of the copper removal agent is another drawback of this method. These have been the key challenges in the smelting process of nickel. Herein, we present a comprehensive review of the nickel removal methods used for nickel anolyte purification, electrochemical purification, chemical precipitation, solvent extraction, and ionexchange resins. The advantages and feasibilities of each technique in industrial applications are also explored and analyzed. Finally, we demonstrate that ion-exchange resin-based extraction method can pave a new path for metallurgical research on nickel.

Nickel-based Superalloy Inconel 718 is widely used in the aerospace industry for its excellent high-temperature strength and thermal stability. However, milling Inconel 718 presents challenges due to significantly increased cutting force and vibration, which is a typical difficult-to-machine material. This paper focuses on the milling process of Inconel 718, establishing a milling force model to analyze the force trends under various processing parameters. Finite element analysis is employed to study the stress and temperature fields during milling. Dynamic equations for milling Inconel 718 are developed, and stability lobe diagrams are generated based on modal experiments. Milling experiments on Inconel 718 validate the milling force model and finite element analysis results. The fmincon optimization algorithm is utilized to identify the optimal machining parameters for Inconel 718. Through this research, valuable insights into enhancing the efficiency and quality of Inconel 718 machining are provided. This study contributes to a deeper understanding of Inconel 718 milling behavior, offering crucial guidance for more efficient machining processes.

Abstract: Interactions in multicomponent Ni-Cr-Mo-Al-Re model alloy were determined by ab initio calculations in order to investigate the Re doping effect on Haynes 282 alloy. Simulation results provided an understanding of short-range interactions in the alloy and successfully pre-dicted the formation of a Cr and Re-rich phase. The Haynes 282 + 3 % wt. Re alloy was manu-factured using the additive manufacturing Direct Metal Laser Sintering (DMLS) technique, in which the presence of the (Cr17Re6)C6 carbide was confirmed by an XRD study. The results ob-tained provide useful information about the interactions between Ni, Cr, Mo, Al, and Re as a function of temperature. The 5-element model designed can lead to a better understanding of phenomena that occur during the manufacturing or heat treatment of modern, complex, multi-component Ni-based superalloys.

Metal-organic frameworks (MOFs) are investigated for the oxygen evolution reaction (OER) due to their structure diversity, high specific surface area, adjustable pore size and abundant active sites. However, the poor conductivity of most MOFs restricts this application. Herein, through a facile one-step solvothermal method, the Ni-based pillared metal-organic framework [Ni2(BDC)2DABCO] (BDC = 1,4-benzenedicarboxylate, DABCO = 1,4-diazabicyclo[2.2.2]octane), its bimetallic nickel-iron form [Ni(Fe)(BDC)2DABCO] and their modified Ketjenblack (mKB) composites were synthesized and tested towards OER in an alkaline medium (KOH 1 mol L–1). A synergistic effect of the bimetallic nickel-iron MOF and the conductive mKB additive enhance the catalytic activity of the MOF/mKB composites. All MOF/mKB composite samples (7, 14, 22, 34 wt.% mKB) indicated much higher OER performances than the MOFs and mKB alone. The Ni-MOF/mKB14 composite (14 wt. % of mKB) demonstrated an overpotential of 294 mV at a current density of 10 mA cm–2 and Tafel slope of 32 mV dec–1, which is comparable with commercial RuO2 commonly used as a benchmark material for OER. The catalytic performance of Ni(Fe)MOF/mKB14 (0.57 wt% Fe) was improved further to an overpotential of 279 mV at a current density of 10 mA cm–2. The low Tafel slope of 25 mV dec–1 as well as a low reaction resistance due to electrochemical impedance spectroscopy (EIS) measurement confirm the excellent OER performance of the Ni(Fe)MOF/mKB14 composite. For practical applications, the Ni(Fe)MOF/mKB14 electrocatalyst was impregnated into commercial nickel foam (NF), where overpotentials of 247 and 291 mV at current densities of 10 and 50 mA cm–2, respectively, were realized. The activity was maintained for 30 h at the applied current density of 50 mA cm–2. The electrocatalytic system consisting of earth-abundant Ni and Fe metals only would be attractive for the development of efficient, practical and economical energy conversion materials for efficient OER activity.

Nickel foam substrates are frequently utilised for renewable energy applications as porous 3D-substrates. Preparation of these substrates usually includes an acid washing step, however the degree to which this step affects the final electrochemical performance after spray coating a catalyst ink is unreported. Herein, we report the effect of acid washing through physicochemical and electrochemical characterisation. The electrochemical performance was determined by repeated measurements of catalyst-coated nickel foam substrates both with and without the initial step of acid washing. Acid washing increased current density by 17.9% for the acid treated, MoS2-coated nickel foam electrode. This increment was affiliated with an electrochemically active surface area which increased by 87.1%, where Tafel analysis indicated that the acid treated, MoS2-coated electrodes facilitates the initial water dissociation step of the hydrogen evolution reaction with greater ease. Similar effects were also discovered for acid treated PtIr(1:3)/C-coated nickel foam substrates, albeit with less pronounced effects. Stability was also improved where the degradation rate was reduced by 18.9% for the acid treated, MoS2-coated electrodes. This proves the utility of acid washing nickel foam electrodes.

Dental caries is a public health problem worldwide according to WHO data. Among treatments in pediatric dentistry, prefabricated metal crowns (PMCs) have been one of the most successful options since they were introduced in cases of considerable tooth destruction. Our objective was to detect the presence and concentration of iron (Fe), chromium (Cr), and nickel (Ni) in saliva of patients who require rehabilitation with PMCs, before and after their placement. A quasi-experimental study was performed in 32 patients who attended dental care in a pediatric dentistry clinic at a public university and who required rehabilitation with PMCs. Parametric tests (ANOVA and Pearson correlation) were performed, and a p ≤ 0.05 was considered statistically significant. Statistically significant differences were found when comparing the Ni release before, 1 week, and 1 month after placing the crowns. Similarly, we observed a positive correlation between the number of crowns and Ni release. No tests were performed for Fe and Cr because the amounts of these metals were less than 0.1 ppb, which was not detectable by inductively coupled plasma optical emission spectrometry (ICP-OES). The levels of Fe, Cr, and Ni released were below toxic health levels. Studies are required to evaluate whether this release has negative effects at cellular levels.

The rapid expansion of flexible and wearable electronics has necessitated a focus on ensuring their safety and operational reliability. Gel Polymer Electrolytes (GPEs) have become preferred alternatives to traditional liquid electrolytes, offering enhanced safety features and adaptability to the design requirements of flexible lithium-ion batteries. This review provides a comprehensive and critical overview of recent advancements in GPEs technology, highlighting significant improvements in their physicochemical properties, which contribute to superior long-term cycling stability and high-rate capacity compared to traditional organic liquid electrolytes. Special attention is given to the development of smart GPEs endowed with advanced functionalities such as self-protection, thermotolerance, and self-healing properties, which further enhance battery safety and reliability. The review also critically examines the application of GPEs in high-energy cathode materials, including Lithium Nickel Cobalt Manganese (NCM), Lithium Nickel Cobalt Aluminum (NCA), and thermally stable Lithium Iron Phosphate (LiFePO4). Despite the advancements, several challenges in GPE development remain unresolved, such as improving ionic conductivity at low temperatures and ensuring mechanical integrity and interfacial compatibility. The review concludes by outlining future research directions and the remaining technical hurdles, providing valuable insights to guide ongoing and future efforts in the field of GPEs for lithium-ion batteries, with a particular emphasis on applications in high-energy and thermally stable cathodes.

The creation of nano-zero-valent iron (nZVI) by implementing plant extracts is an environmentally friendly process. High antioxidant capacity and phenol content indicated the possibility of oak-nZVI synthesis using oak leaf extract as a stable material with minimal agglomeration. Simultaneously removal of Cd and phosphates and Ni and phosphates was optimized by a statistically designed experiment with a definitive screening design. In terms of significance, 4 input parameters on process productivity were monitored: initial metal concentration (1 - 9 mgL-1), initial ion concentration (1- 9 mgL-1), pH value (2 - 10) and oak-nZVI dosage (2 - 16 ml). Phosphate removal efficiency, in the presence of cadmium, was the most influenced by oak-nZVI dose and cadmium concentration, while pH gave three statistically significant interactions with oak-nZVI dosage, cadmium concentration, and phosphate concentration. Phosphate removal efficiency, in the presence of Ni, is the most influenced by nickel concentration, phosphate concentration, pH, two-factor interaction between nZVI dose and Ni concentration, and quadratic phosphate interaction. The process optimization yielded the highest simultaneous removal efficiency of 98.99% and 87.30% for cadmium and phosphate ions, respectively. Also, the highest simultaneous removal efficiency of nickel and phosphates ion was 93.44% for 96.75%, respectively. The optimization process fits into the confidence intervals, confirming the assumption that the adopted regression model describes the process well. This work demonstrated an enormous potential and prosperous application for the Cd(II), Ni(II), and phosphate removal from water matrices.

In pursuit of carbon neutrality, the demand for metals that are necessary for the development of clean energy technologies is rapidly increasing. Metallurgical waste, such as slag, presents a promising secondary source of these key metals. This research aims to develop an eco-friendly hydrometallurgical process to recover Cu, Ni, and Co from discarded copper/nickel slag. The high-pressure acid leaching (HPAL) was used to selectively leach Ni, Cu, and Co from the fayalite slag, yielding high leaching efficiencies of 99.9%, 89.4%, and 99.9%, respectively, with low Fe and Si tenors to the pregnant leach solution (PLS). The solvent extraction (SX) technique utilizing LIX 984N was used to selectively extract and enrich copper from the dilute PLS to about 23 g/L Cu with a very low Fe concentration of 0.05 g/L. Potassium amyl xanthate (PAX) solution was used to form Ni and Co xanthate complexes from the raffinate solution. Nickel was selectively recovered using ammonia solution, while cobalt xanthate complex was thermally decomposed and recovered as cobalt oxide solids of about 25 wt.% Co. A comprehensive process flowsheet is presented, furthermore, to realize the real application of the developed slag cleaning process, a preliminary economic evaluation was performed.

In this experimental work, pure nickel oxide and Al-doped NiO thin films have successfully been elaborated onto glass substrates by solar spray pyrolysis technique. The substrates were heated at around 450°C using a solar heater (furnace). The structural, optical and electrical properties of the elaborated Al-doped films have been studied at different atomic percentage ratios (0, 0.5, 1, 1.5 and 2 at. %). The results of Al-doped NiO films XRD patterns were, the formation of (NiO) phase under a cubic crystalline structure (polycrystalline) with a strong favored orientation along (111) plane were noticed at all sprayed films. When Al doping ratio reaches 1 at.%, an growth in crystallite size over 31.9 nm was obtained denoting the nano-structure of the product, which confirmed by SEM images. In addition, aluminum oxide Al₂O₃ was clearly observed at 1.5 at.% Al ratio. Otherwise, all thin films have a good optical transmission in the visible region of about 65%, the optical band gap energy decreased from 3.69 to 3.64 eV with increasing Al doping ratio. It is shown that the layer deposited with 0.5 at.% has less disorder with few defects. The investigation on electrical properties of elaborated thin films confirmed that the conductivity of NiO films was improved, after doping them with Al which affirms their p-type character of semiconductor. However, an addition of an excessive quantity of Al content causes the formation of Al₂O₃ which leads to a decrease in the conductivity. It is worth mentioning that the Al content of 0.5 at.% is the optimum ratio in terms of electrical conductivity and formation defect. Al-doped NiO can be used in various optoelectronic devices due to its good transparency and high electrical conductivity.

Laser shock peening as an innovative surface treatment technology can effectively improve the fatigue life, sur-face hardness, corrosion resistance, and residual compressive stress. Compared with the laser shock peening, the warm laser shock peening (WLSP) is a new surface treatment technology to improve materials’ surface performances, which takes advantage of thermal mechanical effects on stress strengthening and micro-structure strengthening, results in more stable distribution of the residual compressive stress under heating and cyclic loading process. In this paper, the microstructure of GH4169 nickel super-alloy processed by WLSP technology with differ-ent laser parameters were investigated. The proliferation and tangling of dislocations in GH4169 were observed and the dislocation density increased after WLSP treatment. The influences of different treatment by LSP and WLSP on the microhardness distribution of the surface and along cross-sectional depth were investi-gated. The microstructure evolution of the GH4169 alloy being shocked with WLSP were studied by TEM. The effect of temperature on the stability of high temperature microstructure and properties of GH4169 alloy WLP was investigated.

Inclusions in steels and alloys are known as factors that could lower deformation, mechanical, corrosion and other properties. Study of inclusions in nickel based alloys is important since these materials could suffer from corrosion degradation in harsh operational conditions, where inclusions could lead to a pitting initiation. For estimation of a harmful effect of different inclusions on corrosion resistance of Ni-based alloys, inclusion characteristics (such as composition, morphology, size, number and location) on film filter and dissolution of metal matrix around different inclusions on surfaces of metal samples after electrolytic extraction (EE) were investigated in two samples of industrial Ni-based alloys (alloy 718 and EP718). It was found that both Ni-based alloys have various inclusions: carbides (large size NbTi-C and small multicomponent carbides), nitrides TiNb-N and sulfides (TiNb-S in EP718 alloy). The higher harmful effect on corrosion resistance of metal was detected around sulfides and small carbides containing Mo, W, Cr. Dissolution effect was also observed around large carbides and nitrides, especially around inclusions having size more than 10 µm. Moreover, the dissolution of metal matrix around inclusions and clusters located on the grain boundaries is 2.1-2.7 times larger compared to that for those inclusions inside of grains of the given alloy samples.

The rapidly evolving field of additive manufacturing requires a periodic assessment of the progress made in understanding the properties of metallic components. Although extensive research has been undertaken by many investigators, the data on properties such as hardness from individual publications are often fragmented. When these published data are critically reviewed, several important insights that cannot be obtained from individual papers become apparent. We examine the role of cooling rate, microstructure, alloy composition, and post process heat treatment on the hardness of additively manufactured components. Hardness data for steels and aluminum alloys processed by additive manufacturing and welding are compared to understand the relative roles of manufacturing processes. Furthermore, the findings are useful to determine if a target hardness is easily attainable either by adjusting AM process variables or through appropriate alloy selection.

This study concerns calculation and comparison of Fe, Co, Ni and Cu deposition rates in tungsten codeposition process based on electrodeposition of numerous tungsten alloys. 8 different tungsten alloys containing from 2 to 5 metals were electrodeposited in constant conditions in order to compare exact reduction rates. Calculated rates enabled control of the alloy composition precise enough to obtain a high-entropy WFeCoNiCu alloy with well-balanced composition. Introduction of copper to form the quinternary alloy was found to catalyze the whole process, increasing deposition rates of all components of the high-entropy alloy.

Three types of the composites were tested for electromagnetic interference (EMI) absorption shielding effectiveness, curing process and physical-mechanical properties. In the first type of composites, manganese-zinc ferrite, nickel-zinc ferrite, and both fillers in their mutual combinations were incorporated into acrylonitrile-butadiene rubber. The overall content of the filler, or fillers combinations was kept on 200 phr. Then, carbon black, or carbon fibres, respectively were incorporated into each rubber formulation in constant loading - 25 phr, while the content of magnetic fillers was unchanged - 200 phr. The work was focused on the understanding of correlation among electromagnetic shielding parameters and electrical conductivity of composites in relation to their EMI absorption shielding effectiveness. The absorption shielding ability of materials was evaluated within the frequency range from 1 MHz to 6 GHz. The study revealed good correlation among permittivity, conductivity, and EMI absorption effectiveness. Although, the absorption shielding efficiency of composites filled only with ferrites seems to be the highest, the absorption maxima of those composites were reached over 6 GHz. The application of carbon based fillers resulted in higher electrical conductivity and higher permittivity of composites, which was reflected in their lower absorption shielding performance. Though, the composites with filled with ferrites and carbon based fillers absorbed electromagnetic radiation within the desired frequency range. The presence of carbon based fillers caused the improvement in tensile behavior of composites. The study also demonstrated that the higher was the ratio of nickel-zinc ferrite in magnetic fillers combinations, the higher was the absorption shielding performance.

This study presents a combined electrochemical impedance spectroscopy (EIS) and atomic force microscopy (AFM) and Scanning Kelvin Probe Force Microscopy(SKPFM) investigation on the natural passivation process of stainless steels (AISI 316 and AISI 304) and nickel-based alloy (INCONEL 600) as a function of immersion time in an alkaline medium (pH = 13). EIS measurements show an increase in the resistance of the film with increasing immersion time in the electrolyte. After 3 days of immersion, for the three alloys, the films formed constitute an effective barrier to the dissolution of the alloys as shown by AFM and SKPFM. The oxide film growth on each substrates is only influenced by trenches formed during the polishing step and don’t depend on the chemical composition.

A comparative study of the physicochemical properties of natural bentonite clays of Pogodayevо (Republic of Kazakhstan, mod.1) and Dash-Salakhli (Republic of Azerbaijan, mod.2) deposits and modification of the bentonite clay with polyhydroxocations of iron (III) and aluminium (III). It-wasestablished that the modification of natural bentonitesusing polyhydroxocations of iron (III) and aluminium(III) by the method of "co-precipitation" leads to a change in their chemical composition, structural and sorption properties. The results showed that hydroxy-aluminum cations ([Al3O4(OH)24(H2O)12]7+) and poly-hydroxyl-Fe or polyoxo-Fe were intercalated into clay layers, which led to an increase in the values of d001 and specific surface areas compared to those of the original bentonite, from 37 to 120 for the Pogodaevo bentonite and from 51 to 172 respectively for bentonite from the Dash-Salakhli deposit. It is shown that modified sorbents based on natural bentonite are finely porous objects with a predominance of pores of 1.5−6.0 nm in size. As a result, there is a significant increase in the specific surface area of sorbents. Modification of bentonite with polyhydroxocations of iron (III) and aluminium (III) by the "co-precipitation" method also leads to an increase in the sorption capacity of the sorbents obtained with respect to nickel (II) cations. Modified bentonites were used for the adsorption of Ni (II) ions from the model solution. Ni (II) was absorbed in a neutral pH solution. The study of equilibrium adsorption showed that the data are in good agreement with the Langmuir isotherm model. The maximum adsorption capacity of the Ni (II) monolayer obtained from the Langmuir equation was 25.0 mg/g (mod. 1_Al_5-c), 18.2 mg/g (mod. 2_Al_5-c) for Al-bentonite and 16.7 mg/g (mod. 1_Fe_5-c), 10.1 (mod. 2_Fe_5-c) for Fe-bentonite. The kinetics of adsorption is considered. The high content of Al-OH anion exchange centresin them determines the higher sorption activity of Al-modified bentonites.

The paper investigates the influence of ion nitriding on the microstructure, corrosion resistance, and tensile strength at elevated temperatures of Haynes 282 nickel superalloy specimens produced by the Direct Metal Laser Sintering-DMLS technique. Analysis of the specimens’ surface morphology revealed that the ion nitriding process significantly affects the physical and chemical phenomena occurring on the surface of the specimens. Phase composition and stress analysis showed that Haynes 282 nickel alloy specimens produced by the DMLS technique and a chromium nitride layer produced in the ion nitriding process have tensile stress. The layer is also characterized by high nanohardness compared to specimens produced using the classical method (wrought) and DMLS technique. The conducted corrosion resistance tests confirmed the positive effect of the nitrided layer on the corrosion resistance of Haynes 282 nickel alloy produced by the DMLS technique. The ion nitriding process did not significantly affect the elevated-temperature tensile strength of Haynes 282 nickel alloy specimens produced by the DMLS technique.

Difficult-to-cut materials are being increasingly used in many industries because of their superior properties, including high corrosion resistance, heat resistance and specific strength. However, these same properties make the materials difficult to machine using conventional machining techniques. Laser-assisted milling (LAM) is one of the effective methods for machining difficult-to-cut materials. In laser-assisted milling machining occur after the workpiece is locally preheated using a laser heat source. Laser assisted machining has been studied by many researchers on flat workpiece or micro end-milling. However, there is no research on the curved shape using laser assisted milling. This study investigated the use of laser assisted milling to machine a three-dimensional curved shape workpiece based on NURBS. A machining experiment was performed on Inconel 718 using different tool paths (ramping, contouring) under various machining conditions. Finite elements analysis was conducted to determine the depth of cut. Cutting force, specific cutting energy and surface roughness characteristics were measured, analyzed and compared for conventional and LAM machining. LAM significantly improved these machining characteristics, compared to conventional machining. There results can be applied to the laser-assisted machining of various three-dimensional shapes.

Chromium-nickel austenitic stainless steels are widely used due to their high corrosion resistance, good weldability and deformability. To some extent, their application is limited by their mechanical characteristics. As a result of their austenitic structure, increasing the static and dynamic strength of the components can be achieved by surface cold work. Due to the tendency of these steels to undergo intercrystalline corrosion, another approach to improve their mechanical characteristics is the use of low-temperature thermo-chemical diffusion processes. This article proposes a new combined process based on sequentially applied diamond burnishing (DB) and low-temperature gas nitriding (LTGN) to optimally improve the fatigue strength of 304 steel. The essence of the proposed approach is to combine the advantages of the two processes (DB and LTGN) to create a zone of residual compressive stresses in the surface and subsurface layers–the enormous surface residual stresses (axial and hoop) introduced by LTGN, with the significant depth of the compressive zone characteristic of static surface cold working processes. DB (both smoothing and single-pass hardening), in combination with LTGN, achieves a fatigue limit of 600 MPa, an improvement of 36.4% compared to untreated specimens. Individually, smoothing DB, single-pass DB and LTGN achieve 540 MPa, 580 MPa and 580 MPa, respectively. It was found that as the degree of plastic deformation of the surface layer introduced by DB increases, the content of the S-phase in the nitrogen-rich layer formed by LTGN decreases, with resultant increased content of -phase, and a new (also hard) phase: stabilized nitrogen-bearing martensite.

In the past decade, under the background of the carbon peaking and carbon neutrality era, the rapid development of new energy vehicles has put forward higher requirements for the performance of strike forces such as battery cycle life, energy density and cost. Lithium-ion batteries have gradually become the mainstream of electric vehicle power batteries due to their excellent energy density, rate performance and cycle life. At present, the most widely used cathode materials for power batteries are lithium iron phosphate (LFP) and ternary nickel-cobalt-manganese (NCM). However, these materials exhibit the bottlenecks that limit the improvement and promotion of power battery performance. In this review, the performance characteristics, cycle life attenuation mechanism (including structural damage, gas generation and active lithium loss, etc.) and improvement methods (including surface coating and element-doping modification) of LFP and NCM batteries are reviewed. Finally, the development prospects of this field are proposed.

The application of diffusion dialysis using various types of ion-exchange membranes for the separation of sulfuric acid and nickel sulfate has been evaluated. The process of dialysis separation of a real waste solution from an electroplating facility containing 252.3 g/L of sulfuric acid, 20.9 g/L of nickel ions and small amounts of zinc, iron, copper ions, etc. has been studied. Heterogeneous cation-exchange membrane containing sulfo groups and heterogeneous anion-exchange membranes with different thicknesses (from 145 μm to 550 μm) and types of fixed groups (4 samples with quaternary amino groups and 1 sample with secondary and tertiary amino groups) are used. The diffusion fluxes of sulfuric acid, nickel sulfate, and the total and osmotic fluxes of the solvent are determined. The use of a cation-exchange membrane does not allow separation of the components, since the fluxes of both components are low and comparable in magnitude. The use of anion-exchange membranes makes it possible to efficiently separate sulfuric acid and nickel sulfate. At the same time, the thin dialysis membrane turns out to be the most effective, as well as the membranes with quaternary amino groups, and the membrane with secondary and tertiary amino groups proved to be the least effective.

Sputtered reactive multilayers applied as a heat source in electronic joining processes are an emerging technology. Their use promises low-stress assembly of components while improving the thermal contact and reducing the thermal resistance. Nanostructured surface modifications can significantly enhance adhesion and reliability of joints between different materials. This work examines reactive multilayer of nickel and aluminum, directly sputtered on nanostructured black silicon surfaces and compares their phase transformation with reference samples deposited on pristine silicon surface. The investigation of the quenched self-propagating reaction reveals a clear influence of the nanostructured surface on the prolongation of the phase transition. Rapid thermal annealing tests result in the formation of Al_1.1Ni_0.9 phase. The nanostructured interface seems to hinder the full transformation of the parent material. The surface modification improves the adhesion of the formed alloy on silicon surfaces and can possibly increase the reliability of joints based on reactive aluminum/nickel multilayer. The use of black silicon, a nanostructured surface modification, is thus a promising approach to realize reliable multi-material joints in complex systems.

The 70/30 copper–nickel alloy is mainly used in critical parts with more demanding conditions in marine settings. There is a need for innovative methods that offer fast production and cost-effectiveness to supplement current copper–nickel alloy manufacturing processes. In this study, we employ wire-arc additive manufacturing (WAAM) to fabricate the 70/30 copper–nickel alloy. The as-built microstructure is characterized by columnar grains with prominent dendrites and chemical segregation in the inter-dendritic area. The aspect ratio of the columnar grain increases with increasing travel speed (TS) at the same wire feed speed (WFS). This is in contrast to an equiaxed grain structure with a more random orientation of conventional sample. The sample built with a WFS of 8 m/min, TS of 1000 mm/min, and a track distance of 3.85 mm exhibits superior corrosion properties in the 3.5 wt% NaCl solution compared to the conventional one, as evidenced by a higher film resistance and breakdown potential, along with a lower passive current density of the WAAM sample. The corrosion morphology reveals the critical roles played by the nickel element unevenly distributed between the dendrite core and inter-dendritic area.

In this work, a systematic study was conducted on the fabrication of multi-material components obtained employing Laser-Powder Bed Fusion (L-PBF) technology. The idea of making multi-material components is a winning capability of additive technologies because it allows the fabrication of Functionally Graded Materials (FGMs) with the customization of parts according to different required properties. The transition from one material to another was achieved gradually and continuously within the same layer using ad-hoc equipment designed for L-PBF systems with a powder spreading technique based on coaters or rollers. The influence of the relative position of the different materials within the powder chamber and the geometry of the developed equipment on the metallurgical and mechanical properties of the manufactured samples was evaluated. The performed tests involved the use of two materials, a nickel-based superalloy, and a stainless steel, having different chemical, physical and mechanical properties to obtain gradual properties variation in the manufactured samples. Based on the results of post-process characterization obtained through metallographic, chemical, and mechanical analysis, the relative positions of the materials and the geometry of the developed equipment have a limited effect on the sample’s manufactured properties. The characteristics of the FGM zone depend on the nature of the employed powders, and its extent coincides with that defined during the design of the divider.

The effects of heating rate before solution treatment and cooling rate after solution treatment on the morphological distribution and evolution of precipitation phase of nickel-based single crystal superalloy were studied. The dissolution, precipitation and growth of precipitation phase and matrix phase during heat treatment were analyzed by means of high power scanning electron microscopy. The results show that the morphology of precipitated phase has nothing to do with the distribution of precipitated phase and the heating rate in the heating process, but the cooling rate in the cooling process affects the shape, size and distribution of precipitated phase. The faster the cooling rate, the smaller the precipitated phase is, the more irregular the shape is, the smaller the equivalent edge length is, and the smaller the channel width of matrix phase is.

Immobilized metal affinity chromatography (IMAC) is a popular and valuable method for the affinity purification of polyhistidine-tagged recombinant proteins. However, it often shows practical limitations, which might require cumbersome optimizations, additional polishing, and enrichment steps. Here, we present functionalized corundum particles for the efficient, economical, and fast purification of recombinant proteins in a column-free format. The corundum surface is first derivatized with the amino silane APTES, then EDTA dianhydride, and subsequently loaded with nickel ions. The Kaiser test, well-known in solid-phase peptide synthesis, was used to monitor amino silanization and the reaction with EDTA dianhydride. In addition, ICP-MS was performed to quantify the metal-binding capacity. His-tagged protein A/G (PAG), mixed with bovine serum albumin (BSA), was used as a test system. The PAG binding capacity was around 3 mg protein per gram of corundum. Cytoplasm obtained from different E. coli strains was examined as an example of a complex matrix. The imidazole concentration was varied in the loading and washing buffers. As expected, higher imidazole concentrations during loading are usually beneficial when higher purities are desired. Even when higher sample volumes, such as one liter, were used, recombinant protein down to a concentration of 1 µg/mL could be isolated selectively. Comparing the corundum material with standard Ni-NTA agarose beads indicated higher purities of proteins isolated using corundum. His6-MBP-mSA2, a fusion protein consisting of monomeric streptavidin and maltose-binding protein in the cytoplasm of E. coli, was purified successfully. To show that this method is also suitable for mammalian cell culture supernatants, purification of the SARS-CoV-2-S-RBD His8 expressed in human Expi293F cells was performed. The material cost of the nickel-loaded corundum material (without regeneration) is estimated to be less than 30 cents for 1 gram of functionalized support or 10 cents per milligram of isolated protein. Another advantage of the novel system is the corundum particles' extremely high physical and chemical stability. The new material should be applicable in small laboratories and large-scale industrial applications. In summary, we could show that this new material is an efficient, robust, and cost-effective purification platform for the purification of His-tagged proteins, even in challenging, complex matrices and large sample volumes of low product concentration.

Solidification microstructure is formed under high cooling rates and temperature gradients in powder-based additive manufacturing. In this study, a non-equilibrium multi-phase field method (MPFM), which was based on a finite interface dissipation model proposed by Steinbach et. al., coupled with a CALPHAD database was developed for a multicomponent Ni alloy. A qua-si-equilibrium MPFM was also developed for comparison. Two-dimensional equiaxed micro-structural evolution for the Ni (Bal.)–Al–Co–Cr–Mo–Ta–Ti–W–C alloy was performed at various cooling rates. The temperature–γ fraction profiles obtained under 10^5 K/s using non- and qua-si-equilibrium MPFMs were in good agreement with each other. Over 10^6 K/s, the differences between non- and quasi-equilibrium methods grew as the cooling rate increased. The non-equilibrium solidification was strengthened over a cooling rate of 10^6 K/s. Colum-nar-solidification microstructural evolution was performed under cooling rates from 5×10^5 K/s to 1×10^7 K/s at various temperature gradient values under the constant interface velocity (0.1 m/s). The results showed that as the cooling rate increased, the cell space decreased in both methods, and the non-equilibrium MPFM agreed well with experimental measurements. Our results show that the non-equilibrium MPFM can simulate solidification microstructure in powder bed fusion additive manufacturing.

The bipartite entanglement is comprehensively investigated in the mononuclear molecular complex (Et3NH)[Ni(hfac)2L], where HL denotes 2-(2-hydroxy-3-methoxy-5-nitrophenyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-3-oxide-1-oxyl and hfacH stands for hexafluoroacetylacetone. From the magnetic point of view, the molecular compound (Et3NH)[Ni(hfac)2L] consists of an exchange-coupled spin-1 Ni2+ magnetic ion and a spin-12 nitronyl-nitroxide radical substituted nitrophenol. The nickel-radical molecular complex affords an experimental realization of a mixed spin-(12, 1) Heisenberg dimer with a strong antiferromagnetic exchange coupling J/kB= 505 K and two distinct g-factors gRad=2.005 and gNi=2.275. By adopting this set of magnetic parameters we demonstrate that the Zeeman splitting of a quantum ferrimagnetic ground-state doublet due to a weak magnetic field may substantially reinforce the strength of bipartite entanglement at low temperatures. The molecular compound (Et3NH)[Ni(hfac)2L] maintains sufficiently strong thermal entanglement even at room temperature, vanishing only above 546 K. Specifically, the thermal entanglement in the nickel-radical molecular complex retains approximately 40% of the maximum value corresponding to perfectly entangled Bell states at room temperature, which implies that this magnetic compound provides suitable platform of a molecular qubit with potential implications for room-temperature quantum computation and quantum information processing.

The selective extraction of metals from aqueous solutions is very important stage in hydrometallurgical processing of metallic waste. Leach solutions are usually a multi-component mixture. The main impurity of aqueous solutions obtained after leaching using inorganic acids is iron. In this work, the membrane separation of iron(III) from nickel(II), cobalt(II) and lithium(II) was studied. The facilitated transport of metal ion using the polymer inclusion membranes (PIMs) with tetrabutylammonium bromide (TBAB) as an ion carrier under various conditions was analyzed in detail. The several factors such as the ion carrier concentration in the membrane as well as the effect of the inorganic acids concentration in the source/receiving phases on the kinetic parameters were investigated. The results show that ionic liquid TBAB is a very selective ion carrier of Fe(III) towards Ni(II), Co(II) and Li(I) .

Hepcidin-25 was identified as the main iron regulator in the human body by binding to the sole iron-exporter ferroportin. Studies showed that the N-terminus of hepcidin is responsible for this interaction, the same N-terminus that encompasses a small copper(II)-binding site known as ATCUN (amino terminal Cu(II)- and Ni(II)- binding) motif. Interestingly, this copper-binding property is largely ignored in most papers dealing with hepcidin-25. In this context, detailed investigations of the formed complex of hepcidin-25 with copper could reveal insights into its biological role. The present work is mainly focused on the study of the metal-bound form of hepcidin-25, which could be considered the biologically active form. The first part is devoted to the reversed-phase chromatographic separation of copper-bound and copper-free hepcidin-25, which was achieved by applying basic mobile phases containing 0.1% ammonia. Further, mass spectrometry (tandem mass spectrometry MS/MS, high resolution mass spectrometry HRMS) and nuclear magnetic resonance (NMR) spectroscopy were employed to characterize the copper-peptide. Lastly, a 3D model of hepcidin-25 with bound copper(II) is presented. The identification of metal complexes and potential isoforms and isomers, from which the latter usually are left undetected by mass spectrometry, led to the conclusion that complementary analytical methods are needed to characterize a peptide calibrant or reference material comprehensively. Quantitative nuclear magnetic resonance (qNMR), inductively-coupled plasma mass spectrometry (ICP-MS), ion-mobility spectrometry (IMS) and chiral amino acid analysis (AAA) should be considered among others.

Carbon supported nanoparticles of monometallic Ni catalyst and binary Ni-Transition Metal (Ni-TM/C) electrocatalytic composites were synthesized via chemical reduction method, where TM stands for the doping elements Fe, Co, and Cu. The chemical composition, structure and morphology of the Ni-TM/C materials were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffractometry (XRD), transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM) and energy-dispersive X-ray spectroscopy (EDS). The electrochemical properties towards hydrogen oxidation reaction in alkaline medium were studied using the rotating disc electrode and cycling voltammetry methods. A significant role of the TM dopant in the promotion of the hydrogen electrooxidation kinetics of the binary Ni-TM/C materials were revealed. A record-high in exchange current density value of 0.060 mA cm²_Ni was measured for Ni₃Fe₁/C, whereas the monometallic Ni/C counterpart has only shown 0.039 mA cm²_Ni. In order to predict the feasibility of the electrocatalysts for hydrogen chemisorption, density functional theory was applied to calculate the hydrogen binding energy and hydroxide binding energy values for bare Ni and Ni₃TM₁.

Copper(II), nickel(II) and zinc(II) complexes of various peptide fragments of tau protein were studied by potentiometric and spectroscopic techniques. All peptides contained one histidyl residue and represented the sequences of tau(91-97) (Ac-AQPHTEI-NH2), tau(385-390) (Ac-KTDHGA-NH2) and tau(404-409) (Ac-SPRHLS-NH2). Imidazole-N donors of histidine were the primary metal binding sites for all peptides and all metal ions but in case of copper(II) and nickel(II) the deprotonated amide groups were also involved in metal binding by increasing pH. The most stable complexes were formed with copper(II) ion but the presence of prolyl residues resulted in significant changes in the thermodynamic stability and speciation of the systems. It was also demonstrated that nickel(II) and especially zinc(II) complexes have relative low thermodynamic stability with these peptides. Copper(II) catalyzed oxidation of the peptides was also studied. In the presence of H2O2 the fragmentation of peptides can be detected in all cases. In the simultaneous presence of of H2O2 and ascorbic acid the extent of the fragmentation of the peptide is less preferred, and the formation of 2-oxo-histidine also occurs.