Nickel Lattice Research Articles

Tailoring structural and magnetic properties of NiCu nanowires by electrodeposition

In this work, we investigated the tailoring of structural and magnetic properties of NiCu nanowires through electrodeposition. Continuous (S1) and composition-modulated (S2) wires were fabricated by electrodeposition using porous alumina membranes as a template. Morphological characterization revealed that the total length of the wires was 8 ± 3 µm in both S1 and S2. For the composition-modulated wires, the length of the segments with the lowest and highest Cu concentrations was 1.2 ± 0.4 µm and 226 ± 65 nm, respectively. Mapping by energy dispersive spectroscopy (EDS) revealed that the concentration of copper and nickel varied along the length of the composition-modulated nanowires, while the continuous nanowires contained a relatively constant concentration of both metals. It is demonstrated that the change in Cu concentration along the wire modifies the lattice parameter, average crystallite size (D) and lattice strain (ε) of Ni. This result is pivotal for understanding the magnetic properties of the wires, as nickel is primarily responsible for the magnetic behavior of the wires. From the ferromagnetic resonance (FMR) results, the linewidth and resonance field values for samples S1 and S2 were determined. It was demonstrated that the greater deformation in the nickel lattice in NiCu nanowires increases the angular dependence of the resonance field. Furthermore, the smaller nickel crystallite size was shown to increase spin dispersion and magnetic damping, leading to complex behavior in FMR responses. Finally, it was demonstrated how Cu can influence the magnetic properties such as coercivity (HC) and squareness (MR/MS) of the wires. Overall, this work contributes to understanding the tailoring of structural and magnetic properties of NiCu nanowires through electrodeposition.

Nanocone-Modified Surface Facilitates Gas Bubble Detachment for High-Rate Alkaline Water Splitting

Alkaline water splitting (AWS) is one of the most attractive technologies for green hydrogen production. In comparison to the acidic proton exchange membrane (PEM), AWS offers greater flexibility in using non-platinum group metal catalysts and could generate higher-purity hydrogen. However, commercial AWS systems are normally operated at a lower current density (~400 mA cm-2) than PEM electrolyzers. To rapidly generate hydrogen at an industrial scale, it is critical to boost the operating current density of AWS to a level of ~1000 mA cm-2. Nevertheless, the significant amount of gas bubbles generated during high-rate AWS could be detrimental to the process. Bubbles can block the catalysts’ active site, hinder electrolyte diffusion, and increase Ohmic resistance, thus deteriorating the reaction rate and restricting the cell voltage efficiency. The detachment of gas bubbles may also damage the catalyst layer. In this study, we demonstrate a general strategy for facilitating bubble detachment by modifying the nickel electrode surface with nickel nanocone nanostructures, which turns the surface into underwater superaerophobic. The simulation and experimental data show that bubbles take a considerably shorter time to detach from the nanocone-modified nickel foil than the unmodified foil. As a result, these bubbles also have a smaller detachment size and less chance for bubble coalescence. The nanocone-modified electrodes, including nickel foil, nickel foam, and 3D-printed nickel lattice, all show substantially reduced overpotentials at 1000 mA cm-2 compared to their pristine counterpart. The electrolyzer assembled with two nanocone-modified nickel lattice electrodes retains >95% of the performance after testing at ~900 mA cm-2 for 100 hours and the surface NC structure is also well preserved, demonstrating its excellent electrochemical and mechanical stability at high current density. Our findings offer an exciting and simple strategy for enhancing the bubble detachment and, thus, the electrode activity for high-rate AWS.

Influences of Al particles on structure and properties of Ni–Al composite coatings with nanoscale twin structure

Nickel-aluminum (Ni–Al) composite coatings containing nickel nanoscale twins have been prepared by co-electrodeposition on copper substrate. Effects of Al particles on microstructure, chemical composition, friction properties, and corrosion resistance of Ni–Al coatings were investigated. It presents an even and compact structure with granular surface that Al are evenly dispersed in pyramidal-like nickel lattice. Adding Al could alter crystal orientation, refine grains and promote strengthening effects induced by nanoscale twinning. It can enhance anti-corrosion properties and decrease the coefficient of friction (COF). The minimum COF was obtained at 10 g L−1 Al. The larger amounts and even dispersion of Al, the better corrosion resistance and the smaller COF. Increasing Al from 20 to 40 g L−1, incorporated Al in top surface rose from 20.86 to 30.13 wt%, which was larger than in cross section from 13.93 to 18.86 wt%. As the incorporated depth increased, the particle color changed from grey to dark. Nano-twins were generated around enveloped Al particles. The roughness increased as Al rose from 10 to 40 g L−1. The average roughness (Ra) was of 191–231 nm. Ni–Al-5g and Ni–Al-80g have excellent anti-corrosion features, owning the maximum Rct of 1437.2 and 1565.1 kΩ cm2, respectively, associated with the amount and distribution of Al particles, preferred orientation, grain sizes, and twinned structure. The enhanced corrosion resistance might be due to the generation of uniform, compact aluminum oxide layer by doping Al in nickel.

Enhancing hydrogen evolution and oxidation kinetics through oxygen insertion into nickel lattice

Nickel-based materials, including metallic Ni and Ni oxide, have been widely studied in the exploration of non-precious-metal hydrogen electrocatalysts, but neither pure Ni nor NiO is ideal for the hydrogen evolution reaction (HER) and hydrogen oxidation reaction (HOR). In this paper, an oxygen insertion strategy was applied on nickel to regulate its hydrogen electrocatalytic performance, and the oxygen-inserted nickel catalyst was successfully obtained with the assistance of tungsten dioxide support (denoted as O-Ni/WO2). The partial insertion of oxygen in Ni maintains the face-centered cubic arrangement of Ni atoms, simultaneously expanding the lattice and increasing the lattice spacing. Consequently, the adsorption strength of *H and *OH on Ni is optimized, thus resulting in superior electrocatalytic performance of O-Ni/WO2 in alkaline HER/HOR. The Tafel slope of O-Ni/WO2@NF for HER is 56 mV dec−1, and the kinetic current density of O-Ni/WO2 for HOR reaches 4.85 mA cm−2, which is ahead of most currently reported catalysts. Our proposed strategy of inserting an appropriate amount of anions into the metal lattice could provide more possibilities for the design of high-performance catalysts.

Probing the (de)activation of Raney nickel–iron anodes during alkaline water electrolysis by accelerated deactivation testing

We investigated the (de)activation of Raney nickel–iron anodes in various oxygen evolution reaction (OER) environments using accelerated deactivation testing (ADT) under the conditions of on/off voltage control (ADT1), constant current density (ADT2), and cyclic voltammetry (ADT3). ADT1 caused activation under OER conditions by promoting the leaching of residual zinc and thus increasing the electrode surface area and oxygen vacancy content, whereas deactivation was observed under the conditions of the hydrogen evolution reaction(H-ADT1). ADT2 decreased the OER activity by promoting NiO formation and iron leaching, while ADT3 slightly increased the OER activity by favoring the incorporation of iron into the nickel lattice and promoting nickel–iron hydroxide formation. Thus, this work facilitates the design of more efficient and durable Raney nickel–based OER anodes by providing insights into their (de)activation mechanisms.

The origin of extraordinary selectivity in dehydrogenation of methylcyclohexane over Ni-Sn-based catalysts

High-loaded nickel catalysts (HLNCs) modified with Sn were synthesized and tested in dehydrogenation of methylcyclohexane (MCH) as a liquid organic hydrogen carrier. The catalyst composition and its reduction temperature were optimized that enabled to achieve the dehydrogenation selectivity of 99.0 % at a MCH conversion of 92 % and WHSV of 6.0 h−1, while the 99.9 % selectivity was reached at the conversion of 60.4 %, and WHSV of 18.5 h−1. Further, stability of the high selectivity of Sn-modified HLNCs was demonstrated in the long-run (100 h) catalyst test. The genesis of the HLNCs during their modification with Sn and reductive activation in hydrogen was studied. It was shown that the activation at temperatures above 450 °C resulted in a uniform distribution of Sn with the predominant formation of solid NiSn solutions having a crystal lattice of metallic nickel. The formation of the solid solutions provided a decrease in the adsorptive properties relating to the reaction product, toluene, which, in turn, led to an increase in the selectivity of MCH dehydrogenation.

Mechanism study of strain-induced magnetic properties changes for nickel-based materials at atomic scale

Based on the magneto-mechanical coupling effect, magnetic non-destructive testing technology is widely used to test stress and defect in ferromagnetic materials. To analyze the effect of strain/stress on the atomic magnetism of Ni-based materials strain-induced changes of magnetic properties of FCC-Ni 2 × 2 × 2 supercell and its doped systems with Cu and Nb atoms are studied by the first principal density functional theory. Firstly, addition of Cu or Nb promote the expansion of nickel lattice, and Nb makes this effect more significant. Cu atoms enhance the magnetic moment of Ni atoms, while Nb atoms play an inhibitory role. Secondly, for uniaxial strain, the magnetic moments of atoms in the doping-free systems show a nearly monotonic increasing trend from compression to tension, while the doped systems show a trend of first increases and then decreases. Furthermore, for shear loading, the atomic magnetic moment decreases with increases of the shear strain. Further investigation shows that Ni atoms at different distances exhibit completely different magnetic behavior due to the influence of loadings and doping atoms. This study would be an important supplement to the physical mechanism of multi-field coupling in magnetic non-destructive testing.

Nanocone‐Modified Surface Facilitates Gas Bubble Detachment for High‐Rate Alkaline Water Splitting

AbstractThe significant amount of gas bubbles generated during high‐rate alkaline water splitting (AWS) can be detrimental to the process. The accumulation of bubbles will block the active catalytic sites and hinder the ion and electrolyte diffusion, limiting the maximum current density. Furthermore, the detachment of large bubbles can also damage the electrode's surface layer. Here, a general strategy for facilitating bubble detachment is demonstrated by modifying the nickel electrode surface with nickel nanocone nanostructures, which turns the surface into underwater superaerophobic. Simulation and experimental data show that bubbles take a considerably shorter time to detach from the nanocone‐modified nickel foil than the unmodified foil. As a result, these bubbles also have a smaller detachment size and less chance for bubble coalescence. The nanocone‐modified electrodes, including nickel foil, nickel foam, and 3D‐printed nickel lattice, all show substantially reduced overpotentials at 1000 mA cm−2 compared to their pristine counterpart. The electrolyzer assembled with two nanocone‐modified nickel lattice electrodes retains >95% of the performance after testing at ≈900 mA cm−2 for 100 h. The surface NC structure is also well preserved. The findings offer an exciting and simple strategy for enhancing the bubble detachment and, thus, the electrode activity for high‐rate AWS.

Influence of the composition of the cumulative lattice during thermal diffusion chromiing on the depth of the diffusion layer

Presents the results of experiments on improving the technology of thermal diffusion chromium plating of structural steels through the use of an internal emission field created in the technological backfill during heating. To create a field in the separating part of the technological backfill, aluminum oxide was completely replaced by mixtures of two compositions: a mixture of scheelite (CaWO4) and serpentine (Mg3Si2O7); a mixture of scheelite (CaWO4), serpentine (Mg3Si2O7), MgO, dicalcium silicate (γ-2•CaO•SiO2). The choice of these materials was based on the results of preliminary experiments on measuring the thermionic current in them. Saturation of samples of steel 35CrNi2-3 with chromium was carried out at a temperature of 1000°C for 24 hours. For both variants of technological fillings, the ab-sence of sintering and good knockout of parts were noted. The chemical composition of the diffusion layer on metal samples was controlled using a JEOL JSM-6460LV universal scanning (scanning) electron microscope. The micro-hardness of the coatings was measured using an FM-800 microhardness tester. The results show that the additional use of cumulative lattices of nickel and nichrome for thermal diffusion chromium plating provides an increase in the depth of chromium diffusion by 1.5 times when saturated in the backfill of the same composition. In this case, the lattice material has little effect on the depth of chromium diffusion, but it influences the intensity of surface microalloying with nickel. The electron yield work of nichrome X20H80, equal to 4.5 eV, has been determined. It was found that the hardness of the diffusion layers formed on the surface correlates with the content of chromium and nickel in them. The hardness of the chrome layer is 790±10 HV and 820±10 HV, using nickel and nichrome cumulative lattices, respective-ly. In the case of saturation without grids, the hardness is 50 and 20 HV respectively lower.

The application of cumulating lattice to accelerate diffusion during thermal diffusion chromiing

The creation of coatings on parts with improved corrosion resistance, throughput at low and high temperatures, wear resistance makes it possible to expand the possibilities of using low and medium alloy steels. Traditional methods for creating protective coatings are various types of chemical-thermal treatment and thermal diffusion chromium plating, in particular. In recent decades, attempts have been repeatedly made to increase the efficiency of the process of thermal diffusion saturation of chromium metal, mainly due to complex saturation with vanadium, boron and other elements, as well as the use of external physical influences that accelerate diffusion. Previously, in the works of the authors, it was shown that the introduction of electron-emitter metal powder into the composition of the metal part of the filling ensures the acceleration of diffusion processes during thermal diffusion chromium plating due to the action of an internal emission field. A similar effect is also observed when replacing corundum in the separating part of the filling with powders of solid electrolytes (minerals such as serpentine and scheelite, which are emitters of electrons and anions of the oxygen when heated). An additional enhancement of the internal emission field was noted when cumula-tive nickel and molybdenum lattice were used, however, the effect of the geometric characteristics of these lattice on the magnitude of the thermal emission of electrons and oxygen anions and, as a result, the diffusion acceleration was not established. The paper presents the results of saturation of samples of steel X35CrNi2-3 at a temperature of 1000°C for 24 hours using cumulative lattice that differ in the density of holes per unit area: 20, 10 and 6 holes/cm2. The control of the elemental composition of the diffusion layer was carried out on transverse sections in the direction from the saturated surface to base metal of the sample using a JEOL JSM-6460LV universal scanning (scanning) electron microscope. X-ray phase analysis was performed on an Ultima IV diffractometer, the radiation used was Cu-Kα. The microstructure was studied using an optical microscope Axio Observer D1.m. The microhardness of the coatings was measured using an FM-800 microhardness tester. It has been established that the use of cumulative nickel lattices provides an increase in the depth of the diffusion layer in the base metal by at least 25% and additional alloying coating with a grating metal element with a hole density of 10 pieces/cm2 or more. At a lower density of perforating the lattice, the opposite effect is observed

Synthesis and Properties of Octet NiCr Alloy Lattices Obtained by the Pack Cementation Process

NiCr alloys with different components were obtained by pack chromation and homogenization heat treatment of octet Ni lattice. The microstructure, alloy composition, microhardness and quasi-static compression properties of the NiCr lattice were tested. The results showed that after homogenization heat treatment, the NiCr alloy lattice had an austenitic structure with uniform composition. Compared with the pure nickel lattice, the microhardness, compressive strength, elastic modulus and energy absorption of the NiCr lattice increased with the increase of chromium content. The microhardness, specific strength, specific modulus and specific energy absorption of the Ni-45Cr alloy were 363 HV, 11.1 MP/(g/cm3), 1169.1 MP/(g/cm3) and 10 J/g, respectively, which were attributed to the solid solution strengthening provided by chromium and the increase in density. NiCr alloy lattices have high strength and toughness and may have potential applications in high-temperature filters or heat exchangers.

Microstructure and Properties of Hollow Octet Nickel Lattice Materials.

In this study, electroless nickel plating and electrodeposition were used to deposit thin films on the polymer lattice template prepared by 3D printing, then seven Octet hollow nickel lattice materials with different structural parameters were synthesized by etching process at the expense of the polymer backbone. The microstructure and properties of the Octet structure nickel lattice were characterized by X-ray diffraction, Electron backscattering diffraction and transmission electron microscopy. According to the results, the average grain size of the electrodeposition Ni lattice material was 429 nm, and (001) weak texture was found along the direction of the film deposition. The lattice deformation mode changed with the increase of the lattice length-to-diameter ratio, and it shifted from the lattice deformation layer-by-layer and the overall deformation to the shear deformation in the 45° direction. The strength, modulus and energy absorption properties of the Octet lattice increased with the density, and they were exponentially related to density. In the relative density range of 0.7~5%, Octet hollow Ni lattices with the same density conditions but different structural parameters showed similar compressive strength and elasticity modulus; the energy absorption capacity, however, was weakened as the length-to-diameter ratio increased.

Effect of Cr on a Ni-Catalyst Supported on Sibunite in Bicyclohexyl Dehydrogenation in Hydrogen Storage Application

A comparison of the activity of mono- and bimetallic Ni-Cr/C catalysts deposited on a carbon carrier (sibunite) in the bicyclohexyl dehydrogenation reaction as a stage of hydrogen evolution in hydrogen storage systems is carried out. The interaction of Ni and Cr supported onto the carbon carrier—sibunite in bimetallic NiCr systems affects the change in the parameters of the crystal lattice of nickel, compared with the FCC lattice of Ni, as shown by the methods of XPS, TPR, XRD, high-resolution TEM and electron diffraction.

ЕЛЕКТРООСАДЖЕННЯ НАНОКРИСТАЛІЧНОГО СПЛАВУ НІКЕЛЬ-ЗАЛІЗО З ЕЛЕКТРОЛІТУ НА ОСНОВІ НОВОГО ТИПУ ЙОННИХ РІДИН – НИЗЬКОТЕМПЕРАТУРНОГО ЕВТЕКТИЧНОГО РОЗЧИННИКА

The paper reports the main features of electrochemical deposition of nickel-iron alloy from electrolyte based on the eutectic mixture of choline chloride and ethylene glycol, which is a typical representative of a new type of ionic liquids, deep eutectic solvents (DES). It is found that the iron content in the deposited alloy increases with both increasing the applied cathode current density and increasing the concentration of iron ions in the electrolyte and the introduction of water additives. Thus, variation in the current density and the concentration of water additive in electrolytes based on DES is the factor of influence on the kinetics of partial electrode reactions, and hence on the composition and properties of the coating. It is shown that it is possible to deposit uniform coatings with iron content up to 10–13% from the investigated electrolyte containing water additive (up to 10 wt.%) at the deposition current density not exceeding 1–1.2 A/dm2. The current efficiency of the alloy deposition is close to the theoretical value (97–99%), i.e. the electrodeposition is practically not complicated by electrochemical processes involving components of a deep eutectic solvent. The surface of pure nickel deposited from an electrolyte based on DES without additional water is quite uniform with a small number of defects, pitting and small pores, while coatings deposited from the electrolyte containing water additives are characterized by granular surface morphology with many asymmetric spheroidal crystallites. The electrodeposition of a nickel-iron alloy yields the surface built of irregular spheroids that overlap and form a scaly-like type of surface morphology. Nickel-iron electrolytic coatings containing up to ~7% Fe, formed from the ethaline-based electrolyte, are nanocrystalline solutions of iron in nickel with a face-centered cubic nickel lattice and an average nanocrystallite size of about 6–15 nm. Nickel-iron alloy coatings electrochemically deposited under the conditions established in this work may be considered as promising electrode materials for the creation of new cheap and highly efficient electrocatalysts for water electrolysis in hydrogen energy.

PHASE COMPOSITION AND STRUCTURE OF CARBONADO DIAMOND POLYCRYSTALS AFTER LASER TREATMENT

Synthetic polycrystalline diamonds are mainly composed of inclusions of graphite and a catalyst metal (Me). The presence of these inclusions and their amount significantly affects many of the physical and mechanical properties of diamonds and, ultimately, the performance of diamonds in a tool. Therefore, the study of the quantitative phase composition of synthetic diamonds (SD) is very important. The paper considers the change in the period of the crystal lattice of SD polycrystals and nickel (Ni) impurities after exposure to laser radiation with a wavelength of 1.06 μm. The time of laser irradiation varied from 3 to 60 sec. To determine the crystal lattice period of SA polycrystals, powders with a grain size of 315/250, 200/160, and 100/80 μm were used. A decrease in the crystal lattice period of the studied diamonds was found. We assume that this is due to the diffusion process of ordering of the diamond lattice, when the metal-enriched sections of the diamond-metal-catalyst system are locally heated. The results obtained will make it possible to understand the physical mechanism for increasing the strength of the studied crystals after exposure to laser beams under certain conditions.

Simulation research on nucleation mechanism of graphene deposition assisted by diamond grain boundary

The growth of high-quality graphene is always a focused issue in the field of two-dimensional materials, and the growth of graphene on brand new substrates has received considerable attention from scholars especially. The research on the nucleation mechanism of graphene deposited on a polycrystalline diamond substrate is of significance in the large-scale preparation of graphene in practice. Here in this work, the direct growth without transfer process of graphene on a diamond substrate is used to obtain the high-quality graphene. The reactive molecular dynamics simulation technology is adopted to imitate the process of graphene deposition and growth on bi-crystal diamond assisted by nickel catalyzed at an atomic level. The effect of the bi-crystal diamond grain boundary on the dynamic behavior of graphene nucleation and growth process is studied. The results demonstrate that the grain boundary carbon atoms can be used as a supplementary carbon source to diffuse into the nickel free surface and participate in the nucleation and growth of graphene. Furthermore, the effect of temperature on the diffusion behavior of carbon atoms is explored, finding that high temperature facilitates the dissociation of atoms in the grain boundary. When the deposition temperature equals 1700 K, it is most conducive to the diffusion of grain boundary carbon atoms in the nickel lattice, which effectively enhances the nucleation density of graphene. Besides, the effect of the deposition carbon source flow rate on the surface quality of graphene is explored, finding that the high-quality graphene surface can be obtained by adopting a lower carbon deposit rate of 1 ps<sup>–1</sup> at 1700 K. In brief, the research results obtained not only provide an effective theoretical model and analysis of the mechanism for diamond grain boundary assisted graphene deposition and growth, but also reveal the regular pattern of influence of deposition temperature and deposition carbon source flow rate on the surface quality of synthesized graphene. The present study can lay a theoretical foundation for the fabrication and application of new functional graphene-polycrystalline diamond heterostructures in the fields of ultra-precision manufacturing and microelectronics.

Synthesis and characterization of the novel nanostructured NiC carbide obtained by mechanical alloying

In the present work, a comprehensive study of mechanical alloying of Ni-carbon nanotubes (CNT) and Ni-Graphite equiatomic powder mixtures under the same technological modes has provided to reveal the features of using different types of carbon (CNT or graphite) as a charge component. The as-milled powders were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and magnetometric study. A novel nanoscale fcc NiC monocarbide was synthesized regardless the type of the charge used. According to the XRD study the formation of this phase takes place in two stages. A two-step carbide formation mechanism has been proposed. The associated changes in the nickel lattice, such as changes in the lattice parameter, lattice strain and residual stresses, which led to the formation of NiC monocarbide were also evaluated and discussed. Parameters of the electronic structure of NiC were calculated using the MStudio MindLab 7.0 software package with the experimental data on the crystal structure of the NiC phase obtained as input. Temperature dependencies of magnetic susceptibility of NiC synthesized have been studied up to 950 K. Carbides synthesized were found to be weak ferromagnets at the room temperature and their Curie temperature TC ranges within 670 – 725 K. The calculated value of the magnetic moment per nickel atom (2.83μB) is higher than that of a bulk Ni (1.3μB). Likely, the observed increase of μ is caused by the presence of a certain amount of residual single-domain ferromagnetic Ni nanoparticles in the samples synthesized.

Carbon transformations in rapidly solidified nickel–carbon ribbon

We report the structural transformations of carbon via the melt spinning and subsequent annealing of nickel-carbon alloys. We attained metastable solid solubility of carbon in nickel ribbon by achieving a rapid solidification rate of up to 1.6 × 106 K/s. Excess carbon atoms were found to be dissolved in the nickel lattice causing up to 1.4% strain for an alloy spun at 70 m/s tangential wheel speeds. High temperature heat treatments led to precipitation of carbon from the nickel lattice on the ribbon free surfaces but also led to growth of spherical precipitates within the nickel matrix, an effect consistent with bulk diffusion-driven Ostwald ripening. Carbon was excavated from the ribbons via chemical dissolution of the metal and characterized by electron microscopy and Raman spectroscopy. We found that the microstructure of carbon precipitated from the rapidly quenched ribbon could be tuned by varying the carbon content from 4 to 12 at. % in the precursor and annealing the ribbon at temperatures that ranged from 400 to 1200 °C. Via the step-wise variation of these two parameters, we sequentially transformed amorphous carbon nanospheres with a high BET surface area of 203 m2/g into thick, highly crystalline flakes of graphite that conformed to the shape of the as-spun ribbon.

Heterogeneous NiS/NiSe/3D porous biochar for As removal from water by interface engineering-induced nickel lattice distortion

Biochar has been widely used in the removal of heavy metals from wastewater due to its obligate adsorption properties. The reutilization of exhausted biochar has become a challenge for chemical researchers. In this study, diazotization-modified biochar adsorbing Ni2+ was used as a precursor to prepare heterogeneous NiS/NiSe/3D porous biochar (DAC-Ni/NiS/NiSe) using vulcanization followed by in situ competitive hydrogen reduction. The composites exhibited excellent performance in As(III) removal from water via both adsorption and photocatalysis processes, removing 100% of 10 mg/L As(III) within 110 min with 20 mg catalyst, and 90% removal rate was maintained even after five recyclability runs. The influencing factors of As(III) oxidation in reactive DAC-Ni/NiS/NiSe suspensions were also investigated. The photocatalytic oxidation efficiency of As(III) was susceptible to initial pH. The coexisting species of PO43− and CO32− exhibited obvious suppression on the total As removal, while the presence of Cl− and NO3− exhibited no obvious effect on the oxidation efficiency of As. This study provides a feasible and simple strategy for reclaiming waste biochar after adsorbing nickel to prepare energy-intensive materials and implies the possibility and necessity of biowaste applications for environmental remediation.

Potential possibilities of hydrogen accumulation in Nickel-based solid-state materials

A variant of a hydrogen accumulator based on electrochemical systems has been investigated. Niwas used as the basis, as a material with a greater tendency to absorb hydrogen. Nix-By-H (D)z composites were synthesized by the electrochemical method. Adding B to the Nix-By composite increases the accumulation of hydrogen. In Ni-B composites, boron plays the role of a hydrogen atom catcher, since tensile stresses arise in the vicinity of the substitutional impurity of a small atomic radius - boron placed in the FCC nickel lattice, therefore, hydrogen, as compared to nickel, segregates with higher synergism near boron. The potential of interaction of a hydrogen atom with an impurity trap in the form of a boron atom is estimated at 42 eV. The thermal desorption spectra of deuterium were studied of Ni–B composites at T ~ 100 K, pre-implanted with deuterium (testing element). The ratio of Ni and deuterium Ni: D = 1:1, and for the composite Ni95B5 [Ni95: B5]: D = 1:1.25. Desorption peak - 325 K.