Values Of Cohesive Energy Research Articles

Electronic, optical, and thermoelectric efficiency of novel Li-based ternary chalcogenides: First-principles study

The distinguishing features of Li-based ternary chalcogenides are their high thermal stability and adjustable optical characteristics. The presentcomputational investigations focused on the complex interactions between the optical, thermal, and electronic properties of novel LiSmX2 (X = S, Se) ternary chalcogenides. The calculated formation energy and cohesive energy values confirm the stability of these materials. The phonon dispersion results confirm their thermodynamic stability. The predicted spin-polarized band structure calculation signifies an indirect energy gap in both materials. The negative trend in the ε1(ω), indicates that the response of these materials is more analogous to a metal within the given energy range. The intense peaks in the reflectivity spectra suggest that these materials can be employed as filter against UV radiations. Electronic band structures of LiSmS2 and LiSmSe2 may further improve the noticed linear rise in the thermal conductivity that helps electrons transmit heat more efficiently. Our present study may open the door to deeper investigations into these semiconductors’ optoelectronic and thermoelectric characteristics andpotential use in optoelectronic and thermoelectric devices.

Thionation‐Induced Enhancement of Optical and Electronic Properties in NDI Molecule for Molecular Electronic Applications: A Computational Study Using DFT/TD‐DFT and QTAIM Theory

AbstractThe study investigates the impact of thionation on N,N'‐di(dodecyl)‐4,5,8,9‐naphthalene diimide (NDI) through computational methods such as density functional theory (DFT/TD‐DFT), quantum theory of atoms in molecules (QTAIM), and Landauer theory (LT). Thionation, involving the replacement of diamide oxygens with sulfurs in NDI, significantly enhances quantum‐electronic/thermoelectric properties. Computational analyzes of energy of frontier orbitals HOMO/LUMO, dipole moment, polarizability, first superpolarizability, UV spectrum, and cohesive energy show the superior performance of the thione structure (M2) compared to the pristine structure (M1). Thionation decreased the energy gap from 01.3 eV (in M1 structure) to 1.87 eV (in M2 structure). The absorption wavelength in the pristine structure (M1) is calculated to be 507 nm, which increased to 1067 nm after thionation (M2). Cohesive energy values for each of M1 and M2 structures are calculated as 12.76 and 12.89 Kcal mol−1, respectively, which indicates the improvement of stability after thionation. After connecting M1 and M2 to gold electrodes (Au‐M1‐Au and Au‐M2‐Au) and applying electric fields, the Au‐M2‐Au structure shows a lower energy gap, lower thermoelectric activity and higher conductivity at field intensities with higher than 140 × 10−4 (a.u.), indicating its use as a field‐effect molecular device (such as molecular wire or molecular switch).

Strain-dependent electronic, mechanical and piezoelectric properties of ZrSiO3 2D monolayer: A first principle approach

This study investigated the mechanical stability, elastic anisotropy, electronic and piezoelectric properties of ZrSiO₃ 2D monolayer subjected to varying degrees of strain. The monolayer films were characterized under strains ranging from −6% to +6 %, and different material properties were analyzed to understand their response to mechanical deformation using density functional theory with the Quantum Espresso code. The calculated values of cohesive and strain energy revealed that the material exhibited a symmetrical response to tension and compression within a strain value range of −2% to +2 %. Electronic properties showed strain-induced modifications: the band gap of the material decreases under tensile strain and increases under compressive strain. The material remained mechanically stable and ductile under the applied strain range of −6% to +6 %. Present investigations conveyed the modifications produced by strain on elastic anisotropy and piezoelectric characteristics of the material, finding their applications in strain-sensitive sensors, actuators, and energy-harvesting devices.

Investigating Structural, Mechanical, Electronic and Magnetic Properties of Spin-Gapless Quaternary Heusler Alloy Crmnval

Utilizing density functional theory (DFT), the study thoroughly investigates the equiatomic quaternary Heusler compound CrMnVAl, revealing its promising properties across multiple domains. The energy minimization curve shows its structural stability with lattice parameter 5.91Å in ferromagnetic phase. The negative values of formation and cohesive energy indicate its chemical stability, while electronic structure analysis demonstrates spin gapless semiconducting behavior. The total spin magnetic moment of this compound is almost 3.00 μB obeying the Slater-Pauling 18 electron rule (Mt = Zt – 18). The 100% spin polarisation and the Curie temperature higher than ambient temperature indicate that this compound acts as a promising material for spin dependent applications. Furthermore, exploring its mechanical properties complements these findings, offering insights into its structural integrity and suitability for diverse applications. Overall, the study underscores CrMnVAl's potential as a versatile material for spintronics and beyond.

Pressure effect on the structural, electronic, elastic, thermodynamic and optical properties of LiZnZ (Z = N, P, and As) Li-based half-Heusler

ABSTRACT Using first-principle calculations based on the density functional theory, we investigated the pressure effect on the structural, electrical, elastic, thermodynamic,electronic and optical properties of Li-based half-Heusler compounds LiZnZ (Z = N, P, and As). We found that the most stable structural phase is the α-phase at 0 GPa for all studied compounds. The obtained lattice parameters at 0 GPa align with existing experimental and theoretical findings for all compounds. The negative values of cohesive and formation energies of LiZnZ indicate that the studied compounds are chemically stable. Band structure calculations confirm the semiconductor behavior of all studied compounds. The calculated elastic and thermodynamic properties show that these compounds are mechanically and thermodynamically stable. The reflectivity values, which are approximately 39%, 54%, and 57% for LiZnN, LiZnP, and LiZnAs, respectively, suggest that the semiconductors LiZnZ are well-suited for optoelectronic applications.

Probing the electronic structure, optical, and transport nature of lanthanide-based ternary materials: A First-principles perspective

High thermal stability and adjustable optoelectronic properties are the unique characteristics of lanthanide-based materials. The complex interplay between unique electronic, optical, and thermoelectric characteristics of lanthanide-based ternary chalcogenides is investigated by first principles modeling. The cohesive energy values were anticipated to be −4.54 eV/atom for PrSF and −4.87 eV/atom for PrSBr suggesting PrSBr to have the greatest bonding properties and is the most stable material. The computed formation energies range from −1.3 to −3.0 (eV/f. u), demonstrating their stability. The inclusion of bromine, a more electronegative element than fluorine, produces unique hybridization patterns and spin polarization effects. Compared to PrSBr, PrSF bonding employs more effective orbital hybridization, resulting in a greater band gap. PrSF has a higher frequency dielectric constant compared to PrSBr. The absorption edges in the ε2(ω) result from optical transitions between the Pr-f, S-p, F-p, and Br-p states. As the temperature rises, the Seeback coefficients for PrSF and PrSBr decrease exponentially. The thermal conductivity spectra of PrSF and PrSBr materials exhibit a linear increase across the temperature range. As temperature rises, the concentration of carriers and mobility increases, resulting in increased electrical conductivity values.

A DFT study on boron carbon nitride and in-plane graphene-boron nitride nanosheets for O3 and F2 gas sensing

In the industry era, nanostructures-based gas sensors have been more striking for environmental monitoring. In this research, we investigated the properties and the adsorption ability of boron carbon nitride (BCN) and in-plane graphene-boron nitride (G_BN) nanosheets for toxic (F2 and O3) gas molecules. The geometrical, electronic, and optical properties of the selected structures are analyzed using the density functional theory. The negative value of cohesive energy signifies that both BCN and G_BN are energetically stable. Both structures show strong attractive energy for the selected gas molecules with recovery times of 0.266 ps−5.482 ns. A significant change decrease in the band gap of the adsorbents occurred after gas adsorption. All the adsorbents show a high absorption coefficient of over 104 cm−1 in the visible wavelength range. A slight variation in the optical properties is observed after gas adsorption. Both the adsorbents demonstrate significant sensitivity toward F2 and O3 gases.

First principle calculations to explore the electronic, mechanical and optical properties of 2D NiX2 (X = O, S, Se) monolayers

This investigation employs ab-initio calculations to investigate the structural, dynamical, mechanical, and optoelectronic attributes of 1T-NiX2 (X = O, S, Se) monolayers. The confirmation of structural and dynamical stability is derived from negative cohesive energy values and the absence of negative frequencies in phonon dispersion spectra. Mechanical stability is established through the application of the Born-Huang stability criterion. Results indicate that an increase in the X-atom size from O to Se induces a reduction in material stiffness from 137.64 Nm−1 to 77.56 Nm−1 and thus, enhances the flexibility of the monolayers. The NiX2 monolayers exhibit indirect bandgap features with values 1.33 eV (1.81 eV), 0.63 eV (0.61 eV) and 0.28 eV (0.28 eV) using PBE (PBE+U) methods. Present results show an inverse relations between the band gap and the size of the X atom. The scanning tunnelling microscope (STM) images of 2D NiX2 monolayers are also simulated for experimental observations. Additionally, exploration of optical characteristics reveals high optical absorption (105 cm−1), which lies from infrared to UV-region. Moreover, NiO2 can be utilized as good wave anti-reflectors with reflection of incident light less than 7%. These results suggest NiX2 materials as promising candidates for diverse applications in optoelectronic and photovoltaic devices.

Hydrogen storage properties of Ti-doped C20 nanocage and its derivatives: A comprehensive density functional theory investigation

We have innovatively designed and assessed the hydrogen storage properties of a single Ti-doped C20 nanocage and its B, N or B and N heteroatom substituted derivatives with the help of the density functional theory approach for the first time to the best of our knowledge. Out of fifteen designed structures by substituting heteroatoms, only 8 structures are found to be suitable for Ti doping and H2 adsorption viz. C20, C12N8, C12B8, C12B4N4, C10B5N5, C10B10, B10C10 and B10N10. Their formation energy and cohesive energy values confirm the stability of all the structures. Ti atom binds more strongly with B, N or B and N heteroatom substituted C20 nanocage than unsubstituted C20 nanocage which is necessary to avoid clustering for multiple Ti doped nanocages. Among the eight Ti doped nanocages considered, H2 molecules strongly interact with Ti-doped C12B4N4 nanocage. The binding strength of Ti atom with nanocages decreases during the hydrogen adsorption process. The obtained H2 adsorption energy values for all the structures are within the range of 0.2–0.7 eV, which is conducive to reversible hydrogen storage. Calculated Gibbs free energy-corrected H2 adsorption energy values at different temperature and pressure indicate favorable H2 adsorption over the entire pressure range at room temperature. For Ti doped C20, C12N8, C12B8, C10B5N5, C10B10, B10N10, and B10C10 nanocages, H2 adsorption is thermodynamically favorable below 360, 350, 300, 285, 235, 277, and 251 K, respectively at 1 atm pressure. From PDOS analysis, it is observed that the 1s orbital of H overlaps with 3d orbital of Ti atom. The highest H2 desorption temperature is observed for the C12B4N4Ti nanocage, and the lowest for C10B10Ti, aligning well with the calculated adsorption energy values. As H2 desorption temperature is high, the stability of Ti-doped nanocages at high temperature (634 K) is confirmed using ab initio molecular dynamics simulations. Bader's quantum theory in atoms in molecules is used to prove the weak non-covalent interaction between all the atoms.

Tailoring of physical, optical, and thermal properties of Se50-xTe30Ge20Sbx chalcogenide glasses: Influence of metalloids

The compositional dependence on physical and spectroscopic characteristics of chalcogenide Se50-xTe30Ge20Sbx (x = 5, 10, 15, and 20 at. wt%) bulk glassy systems has been explored in this communication. Numerous physical and optical features are rigorously examined by using the best glass sample among all the prepared samples. The XRD pattern reveals the amorphous character of the synthesized materials. Some of the physical parameters like density, and compactness are gradually increasing with the Sb addition, while the free volume percentage and excess volume follow the decreasing trend. The optical properties have been precisely inspected by UV-Vis spectroscopy in the (200–800) nm spectral range. The optical bandgap (Eopt) values are found to decline from (1.09–0.85) eV with Sb content. The observed refractive index, n values experience a subsequent decline with incident energy. By using the Wemple and DiDomenico (WDD) single oscillator model, the refractive index dispersion curve has been studied, and the dispersion parameters are discussed. The valence band (VB) and conduction band (CB) locations are estimated, and the obtained result reveals the VB potential increases from −15,089 eV to −1.3899 eV, while that of CB decreases from −0.4113 eV to −0.5303 eV with the rise of Sb-concentration. The cohesive energy (CE) values have been estimated by using the chemical bond approach (CBA). Investigation reveals the CE of the system decreases from 45.237 kcal/mole to 44.229 kcal/mole justifying the decrement in obtained band gap energy values of the studied glassy systems. Furthermore, the compositional dependency of various thermal parameters is investigated by using the DSC approach. The glass transition (Tg), and peak crystallization (Tp) were significantly affected by Sb addition. The obtained values of Tg are found to decrease from (337–305 K), while the thermal stability is found to increase with the Sb incorporation.

Analysis of the structural, electronic, optical and mechanical properties of CsGeI2Br under tensile and compressive strain for optoelectronic applications: A DFT computational perspective

In this work, the impact of triaxial strain on the structural, optoelectronic and mechanical properties of CsGeI₂Br is thoroughly investigated, with a particular emphasis on its applicability in optical technologies spanning the visible and ultraviolet spectra. This research fills a notable gap in the literature, highlighting the intriguing properties of this material under external strain. First, the unstrained CsGeI₂Br is identified as a direct band gap semiconductor, revealing an energy gap of 0.714 eV. Moreover, the obtained results show a remarkable sensitivity of CsGeI₂Br's band gap to triaxial strain. Under a triaxial deformation ranging from −6% to 6 %, the energy of the bandgap undergoes a remarkable transformation, varying from 1.81 eV under tensile stress to 0.101 eV under compressive strain; The material approaches the metallic state under compressive strain and exhibits increased bandgap energy under tensile stress. Furthermore, the investigation delves into the optical coefficients in both x = y, z directions, revealing that triaxial strain can significantly enhance absorbance, particularly within the visible and ultraviolet energy spectra. Additionally, triaxial strain introduces significant anisotropy and influences the optical band gap. This results in increased absorption capacity and optical conductivity under tensile stress, making it more effective and better suited for various optical applications, including surgical tools, integrated circuits, QLED, OLED, solar cells, waveguides, and materials for solar heat reduction. The mechanical stability of CsGeI₂Br across the entire range of applied strain is validated by the elastic constants, which impeccably adhere to stability criteria. The negative cohesive energy values determined for unconstrained and constrained CsGeI₂Br signify their thermodynamic stability, establishing their experimental feasibility. Compression strain significantly influences the mechanical properties, enhancing the ductility of this compound.

Structural, optoelectronic and thermodynamical insights into 2H-ZrO2: A DFT investigation

The monolayer transition metal dichalcogenides have appeared to be an intriguing area of ongoing research in two-dimensional materials. In this study, we have investigated the structural, lattice dynamic, optoelectronic and thermodynamic properties of 2H-ZrO2 monolayer using first-principle calculations. The negative value of cohesive energy (-0.42 eV) manifests that 2H-ZrO2 is structurally stable and can be fabricated experimentally. The optimized lattice constant is found to be 3.15 Å. Lattice dynamic stability is assessed by the phonon dispersion curves and phonon density of states, which indicating that 2H-ZrO2 monolayer is dynamic stable. In order to analyze the thermal stability of 2H-ZrO2, we have computed thermodynamic properties within the range of 0–1000 K. The negative values of free energy indicate the thermal stability of the monolayer. Various electronic parameters such as density of states, partial density of states and electronic band structure have been obtained. It is found that 2H-ZrO2 is a p-type semiconductor, which possesses an indirect bandgap of 1.58 eV between valence and conduction bands. A number of in-plane and out-of-plane optical spectra have been discussed in detail. This study suggested that monolayer 2H-ZrO2 is a suitable candidate for energy related applications and may aid in the creation of effective optoelectronic devices.

Exploring novel Zr2GeX (X = C, N, F) MAX phases by first-principles approach

In recent years, there has been a surge of interest in the thermodynamically stable nanolaminate ternary carbides/nitrides known as MAX phases. In this first-principles research work, we focus on the MAX phases with a particular emphasis on Zr2GeX (X = C, N, F) compounds. These novel Zr2GeX compounds exhibited considerable values of cohesive energy, demonstrating stability comparable to well-established MAX compounds. Our calculations for the structural parameters of Zr2GeX agree well with the literature, indicating the reliability of our results. The absorption coefficients for ultraviolet (UV) light are approximately 105/cm and 106/cm, respectively, highlighting their significance for energy harvesting devices. Additionally, these metallic compounds demonstrate impressive reflectivity, reflecting over 50% of infrared and visible light. Similarly, they exhibit the highest refraction for infrared light, with a significant decrease in refraction for visible and UV light. Consequently, the transparency of Zr2GeX compounds diminishes, rendering them opaque against UV light and highly likely to absorb most incident UV radiation. Results presented in this paper highlight the potential applications of Zr2GeX MAX phases for optoelectronic devices due to their exceptional electronic and optical properties.

Mechanical and thermodynamic behaviors of the second phases in Al–Zn–Mg–Cu alloys

The mechanical and thermodynamic behaviors of intermetallics in Al–Zn–Mg–Cu alloys are studied by first-principles calculations. All studied second phases have negative values of formation enthalpy and cohesive energy indicating their excellent thermodynamic stability. Al3Er_D0[Formula: see text] has the most significant metallic nature, while Mg2Si shows the least metallicity. TiAl3 shows the highest bulk, shear, and Young’s moduli. All Al3M polymorphs, Mg2Si and TiAl3 phases show covalent/metallic hybrid bonding. The mechanical anisotropic behaviors obey the trend of: MgZn[Formula: see text]Er_D0[Formula: see text]Sc_D0[Formula: see text]Sc_D0[Formula: see text]Er_D0[Formula: see text]Er_L1[Formula: see text]Sc_L1[Formula: see text]Si, where MgZn2 is the most mechanically anisotropic phase. The calculated room-temperature linear thermal expansion coefficient values for the studied phases are from [Formula: see text] K[Formula: see text] to [Formula: see text] K[Formula: see text]; where Al3Er_L12 has the highest value ([Formula: see text] K[Formula: see text], followed by Al3Sc_L12 ([Formula: see text] K[Formula: see text]; both of which are close to that of the Al matrix, thus making the relatively lower thermal misfit.

Compositional effects of Ga incorporation on electrical and dielectric parameters in Ge-Se-Sb-Ga thin films

In this paper, the existence of new selenium-rich chalcogenide glassy systems i.e. (Ge20Se80)90-xSb10Gax (x = 2, 4, 6 and 10 at %) had been reported. (Ge20Se80)90-xSb10Gax glassy systems were prepared using melt-quenching technique. Thin films of (Ge20Se80)90-xSb10Gax were prepared on properly cleaned glass substrates using vacuum evaporation technique. Planar geometry of indium (In) electrodes (electrode spacing 0.08 cm) was used for electrical measurements. The physical parameters – average number of constraints, cohesive energy, mean bond energy, average coordination number, heat of atomization, glass transitition temperature and lone pair electrons had been estimated. The high values for the lone pair electrons proves the investigated system to be a good glass former. The increasing values of cohesive energy, glass transition temperature and mean bond energy with the incorporation of Ga, reveal that Ge-Se-Sb-Ga glassy systems are thermally stable glasses. The current transport mechanisms had been studied within the temperature range 173–363 K. Thermionic emission dominated in the high temperature region above 333 K. Within the intermediate temperature range 273–333 K, thermally-assisted tunneling of the charge carriers through grain boundary potential as well as thermionic emission over grain boundary potential contributed to the conduction mechanism. Below 273 K, Mott’s hopping process dominated the conduction mechanism. Dielectric measurements had been examined within the temperature range 173–363 K and the frequency range 50 Hz–1 MHz. Dielectric constant as well as dielectric loss decreased as the frequency was increased and increased as the temperature was increased. Orientation polarization described the temperature-dependence and frequency-dependence of dielectric constant. Temperature-dependence and frequency-dependence of dielectric loss was explained by conduction loss as well as hopping of charger carriers. The ac conductivity agrees with the power law: ωs where s < 1. The present investigation of dielectric parameters could be explained in terms of correlated barrier hopping (CBH) model. Profound analysis of the physical, electrical and dielectric properties and their variation as a function of Ga-content suggest the utilization of these glasses in optoelectronic devices.

Structural, electronic, and transport properties of Janus XMoSiP2 ( S, Se, Te) monolayers: a first-principles study

Based on density functional theory calculation, herein we propose XMoSiP2 ( S, Se, Te) monolayers for new two-dimensional (2D) Janus materials. Their crystal structures with dynamical, mechanical, and thermal stabilities, electronic and transport properties are systematically investigated. The results reveal that all three XMoSiP2 monolayers exhibit isotropic elastic properties with high Young’s modulus and negative cohesive energy values, as well as the elastic constants follow the Born-Huang’s criteria, demonstrating their mechanical stability and suggesting the high ability for the experimental synthesis of these materials. From the Perdew–Burke–Ernzerhof functional, the SMoSiP2 is observed as a semiconductor with an indirect bandgap of 1.01 eV, while the SeMoSiP2 and TeMoSiP2 monolayers are observed as direct semiconductors with the bandgap energy of 1.09 and 1.12 eV, respectively. Notably, the bandgap energy of the materials is changed significantly by applying the biaxial strain, and the transition between direct and indirect semiconductors is observed. For the transport ability of the materials, the carrier mobilities are found to be anisotropic for both electron and hole in our studied materials. These findings further highlight the extraordinary properties of the 2D Janus XMoSiP2 materials and their promise for application in electronic devices.

Nonlinear optical response and characteristic Raman spectra of phagraphene quantum dots

In the field of optoelectronics, quantum dots (QDs) have gained interest due to the easy modification of electronic properties. Subsequently, the importance of nonlinear optical (NLO) properties is increasing day by day. In this work, we have systematically analyzed the NLO properties of phagraphene QDs with different shapes and sizes, employing density functional theory (DFT). A negative value of cohesive energy and the absence of imaginary modes in the Raman spectra confirm the energetical stability of the QDs. Successful experimental realization of phagraphene nanoribbon has triggered the possibility of experimental feasibility of the QDs. Additionally, most of the QDs showcase high absorption in the UV region. Particularly, the variation of electronic bandgap and the number of delocalized π electrons in the structure control the NLO responses of materials. Both the electronic bandgap and the number of π electrons in the system can be tuned easily by varying the shapes and sizes of the phagraphene QDs. Both static and dynamical variations of polarizability 〈α〉, first-order 〈β〉, and second-order hyperpolarizability 〈γ〉 are calculated here. Maximum value of 〈α〉, 〈β〉 and 〈γ〉 are observed for different QDs. The variation of NLO responses with perturbing electric fields leads to the feasibility of applications in optoelectronics.

Novel Ultrahard Extended Hexagonal C10, C14 and C18 Allotropes with Mixed sp2/sp3 Hybridizations: Crystal Chemistry and Ab Initio Investigations

Based on 4H, 6H and 8H diamond polytypes, novel extended lattice allotropes C10, C14 and C18 characterized by mixed sp3/sp2 carbon hybridizations were devised based on crystal chemistry rationale and first-principles calculations of the ground state structures and energy derived properties: mechanical, dynamic (phonons), and electronic band structure. The novel allotropes were found increasingly cohesive along the series, with cohesive energy values approaching those of diamond polytypes. Regarding mechanical properties, C10, C14, and C18 were found ultrahard with Vickers hardness slightly below that of diamond. All of them are dynamically stable, with positive phonon frequencies reaching maxima higher than in diamond due to the stretching modes of C=C=C linear units. The electronic band structures expectedly reveal the insulating character of all three diamond polytypes and the conductive character of the hybrid allotropes. From the analysis of the bands crossing the Fermi level, a nesting Fermi surface was identified, allowing us to predict potential superconductive properties.

Mechanism research reveals the role of Fen (n = 2-5) supported C2N as single-cluster catalysts (SCCs) for the non-oxidative propane dehydrogenation in the optimization of catalytic performance.

Single cluster catalysts show excellent potential for propane dehydrogenation, compensating for the limited catalytic performance of single-atom catalysts in reactions involving multiple reaction steps and intermediates. Herein, density functional theory is used to investigate the catalytic activity and mechanism for non-oxidized propane dehydrogenation on Fen-C2N (n = 2-5). Firstly, the stability of Fen-C2N (n = 2-5) is evaluated by comparing the mean values of binding energy and cohesive energy. The results show that Fen-C2N (n = 2-4) can exist stably, which is also verified by the molecular dynamics calculation at 873 K. Band structure analysis shows that the screened catalysts have metal properties, which are conducive to charge transfer. Fukui function analysis is used to predict the optimal adsorption site. The electronic properties of propane and propylene adsorbed on catalysts are further studied by the partial density of states and deformation charge density. The activation barrier (Ea) and reaction energy (ΔE) of the main reaction steps are evaluated. The results show that Fe2-C2N (Ea = 0.97 eV, ΔE= 0.22 eV) has the best catalytic activity. The Ea for further propylene dehydrogenation is also used to evaluate the yield of propylene. Compared with Fe-C2N, Fe2-C2N can regulate the adsorption strength of propane and propylene, showing better catalytic ability and higher selectivity for propylene. The above research provides ideas for the design of new catalysts with high selectivity and activity for non-oxidative propane dehydrogenation.

First-principles calculations to investigate structural, electronic, optical and mechanical properties of Mg-doped CaMoO3 cubic perovskites for fuel cell applications

The structural, optical, electrical, and mechanical characteristics of pure and Mg-doped CaMoO3 perovskites materials were examined in a first-principle research based on density functional theory. The current study employs the PBE (Perdew Burke-Ernzerhof) exchange co-relational functional of GGA along with the USP (Ultra-soft Pseudo-potential) plan wave and CASTEP (Cambridge Serial Total Energy Package) code (Generalized Gradients Approximation). The impact of Mg on the structural, optical, electrical, and mechanical characteristics of CaMoO3 is examined using a generalized gradient approximation (GGA) and an ultra-soft pseudo-potential. After adding Mg to the Mo site, it is discovered that the band gap of CaMoO3 with Mg doping has significantly decreased. According to the DFT investigation, Mg is an ideal material to lower CaMoO3's band gap. The volume of crystal cells similarly fell from 61.99 to 57.94 A3 with the addition of Mg due to the difference in ionic radii between Mo and Mg. The incorporation of Mg in CaMoO3 results in a highly stable material, which is demonstrated by the as-calculated negative cohesive energy values, according to the as-obtained elastic constants (Cij). The elastic constants, ductility, elastic moduli, and elastic anisotropy of pure and Mg-doped CaMoO3 cubic perovskite materials have also been investigated. These findings demonstrate that Mg doping successfully raises CaMoO3's elastic moduli. The Mg-doped CaMoO3 material transforms from brittle to ductile due to the introduction of Mg at sites of Mo, as computed Pugh's ratio is dropped from 2.499 to 1.995 and Poisson's ratio from 0.323 to 0.285. For both pure and Mg-doped CaMoO3, band topologies, densities of states, and charge density re-locations are also expected.