scholarly journals Nitrated Graphene Oxide Derived from Graphite Oxide: A Promising Energetic Two-Dimensional Material

Nanomaterials ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 58
Author(s):  
Fayang Guan ◽  
Hui Ren ◽  
Lan Yu ◽  
Qingzhong Cui ◽  
Wanjun Zhao ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Graphene Oxide ◽  
Graphite Oxide ◽  
Energetic Materials ◽  
Density Functional ◽  
Electrode Materials ◽  
Energetic Material ◽  
Structure Characterization ◽  
Hydroxyl Groups ◽  
Two Dimensional

In order to synthesize a novel two-dimensional energetic material, nitrated graphene oxide (NGO) was prepared by the nitrification of graphite oxide to make a functional modification. Based on the morphological characterization, the NGO has a greater degree of curl and more wrinkles on the surface. The structure characterization and density functional theory calculation prove that epoxy and hydroxyl groups on the edge of graphite oxide have reacted with nitronium cation (NO2+) to produce nitro and nitrate groups. Hydrophobicity of NGO implied higher stability in storage than graphene oxide. Synchronous simultaneous analysis was used to explore the decomposition mechanism of NGO preliminarily. The decomposition enthalpy of NGO is 662.0 J·g−1 and the activation energy is 166.5 kJ·mol−1. The thermal stability is similar to that of general nitrate energetic materials. The hygroscopicity, thermal stability and flammability of NGO prove that it is a novel two-dimensional material with potential applications as energetic additives in the catalyst, electrode materials and energetic devices.

scholarly journals Computational Study on Substituteds-Triazine Derivatives as Energetic Materials

2012 ◽  
Vol 9 (2) ◽  
pp. 583-592 ◽  
Author(s):  
Vikas D. Ghule ◽  
S. Radhakrishnan ◽  
Pandurang M. Jadhav ◽  
Surya P. Tewari
Keyword(s):  
Thermal Stability ◽  
Energetic Materials ◽  
Density Functional ◽  
Crystal Packing ◽  
Computational Study ◽  
Heats Of Formation ◽  
Dissociation Energies ◽  
The Density Functional Theory ◽  
Triazine Derivatives ◽  
Derivatives Of

s-Triazine is the essential candidate of many energetic compounds due to its high nitrogen content, enthalpy of formation and thermal stability. The present study explores s-triazine derivatives in which different -NO2, -NH2and -N3substituted azoles are attached to the triazine ring via C-N linkage. The density functional theory is used to predict geometries, heats of formation and other energetic properties. Among the designed compounds, -N3derivatives show very high heats of formation. The densities for designed compounds were predicted by using the crystal packing calculations. Introduction of -NO2group improves density as compared to -NH2and -N3, their order of increasing density can be given as NO2>N3>NH2. Analysis of the bond dissociation energies for C-NO2, C-NH2and C-N3bonds indicates that substitutions of the -N3and -NH2group are favorable for enhancing the thermal stability ofs-triazine derivatives. The nitro and azido derivatives of triazine are found to be promising candidates for the synthetic studies.

scholarly journals Van der Waals Density Functional Theory vdW-DFq for Semihard Materials

Crystals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 243 ◽  
Author(s):  
Qing Peng ◽  
Guangyu Wang ◽  
Gui-Rong Liu ◽  
Suvranu De
Keyword(s):  
Density Functional Theory ◽  
Energetic Materials ◽  
Density Functional ◽  
Energetic Material ◽  
Van Der Waals ◽  
Molecular Crystals ◽  
Soft Materials ◽  
Dispersion Force ◽  
Electronic Charge ◽  
Functional Theory

There are a large number of materials with mild stiffness, which are not as soft as tissues and not as strong as metals. These semihard materials include energetic materials, molecular crystals, layered materials, and van der Waals crystals. The integrity and mechanical stability are mainly determined by the interactions between instantaneously induced dipoles, the so called London dispersion force or van der Waals force. It is challenging to accurately model the structural and mechanical properties of these semihard materials in the frame of density functional theory where the non-local correlation functionals are not well known. Here, we propose a van der Waals density functional named vdW-DFq to accurately model the density and geometry of semihard materials. Using β -cyclotetramethylene tetranitramine as a prototype, we adjust the enhancement factor of the exchange energy functional with generalized gradient approximations. We find this method to be simple and robust over a wide tuning range when calibrating the functional on-demand with experimental data. With a calibrated value q = 1.05 , the proposed vdW-DFq method shows good performance in predicting the geometries of 11 common energetic material molecular crystals and three typical layered van der Waals crystals. This success could be attributed to the similar electronic charge density gradients, suggesting a wide use in modeling semihard materials. This method could be useful in developing non-empirical density functional theories for semihard and soft materials.

Buckling of Two-Dimensional Covalent Organic Frameworks Under Thermal Stress

2019 ◽  
Author(s):  
Austin Evans ◽  
Matthew Ryder ◽  
Nathan C. Flanders ◽  
Edon Vitaku ◽  
Lin Chen ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Thermal Stress ◽  
Density Functional ◽  
Structural Changes ◽  
Gravimetric Analysis ◽  
Two Dimensional ◽  
Covalent Organic Frameworks ◽  
X Ray Diffraction ◽  
Excellent Thermal Stability ◽  
X Ray

Two-dimensional Covalent organic frameworks (2D COFs) are periodic, permanently porous, and lightweight solids that are polymerized from topologically designed monomers. The predictable design and structural modularity of these materials make them promising candidates for applications including catalysis, environmental remediation, chemical separations, and organic electronics, many of which will require stability to mechanical and thermal stress. Based on their reinforced structures and high degradation temperatures as determined by thermal gravimetric analysis (TGA), many reports have claimed that COFs have excellent thermal stability. However, their stability to heat and pressure has not been probed using methods that report on structural changes rather than the loss of volatile compounds. Here we explore two structurally analogous 2D COFs with different polymerization chemistries using in operando X-ray diffraction, which demonstrates the loss of crystallinity at lower temperatures than the degradation temperatures measured by TGA. Density functional theory calculations suggest that an asymmetric buckling of the COF lattice is responsible for the observed loss of crystallinity. In addition to their thermal stability, x-ray diffraction of the 2D COFs under gas pressures up to 100 bar showed no loss in crystallinity or structural changes, indicating that these materials are robust to mechanical stress by applied pressure. We expect that these results will encourage further exploration of COF stability as a function of framework design and isolated form, which will guide the design of frameworks that withstand demanding application-relevant conditions.

New concept for the design of zero-hydrogen energetic materials with high energy and low sensitivity: achieving a good balance among parent compounds, nitro groups, and N-oxides

2017 ◽  
Vol 95 (5) ◽  
pp. 505-511 ◽  
Author(s):  
Qiong Wu ◽  
Linghua Tan ◽  
Zusheng Hang ◽  
Weihua Zhu
Keyword(s):  
Energetic Materials ◽  
Density Functional ◽  
Energetic Material ◽  
Parent Compound ◽  
High Energy ◽  
Design Concept ◽  
New Novel ◽  
Energetic Compound ◽  
The Density Functional Theory ◽  
Low Sensitivity

A new powerful zero-hydrogen energetic compound DNDOBTT (2,7-dinitro-4N,9N-dioxide-bis[1,2,4]-triazolo)[1,5-b:1′,5′e][1,2,4,5] tetrazine) was produced by a new design concept of achieving a balance among the parent compound, nitro groups, and N-oxides. Its structure and properties was studied by the density functional theory. The breaking of N–N bond in the tetrazine ring is an initial decomposition step of DNDOBTT, and the energy barrier was predicted to be 175 kJ·mol−1. DNDOBTT has comparable detonation performance with some CHNO energetic compounds, including the most powerful ONC (octanitrocubane), whereas its sensitivity and thermal stability are obviously lower and better than those of ONC, respectively, indicating that DNDOBTT has both the high energy and reduced sensitivity and may be a valuable candidate for experiments. Therefore, a new novel energetic material DNDOBTT with good overall performance has been obtained successfully by the new design concept, and it may be applied to design and develop other novel improved zero-hydrogen energetic materials.

Ammonia Dissociation on Graphene Oxide: An Ab Initio Density Functional Theory Calculation

2015 ◽  
Vol 229 (7-8) ◽  
Author(s):  
Liangliang Huang ◽  
Keith E. Gubbins
Keyword(s):  
Density Functional Theory ◽  
Graphene Oxide ◽  
Ab Initio ◽  
Functional Groups ◽  
Density Functional ◽  
Density Functional Theory Calculation ◽  
Exothermic Reaction ◽  
Density Functional Theory Method ◽  
Hydroxyl Groups ◽  
Functional Theory

AbstractInteractions of ammonia and water with the oxygen-containing functional groups of graphite oxide have been studied by ab initio density functional theory method. The results show that ammonia can dissociate on the carboxyl, epoxy and hydroxyl groups. The dissociation on the epoxy group is an exothermic reaction with a small activation energy barrier. Water is found to form a hydrogen bond with the carboxyl, epoxy and hydroxyl groups, and thus will block ammonia from interacting with those functional groups. The results in this work provide a fundamental understand of previous experiments about ammonia adsorption on graphene oxide materials.

Thermo-chemical metastability of multilayer epitaxial graphene oxide: Experiments and density functional theory calculations

2012 ◽  
Vol 1451 ◽  
pp. 39-44
Author(s):  
Si Zhou ◽  
S. Kim ◽  
Y. Hu ◽  
C. Berger ◽  
W. de Heer ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Graphene Oxide ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Epitaxial Graphene ◽  
Great Promise ◽  
Hydroxyl Groups ◽  
Minimal Amount ◽  
Multilayer Graphene ◽  
Functional Theory

ABSTRACTGraphene oxide holds great promise for future applications in nano-technology. The chemistry of this material is not well understood. This understanding is crucial to enable future applications of graphene oxide. In this study, experiments and density functional theory calculations are combined to elucidate the chemical properties of multilayer graphene oxide obtained by oxidizing epitaxial graphene grown on silicon carbide via the Hummers method. This study shows that at room temperature as prepared graphene oxide films exhibit a uniform and homogeneous structure, include a minimal amount of edges and holes, and have an oxidation ratio of about 0.44. The comparison with density-functional calculations shows that graphene oxide includes a minimal amount of intercalated water molecules and well-defined fractions of epoxide and hydroxyl groups.

scholarly journals Structure Characterization of [N-Phenylamino(2-boronphenyl)-R-methyl]phosphonic Acid by Vibrational Spectroscopy and Density Functional Theory Calculations

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Natalia Piergies ◽  
Edyta Proniewicz
Keyword(s):  
Density Functional Theory ◽  
Fourier Transform ◽  
Phosphonic Acid ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Density Functional Theory Calculations ◽  
Structure Characterization ◽  
Hydroxyl Groups ◽  
Functional Theory ◽  
Ft Ir

We present the first Fourier-transform infrared absorption (FT-IR) and Fourier-transform Raman (FT-Raman) analysis of vibrational structure of [N-phenylamino(2-boronphenyl)-R-methyl]phosphonic acid ([PhN-(2-PhB(OH)2)-R-Me]PO3H2). Assignments of experimental wavenumbers are based on performed theoretical calculations using density functional theory (DFT). Theoretical calculations show that the most stable structure of the investigated molecule is dimer incis-transconformation created by a pair of intermolecular hydrogen bonds between the boron hydroxyl groups of two monomers.

scholarly journals Theoretical Prediction of P-Triphenylene-Graphdiyne as an Excellent Anode Material for Li, Na, K, Mg, and Ca Batteries

2021 ◽  
Vol 11 (5) ◽  
pp. 2308
Author(s):  
Mohammad Salavati ◽  
Naif Alajlan ◽  
Timon Rabczuk
Keyword(s):  
Anode Material ◽  
Metal Ion ◽  
Density Functional ◽  
Electrode Materials ◽  
Electronic Conductivity ◽  
Two Dimensional ◽  
Efficient Performance ◽  
Fast Charging ◽  
Structural And Electronic Properties ◽  
Ca Ions

The efficient performance of metal-ion batteries strongly depends on electrode materials characteristics. Two-dimensional (2D) materials are among promising electrode materials for metal-ion battery cells, owing to their excellent structural and electronic properties. Two-dimensional graphdiyne has been recently fabricated and revealed unique storage capacities and fast charging rates. The current study explores the performance of the novel phosphorated-triphenylene graphdiyne (P-TpG) monolayer as an anode material for Li-, Na-, K-, Mg-, and Ca-ions storage via extensive density functional theory (DFT) simulations. Our results reveal that the stable structure of P-TpG monolayers delivers ultra-high storage capacities of ~2148, ~1696, ~1017, and ~2035 mA·h·g−1 for Li-, Na-, K-, and Ca- ions, respectively. Notably, the metallic electronic behavior is illustrated by adsorbing metal-ions on the P-TpG nanosheets, suggesting a good electronic conductivity. The NEB results demonstrate that P-TpG can serve as an outstanding candidate for the optimal charging/discharging process. This theoretical study suggests P-TpG nanosheets as a highly promising candidate for the design of advanced metal-ion batteries with remarkable charge capacities and optimal charging/discharging rates.

scholarly journals Interactions between Reduced Graphene Oxide with Monomers of (Calcium) Silicate Hydrates: A First-Principles Study

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2248
Author(s):  
Mohammadreza Izadifar ◽  
Jorge S. Dolado ◽  
Peter Thissen ◽  
Andres Ayuela
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Calcium Ions ◽  
Calcium Silicate ◽  
Density Functional ◽  
Pristine Graphene ◽  
Chemical Compositions ◽  
Hydroxyl Groups ◽  
Condensation Reactions ◽  
Reduced Graphene

Graphene is a two-dimensional material, with exceptional mechanical, electrical, and thermal properties. Graphene-based materials are, therefore, excellent candidates for use in nanocomposites. We investigated reduced graphene oxide (rGO), which is produced easily by oxidizing and exfoliating graphite in calcium silicate hydrate (CSHs) composites, for use in cementitious materials. The density functional theory was used to study the binding of moieties, on the rGO surface (e.g., hydroxyl-OH/rGO and epoxide/rGO groups), to CSH units, such as silicate tetrahedra, calcium ions, and OH groups. The simulations indicate complex interactions between OH/rGO and silicate tetrahedra, involving condensation reactions and selective repairing of the rGO lattice to reform pristine graphene. The condensation reactions even occurred in the presence of calcium ions and hydroxyl groups. In contrast, rGO/CSH interactions remained close to the initial structural models of the epoxy rGO surface. The simulations indicate that specific CSHs, containing rGO with different interfacial topologies, can be manufactured using coatings of either epoxide or hydroxyl groups. The results fill a knowledge gap, by establishing a connection between the chemical compositions of CSH units and rGO, and confirm that a wet chemical method can be used to produce pristine graphene by removing hydroxyl defects from rGO.

Toward reliable characterization of energetic materials: interplay of theory and thermal analysis in the study of the thermal stability of tetranitroacetimidic acid (TNAA)

2018 ◽  
Vol 20 (46) ◽  
pp. 29285-29298 ◽  
Author(s):  
Vitaly G. Kiselev ◽  
Nikita V. Muravyev ◽  
Konstantin A. Monogarov ◽  
Pavel S. Gribanov ◽  
Andrey F. Asachenko ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Thermal Analysis ◽  
Thermal Decomposition ◽  
Quantum Chemistry ◽  
Energetic Materials ◽  
Energetic Material ◽  
Kinetics And Mechanism ◽  
Mechanism Of Thermal Decomposition ◽  
Thermal Stability Of

Kinetics and mechanism of thermal decomposition of tetranitroacetimidic acid, a novel green energetic material, were studied using complementary thermoanalytical methods (DSC and TGA) and quantum chemistry (CCSD(T)-F12).

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