Correction for 'Topological behaviour of ternary non-symmorphic crystals KZnX (X = P, As, Sb) under pressure and strain: a first principles study' by Atahar Parveen
et al.
,
Phys. Chem. Chem. Phys.
, ...2018,
20
, 5084-5102.
Mo5SiB2 is an ideal candidate for high temperature material. Although the D8l‐Mo5SiB2 has been published, the other phases and the related properties of Mo5SiB2 are still unclear. Here, two possible ...Mo5SiB2 phases (D8m‐Mo5SiB2 and Cmcm‐Mo5SiB2) are predicted by using the first principles method. The structural stability, mechanical properties, melting point and electronic structure of Mo5SiB2 are studied. The results show that the D8m‐Mo5SiB2 and Cmcm‐Mo5SiB2 are thermodynamically and dynamically stables. The calculated bulk elastic modulus, shear modulus and Young's modulus of the Cmcm‐Mo5SiB2 are close to D8l‐Mo5SiB2. In addition, the predicted Cmcm‐Mo5SiB2 has high melting point (2518.5°C) compared to the D8l‐Mo5SiB2 and D8m‐Mo5SiB2. In particular, the predicted D8m‐Mo5SiB2 exhibits better plasticity than the D8l‐Mo5SiB2. The calculated density of states and Mulliken overlap population shows that the D8m‐Mo5SiB2 and Cmcm‐Mo5SiB2 all exhibit metallic behavior. The metallic behavior mainly depends on the electronic interaction between Mo atom and B atom near Fermi level. Furthermore, the bond length of Mo‐B bond in the D8m‐Mo5SiB2 is longer than the other two structures, which may be the reason why the ductility of the former is better than the latter.
This work investigates the structural, mechanical and melting point of three Mo5SiB2 by using the first‐principles calculations. The results show that the two novel Mo5SiB2 (D8m‐Mo5SiB2 and Cmcm‐Mo5SiB2) are predicted. Three Mo5SiB2 exhibit high bulk modulus and strong elastic stiffness. In particular, these ternary silicides also show better ductility and high melting point. The calculated melting of Cmcm Mo5SiB2 is up to 2518.5°C, which is higher than the other Mo5SiB2.
Enabling all‐solid‐state Li‐ion batteries requires solid electrolytes with high Li ionic conductivity and good electrochemical stability. Following recent experimental reports of Li3YCl6 and Li3YBr6 ...as promising new solid electrolytes, we used first principles computation to investigate the Li‐ion diffusion, electrochemical stability, and interface stability of chloride and bromide materials and elucidated the origin of their high ionic conductivities and good electrochemical stabilities. Chloride and bromide chemistries intrinsically exhibit low migration energy barriers, wide electrochemical windows, and are not constrained to previous design principles for sulfide and oxide Li‐ion conductors, allowing for much greater freedom in structure, chemistry, composition, and Li sublattice for developing fast Li‐ion conductors. Our study highlights chloride and bromide chemistries as a promising new research direction for solid electrolytes with high ionic conductivity and good stability.
Halide solid electrolytes: Lithium chloride and bromide materials exhibit low energy barriers for Li‐ion migration, wide electrochemical window, and good interface compatibility in all‐solid‐state Li‐ion battery, as illustrated by first principles computation study. These new classes of chemistries are suggested as promising new research direction of lithium solid electrolytes with both high ionic conductivity and good electrochemical stability for all‐solid‐state Li‐ion batteries.
Ferroelectricity of CH3NH3PbI3 Perovskite Fan, Zhen; Xiao, Juanxiu; Sun, Kuan ...
The journal of physical chemistry letters,
04/2015, Volume:
6, Issue:
7
Journal Article
Peer reviewed
Ferroelectricity has been believed to be an important but controversial origin of the excellent photovoltaic performance of organometal trihalide perovskites (OTPs). Here we investigate the ...ferroelectricity of a prototype OTP, CH3NH3PbI3 (MAPbI3), both theoretically and experimentally. Our first-principles calculations based on 3-D periodic boundary conditions reveal that a ferroelectric structure with polarization of ∼8 μC/cm2 is the globally stable one among all possible tetragonal structures; however, experimentally no room-temperature ferroelectricity is observed by using polarization–electric field hysteresis measurements and piezoresponse force microscopy. The discrepancy between our theoretical and experimental results is attributed to the dynamic orientational disorder of MA+ groups and the semiconducting nature of MAPbI3 at room temperature. Therefore, we conclude that MAPbI3 is not ferroelectric at room temperature; however, it is possible to induce and experimentally observe apparent ferroelectric behavior through our proposed ways. Our results clarify the controversy of the ferroelectricity in MAPbI3 and also provide valuable guidance for future studies on this active topic.
Gallium oxide is increasingly used in a variety of applications, but confusion reigns over the Brillouin zone and the band structure of monoclinic β‐Ga2O3. We present a detailed study of the shape of ...the Brillouin zone and the location of high‐symmetry points. Combined with a study of electronic structure based on hybrid density functional theory, this allows us to derive an accurate band structure. We discuss the nature of the band gap and the location of the band extrema.
Selective nitrate‐to‐ammonia electrochemical conversion is an efficient pathway to solve the pollution of nitrate and an attractive strategy for low‐temperature ammonia synthesis. However, current ...studies for nitrate electroreduction (NO3RR) mainly focus on metal‐based catalysts, which remains challenging because of the poor understanding of the catalytic mechanism. Herein, taking single transition metal atom supported on graphitic carbon nitrides (g‐CN) as an example, the NO3RR feasibility of single‐atom catalysts (SACs) is first demonstrated by using density functional theory calculations. The results reveal that highly efficient NO3RR toward NH3 can be achieved on Ti/g‐CN and Zr/g‐CN with low limiting potentials of −0.39 and −0.41 V, respectively. Furthermore, the considerable energy barriers are observed during the formation of byproducts NO2, NO, N2O, and N2 on Ti/g‐CN and Zr/g‐CN, guaranteeing their high selectivity. This work provides a new route for the application of SACs and paves the way to the development of NO3RR.
Selective nitrate‐to‐ammonia electrochemical conversion is an advantageous strategy to solve the plight of both energy and environment. Taking single transition metal supported on graphitic carbon nitrides as an example, it is first demonstrated that the process of nitrate electroreduction can be efficiently achieved with low limiting potential on single‐atom catalysts by first‐principles calculations.
An intricate sea-urchin-like hexagonal WO3 nanostructure was synthesized by a facile hydrothermal approach. Sensing properties of the as-fabricated sensor exhibited surpassing response and ...selectivity for NO2 in comparison of H2 after corroborating the composition, phase-purity and surface morphology using X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Formation of the urchin-like structure was ascribed to the capping effects of potassium sulfate that prompts the anisotropic growth of WO3, leading to hierarchical complex with a large surface-volume ratio. In particular, first-principle calculation had provided a new perspective for us to delve into the sensing process of H2 and NO2 from an atomic level. It was found that the sensing properties mainly arose from the tuning of electronic structure and electrons transfer between the adsorbed gas and the sensitized surface along with the charge relocation between them. Finally, a plausible mechanism was proposed as theoretical guidance for achieving high-performance sensors experimentally and supposedly.
The formation possibility of (Hf0.2Zr0.2Ta0.2Nb0.2Ti0.2)C high‐entropy ceramic (HHC‐1) was first analyzed by the first‐principles calculations, and then, it was successfully fabricated by ...hot‐pressing sintering technique at 2073 K under a pressure of 30 MPa. The first‐principles calculation results showed that the mixing enthalpy and mixing entropy of HHC‐1 were −0.869 ± 0.290 kJ/mol and 0.805R, respectively. The experimental results showed that the as‐prepared HHC‐1 not only had an interesting single rock‐salt crystal structure of metal carbides but also possessed high compositional uniformity from nanoscale to microscale. By taking advantage of these unique features, it exhibited extremely high nanohardness of 40.6 ± 0.6 GPa and elastic modulus in the range from 514 ± 10 to 522 ± 10 GPa and relatively high electrical resistivity of 91 ± 1.3 μΩ·cm, which could be due to the presence of solid solution effects.
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