Ni 2p Research Articles

Lithium-based transition-metal oxides for battery electrodes analyzed by x-ray photoelectron spectroscopy. V. LiNi0.4Co0.3Mn0.3O2

X-ray photoelectron spectroscopy (XPS) and x-ray-induced Auger electron spectroscopy were used to analyze untreated LiNi0.4Co0.3Mn0.3O2 powder obtained from TODA America. X-ray photoelectron and x-ray-induced Auger electron spectra were obtained using incident monochromatic Al Kα radiation at 0.834 01 nm. A survey spectrum together with Ni 2p, Co 2p, Mn 2p, Ni LMM, O 1s, C 1s, Ni 3s, Co 3s, Mn 3s, Ni 3p, Co 3p, Li 1s, and Mn 3p are presented. The spectra indicate the principal core level photoelectron and Auger electron signals. Making use of the O 1s, Ni 3p, Co 3p, Mn 3p, and Li 1s lines and neglecting the components related to surface contaminants, XPS quantitative analysis reveals an altered stoichiometry of the air-exposed powder surface of LiNi0.4Co0.2Mn0.3O1.6.

Lithium-based transition-metal oxides for battery electrodes analyzed by x-ray photoelectron spectroscopy. VII. LiNi0.33Co0.33Mn0.33O2

X-ray photoelectron spectroscopy (XPS) and x-ray-induced Auger electron spectroscopy were used to analyze fresh LiNi0.33Co0.33Mn0.33O2 powder obtained from TODA America. X-ray photoelectron and x-ray-induced Auger electron spectra were obtained using incident monochromatic Al Kα radiation at 0.834 01 nm. A survey spectrum together with Ni 2p, Co 2p, Mn 2p, Ni LMM, O 1s, C 1s, Ni 3s, Co 3s, Mn 3s, Ni 3p, Co 3p, Li 1s, and Mn 3p are presented. The spectra indicate the principal core level photoelectron and Auger electron signals and show carbon with only minor fluorine contamination. Making use of the O 1s, Ni 3p, Co 3p, Mn 3p, and Li 1s lines and neglecting the components related to surface contaminants, XPS quantitative analysis reveals an altered stoichiometry of the air-exposed powder surface of LiNi0.4Co0.1Mn0.7O2.0.

Lithium-based transition-metal oxides for battery electrodes analyzed by x-ray photoelectron spectroscopy. I. LiNi0.8Co0.15Al0.05O2

X-ray photoelectron spectroscopy (XPS) and x-ray-induced Auger electron spectroscopy were used to analyze untreated LiNi0.8Co0.15Al0.05O2 powder obtained from TODA America. X-ray photoelectron and x-ray-induced Auger electron spectra were obtained using incident monochromatic Al Kα radiation at 0.83401 nm. A survey spectrum together with Ni 2p, Co 2p, Ni LMM, O 1s, C 1s, Al 2s, Ni 3s, Co 3s, Al 2p, Ni 3p, Co 3p, and Li 1s are presented. The spectra indicate the principal core level photoelectron and Auger electron signals and show carbon with only minor sulfur contamination. Making use of the O 1s, Al 2s, Ni 3p, Co 3p, and Li 1s lines and neglecting the components related to surface contaminants, XPS quantitative analysis reveals an altered stoichiometry of the air-exposed powder surface of LiNi0.2Co0.03Al0.1O0.7.

Stabilizing Terminal Ni(III)–Hydroxide Complex Using NNN-Pincer Ligands: Synthesis and Characterization

The reaction of [Ni(COD)2] (COD; cyclooctadiene) in THF with the NNN-pincer ligand bis(imino)pyridyl (L1) reveals a susceptibility to oxidation in an inert atmosphere ([O2] level <0.5 ppm), resulting in a transient Ni:dioxygen adduct. This reactive intermediate abstracts a hydrogen atom from THF and stabilizes an uncommon Ni(III) complex. The complex is crystallographically characterized by a molecular formula of [NiIII(L1··)2-(OH)] (1). Various isotopically labeled experiments (16O/18O) assertively endorse the origin of terminal oxygen based ligand in 1 due to the activation of molecular dioxygen. The presence of proton bound to the terminal oxygen in 1 is well supported by NMR, IR spectroscopy, DFT calculations, and hydrogen atom transfer (HAT) reactions promoted by 1. The observation of shakeup satellite peaks for the primary photoelectron lines of Ni(2p) in the X-ray photoelectron spectroscopy (XPS) unambiguously confirms the paramagnetic signature associated with the distorted square planar nickel ion, which is consistent with the trivalent oxidation state assigned for the nickel ion in 1. The variable temperature magnetic susceptibility data of 1 shows dominant antiferromagnetic interactions exist among the paramagnetic centers, resulting in an overall S = 1/2 ground state. Variable temperature X-band EPR studies performed on 1 show evidence for the S = 1/2 ground state, which is consistent with magnetic data. The unusual g-tensor extracted for the ground state S = 1/2 is analyzed under a strong exchange limit of spin-coupled centers. The electronic structure predicted for 1 is in good agreement with theoretical calculations.

XPS fitting model proposed to the study of Ni and La in deactivated FCC catalysts

Herein, a methodology to study the content of nickel and lanthanum by X-Ray photoelectron spectroscopy - XPS in FCC catalyst was developed. A critical problem to study the nickel in this type of material is related to the overlapping between Ni 2p3/2 and La 3d3/2 signals. In order to have an accurate and correct interpretation of XPS spectra, La 3d and Ni 2p signals were studied individually employing synthesized and FCC catalyst samples. Fitting parameters such as: background modeling method and fitting constraints were determined and tested in synthesized and FCC catalysts samples. Finally, the XPS fitting method obtained was employed to study the La 3d/Ni 2p region in FCC catalyst samples, showing a good performance to study this region.

Introducing Nonstructural Ligands to Zirconia-like Metal–Organic Framework Nodes To Tune the Activity of Node-Supported Nickel Catalysts for Ethylene Hydrogenation

Previous work has shown that introduction of hexafluoroacetylacetone (Facac) units as nonstructural ligands for the zirconia-like nodes of the eight-connected metal–organic framework (MOF), NU-1000, greatly alters the selectivity of node-supported oxy-nickel clusters for ethylene dimerization vs oligomerization. Here we explore a related concept: tuning of support/catalyst interactions, and therefore, catalyst activity, via parallel installation of organic modifiers on the support itself. As modifiers we focused on para-substituted benzoates (R-BA–; R = −NH2, −OCH3, −CH3, −H, −F, and −NO2) where the substituents were chosen to present similar steric demand, but varying electron-donating or electron-withdrawing properties. R-benzoate-engendered shifts in the node-based aqua O–H stretching frequency for NU-1000, as measured by DRIFTS (diffuse-reflectance infrared Fourier-transform spectroscopy), together with systematic shifts in Ni 2p peak energies, as measured by X-ray photoelectron spectroscopy, show tha...

Micromorphology change and microstructure of Cu-P based amorphous filler during heating process

Abstract The changes that occur in the microstructure of crystalline and amorphous Cu-P-Sn-Ni filler metals during the heating process were studied by high-temperature microscopy, and the composition of solders at certain temperatures were analyzed by scanning electron microscopy and X-ray diffraction. The amorphous solder was observed to transform from amorphic to crystalline during the process of heating and distinct surface morphology changes were apparent, while the internal structure of the crystalline brazing filler metal was found to be relatively stable. During the heating process, the amorphous brazing filler metal formed a ϒ-Cu solid solution with a small amount of Cu3P compounds, Cu88Sn22 and (Cu, Ni)3P phase compounds, ultimately forming the Cu88Sn22 + Ni12P5 + (Cu, Ni)3P3 three-element eutectic structure.

Synthesis and characterization of nickel antimonate nanoparticles: sensing properties in propane and carbon monoxide

Nickel antimonate (NiSb2O6) was synthesized by a microwave-assisted wet chemical method for its application as a potential gas sensor. The powders calcined at 600 °C were corroborated by X-ray diffraction. The microstructure of the material was analyzed by electron microscopy in its scanning and transmission versions, finding different morphologies. The average size of the nanoparticles was estimated at ~ 14.3 nm. X-ray photoelectron spectroscopy showed that the bond energies for Ni (2p) were of 855.2 and 872.9 eV, for Sb, they were of 530.28 and 539.66 eV, and for O(1s), it overlapped the Sb at 530.28 eV. Photoluminescence and UV–Vis spectroscopy measurements confirmed that the emission energy values were of 2.8 and 1.4 eV. Tests carried out in propane and CO atmospheres indicated that the NiSb2O6 nanoparticles possess good response at several concentrations and temperatures of both gases. According to our results, NiSb2O6 is a strong candidate to be applied as a gas sensor.

Microstructural properties and antibacterial activity of Ce doped NiO through chemical method

The nickel oxide and different concentration of Cerium ions (0.01 M, 0.02 M and 0.03 M) doped NiO nanoparticles (NPs) were synthesized by chemical method. The XRD spectra exhibited the cubic structure of NiO. The average crystalline sizes were observed as 43 nm, 36 nm, 29 nm and 23 nm in NiO and Ce doped NiO NPs, respectively. The Ni (2p), O (1s) and Ce (3d) oxidation states were confirmed by XPS spectra. The FESEM image and TEM image showed the flowers with spherical nanostructure in undoped and doped NiO NPs. The Chemical compositions were identified by EDAX spectra. Metal-oxide (Ni–O) functional groups were found at 439, 435, 445 and 446 cm−1 in undoped and doped samples respectively. The optical studies were carried out using UV–Vis spectra and PL studies. Magnetization values were enhanced in Ce doped NiO NPs as compared to NiO NPs. Antibacterial activities were done by various human pathogens with using NiO and Ce doped NiO NPs.

Allabogdanite, the high-pressure polymorph of (Fe,Ni)2P, a stishovite-grade indicator of impact processes in the Fe\u2013Ni\u2013P system

Allabogdanite, (Fe,Ni)2P, is the only known natural high-pressure phase reported in the Fe–Ni–P system. The mineral, which was previously described from a single meteorite, the Onello iron, is now discovered in the Santa Catharina and Barbianello nickel-rich ataxites. The occurrence of allabogdanite in Santa Catharina, one of the largest and well-studied meteorites, suggests that this mineral is more common than was believed. The formation of allabogdanite-bearing phosphide assemblages in a given meteorite provides evidence that it experienced peak pressure of at least 8 GPa at a temperature above 800 °C. Since the pressure-temperature stability parameters of allabogdanite fall within the margins of the stishovite (rutile-type SiO2) stability area, the former can be employed as a convenient stishovite-grade indicator of significant impact events experienced by iron and stony-iron meteorites and their parent bodies.

Co9S8–Ni3S2 heterointerfaced nanotubes on Ni foam as highly efficient and flexible bifunctional electrodes for water splitting

Large-scale commercialization of water splitting is still challenging due to the lack of efficient, cost-effective and robust electrodes. In this work, Co9S8–Ni3S2 heterointerfaced nanotubes on Ni foam (Co9S8–Ni3S2 HNTs/Ni) have been successfully developed via a two-step hydrothermal method as a highly efficient, robust and flexible bifunctional electrodes for water splitting. Co9S8–Ni3S2 HNTs are composed of inner 1D Co9S8 nanotubes surrounded by outer 2D Ni3S2 nanosheets. Co9S8–Ni3S2 HNTs/Ni electrode achieves 10 mA cm−2 at overpotentials of 85 mV for H2 evolution reaction (HER) and 50 mA cm−2 at overpotential of 281 mV for O2 evolution reaction (OER) in 1 M KOH solution, substantially better than that on single-phased Co9S8 nanotubes and Ni3S2 nanosheets on Ni foam. The reason is most likely due to formation of defect-rich heterointerfaces between Co9S8 nanotubes and Ni3S2 nanosheets, and the significant change of binding energies of Co 2p and Ni 2p level between the Co9S8 and Ni3S2, leading to the synergistic effect on the enhanced catalytic activity for HER and OER. The robust and flexibility of Co9S8–Ni3S2 HNTs/Ni electrodes are demonstrated in an alkaline electrolyzer, delivering 10 mA cm−2 electrolysis current at a cell voltage of 1.59 V, one of the best bifunctional electrodes for water splitting. Owing to the fact that reaction occurs at the defects-rich heterointerfaces, the Co9S8-Ni3S2 HNTs/Ni electrodes are structurally very stable.

F or V-induced activation of (Co, Ni)2P during electrocatalysis for efficient hydrogen evolution reaction

A series of (Co, Ni)2P–xF and post-(Co, Ni)2P–xF electrocatalysts with different compositions, morphologies and HER performances were synthesized. Among them, post-(Co, Ni)2P–10F exhibits the best HER activity.

Plasma and Annealing Treatments to Form Height-Barrier Ni-Based Schottky Contact to n-GaN

We investigated the combined effects of plasma and annealing treatments on the electrical and interfacial reactions of Ni/Au Schottky contacts on n-GaN for high-efficiency electronic and optoelectronic devices. Thermionic emission (TE)-based ideal current-voltage model showed that the Schottky barrier heights (SBHs) ranged from 0.68 to 0.92 eV and the ideality factors were in the range of 1.16–2.15. On the other hand, inhomogeneity model and capacitance-voltage characteristics gave similar SBHs in the range of 1.11–1.45 eV. X-ray photoemission spectroscopy (XPS) results displayed that annealing caused the Ga 2p core level to shift toward lower energies by 0.17–0.18 eV, while plasma treatment induced the Ga 2p core level to shift toward higher energies by 0.12 eV. The XPS Ni 2p core level results exhibited that annealing samples at 600°C gave rise to the formation of NiO and Ni2O3 in addition to Ni3Ga4 and Ni3Ga interfacial phases, which were confirmed by X-ray diffraction (XRD) and scanning transmission electron microscopy (STEM) results. Based on the XPS, XRD, and STEM results, the annealing and plasma-treatment-induced increase in the SBHs is described and discussed.

Murashkoite, FeP, a new terrestrial phosphide from pyrometamorphic rocks of the Hatrurim Formation, South Levant

Murashkoite, FeP, is a new mineral found in pyrometamorphic rocks of the Hatrurim Formation, South Levant. It is a typical accessory phase in the marbles and paralavas in the southern Negev Desert, Israel and on the Transjordan Plateau, Jordan. Murashkoite occurs as grains and aggregates up to 2 mm closely associated with barringerite, (Fe,Ni)2P, and zuktamrurite, FeP2. The rock-forming minerals include pyroxenes of the diopside-hedenbergite series, anorthite with subordinate gehlenite, tridymite, cristobalite, pyrrhotite, fluorapatite, chromite, magnetite, hematite, merrillite and late hydrothermal carbonates, silicates and sulfates. Macroscopically, murashkoite is yellowish-grey in colour and has a metallic lustre. In reflected light, the mineral is white with a beige tint and it is non-pleochroic. The anisotropy is distinct, from yellow-grey to greyish-blue. Selected reflectance values [Rmax–Rmin, % (λ, nm)] are: 42.7–40.8 (400), 42.0–40.6 (500), 44.5–43.4 (600), 48.0–47.7 (700). It is brittle. VHN20 = 468 kg mm−2. The holotype material has the chemical composition (electron microprobe): Fe 63.82; Ni 0.88; P 35.56; total 100.26 wt.%. The empirical formula calculated on the basis of 2 apfu is (Fe0.99Ni0.01)1.00P1.00 corresponding to FeP. Murashkoite is orthorhombic, space group Pnma, unit cell parameters refined from the single-crystal data are: a 5.099(2), b 3.251(2), c 5.695(2) A, V 94.41(8) A3, Z = 4, Dx = 6.108(5) g cm−3. The crystal structure was solved and refined to R1 = 0.0305 on the basis of 131 unique reflections with I > 2σ(I). The strongest lines of the powder X-ray diffraction pattern [(d, A) (I, %) (hkl)]: 2.831(75)(002,011); 2.548(22)(200); 2.477(46)(102,111); 1.975(47)(112); 1.895(100)(202,211); 1.779(19)(103); 1.632(45)(013,301,020). The mineral is named in honour of Dr. Mikhail Nikolaevich Murashko (born 1952), for his contributions to the mineralogy of the Hatrurim Formation. Murashkoite is a natural counterpart of synthetic FeP, the compound widely used in heterogeneous catalysis and electrocatalysis.

Effect of Ni2+ doping on chemocatalytic and supercapacitor performance of biosynthesized nanostructured CuO

The synthesis of metal oxide nanostructured materials derived from plant extract embraces the futuristic design of an eco friendly system by reducing the hazardous toxic chemicals. In the present work, copper oxide nanoparticles (CuO NPs) and Ni2+ doped (0.003, 0.006 and 0.009 M) CuO NPs were prepared by green method using Azadirachta indica (A. indica) leaf extract. The XRD pattern reveals that the synthesized CuO NPs exhibits monoclinic structure. Nanoflower like morphology is observed in FESEM and TEM analysis. The oxidation states of Cu (2p), Ni (2p) and O (1s) have been identified in XPS spectra. The weight loss and thermal effects were investigated in TG–DSC analysis. The green synthesized materials effectively degrade the hazardous water pollutants like methylene blue, methyl orange and eosin yellow. The pseudocapacitive properties of CuO and Ni doped CuO NPs have been investigated through cyclic voltammetry and galvanostatic charge–discharge (GCD) studies. The Ni doped (0.009 M) CuO NPs exhibited high specific capacitance of 511 F/g at a current density of 1 A/g, and good reversibility with cycling efficiency of 88% after 3000 GCD cycles for S4 electrode, suggesting its use as promising electrode material in supercapacitors.

Electronic structure of Pr2MnNiO6 from x-ray photoemission, absorption and density functional theory

The electronic structure of double perovskite Pr2MnNiO6 was studied using core x-ray photoelectron spectroscopy and x-ray absorption spectroscopy. The 2p x-ray absorption spectra show that Mn and Ni are in 4+ and 2+ states respectively. Based on charge transfer multiplet analysis of the 2p XPS spectra of both ions, we find charge transfer energies of 3.5 and 2.5 eV for Ni and Mn respectively. The ground state of Ni2+ and Mn4+ ions reveal a higher d electron count of 8.21 and 3.38 respectively as compared to the ionic values. The partial density of states clearly show a charge transfer character of the system for U − J 2 eV. The O 1s edge absorption spectra reveal a band gap of 0.9 eV, which is close to the value estimated from analysis of Ni and Mn 2p photoemission and absorption spectra. The combined analysis of nature of spectroscopic data and first principles calculations reveal that the material is a p − d type charge transfer insulator with an intermediate covalent character according to the Zannen–Sawatzy–Allen phase diagram.

Zuktamrurite, FeP2, a new mineral, the phosphide analogue of löllingite, FeAs2

Zuktamrurite, FeP2, is a new mineral, a natural iron diphosphide found in the pyrometamorphic rocks of the Hatrurim Formation, in the southern part of the Negev Desert, Israel and on the Transjordan Plateau, Jordan. The mineral occurs as irregular grains up to 50 µm in size associated with murashkoite, FeP, and barringerite, (Fe,Ni)2P. In reflected light, zuktamrurite is white with a distinct bluish tint. It is non-pleochroic but exhibits distinct anisotropy in bluish colours. Reflectance values for the IMA COM recommended wavelengths are [Rmax/Rmin, % (λ, nm)]: 50.40/47.20 (470); 49.16/46.23 (546); 48.97/46.16 (589); 49.40/46.40 (650). It is brittle. Electron microprobe analysis of the holotype specimen gave the following chemical composition (wt%, average of 5 points): Fe 40.23; Ni 7.97; P 51.70; total 99.90. The empirical formula calculated on the basis of 3 apfu is (Fe0.86Ni0.16)1.02P1.98 corresponding to FeP2. Zuktamrurite is orthorhombic, space group Pnnm, unit cell parameters refined from the single-crystal data: a 4.9276(6), b 5.6460(7), c 2.8174(4) A, V 78.38(1) A3, Z = 2. Dx = 5.003 g cm−3. The crystal structure was solved and refined to R1 = 0.0121 on the basis of 109 unique reflections with I > 2σ(I). The strongest lines of the powder X-ray diffraction pattern [(d, A) (I, %) (hkl)]: 3.714 (54) (110); 2.820 (31) (020); 2.451 (100) (120, 101); 2.242 (55) (111); 1.760 (37) (211). The mineral is named for the Zuk-Tamrur cliff (Dead Sea) located nearby the type locality, the Halamish Wadi, southern Negev Desert, Israel. Zuktamrurite is the phosphide analogue of lollingite (loellingite), FeAs2. It is the most phosphorus-rich phosphide ever found in nature.

Structural transformation, Griffiths phase and metal-insulator transition in polycrystalline Nd2−xSrxNiMnO6 (x = 0, 0.2, 0.4, 0.5 and 1) compound

Polycrystalline double perovskite Nd2−xSrxNiMnO6 (x = 0, 0.2, 0.4, 0.5 and 1) samples were synthesized using the solid state reaction method. There occurs a structural transformation from monoclinic (P21/n, for x = 0 to x = 0.5) to cubic (Fmm, for x = 1) with increasing Sr doping. Raman spectroscopy reveals the increase in static disorder with doping. The Curie temperature (TC) shows a small increase from x = 0 to 0.5 (TC ~ 200 K), but for x = 1, TC increases drastically upto ~264 K. The deviation of 1/χ(T) from Curie–Weiss behaviour for doped samples with exponent less than one, indicates a development of the Griffiths phase with doping. The systematic reduction in magnetic moment at 5 K suggests an increase in anti-site disorders with doping. Mn 3s x-ray photoemission spectra show an increase in exchange splitting, indicating a decrease in the valency of Mn. The x-ray absorption spectra at Ni and Mn 2p edges show that the formal valence remains 2+ (Ni) and 4+ (Mn) for all the samples, with changes in spectral weights. Ni 2p x-ray photoemission spectra show characteristic feature similar to Ni3+ systems, only for x = 1 sample. Our GGA-based calculations for the ordered supercell, predict half metallic character for doping (x > 0) samples due to delocalization of Ni eg orbitals. The calculations with anti-site disorders yield drastic reduction in Ni moments, with the disordered anti-ferromagnetic phase having lowest energy at maximum doping. Temperature dependent resistivity measurements exhibit a clear metallic region for x = 0.2 sample, while for higher dopings (x > 0.2), the metallicity gets suppressed due to increase in anti-site disorders in these samples.

Nanostructured mesoporous NiO as an efficient photocatalyst for degradation of methylene blue: Structure, properties and performance

Nanostructured NiO with an average crystallite size ∼2–3 nm is synthesized through a two step process. X-ray diffraction analysis reveals high value of microstrain indicating the presence of large concentration of point defects. Sample is found to be mesoporous with a high specific surface area of 187.27 m2/g. Raman and Infrared spectra shows the presence of surface modes and forbidden vibrations respectively due to the small size and broken symmetry. Ni 2p and O 1s X-ray photoelectron spectra confirms the presence of large percentage of Ni2+ vacancies. UV–visible absorption spectra show efficient absorption in both ultraviolet and visible regions, while, Photoluminescence emission spectra show two emission bands characteristic of O2− vacancies. DC electrical conductivity studies reveal the semiconducting nature of the sample. The sample is found to be an efficient photocatalyst for the degradation of methylene blue in water with a pseudo first order rate constant of k=1.97×10−2 min−1. It is proposed that the high surface area, efficient absorption in the ultraviolet and visible regions and presence of Ni2+ and O2− vacancies leads to the efficient photocatalytic activity.

Compressibility of natural schreibersite up to 50 GPa

Schreibersite-(Fe, Ni)3P is a common accessory of iron meteorites, which carry direct information of planetary cores. Herein, in situ synchrotron-radiation X-ray diffraction (XRD) experiments of a natural single-crystal schreibersite have been carried out up to ~ 50 GPa in a diamond anvil cell (DAC) at room temperature. Experimental results show that schreibersite-Fe2.15Ni0.85P is very stable and remains the tetragonal structure ( $$I\overline {4}$$ ) throughout the investigated pressure range. The pressure–volume (P–V) data were fitted by a third-order Birch–Murnaghan equation of state (B–M EoS), yielding K0 = 184(4) GPa, V0 = 365.9(1), $$K_{0}^{'}$$ = 4.1(2), and also a second-order B–M EoS, yielding K0 = 185(1) GPa, V0 = 365.8(1), $$K_{0}^{'}$$ = 4.0 (fixed). Unlike its isostructural minerals (e.g., Fe3S and Fe3P), schreibersite-Fe2.15Ni0.85P demonstrates an isotropic axial compressibility and an inhibition of magnetic transition under compression. Comparison in densities of Fe2.15Ni0.85P, Fe3S, Fe3P, FeS, and FeP at relative pressure–temperature conditions of the Martian core shows that the doping of Ni and P has strong effects on density reduction of iron sulfides, and schreibersite-(Fe, Ni)3P could provide a needful compensation for iron sulfides in the Martian core.