Nitrogen In Zirconium Research Articles

Electrochemical properties of two-dimensional zirconium nitrogen anode materials for K-ion battery by first-principles insights

Electrochemical properties of two-dimensional zirconium nitrogen anode materials for K-ion battery by first-principles insights

A new metallic composite cathode originated from hyperbranched polymer coated MOF for High-performance Lithium-Sulfur batteries

To improve the polysulfides redox conversion and mitigate the shuttle effect for lithium-sulfur (Li-S) batteries, a hyperbranched polymer coated MOF-derived zirconium nitrogen oxides and N-doping carbon composites (Zr2N2O/NC-6) are designed and prepared by pyrolytic method. Thanks to some advantages of this type of new composites including fast lithium-ion transport, lithium polysulfides (LiPSs) anchoring and multiple functional sites, the cells with S/Zr2N2O/NC-6 cathode exhibit good cycle stability (the capacity retention is 81.8% at 1C after 300 cycles) and rate capability (566.8 mAh g−1 at 5C). More importantly, even if the sulfur loading is up to 8.16 mg cm−2 and low electrolyte/sulfur (E/S) ratio (7.79 µL mg−1), the cells with S/Zr2N2O/NC-6 cathode deliver an initial area capacity of 7.2 mAh cm−2 and the capacity also can maintain at 5.34 mAh cm−2 after 80 cycles at 0.2C, which are much better than the commercial lithium-ion batteries. This work exhibits a MOF-derived novel material Zr2N2O/NC used as the sulfur host for the first time, which can have a guiding role in designing multifunctional materials with adsorption, ion transport and catalytic features for the high-performance lithium sulfur batteries with application potential.

Механические свойства и структура композиционного материала ZrN – Zr, полученного методом окислительного конструирования

Using the approach of oxidative constructing due to diffusion saturation, massive samples of compact metal-ceramic composite materials with a gradient structure were obtained: a nitride ceramic shell is a near-surface layer of ZrN, a solid solution of nitrogen in zirconium is a core, which is a solid solution of nitrogen in zirconium. The synthesized composites have better strength indicators compared to the original metal blanks. Under compression conditions, composite samples ZrN – Zr are characterized by plasticity, under bending conditions, they are brittle. The applied approach of oxidative design makes it possible, in comparison with traditional methods, to obtain rather efficiently and economically gradient ceramic-metal samples of products with dimensions and shapes that maximally repeat those of the original metal workpiece.

First-principles study of two-dimensional zirconium nitrogen compounds: Anode materials for Na-ion batteries

With the rapid development of electric vehicles and portable electronic devices, high-performance energy storage devices such as Na-ion batteries (NIBs) have received increasing attention. Here, the possibility of two-dimensional (2D) zirconium-nitrogen compounds as anode materials for Na-ion batteries has been discussed by first-principles calculations. The results show that t-Zr2N is the most stable compared with other structures (ZrN, h-Zr2N, t-ZrN2, h-ZrN2, and p-ZrN2). On this basis, the most stable adsorption structures of t-Zr2N with various functional groups (-O, -OH, -F) were established, and their performance as NIBs anode materials was evaluated. We found that sodium (Na) ions were not easily adsorbed on Zr2NF2 and therefore were not suitable as electrode materials, while the other three structures (Zr2N, Zr2NO2, and Zr2N(OH)2) were all metallic and had a good performance as anode materials. Zr2N is the most suitable anode material owes to its high theoretical capacity (545.9 mAhg-1), extremely low diffusion barrier (0.018 eV), good stability and suitable open-circuit voltage, which makes its application in battery with great potential. Meanwhile, our investigations found that functional groups will affect the performance of 2D materials as electrode materials, which can provide useful guidance for future relevant researches.

ВЗАИМОДЕЙСТВИЕ МАТЕРИАЛОВ СЕПАРАТОРА ВОДОРОДА С НАТРИЕМ И ПРИМЕСЯМИ В НЕМ

Work is devoted to a research of materials (zirconium and nickel) for hydrogen separation by its production with use of nuclear reactor in relation to the high-temperature fast sodium reactor (BN-VT) developed in IPPE, for production of hydrogen from hydrocarbon raw materials. These materials can be used in relation to the thermal reactor of the operating nuclear power plants or the reactor of new generation of VTGR, the electrolysis of water offered for receiving hydrogen in Research Center KI. Hydrogen on the NPP is formed also at reaction of water with structural materials, at water leak emergencies in sodium and steam - Zr reaction, at nuclear reactions, etc. In the real work results of LAES of the analysis of zirconium and nickel after their interaction with sodium and impurity in it are presented at 1053 K during 100 h in the sodium purified from oxygen to the level which is not exceeding 2 mg/kg and containing 6 mg/kg of hydrogen. Interaction of zirconium and nickel with sodium and impurity in it is revealed (hydrogen, oxygen, carbon). The maximum quantity of carbon, oxygen, nitrogen in zirconium is concentrated in a small layer of a sample by thickness near 10 microns. Hydrogen is concentrated probably near borders of grains, oxygen content in zirconium significantly exceeded oxygen content in initial zirconium that will be coordinated with results of thermodynamic calculations. It is shown that for increase in purity of hydrogen and durability of service of the device it is necessary to have zirconium as well as a nickel membrane in a gas phase.

Structural and phase transformations and hardness of ceramics produced by high-temperature zirconium nitriding

Resistive heating of zirconium in a gaseous nitrogen atmosphere yields ceramics based on zirconium nitride with a heterophase structure. X-ray powder diffraction analysis determined the compositions of phases of the synthesized ceramics. The surface of the material consists of zirconium nitride close in composition to ZrN. In the bulk of the materials, in shallower layers, a nitrogen-deficient nitride phase forms, and in deeper layers, a phase of solid solution of nitrogen in zirconium does. The hardness of ceramics based on heterostructures of the type Zrsolid solution/ZrN1–x /ZrN was studied. Changes in the structure and phase composition during high-temperature nitriding of zirconium foil at 1500 and 2400°C were described.

Electric field effects in ultrathin β-ZrNBr nano-crystals

Layered materials with a non-zero band gap have emerged in the past few years because of their potential to supersede graphene in nano-electronics. Zirconium nitrogen halides (ZrNX, X = Cl,Br) are indirect gap semiconductors with a layered crystal structure. Here, we report the realization of electric field effects in exfoliated nano-crystals of β-ZrNBr using degenerately doped silicon as a back-gate. The as-produced devices demonstrate n-type transport with field effect carrier mobility of 5.8 cm2 V−1 s−1. The conduction is dominated by variable range hopping for the range of temperature from 295 K to 32 K. Our results present a promising candidate for future thin-film electronics application.

Synthesis, Structural Characterization, and Quantitative Basicity Studies of Lithium Zirconimidate Complexes

Synthesis, Structural Characterization, and Quantitative Basicity Studies of Lithium Zirconimidate Complexes

Carboxylation of an ansa-Zirconocene Dinitrogen Complex: Regiospecific Hydrazine Synthesis from N2 and CO2

Addition of 2 equiv of carbon dioxide to the ansa-zirconocene dinitrogen complex resulted in selective insertion into each zirconium nitrogen bond, forming a C2 symmetric dicarboxylated diazenido compound. Treatment with excess Me3SiI furnished the ansa-zirconocene diiodide along with the N,N'-dicarboxylated silylated hydrazine. New nitrogen-carbon bonds were also assembled by addition of methyl triflate. Tri- and tetrasubstituted hydrazines could be formed by treatment with water and Me3SiI, respectively. The regiochemistry of the N2 carboxylation is controlled by the ansa-cyclopentadienyl ligand where the sterically demanding tert-butyl substituents and the C2 symmetry of the dimer dictates the stereochemistry of CO2 insertion. These results demonstrate the ability of zirconium dinitrogen compounds to participate in heterocumulene insertion chemistry.

On the Origin of Dinitrogen Hydrogenation Promoted by [(η5-C5Me4H)2Zr]2(μ2,η2,η2-N2)

The origin of the hydrogenation of the dinitrogen ligand in [(eta5-C5Me4H)2Zr]2(mu2,eta2,eta2-N2) has been investigated by a combined computational and experimental study. Density functional theory calculations on the zirconocene dinitrogen complex demonstrate significant imido character in the zirconium nitrogen bonds, arising from effective pi-back-bonding from the low-valent zirconium and the side-on bound N2 ligand. The twisted ground-state structure of the N2 complex is a key requirement for nitrogen hydrogenation, as calculations on the model complex [(eta5-C5H5)2Zr]2(mu2,eta2,eta2-N2) reveal reduced overlap as the dihedral angle between the zirconocene wedges approaches 0 degrees . Experimentally, isotopic labeling studies on the microscopic reverse are consistent with a 1,2-addition mechanism for nitrogen hydrogenation.

Insertion of Isocyanides into Group 4 Metal−Carbon and Metal−Nitrogen Bonds. Syntheses and DFT Calculations

The reactions of [Ti(η5-Ind)(NMe2)2Me], [Ti(η5-Ind)(NMe2)Cl2], and [Zr(η5-Ind)(NMe2)2Cl] with 2,6-dimethylphenyl isocyanide (CN(2,6-Me2Ph)) and tert-butyl isocyanide (CN-t-Bu) have been investigated. For the first complex, insertion occurs exclusively into the Ti−C bond to give [Ti(η5-Ind)(NMe2)2{C(Me)N-t-Bu}] (1), which, according to DFT results, is due to the weakness of the Ti−CH3 bond when compared to Ti−NR2. [Ti(η5-Ind)(NMe2)Cl2] was found to react with 1 equiv of CN(2,6-Me2Ph) to yield [Ti(η5-Ind){C(NMe2)N(2,6-Me2Ph)}Cl2] (2). Two equivalents of 2,6-dimethylphenyl isocyanide reacts with [Zr(η5-Ind)(NMe2)2Cl] to give the double insertion compound [Zr(η5-Ind){C(NMe2)N(2,6-Me2Ph)}2Cl] (3). The same reaction performed with CN-t-Bu proceeds slowly and enabled the characterization, by NMR, of [Zr(η5-Ind)(NMe2){C(NMe2)N-t-Bu}Cl] (4) and [Zr(η5-Ind){C(NMe2)N-t-Bu}2Cl] (5). The molecular structures of 2 and 3 have been determined by X-ray diffraction. DFT calculations of the insertion of CNH in the zirconium nitrogen bonds of [Zr(η5-Ind)(NR2)2Cl] (R = H, Me) have been performed and show that the progressive stability of the insertion products accounts for the experimentally found double insertion product.

Carbonyl insertion into zirconium–nitrogen bonds; synthesis and X-ray structure of a carbene complex composed of [Zr(NMe 2) 4] 2 and three Fe(CO) 5 units containing Fe→Zr donor–acceptor interactions

The reaction of [Zr(NMe 2) 4] 2 with Fe(CO) 5 leads to the multicarbene complex ( 1) containing two zirconium and three iron atoms. The crystal structure revealed that 1 results from the insertion of five CO groups into ZrN bonds generating chelating biscarbene ligands at two iron atoms and one terminal carbene ligand at the third iron atom. Thus, a planar and a boat-configured ring are formed ( A and B) with relatively short FeZr distances of 284 and 282 pm, respectively, indicating early–late transition-metal interactions.

Dynamic behavior of implanted nitrogen in zirconium at various stages of implantations

Abstract Depth profiles of nitrogen implanted into Zr with an energy of 50 keV were calculated by dynamic SASAMAL code with three different assumptions for the diffusion of excess atoms over stoichiometry, i.e., ‘no diffusion', ‘both-sides-diffusion’ and ‘upward-diffusion'. To distinguish nitrogens implanted certain stage of implantations, alternate implantations of 15N and 14N were used. The results were compared with the experimental results by the resonance nuclear reaction analysis, NRA. For 15N implantation with fluences from 1 × 1017 to 1 × 1018 ions/cm2, the calculated results with ‘upward-diffusion’ agreed very well with the NRA results for all fluences. For the depth profile of pre-implanted 15N (1 × 1017 ions/cm2), which was changed by the subsequent 14N implantation with fluences of 1 ∼ 10 × 1017 ions/cm2, the agreement with the NRA results was satisfactory until the 14N fluence did not exceed 5 × 1017 ions/cm2, but for higher fluences, the retained probabilities of 15N obtained by the ‘upward-diffusion’ code were too low compared with the experimental value obtained by NRA. For the depth profiles of 15N (1 × 1017 ions/cm2) implanted following after implantations of 14N with fluences of 1 ∼ 10 × 1017 ions/cm2, the agreement with the NRA results was quite good for all 14N fluences. It is concluded that the approximation of ‘upward-diffution’ is proper satisfactorily for the treatment of atoms implanted at the final stage of implantations, but a problem is left for the treatment of atoms implanted at the early stage of implantations.

Ion-channeling investigations of nitrogen in zirconium

In this study, ion-channeling techniques were used to determine the lattice sites of N in the a-Zr hexagonal close-packed (hep) structure and the effect of trapping irradiation-produced defects at the N atoms. A Zr single crystal was implanted along 〈112̄0〉 at 293 K with 300 keV 15N 2 ions to a fluence of 2.2 × 10 15 ionscm −2. The position of 15N atoms in the Zr lattice was studied using measurements of yields of 1H ions (incident energy 800 keV) backscattered from the Zr atoms and the alpha-particle yields from the nuclear reaction 19N(p, α) 12C. Dechanneling of the protons in the Zr crystal provided information on changes in the overall defect concentration during the irradiation and annealing stages. Information was obtained for the 〈112̄0〉 and 〈101̄0〉 channels. The 15N ion implantation resulted in an appreciably larger yield of a particles when the 1H ion beam was incident along 〈112̄0〉 compared to that found for incidence along 〈10 1 0〉. Angular scans through 〈112̄0〉 also indicated an appreciable peaking in the α-particle yield at the aligned 〈112̄0〉 position. These observations indicated that the N atoms occupied the octahedral interstitial positions in the α-Zr hep lattice. Subsequent to the 15N implantation, the Zr crystal was irradiated at 35 K with 800 keV 4He ions to fluences of 1.8 × 10 16 and 9.1 × 10 16 ionscm −2, followed by post-irradiation annealing in both instances. No appreciable displacement of the N atoms from their lattice sites was detected after these irradiations, or during annealing up to 423 K. Hence N atoms in octahedral sites are very stable and their position remains essentially unaltered during subsequent defect formation and migration, at least up to 423 K.

Influence of interstitial impurity on hydrogen solubility in zirconium.

Hydrogen solubility in Zr-N and Zr-C alloys with various compositions has been measured at a temperature of 8731, 048 K at a pressure below 100 Pa. All the solubility data closely obeyed Sieverts' law. The presence of carbon and nitrogen in zirconium increased the hydrogen solubility at a fixed pressure and provided the negative effect on the enthalpy of solution. Partial thermodynamic functions of hydrogen in the Zr-N and Zr-C alloys were obtained by a dilute solution model and compared to those obtained previously for Zr-O alloys. Dependence of partial molar quantities of hydrogen on interstitial impurity content in zirconium was discussed in terms of dilatometric effect, configurational effect and other contributions.

The determination of nitrogen in zirconium by charged-particle activation analysis

The determination of nitrogen in zirconium by charged-particle activation analysis is described. The14N(α,αn)13N and the14N(p,α)11C reactions were used. The13N activity was separated from matrix activity as ammonia by steam-distillation after dissolution of the sample in dilute hydrofluoric acid. The11C activity was separated as carbon dioxide by dissolution of the sample in a mixture of concentrated sulphuric acid, sodium fluoride and potassium periodate, followed by oxidation of the evolved gases with a copper oxideiron oxide-kaolin mixture and trapping of the carbon dioxide in dilute sodium hydroxide solution. The chemical yield of both separations was investigated. The nuclear interference of boron can be neglected, in view of the low boron content. Alpha- and proton-activation yielded the following results for BCR reference materials (alpha-activation results first): CRM 21: 24.6±3.3 and 25.9±0.8μg/g (certified value: 26.4±2.5μg/g); CRM 56: 12.0±1.1 and 10.5±0.3μg/g (certified value: 11.7±1.7μg/g); CRM 57: 11.2±0.3μg/g (alpha-activation) (certified value: 11.9±1.8μg/g).

Etude de la reaction 14N(d.n) 15O a basse energie et application au dosage de l'azote dans le zirconium

Study of the 14N(d,n) 15O reaction at low energy and application to the determination of nitrogen in zirconium The thick target yield for the 14N(d,n) 15O reaction weis determined between 1 MeV and 5.5 MeV; the “average energy” and the sensitivity of the analysis for nitrogen are calculated. Nitrogen can be determined in zirconium samples at the level of 35 μg g −1, by irradiating at 4 MeV and 5.5 MeV in a deuteron beam from a Van de Graaff accelerator. After irradiation, the samples are subjected to reducing fusion in a graphite crucible, to separate 15O. The results are compared with those obtained by other methods on identical samples; there is a difference of 3–17%.

Spectrophotometric determination of traces of nitrogen in zirconium and zircaloy using thymol

The spectrophotometric method for the determination of ammonia nitrogen with thymol which had been established by the authors for uranium metal and its compounds was successfully applied to as low as 3 ppm of nitrogen in zirconium and zircaloy.Satisfactory results were obtained in the analysis of the NBS zircaloy-2 standard and other samples. Twenty milligrams of tin, 3 mg of iron, 4 mg of nickel, . 2 mg of chromium and 0.2 mg each of aluminum, copper, silicon and titanium did not interfere. The molar absorptivity was the same as that previously reported (1.15× 104 at 670 mμ).In the recommended procedure, up to 0.8 g of a sample was dissolved with 2 ml of sulfuric acid (18 N), 3 ml of hydrochloric acid and 5 ml of fluoboric acid (10%) by heating on a water bath. After dissolution, 1 ml of hydrogen peroxide solution (30%) was added to oxidize iron and the solution was then evaporated to almost dryness to remove the excess peroxide and acids. The residue was dissolved with 50 ml of water, and 20 ml of sodium citrate solution (25 w/v%) was added. After adjusting the pH of the solution to 9.8 10.3, 0.5 ml of sodium hypochlorite solution containing 0.3% of active chlorine was added with stirring. After 20seconds, 2.5 ml of a freshly prepared mixture of equal volumes of thymol solution (10% in acetone) and sodium hydroxide solution (1 N) was added. Sodium hydroxide solution (6 N) was then added to dissolve the deposited thymol, and the pH of the solution was adjusted to 11.6 11.9 with sodium phosphate solution (0.05 N) and sulfuric acid (6 N). Four milliliters of acetone was added and the resultant solution was diluted to 100 ml with water. After standing for 1.5 hours in darkness, the absorbance of the colored solution was measured against the blank at 670 mμ.

Determination of gases in plutonium, uranium and zirconium by vacuum fusion

A vacuum fusion system suitable for routine'analysis of gases present in plutonium, uranium, and zirconium was built and acceptable results were obtained with the exception of the determination of nitrogen in zirconium. Hydrogen is evolved by heating the metal in a vacuum while all gaaua are released by fusing the sample at 1900° in a metal bath contained in a graphite crucible. Tho gases evolved from each sample are collected in individual bulbs for later mass spcctrometric analyses. Hydrogen values within 5% and oxygen values within 10% are obtained on zirconium. standards. The results for plutonium samples analyzed by the iron and platinum bath techniques are in satisfactory agreement. The apparatus and techniques described provide a method whereby the gases present in 5 separate metallic samples may be collected in one melting operation of leas than two hours duration.

耐酸化性合金Phosphor Zirconiumの研究（第1報）

This study was undertaken in an effort to provide a clearer picture of the oxidation mechanism where by nitrogen reduces the heat resistance of zirconium and also to develop a new heat-resistant zirconium alloy containing a small amount of phosphorus. The oxidation test was carried out in dry oxygen and in air at temperatures of 700∼900°C using the weight-gain method. Since the oxidation process of zirconium has been explained by the diffusion of negative ion vacancies through the oxide, the factors determining the concentration and the mobility of the vacancies require further examination; Theye are the valency, the ionic radius and the ionization potential of the alloying element and the electroneutrality in the oxide lattice. Under such considerations, phosphorus was chosen for the alloying element. The results obtained are as follows: (1) Addition of a small amount of phosphorus counteracts the harmful effect of nitrogen in zirconium and exceedingly prolongs the breakaway period. It is noted that there is an optimum content of phosphorus. The amount ranges from 0.03 to 0.06 wt% according to the purity of zirconium. The beneficial effect may be attributed tothe solution of phosphorus in ZrO2 lattice as P+5, with consequent reduction of the concentration and the mobility of negative ion vacancies. An excess amount of phosphorus is harmful. (2) The exponent n for the equation of oxidation process was obtained in pure zirconium and phosphor zirconium alloys, as listed in Table 3. The activation energies of 38,000 and 34,000 cal/mol were determined for pure zirconium in dry oxygen and air, respectively.