The Vibrational Spectra and Decomposition ofα-Calcium Nitride (α-Ca3N2) and Magnesium Nitride (Mg3N2)

Heyns, A.M.; Prinsloo, Linda C.; Range, K.‐J.; Stassen, Martin

doi:10.1006/jssc.1997.7672

Cited by 57 publications

(54 citation statements)

References 10 publications

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“…The minimum initial reaction rates for these nitrides at 300°C may originate from the opposing effects of high reactant concentrations at low temperatures (about 25-16 mol H 2 O m -3 at 200-500°C, assuming an ideal gas) and short residence times of the meta-stable NH 3 36 and reported specific rate constants of the Mg 3 N 2 hydrolysis on the same order as those reported here, which supports our interpretation.…”

Section: Nh 3 Liberation Kinetics From S-block Nitridessupporting

confidence: 90%

“…This limits their attractiveness for the proposed concept since this energy can not be easily integrated at the higher temperatures required for the endothermic oxide reduction step. On the other hand, binary transition metal nitrides with relatively high NH 3 equilibrium yields (e.g., Mn 4 Although well-studied for their refractory properties 32,33 hydrolysis of nitrides and NH 3 formation kinetics have been rarely reported 27,[34][35][36] . Pourbaix diagrams providing information on corrosion mechanisms are typically only available for pure elements 37 .…”

Section: Materials Composition Determining Energy Conversion Efficienmentioning

confidence: 99%

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An Ionicity Rationale to Design Solid phase Metal Nitride Reactants for Solar Ammonia Production

Michalsky

Pfromm

2012

J. Phys. Chem. C

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Ammonia provides the basis of nutrition for a large portion of the human population on earth and could be used additionally as a convenient hydrogen carrier. This work studies a solar thermochemical reaction cycle that separates the reductive N2 cleavage from the hydrogenation of nitrogen ions to NH3 without using electricity or fossil fuel. The hydrolysis of binary metal nitrides of magnesium, aluminum, calcium, chromium, manganese, zinc, or molybdenum at 0.1 MPa and 200–1000 °C recovered up to 100 mol % of the lattice nitrogen with up to 69.9 mol % as NH3 liberated at rates of up to 1.45 × 10–3 mol NH3 (mol metal)−1 s–1 for ionic nitrides. These rates and recoveries are encouraging when extrapolated to a full scale process. However, nitrides with lower ionicity are attractive due to simplified reduction conditions to recycle the oxidized reactant after NH3 formation. For these materials diffusion in the solid limits the rate of NH3 liberation. The nitride ionicity (9.96–68.83% relative to an ideal ionic solid) was found to correlate with the diffusion constants (6.56 × 10–14 to 4.05 × 10–7 cm2 s–1) suggesting that the reduction of H2O over nitrides yielding NH3 is governed by the activity of the lattice nitrogen or ion vacancies, respectively. The ionicity appears to be a useful rationale when developing an atomic-scale understanding of the solid-state reaction mechanism and when designing prospectively optimized ternary nitrides for producing NH3 more sustainably and at mild conditions compared to the Haber Bosch process.

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Section: Nh 3 Liberation Kinetics From S-block Nitridessupporting

confidence: 90%

Section: Materials Composition Determining Energy Conversion Efficienmentioning

confidence: 99%

An Ionicity Rationale to Design Solid phase Metal Nitride Reactants for Solar Ammonia Production

Michalsky

Pfromm

2012

J. Phys. Chem. C

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“…However, the observed LiMgN spectrum for the desorption sample was not consistent with literature [28]. The high-shift NH 2 -region for the rehydrogenated sample is consistent with the formation of Mg(NH 2 ) 2 and there is no evidence that LiNH 2 has been reformed indicating that the desorption sample did not rehydrogenate to the starting material It is worth nothing that the spectrum observed doublet closely matches the strongest peaks in the reported spectrum of Mg 3 N 2 [29]. The fate of the Li in the dehydrided sample is less clear.…”

Section: Phase Identificationmentioning

confidence: 50%

“…For example, the shoulder is coincident with a feature attributed to Li 2 Mg(NH) 2 (3180 cm -1 ) [31]. Also, discussion in Heyns et al [29] suggests the possibility that the 3207 cm -1 peak is consistent with the presence of physisorbed NH 3 , especially if the ammonia has some NH 4 + character due to a hydrogen bonding interaction between the N lone pair and bound hydrogen. The observed position is intermediate between the range of "NH 3 in amino complexes" (3115-3330 cm -1 ) and NH 4 + ion (3040 cm -1 ).…”

Section: Phase Identificationmentioning

confidence: 85%

The effects of halide modifiers on the sorption kinetics of the Li-Mg-N-H System

Price

Gray

Lascola

et al. 2012

International Journal of Hydrogen Energy

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The effects of different transition metal halides (TiCl 3 , VCl 3 , ScCl 3 and NiCl 2 ) on the sorption properties of the 1:1 molar ratio of LiNH 2 to MgH 2 are investigated. The modified mixtures were found to contain LiNH 2 , MgH 2 and LiCl. TGA results showed that the hydrogen desorption temperature was reduced with the modifier addition in this order: TiCl 3 > ScCl 3 > VCl 3 > NiCl 2 . Ammonia release was not significantly reduced resulting in a weight loss greater than the theoretical hydrogen storage capacity of the material. The isothermal sorption kinetics of the modified systems showed little improvement after the first dehydrogenation cycle over the unmodified system but showed drastic improvement in rehydrogenation cycles. X-ray diffraction and Raman spectroscopy identified the cycled material to be composed of LiH, MgH 2 , Mg(NH 2 ) 2 and Mg 3 N 2 .

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“…2.8 eV), and thus may serve as a potential high-temperature semiconducting material and/or component of a semiconductor heterostructure useful in nanoelectronics. [12] However, due to the fast decomposition of Mg 3 N 2 in the presence of water in the atmosphere (Mg 3 N 2 + 6 H 2 O → 3 Mg(OH) 2 + 2 NH 3 ), [13] the synthesis of Mg 3 N 2 nanowires has been a challenge. Recently, we employed CNTs as nanoreactors for the fabrication of single-crystalline Mg 3 N 2 nanowires for the first time.…”

mentioning

confidence: 99%

Mg₃N₂‐Ga: Nanoscale Semiconductor–Liquid Metal Heterojunctions inside Graphitic Carbon Nanotubes

Bando

Zhan

et al. 2007

Advanced Materials

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Mg3N2‐Ga nanoscale semiconductor–liquid metal heterojunctions homogeneously coated with very thin graphitic carbon nanotube (GCNT) layers are fabricated (see figure). Most of the junctions have a uniform diameter of ca. 100–200 nm. GCNTs coated on the nanowire junctions are only several nanometers thick. A convergent electron beam generated in a transmission electron microscope is demonstrated to be an effective tool for delicate manipulation of a junction.

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The Vibrational Spectra and Decomposition ofα-Calcium Nitride (α-Ca3N2) and Magnesium Nitride (Mg3N2)

Cited by 57 publications

References 10 publications

An Ionicity Rationale to Design Solid phase Metal Nitride Reactants for Solar Ammonia Production

An Ionicity Rationale to Design Solid phase Metal Nitride Reactants for Solar Ammonia Production

The effects of halide modifiers on the sorption kinetics of the Li-Mg-N-H System

Mg₃N₂‐Ga: Nanoscale Semiconductor–Liquid Metal Heterojunctions inside Graphitic Carbon Nanotubes

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The Vibrational Spectra and Decomposition ofα-Calcium Nitride (α-Ca3N2) and Magnesium Nitride (Mg3N2)

Cited by 57 publications

References 10 publications

An Ionicity Rationale to Design Solid phase Metal Nitride Reactants for Solar Ammonia Production

An Ionicity Rationale to Design Solid phase Metal Nitride Reactants for Solar Ammonia Production

The effects of halide modifiers on the sorption kinetics of the Li-Mg-N-H System

Mg3N2‐Ga: Nanoscale Semiconductor–Liquid Metal Heterojunctions inside Graphitic Carbon Nanotubes

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Product

Resources

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Mg₃N₂‐Ga: Nanoscale Semiconductor–Liquid Metal Heterojunctions inside Graphitic Carbon Nanotubes