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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Realization of an Ideal Cairo Tessellation in Nickel Diazenide NiN 2 : High-Pressure Route to Pentagonal 2D Materials

Most of the studied two-dimensional (2D) materials are based on highly symmetric hexagonal structural motifs. In contrast, lower-symmetry structures may have exciting anisotropic properties leading to various applications in nanoelectronics. In this work we report the synthesis of nickel diazenide NiN 2 which possesses atomic-thick layers comprised of Ni 2 N 3 pentagons forming Cairo-type tessellation. The layers of NiN 2 are weakly bonded with the calculated exfoliation energy of 0.72 J/m 2 , which is just slightly larger than that of graphene. The compound crystallizes in the space group of the ideal Cairo tiling (P4/mbm) and possesses significant anisotropy of elastic properties. The single-layer NiN 2 is a direct-band-gap semiconductor, while the bulk material is metallic. Furthermore, this indicates the promise of NiN 2 to be a precursor of a pentagonal 2D material with a tunable direct band gap.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Materials Data on NiN by Materials Project

NiN crystallizes in the tetragonal P4_2/mmc space group. The structure is one-dimensional and consists of two NiN ribbons oriented in the (1, 0, 0) direction. Ni3+ is bonded in a linear geometry to two equivalent N3- atoms. Both Ni–N bond lengths are 1.68 Å. N3- is bonded in a linear geometry to two equivalent Ni3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca(NiN)2 by Materials Project

Ca(NiN)2 crystallizes in the tetragonal P-4m2 space group. The structure is two-dimensional and consists of one Ca(NiN)2 sheet oriented in the (0, 0, 1) direction. Ca2+ is bonded to four equivalent N3- atoms to form distorted corner-sharing CaN4 tetrahedra. All Ca–N bond lengths are 2.43 Å. Ni2+ is bonded in a linear geometry to two equivalent N3- atoms. Both Ni–N bond lengths are 1.73 Å. N3- is bonded in a rectangular see-saw-like geometry to two equivalent Ca2+ and two equivalent Ni2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Zn(NiN)2 by Materials Project

Zn(NiN)2 crystallizes in the tetragonal P-4m2 space group. The structure is two-dimensional and consists of one Zn(NiN)2 sheet oriented in the (0, 0, 1) direction. Ni2+ is bonded in a linear geometry to two equivalent N3- atoms. Both Ni–N bond lengths are 1.75 Å. Zn2+ is bonded to four equivalent N3- atoms to form corner-sharing ZnN4 tetrahedra. All Zn–N bond lengths are 2.15 Å. N3- is bonded in a see-saw-like geometry to two equivalent Ni2+ and two equivalent Zn2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Extremely Large Response of Phonon Coherence in Twisted Penta‐NiN 2 Bilayer

Abstract Twisting has recently been demonstrated as an effective strategy for tuning the interactions between particles or quasi‐particles in layered materials. Motivated by the recent experimental synthesis of pentagonal NiN 2 sheet [ACS Nano2021, 15, 13539], for the first time, the response of phonon coherence to twisting in bilayer penta‐NiN 2 , going beyond the particle‐like phonon transport is studied. By using the unified theory of phonon transport and high order lattice anharmonicity, together with the self‐consistent phonon theory, it is found that the lattice thermal conductivity is reduced by 80.6% from 33.35 to 6.47 W m −1 K −1 at 300 K when the layers are twisted. In particular, the contribution of phonon coherence is increased sharply by an order of magnitude, from 0.21 to 2.40 W m −1 K −1 , due to the reduced differences between the phonon frequencies and enhanced anharmonicity after the introduction of twist. The work provides a fundamental understanding of the phonon interaction in twisted pentagonal sheets.

Chemistry↗
DOE OSTI2020

Rice NIN-LIKE PROTEIN 4 plays a pivotal role in nitrogen use efficiency

Nitrogen (N) is one of the key essential macronutrients that affects rice growth and yield. Inorganic N fertilizers are excessively used to boost yield and generate serious collateral environmental pollution. Therefore, improving crop N use efficiency (NUE) is highly desirable and has been a major endeavour in crop improvement. However, only a few regulators have been identified that can be used to improve NUE in rice to date. Here we show that the rice NIN-like protein 4 (OsNLP4) significantly improves the rice NUE and yield. Field trials consistently showed that loss-of-OsNLP4 dramatically reduced yield and NUE compared with wild type under different N regimes. In contrast, the OsNLP4 overexpression lines remarkably increased yield by 30% and NUE by 47% under moderate N level compared with wild type. Transcriptomic analyses revealed that OsNLP4 orchestrates the expression of a majority of known N uptake, assimilation and signalling genes by directly binding to the nitrate-responsive cis-element in their promoters to regulate their expression. Moreover, overexpression of OsNLP4 can recover the phenotype of Arabidopsis nlp7 mutant and enhance its biomass. Our results demonstrate that OsNLP4 plays a pivotal role in rice NUE and sheds light on crop NUE improvement.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Materials Data on NiN by Materials Project

NiN is Zincblende, Sphalerite structured and crystallizes in the cubic F-43m space group. The structure is three-dimensional. Ni3+ is bonded to four equivalent N3- atoms to form corner-sharing NiN4 tetrahedra. All Ni–N bond lengths are 1.87 Å. N3- is bonded to four equivalent Ni3+ atoms to form corner-sharing NNi4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr3Li3(NiN)4 by Materials Project

Li3Sr3(NiN)4 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. there are two inequivalent Li sites. In the first Li site, Li is bonded in a linear geometry to two equivalent N atoms. Both Li–N bond lengths are 2.03 Å. In the second Li site, Li is bonded in a linear geometry to two equivalent N atoms. Both Li–N bond lengths are 2.03 Å. There are two inequivalent Sr sites. In the first Sr site, Sr is bonded in a 3-coordinate geometry to three N atoms. There are two shorter (2.65 Å) and one longer (2.71 Å) Sr–N bond lengths. In the second Sr site, Sr is bonded in a square co-planar geometry to four equivalent N atoms. All Sr–N bond lengths are 2.82 Å. Ni is bonded in a linear geometry to two N atoms. There is one shorter (1.76 Å) and one longer (1.77 Å) Ni–N bond length. There are two inequivalent N sites. In the first N site, N is bonded to four Sr and two equivalent Ni atoms to form a mixture of distorted edge and corner-sharing NSr4Ni2 octahedra. The corner-sharing octahedra tilt angles range from 0–50°. In the second N site, N is bonded to three Li, one Sr, and two equivalent Ni atoms to form distorted corner-sharing NSrLi3Ni2 octahedra. The corner-sharing octahedra tilt angles range from 0–50°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Li5(NiN)3 by Materials Project

Li5(NiN)3 crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. there are two inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded in a trigonal planar geometry to three equivalent N3- atoms. All Li–N bond lengths are 2.08 Å. In the second Li1+ site, Li1+ is bonded in a 2-coordinate geometry to three equivalent N3- atoms. There are two shorter (2.13 Å) and one longer (2.42 Å) Li–N bond lengths. Ni+1.33+ is bonded in a linear geometry to two equivalent N3- atoms. Both Ni–N bond lengths are 1.74 Å. N3- is bonded to five Li1+ and two equivalent Ni+1.33+ atoms to form a mixture of distorted edge and corner-sharing NLi5Ni2 pentagonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NiN by Materials Project

NiN is Wurtzite structured and crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. Ni3+ is bonded to four equivalent N3- atoms to form corner-sharing NiN4 tetrahedra. There is three shorter (1.87 Å) and one longer (1.88 Å) Ni–N bond length. N3- is bonded to four equivalent Ni3+ atoms to form corner-sharing NNi4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NiN by Materials Project

NiN is Halite, Rock Salt structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Ni3+ is bonded to six equivalent N3- atoms to form a mixture of corner and edge-sharing NiN6 octahedra. The corner-sharing octahedral tilt angles are 0°. All Ni–N bond lengths are 2.03 Å. N3- is bonded to six equivalent Ni3+ atoms to form a mixture of corner and edge-sharing NNi6 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Anomalous Hall conductivity control in Mn 3⁢ NiN antiperovskite by epitaxial strain along the kagome plane

Antiferromagnetic manganese-based nitride antiperovskites, such as Mn 3 ⁢NiN, hold a triangular frustrated magnetic ordering, thanks to their kagome lattice formed by the Mn atoms along the (111) plane. As such, the magnetic frustration imposes a nontrivial interplay between the symmetric and asymmetric magnetic interactions, which can only reach equilibrium in a noncollinear magnetic configuration. Consequently, the associated electronic interactions and their possible tuning by external constraints, such as applied epitaxial strain, play a crucial role in defining the microscopic and macroscopic properties of such topological condensed matter systems. Here, in this paper, we explored and explained the effect of the epitaxial strain imposed within the (111) plane, in which the magnetic and crystallographic symmetry operations are kept fixed, and only the magnitude of the ionic and electronic interactions are tuned. We found a tangible enhancement in the anomalous Hall conductivity along the (111) plane ($σ^{AHE}_{111}$) for compression values, whereas, for tension, the AHC is dramatically reduced. As such, the $σ^{AHE}_{111}$ component fetches a maximum increase of 26%, with respect to the unstrained structure, for a compression value close to –1.5%. Our findings indicate a distinct correlation between the anomalous Hall conductivity and the Berry curvature along the (111) plane as a function of the strain. Finally, the nondivergent Berry curvature acts as the source and the strain as the control mechanism of this anomalous transport phenomenon.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2022

Investigation of the Structure of Atomically Dispersed NiN x Sites in Ni and N-Doped Carbon Electrocatalysts by 61 Ni Mössbauer Spectroscopy and Simulations

Ni and nitrogen-doped carbons are selective catalysts for CO 2 reduction to CO (CO 2 R), but the hypothesized NiNx active sites are challenging to probe with traditional characterization methods. Here, we synthesize 61 Ni-enriched model catalysts, termed 61 NiPACN, in order to apply 61 Ni Mössbauer spectroscopy using synchrotron radiation ( 61 Ni-SR-MS) to characterize the structure of these atomically dispersed NiNx sites. First, we demonstrate that the CO 2 R results and standard characterization techniques (SEM, PXRD, XPS, XANES, EXAFS) point to the existence of dispersed Ni active sites. Then, 61 Ni-SR-MS reveal significant internal magnetic fields of ~5.4 T, which is characteristic of paramagnetic, high-spin Ni 2+ , in the 61NiPACN samples. Finally, theoretical calculations for a variety of Ni-N x moieties confirm that high-spin Ni 2+ is stable in non-planar, tetrahedrally distorted geometries, which results in calculated isotropic hyperfine coupling that is consistent with 61 Ni-SR-MS measurements.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

An LCO-responsive homolog of NODULE INCEPTION positively regulates lateral root formation in Populus sp.

Abstract The transcription factor NODULE INCEPTION (NIN) has been studied extensively for its multiple roles in root nodule symbiosis within plants of the nitrogen-fixing clade (NFC) that associate with soil bacteria, such as rhizobia and Frankia. However, NIN homologs are present in plants outside the NFC, suggesting a role in other developmental processes. Here, we show that the biofuel crop Populus sp., which is not part of the NFC, contains eight copies of NIN with diversified protein sequence and expression patterns. Lipo-chitooligosaccharides (LCOs) are produced by rhizobia and a wide range of fungi, including mycorrhizal ones, and act as symbiotic signals that promote lateral root formation. RNAseq analysis of Populus sp. treated with purified LCO showed induction of the PtNIN2 subfamily. Moreover, the expression of PtNIN2b correlated with the formation of lateral roots and was suppressed by cytokinin treatment. Constitutive expression of PtNIN2b overcame the inhibition of lateral root development by cytokinin under high nitrate conditions. Lateral root induction in response to LCOs likely represents an ancestral function of NIN retained and repurposed in nodulating plants, as we demonstrate that the role of NIN in LCO-induced root branching is conserved in both Populus sp. and legumes. We further established a visual marker of LCO perception in Populus sp. roots, the putative sulfotransferase PtSS1 that can be used to study symbiotic interactions with the bacterial and fungal symbionts of Populus sp.

Irving, Thomas B. (ORCID:0000000330404543)↗
DOE OSTI2021

Nickel(ii) complexes based on dithiolate–polyamine binary ligand systems: crystal structures, hirshfeld surface analysis, theoretical study, and catalytic activity study on photocatalytic hydrogen generation

To ascertain the influence of binary ligand systems [1,1-dicyanoethylene-2,2-dithiolate (i-mnt -2 ) and polyamine {tetraen = tris(2-aminoethyl)amine, tren = diethylene triamine and opda = o-phenylenediamine}] on the coordination modes of the Ni(II) metal center and resulting supramolecular architectures, a series of nickel(II) thiolate complexes [Ni(tetraen)(i-mnt)](DMSO) (1), [Ni 2 (tren) 2 (i-mnt) 2 ] (2), and [Ni 2 (i-mnt) 2 (opda) 2 ] n (3) have been synthesized in high yield in one step in water and structurally characterized by single crystal X-ray crystallography and spectroscopic techniques. X-ray diffraction studies disclose the diverse i-mnt -2 coordination to the Ni +2 center in the presence of active polyamine ligands, forming a slightly distorted octahedral geometry (NiN 4 S 2 ) in 1, square planar (NiS 4 ) and distorted octahedral geometries (NiN 6 ) in the bimetallic co-crystallized aggregate of cationic [Ni(tren) 2 ] +2 and anionic [Ni(i-mnt) 2 ] -2 in 2, and a one dimensional (1D) polymeric chain along the [100] axis in 3, having consecutive square planar (NiS 4 ) and octahedral (NiN 6 ) coordination kernels. The N–H···O, N–H···S, N–H···N, N–H···S, N–H···N, and N–H···O type hydrogen bonds stabilize the supramolecular assemblies in 1, 2, and 3 respectively imparting interesting graph-set-motifs. The molecular Hirshfeld surface analyses (HS) and 2D fingerprint plots were utilized for decoding all types of non-covalent contacts in the crystal networks. Atomic HS analysis of the Ni +2 centers reveals significant Ni–N metal–ligand interactions compared to Ni–S interactions. We have also studied the unorthodox interactions observed in the solid state structures of 1–3 by QTAIM and NBO analyses. Moreover, all the complexes proved to be highly active water reduction co-catalysts (WRC) in a photo-catalytic hydrogen evolution process involving iridium photosensitizers, wherein 2 and 3 having a square planar arrangement around the nickel center(s) – were found to be the most active ones, achieving 1000 and 1119 turnover numbers (TON), respectively.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Direct Characterization of Atomically Dispersed Catalysts: Nitrogen-Coordinated Ni Sites in Carbon-Based Materials for CO 2 Electroreduction

Metal, nitrogen-doped carbon materials have attracted interest as heterogenous catalysts that contain MN x active sites that are analogous to molecular catalysts. Of particular interest is Ni,N-doped carbon, a catalyst that is active for the electrochemical reduction of CO 2 to CO. Critical to the understanding of these materials is proof of single atomic sites and characterization of the environment surrounding the metal atom; however, directly probing this coordination remains challenging. This challenge is addressed in this study by combining scanning transmission electron microscopy (STEM), single atom electron energy loss spectroscopy (EELS), and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Through STEM imaging, atomic dispersion of Ni in the carbon framework is confirmed and image analyses are utilized to give semiquantitative estimates of neighbor distance distributions and site densities of Ni atoms. Atomic resolution EELS demonstrates that N and Ni are colocated at the single Ni atom sites suggesting Ni–N coordination. ToF-SIMS reveals a distribution of NiN x C y - fragments that reflect the Ni–N bonding environments within Ni,N-doped carbon. The fragmentation from Ni,N-doped carbon is similar to Ni phthalocyanine, suggesting the existence of heterogenized, molecular-like NiN 4 active sites which motivates future studies that leverage insight from molecular catalysis design to develop next-generation heterogeneous catalysts.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Atomically Dispersed Dual‐Metal Site Catalysts for Enhanced CO 2 Reduction: Mechanistic Insight into Active Site Structures

Abstract Carbon‐supported nitrogen‐coordinated single‐metal site catalysts (i.e., M−N−C, M: Fe, Co, or Ni) are active for the electrochemical CO 2 reduction reaction (CO 2 RR) to CO. Further improving their intrinsic activity and selectivity by tuning their N−M bond structures and coordination is limited. Herein, we expand the coordination environments of M−N−C catalysts by designing dual‐metal active sites. The Ni‐Fe catalyst exhibited the most efficient CO2RR activity and promising stability compared to other combinations. Advanced structural characterization and theoretical prediction suggest that the most active N‐coordinated dual‐metal site configurations are 2N‐bridged (Fe‐Ni)N 6 , in which FeN 4 and NiN 4 moieties are shared with two N atoms. Two metals (i.e., Fe and Ni) in the dual‐metal site likely generate a synergy to enable more optimal *COOH adsorption and *CO desorption than single‐metal sites (FeN 4 or NiN 4 ) with improved intrinsic catalytic activity and selectivity.

Li, Yi↗