The adsorption and diffusion of Na, K, and Ca atoms on MXene/graphene heterostructures of MXene systems Sc2C(OH)2, Ti2CO2, and V2CO2 are systematically investigated by using first-principles ...methods. We found that alkali metal intercalation is energetically favorable and thermally stable for Ti2CO2/graphene and V2CO2/graphene heterostructures but not for Sc2C(OH)2. Diffusion kinetics calculations showed the advantage of MXene/graphene heterostructures over sole MXene systems as the energy barriers are halved for the considered alkali metals. Low energy barriers are found for Na and K ions, which are promising for fast charge/discharge rates. Calculated voltage profiles reveal that estimated high capacities can be fully achieved for Na ion in V2CO2/graphene and Ti2CO2/graphene heterostructures. Our results indicate that Ti2CO2/graphene and V2CO2/graphene electrode materials are very promising for Na ion battery applications. The former could be exploited for low voltage applications while the latter will be more appropriate for higher voltages.
Carbyne-enriched nanomaterials are of current interest in nanotechnology-related applications. The properties of these nanomaterials greatly depend on their production process. In particular, ...structural self-organization and auto-synchronization of nanostructures are typical phenomena observed during the growth and heteroatom-doping of carbyne-enriched nanostructured metamaterials by the ion-assisted pulse-plasma deposition method. Accordingly, fine tuning of these processes may be seen as the key step to the predictive designing of carbyne-enriched nano-matrices with improved properties. In particular, we propose an innovative concept, connected with application of the vibrational-acoustic effects and based on universal Cymatics mechanisms. These effects are used to induce vibration-assisted self-organized wave patterns together with the simultaneous manipulation of their properties through an electric field. Interaction between the inhomogeneous electric field distribution generated on the vibrating layer and the plasma ions serves as the additional energizing factor controlling the local pattern formation and self-organization of the nano-structures.
Quadrupole coupling constants were explored to investigate stabilities and properties of hydrogen bonded pairs of 5-fluorouracil (FU) based on density functional theory calculations. Display omitted
...•Stabilities and properties for hydrogen bonded 5-fluorouracil pairs are investigated.•Quadrupole coupling constants are explored to examine structural properties.•Relationship between hydrogen bonding strengths and quadrupole coupling constants are investigated.
Atomic scale properties of quadrupole coupling constants (CQ) have been evaluated for singular and paired 5-fluorouracil (FU) models. Structural possibilities and properties for various types of hydrogen bonded (HB) homo pairs of FU have been investigated based on density functional theory (DFT) calculations. The models have been optimized to obtain the minimum energy level structures and only the planar molecular pairs have been considered. Various types of HB interactions have also managed the molecular shapes for the FU pairs. Different types of energies and also electron transferring properties have been investigated by the evaluated optimized properties. The atomic scale results indicated different strengths of HB interactions for FU pairs according to the changes of CQ properties for atoms in the singular and paired systems depending on the strength of interactions.
We present an experimental and first-principles study to describe the changes in the electrical conductivity properties of the Emeraldine Salt (ES) form of polyaniline when using two different ...synthesis methods. The ES powders obtained by the interfacial synthesis method (PANI-I) exhibit higher electrical conductivity than that of the powders obtained by the conventional method (PANI-C). Investigation of the calculated band structure and density of states together with experimentally obtained optical-absorption spectra and the magnetic measurements indicate that PANI-I differs from PANI-C with respect to its localized defect state type which significantly alters the intrinsic conductivity. Furthermore, comparative studies of bond length, dihedral angles, and relative stabilities of Leucomeraldine Base, Emeraldine Base, ES Bipolaron state (ESB), and Polaron state (ESP) indicate that ESB and ESP states might coexist. Additionally, we confirm that increasing the length of the polymer chain to octamer in the unit cell does not influence the relative stability between ESB and ESP defect states.
A recently proposed, game-changing transformative energetics concept based on predictive synthesis and preprocessing at the nanoscale is considered as a pathway towards the development of the next ...generation of high-end nanoenergetic materials for future multimode solid propulsion systems and deep-space-capable small satellites. As a new door for the further performance enhancement of transformative energetic materials, we propose the predictive ion-assisted pulse-plasma-driven assembling of the various carbon-based allotropes, used as catalytic nanoadditives, by the 2D-ordered linear-chained carbon-based multicavity nanomatrices serving as functionalizing nanocarriers of multiple heteroatom clusters. The vacant functional nanocavities of the nanomatrices available for heteroatom doping, including various catalytic nanoagents, promote heat transfer enhancement within the reaction zones. We propose the innovative concept of fine-tuning the vibrational signatures, functionalities and nanoarchitectures of the mentioned nanocarriers by using the surface acoustic waves-assisted micro/nanomanipulation by the pulse-plasma growth zone combined with the data-driven carbon nanomaterials genome approach, which is a deep materials informatics-based toolkit belonging to the fourth scientific paradigm. For the predictive manipulation by the micro- and mesoscale, and the spatial distribution of the induction and energy release domains in the reaction zones, we propose the activation of the functionalizing nanocarriers, assembled by the heteroatom clusters, through the earlier proposed plasma-acoustic coupling-based technique, as well as by the Teslaphoresis force field, thus inducing the directed self-assembly of the mentioned nanocarbon-based additives and nanocarriers.
MXenes are the newest class of two-dimensional (2D) materials, and they offer great potential in a wide range of applications including electronic devices, sensors, and thermoelectric and energy ...storage materials. In this work, we combined the outstanding electrical conductivity, that is essential for battery applications, of graphene with MXene monolayers (M 2 CX 2 where M = Sc, Ti, V and X = OH, O) to explore its potential in Li battery applications. Through first principles calculations, we determined the stable stacking configurations of M 2 CX 2 /graphene bilayer heterostructures and their Li atom intercalation by calculating the Li binding energy, diffusion barrier and voltage. We found that: (1) for the ground state stacking, the interlayer binding is strong, yet the interlayer friction is small; (2) Li binds more strongly to the O-terminated monolayer, bilayer and heterostructure MXene systems when compared with the OH-terminated MXenes due to the H + induced repulsion to the Li atoms. The binding energy of Li decreases as the Li concentration increases due to enhanced repulsive interaction between the positively charged Li ions; (3) Ti 2 CO 2 /graphene and V 2 CO 2 /graphene heterostructures exhibit large Li atom binding energies making them the most promising candidates for battery applications. When fully loaded with Li atoms, the binding energy is −1.43 eV per Li atom and −1.78 eV per Li atom for Ti 2 CO 2 /graphene and V 2 CO 2 /graphene, respectively. These two heterostructures exhibit a nice compromise between storage capacity and kinetics. For example, the diffusion barrier of Li in Ti 2 CO 2 /graphene is around 0.3 eV which is comparable to that of graphite. Additionally, the calculated average voltages are 1.49 V and 1.93 V for Ti 2 CO 2 /graphene and V 2 CO 2 /graphene structures, respectively; (4) a small change in the in-plane lattice parameters (<1%), interatomic bond lengths and interlayer distances (<0.5 Å) proves the stability of the heterostructures against Li intercalation, and the impending phase separation into constituent layers and capacity fading during charge–discharge cycles in real battery applications; (5) as compared to bare M 2 CX 2 bilayers, M 2 CX 2 /graphene heterostructures have lower molecular mass, offering high storage capacity; (6) the presence of graphene ensures good electrical conductivity that is essential for battery applications. Given these advantages, Ti 2 CO 2 /graphene and V 2 CO 2 /graphene heterostructures are predicted to be promising for lithium-ion battery applications.
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In recent years, transition metal dichalcogenides (TMDs) displaying astonishing properties are emerged as a new class of two-dimensional layered materials. The understanding and ...characterization of thermal transport in these materials are crucial for efficient engineering of 2D TMD materials for applications such as thermoelectric devices or overcoming general overheating issues. In this work, we obtain accurate Stillinger-Weber type empirical potential parameter sets for single-layer WS2 and WSe2 crystals by utilizing particle swarm optimization, a stochastic search algorithm. For both systems, our results are quite consistent with first-principles calculations in terms of bond distances, lattice parameters, elastic constants and vibrational properties. Using the generated potentials, we investigate the effect of temperature on phonon energies and phonon linewidth by employing spectral energy density analysis. We compare the calculated frequency shift with respect to temperature with corresponding experimental data, clearly demonstrating the accuracy of the generated inter-atomic potentials in this study. Also, we evaluate the lattice thermal conductivities of these materials by means of classical molecular dynamics simulations. The predicted thermal properties are in very good agreement with the ones calculated from first-principles.
We present a density functional theory investigation of the adsorption properties of NO and NO2 as well as SO2 and SO3 on BaO and Pt overlayers on anatase TiO2(001) surface. Monolayers, bilayers, and ...trilayers of BaO grow without strain-induced large scale reconstructions. While the bilayer and trilayer preserve, to a large extent, the NO2 adsorption characteristics of the clean BaO(100) surface, the effect of the support is evident in SO2 and SO3 adsorption energies, which are somewhat reduced with respect to the clean BaO(100) surface. When a Pt(100) layer is added on the TiO2 surface, four stable adsorption geometries are identified in the case of NO while NO2 is found to adsorb in only two configurations.
Density functional theory (DFT) calculations were performed to investigate stabilities and properties for uracil (U)-functionalized carbon nanotubes (CNTs). To this aim, the optimized molecular ...properties were evaluated for (
n
, 0) models of CNTs (
n
= 3–16) in the original and U-functionalized forms. The results indicated that the dipole moments and energy gaps were independent of tubular diameters whereas the binding energies showed that the U-functionalization could be better achieved for
n
= 8–11 curvatures of (
n
, 0) CNTs. Further studies based on the evaluated atomic-scale properties, including quadrupole coupling constants (
C
Q
), indicated that the electronic properties of atoms could detect the effects of diameters variations of (
n
, 0) CNTs, in which the effects were very much significant for the atoms around the U-functionalization regions. Finally, the achieved results of singular U, original CNTs, and CNT-U hybrids were compared to each other to demonstrate the stabilities and properties for the U-functionalized (
n
, 0) CNTs.
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