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In this paper, a detailed mechanism is discussed for two processes: deNOx and deN2O. An FAU catalyst was used for the reaction with Cu-Fe bimetallic adsorbates represented by a dimer with bridged oxygen. Partial hydration of the metal centres in the dimer was considered. Ab initio calculations based on the density functional theory were used. The electron parameters of the structures obtained were also analysed. Visualisation of the orbitals of selected structures and their interpretations are presented. The presented research allowed a closer look at the mechanisms of processes that are very common in the automotive and chemical industries. Based on theoretical modelling, it was possible to propose the most efficient catalyst that could find potential application in industry–this is the FAU catalyst with a Cu-O-Fe bimetallic dimer with a hydrated copper centre. The essential result of our research is the improvement in the energetics of the reaction mechanism by the presence of an OH group, which will influence the way NO and NH3 molecules react with each other in the deNOx process depending on the industrial conditions of the process. Our theoretical results suggest also how to proceed with the dosage of NO and N2O during the industrial process to increase the desired reaction effect. [ABSTRACT FROM AUTHOR]

The vast compositional and configurational spaces of multi-element metal halide perovskites (MHPs) result in significant challenges when designing MHPs with promising stability and optoelectronic properties. In this paper, we propose a framework for the design of B-site-alloyed ABX3 MHPs by combining density functional theory (DFT) and machine learning (ML). We performed generalized gradient approximation with Perdew–Burke–Ernzerhof functional for solids (PBEsol) on 3,159 B-site-alloyed perovskite structures using a compositional step of 1/4. Crystal graph convolution neural networks (CGCNNs) were trained on the 3159 DFT datasets to predict the decomposition energy, bandgap, and types of bandgaps. The trained CGCNN models were used to explore the compositional and configurational spaces of 41,400 B-site-alloyed ABX3 MHPs with a compositional step of 1/16, by accessing all possible configurations for each composition. The electronic band structures of the selected compounds were calculated using the hybrid functional (PBE0). Then, we calculated the optical absorption spectra and spectroscopic limited maximum efficiency of the selected compounds. Based on the DFT/ML-combined screening, 10 promising compounds with optimal bandgaps were selected, and from among these 10 compounds, CsGe0.3125Sn0.6875I3 and CsGe0.0625Pb0.3125Sn0.625Br3 were suggested as photon absorbers for single-junction and tandem solar cells, respectively. The design framework presented herein is a good starting point for the design of mixed MHPs for optoelectronic applications. [ABSTRACT FROM AUTHOR]

Context: In this paper, the optimum coverage of 4.44% and the optimum adsorption sites were determined for the Be3N2 adsorption system of O atoms at different coverages based on density functional theory. The electronic and optical properties of the model were investigated by applying bending deformation to the model at these coverage and adsorption sites. Adsorption of O atoms disrupts the geometrical symmetry of Be3N2, resulting in orbital rehybridization and lowering its band gap. Bending deformation causes the band gap of the adsorbed O atom structure of Be3N2 to first increase and then decrease, resulting in the modulation of its band gap. With increasing bending deformation, the adsorbed system is redshifts, and the degree of redshift increases with increasing bending deformation. Methods: All calculations in this paper were performed using the first-principles-based CASTEP module of Materials Studio (MS). The generalized gradient approximation (GGA) plane-wave pseudopotential method and the Perdew-Burke-Ernzerhof (PBE) Perdew et al. Phys Rev Lett 77:3865, 1996 generalized functional were used in the geometry optimization and calculation process to calculate the exchange–correlation potential between electrons. The effect of coverage on the electronic and optical properties of the Be3N2-adsorbed O atom system was investigated by adsorbing different numbers of O atoms on a monolayer of Be3N2. The Be3N2 protocell contains two N atoms and three Be atoms with a space community of P6/MMM (No.191). The original cell was expanded 3 times along the direction of the base vectors a and b in the Be3N2 plane to create a 3 × 3 × 1 monolayer Be3N2 supercell system. A vacuum layer of 15 Å is set in the direction of the crystal plane of the vertical monolayer Be3N2 supercell to eliminate interactions between adjacent layers. In the overall energy convergence test of the Be3N2 supercell, the plane wave truncation energy was set to 500 eV, and the energy difference between the calculations given in the literature Reyes-Serrato et al. J Phys Chem Solids 59:743-6, 1998 using 550 eV was less than 0.01 eV, verifying the reliability of the data at a truncation energy of 500 eV. The Monkhorst–Pack special k-point sampling method Monkhorst et al. Phys Rev B 13:5188, 1976 was used in the structural calculations, and the grid was set to 3 × 3 × 1. The geometric optimization parameters are set as follows: the self-consistent field iteration convergence criterion is 2.0 × 10−6 eV, and the iterative accuracy convergence value is not less than 1.0 × 10−5 eV/atom for the total force of each atom and less than 0.03 eV/Å for all atomic forces. In addition the high-symmetry k-point path is taken as Γ(0,0,0) → M(0,0.5,0) → K(− 1/3,2/3,0) → Γ(0,0,0) Chen et al, AIP Adv 8:105105, 2018. [ABSTRACT FROM AUTHOR]

Copyright of Journal of South China Agricultural University is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

CuS is an encouraging photoelectrode candidate that meets the essential requirements for efficient solar‐to‐hydrogen production, but it has not been thoroughly studied. A CuS light absorber layer is grown by the self‐assembly of copper and sulfur precursors on a carbon paper (CP) electrode. Simultaneously, rGO is introduced as a buffer layer to control the optical and electrical properties of the absorber. The well‐ordered microstructural arrangement suppresses the recombination loss of electrons and holes owing to enhanced charge‐carrier generation, separation, and transport. The potential reaching 10 mA cm−2 in 1.0 m KOH solution is significantly lowered to 0.87 V, and the photocurrent density at 1.23 V is 94.7 mA cm−2. The computational result reveals that the potential‐determining step is sensitive to O* stability; the lower stability of O* in the thin layer of CuS/rGO decreases the free‐energy gap between the initial and final states of the potential‐determining step, resulting in a lowering of the onset potential. The faradaic efficiency for the photoelectrochemical oxygen evolution reaction in the optimized 2CuS/1rGO/CP photoanode is 98.60%, and the applied bias photon‐to‐current and the solar‐to‐hydrogen efficiencies are 11.2% and 15.7%, respectively, and its ultra‐high performance is maintained for 250 h. These record‐breaking achievement indices may be a trigger for establishing a green hydrogen economy. [ABSTRACT FROM AUTHOR]

Context: In this paper, the optimum coverage of 4.44% and the optimum adsorption sites were determined for the Be3N2 adsorption system of O atoms at different coverages based on density functional theory. The electronic and optical properties of the model were investigated by applying bending deformation to the model at these coverage and adsorption sites. Adsorption of O atoms disrupts the geometrical symmetry of Be3N2, resulting in orbital rehybridization and lowering its band gap. Bending deformation causes the band gap of the adsorbed O atom structure of Be3N2 to first increase and then decrease, resulting in the modulation of its band gap. With increasing bending deformation, the adsorbed system is redshifts, and the degree of redshift increases with increasing bending deformation. Methods: All calculations in this paper were performed using the first-principles-based CASTEP module of Materials Studio (MS). The generalized gradient approximation (GGA) plane-wave pseudopotential method and the Perdew-Burke-Ernzerhof (PBE) Perdew et al. Phys Rev Lett 77:3865, 1996 generalized functional were used in the geometry optimization and calculation process to calculate the exchange–correlation potential between electrons. The effect of coverage on the electronic and optical properties of the Be3N2-adsorbed O atom system was investigated by adsorbing different numbers of O atoms on a monolayer of Be3N2. The Be3N2 protocell contains two N atoms and three Be atoms with a space community of P6/MMM (No.191). The original cell was expanded 3 times along the direction of the base vectors a and b in the Be3N2 plane to create a 3 × 3 × 1 monolayer Be3N2 supercell system. A vacuum layer of 15 Å is set in the direction of the crystal plane of the vertical monolayer Be3N2 supercell to eliminate interactions between adjacent layers. In the overall energy convergence test of the Be3N2 supercell, the plane wave truncation energy was set to 500 eV, and the energy difference between the calculations given in the literature Reyes-Serrato et al. J Phys Chem Solids 59:743-6, 1998 using 550 eV was less than 0.01 eV, verifying the reliability of the data at a truncation energy of 500 eV. The Monkhorst–Pack special k-point sampling method Monkhorst et al. Phys Rev B 13:5188, 1976 was used in the structural calculations, and the grid was set to 3 × 3 × 1. The geometric optimization parameters are set as follows: the self-consistent field iteration convergence criterion is 2.0 × 10−6 eV, and the iterative accuracy convergence value is not less than 1.0 × 10−5 eV/atom for the total force of each atom and less than 0.03 eV/Å for all atomic forces. In addition the high-symmetry k-point path is taken as Γ(0,0,0) → M(0,0.5,0) → K(− 1/3,2/3,0) → Γ(0,0,0) Chen et al, AIP Adv 8:105105, 2018. [ABSTRACT FROM AUTHOR]

In this paper, a statistical physical derivation of thermodynamically consistent fluid mechanical equations is presented for non-isothermal viscous molecular fluids. The coarse-graining process is based on (i) the adiabatic expansion of the one-particle probability density function around local thermodynamic equilibrium, (ii) the assumption of decoupled particle positions and momenta, and (iii) the variational principle. It is shown that there exists a class of free energy functionals for which the conventional thermodynamic formalism can be naturally adopted for non-equilibrium scenarios, and describes entropy monotonic fluid flow in isolated systems. Furthermore, the analysis of the general continuum equations revealed the possibility of a non-local transport mode of energy in highly compressible dense fluids. [ABSTRACT FROM AUTHOR]

In this paper, the electronic structures of rare earth (Nd, Er)-doped MgO were investigated using density functional theory (DFT), with Hubbard on-site corrections (Ueff) applied to rare earth elements. Li was considered a co-dopant. Defect complexes were involved, instead of a single dopant atom, in the supercell. The splitting and distribution of the 4f ground states of Nd and Er dopants in the band gap changed by co-doping Li. The calculation results provide insights into the influences of Li on the optical properties of rare-earth-doped MgO. [ABSTRACT FROM AUTHOR]

Calix[8]arene has been used as a promising type of macrocyclic ligand for the construction of multinuclear metal-oxo clusters (MOCs), but not for zirconium/hafnium-oxo clusters (Zr/HfOCs). In this paper, we report the first series of ZrOCs (HfOCs) based on calix[8]arene: Zr4, Zr8, Hf4, and Hf8. Zr8/Hf8 has a rhombohedral conformation and can be regarded as a derivative of the octahedral Zr6 cluster. Remarkably, I2 adsorption experiments indicate that Zr4 (Zr8) adsorbs much faster than Hf4 (Hf8). Density functional theory (DFT) calculations show that metallic Zr atoms interact more strongly with I2 than metallic Hf atoms. The successful application of calix[8]arene for the synthesis of well-defined ZrOCs (HfOCs) shows a bright future for MOCs protected by macrocyclic ligands. [ABSTRACT FROM AUTHOR]

The present paper reports a remote carbon‐to‐carbon boryl migration via an intramolecular 1,4‐B/Cu shift, which establishes an in situ stereospecific electrophilic trap on the alkene moiety. The synthetic application is developed to prepare functionalized cyclopentenes by means of a palladium‐catalyzed regioselective intramolecular coupling that completes a strategic cyclopropanation and generates valuable structural bicyclic systems. The mechanism is characterized by DFT (density functional theory) calculations which showed that the 1,4‐migration proceeds through an intramolecular, nucleophilic attack of the copper‐alkyl moiety on the boron atom bonded to the C(sp2), leading to a 5‐membered boracycle structure. The computation of the 1,3‐ and 1,4‐B/Cu shifts is also compared as is the impact of the endo‐ or exocyclic alkene on the reaction kinetics. [ABSTRACT FROM AUTHOR]

Electrolysis of water for production of hydrogen has become one of the most fascinating methods to relieve the energy crisis and environmental pollution. In this paper, a series of M-NiS/Mo 2 S 3 (M = Co, Fe, Ce and Bi) materials was in situ grown on Ni foam through a two-step hydrothermal process, and the synthesized Co–NiS/Mo 2 S 3 material present excellent hydrogen evolution reaction (HER) properties. Under an alkaline condition of 1 M KOH, Co–NiS/Mo 2 S 3 requires only overpotential of 142 mV to achieve a current density of 10 mA cm−2, and using Co–NiS/Mo 2 S 3 as both cathode and anode, only the potential of 1.574 V is required to drive a current density of 50 mA cm−2, with a relatively good durability over 15 h. Density functional theory (DFT) analysis show that the ΔG H* of Co–NiS is closer to 0 and its density of states near the Fermi energy level is higher, suggesting that Co–NiS improves the electrical conductivity of Co–NiS/Mo 2 S 3 and plays a significant catalytic action. This work proposes novel insights for the future exploration of novel sulfur-based composite electrocatalysts with excellent HER performance. In this paper, a series of M-NiS/Mo 2 S 3 (M = Co, Fe, Ce and Bi) materials was in situ grown on Ni foam by a two-step hydrothermal method, and the synthesized Co–NiS/Mo 2 S 3 material present excellent hydrogen evolution reaction (HER) properties. [Display omitted] • M-NiS/Mo 2 S 3 (M = Co, Fe, Ce and Bi) materials were successfully synthesized by hydrothermal processes. • Co–NiS/Mo 2 S 3 electrode shows excellent catalysis in the cathode reaction of water and water electrolysis. • Co–NiS/Mo 2 S 3 requires only overpotential of 142 mV to achieve a current density of 10 mA cm−2. [ABSTRACT FROM AUTHOR]

Two-dimensional transition metal chalcogenides (2D-TMDs) have attracted much attention because of their unique layered structure and physical properties for transistor applications. Mechanically transferred metal contacts on these low-dimensional materials or their homogeneous and heterogeneous multilayers have generated huge interest to avoid deposition damages. In this paper, we show that there are large physical gaps at both the edge contact and surface contact between the transferred electrodes and the 2D materials. A method called laser shock induced superplastic deformation (LSISD) is proposed to tackle this issue and enhance the performance of the transistors. The enhancement mechanism was investigated by molecular dynamics (MD) simulations of the nanoforming process, atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) characterizations of the interfaces, and density functional theory (DFT) modeling. The force effect of laser shock can reduce the contact gap between metals and semiconductors. The electrical performances of the transistors before and after LSISD, along with MD simulations, are used to find the optimal process parameters. In addition, this paper applies the LSISD method to the short-channel MoS2/graphene vertical transistors to show potential improvement in interface contact and electrical properties. This paper demonstrates the first report on using mechanical force induced by laser shock to enhance metal–semiconductor interfaces and transistor performances. [ABSTRACT FROM AUTHOR]

Nitrogen-doped graphene has been increasingly utilized in a variety of energy-related applications, serving as a catalyst or support material for fuel cells, and as an anode material for lithium-ion batteries, among others. The thermal reduction of graphene oxide (GO) in nitrogenous sources to incorporate nitrogen, producing nitrogen-doped reduced graphene oxide (NRGO), is the most favored method. Controlling atomic configurations of nitrogen-doped sites is the key factor for tailoring the physico-chemical properties of NRGO, but major challenges remain in identifying detailed atomic arrangements at nitrogen binding sites on highly defective and chemically functionalized GO surfaces. In this paper, we present atomistic-scale modeling of the nitrogen doping process of GO with different types of vacancy defects. Molecular dynamics simulations using a reactive force field indicate that the edge carbon atoms on defect sites are the dominant initiation location for nitrogen doping. Further, first-principles calculations using density functional theory present energetically favorable chemical transition pathways for nitrogen doping. The significance of this work lies in providing important chemical insights for the effective control of the desired properties of NRGO by suggesting a detailed mechanism of the nitrogen doping process of GO. [ABSTRACT FROM AUTHOR]

The emergence of oxygenic photosynthesis was a major event in Earth's evolutionary history and was facilitated by chlorophylls (a major category of photopigments). The accurate modelling of photopigments is important to understand the characteristics of putative extraterrestrial life and its spectral signatures (detectable by future telescopes). In this paper, we perform a detailed assessment of various time-dependent density-functional theory (TD-DFT) methods for predicting the absorption spectra of chlorophyll a, with particular emphasis on modern low-cost approximations. We also investigate a potential extraterrestrial photopigment called phot0 and demonstrate that the electronegativity of the metal ion may exert a direct influence on the locations of the absorption peaks, with higher electronegativity inducing blue-shifting and vice-versa. Based on these calculations, we established that global-hybrid approximations with a moderate percentage of exact exchange – such as M06 and PW6B95 – are the most appropriate compromise between cost and accuracy for the computational characterisation of photopigments of astrobiological interest. We conclude with a brief assessment of the implications and avenues for future research. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Atomic & Molecular Physics (1000-0364) is the property of Journal of Atomic & Molecular Physics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Atomic & Molecular Physics (1000-0364) is the property of Journal of Atomic & Molecular Physics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper, a new GaSe/ZnS van der Waals heterostructure (vdWH) is devised and subjected to systematic analysis through first principles calculations in terms of its geometric, electronic and transport properties. The stability of GaSe/ZnS vdWH is verified through binding energy, phonon spectrum, and ab initio molecular dynamics (AIMD) simulation. Additionally, detailed calculations of plane average electron density difference and average electrostatic potential in the features of GaSe/ZnS vdWH interface are provided. The results show that GaSe/ ZnS vdWH comprises a heterostructure with a direct band gap of 2.19 eV and high carrier mobility. Among them, the electron mobility along the x direction reaches 1 394.63 cm²V-1⋅s-1, while the electron mobility along the y direction reaches 1 913.18 cm² ⋅V-1 ⋅s-1, demonstrating excellent performance and potential applications in electronic nano devices. [ABSTRACT FROM AUTHOR]

To address the challenge of performance portability and facilitate the implementation of electronic structure solvers, we developed the basic matrix library (BML) and Parallel, Rapid O(N), and Graph-based Recursive Electronic Structure Solver (PROGRESS) library. The BML implements linear algebra operations necessary for electronic structure kernels using a unified user interface for various matrix formats (dense and sparse) and architectures (CPUs and GPUs). Focusing on density functional theory and tight-binding models, PROGRESS implements several solvers for computing the single-particle density matrix and relies on BML. In this paper, we describe the general strategies used for these implementations on various computer architectures, using OpenMP target functionalities on GPUs, in conjunction with third-party libraries to handle performance critical numerical kernels. We demonstrate the portability of this approach and its performance in benchmark problems. [ABSTRACT FROM AUTHOR]

Hydration and, in particular, the coordination number of a metal ion is of paramount importance as it defines many of its (bio)physicochemical properties. It is not only essential for understanding its behavior in aqueous solutions but also determines the metal ion reference state and its binding energy to (bio)molecules. In this paper, for divalent metal cations Ca 2 + , Cd 2 + , Cu 2 + , Fe 2 + , Hg 2 + , Mg 2 + , Ni 2 + , Pb 2 + , and Zn 2 + , we compare two approaches for predicting hydration numbers: (1) a mixed explicit/continuum DFT-D3//COSMO-RS solvation model and (2) density functional theory based ab initio molecular dynamics. The former approach is employed to calculate the Gibbs free energy change for the sequential hydration reactions, starting from [M( H 2 O)2]2+ aqua complexes to [M( H 2 O) 9]2+, allowing explicit water molecules to bind in the first or second coordination sphere and determining the most stable [M( H 2 O) n]2+ structure. In the latter approach, the hydration number is obtained by integrating the ion–water radial distribution function. With a couple of exceptions, the metal ion hydration numbers predicted by the two approaches are in mutual agreement, as well as in agreement with the experimental data. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: In recent years, the construction of stable multicomponent assembled structures on surfaces and the exploration of the assembled mechanism have become research hotspots. In this paper, the azobenzene‐carboxylic acid called (E)‐4',4"'‐(diazene‐1,2‐diyl) bis(([1,1'‐biphenyl]‐3,5‐dicarboxylic acid)) (H4DBBD) could self‐assemble into regular network structure at heptanoic acid/graphite via hydrogen bonding, and could be regulated into analogous kagomé network by coronene (COR) molecules. In addition, a series of bipyridine derivatives were further introduced to construct bi‐component systems with H4DBBD molecules, and successfully induced diversified structural transitions of H4DBBD on the graphite surface. Combined with scanning tunneling microscope (STM) and density functional theory (DFT) calculations, we have investigated the diversified structural transitions and analyzed the formation mechanism of the assembled systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • Simple bispyrene-based probe (BisPyH) with aggregation-induced enhanced emission for PA and DNP ultrasensitive detection, respectively was constructed. • BisPyH exhibited relatively bright green intermolecular excimer emission with AIEE effect in DMSO/H 2 O (1:1, v/v) via intermolecular π-π interactions among pyrene units. • Qualitative and quantitative detection of PA or DNP in real water. • Naked-eye detection of PA or DNP in solid state by TLC plates and test strips. It was still important to explore excimer emission-based fluorescence probes for nitroaromatics detection by formation or destruction of pyrene excimer with strong emission change. In this work, we have synthesized a simple bis(pyrene) derivative (BisPyH) and studied its optical behavior by using UV–vis and fluorescent spectroscopy. In pure DMSO solution, it emitted a weak blue fluorescence due to the formation of excimer states, on the contrary, the BisPyH in the DMSO/H 2 O (v/v, 1:1) mixture solution was self-assembled to form aggregates via intermolecular π-π interactions among pyrene units, giving almost 10-fold fluorescence enhancement compared to that in pure DMSO solution. The formed aggregates just offered a perfect platform for the selective detection PA and DNP explosives by quenching the bright green intermolecular-excimer emission in competitive environment. BisPyH exhibited a limit of detection (LOD) towards PA, and DNP as low as 7.32 × 10−8, and 8.11 × 10−8 M, respectively. Subsequently, the fluorescence quenching mechanism was demonstrated by the density functional theory (DFT), UV–vis and fluorescence spectra, SEM, and the quenching constants. Furthermore, filter paper strips and thin-layer chromatography (TLC) plates coated with BisPyH were able to detect PA and DNP in the practical application. [ABSTRACT FROM AUTHOR]

In this paper, we present the theory and implementation of nuclear magnetic resonance shielding constants with gauge-including atomic orbitals for the hybrid multiconfigurational short-range density functional theory model. As a special case, this implementation also includes Hartree–Fock srDFT (HF-srDFT). Choosing a complete-active space (CAS) wave function as the multiconfigurational parameterization of the wave function, we investigate how well CAS-srDFT reproduces experimental trends of nuclear shielding constants compared to DFT and complete active space self-consistent field (CASSCF). Calculations on the nucleobases adenine and thymine show that CAS-srDFT performs on average the best of the tested methods, much better than CASSCF but only marginally better than HF-srDFT. The performance, compared to regular DFT, is similar when functionals containing exact exchange are used. We generally find that the inclusion of exact exchange is important for an accurate description of the shielding constants. In cases where no exact exchange is included, we observe that the HF- and CAS-srDFT often outperform regular DFT. For calculations on transition metal nuclei in organometallic compounds with significant static correlation, the CAS-srDFT method again outperforms CASSCF compared to experimental shielding constants, and the change from HF-srDFT is substantial. In conclusion, the static correlation posed by the metal complexes seems to be captured by CAS-srDFT, which is promising since this type of correlation is not well described by regular DFT. [ABSTRACT FROM AUTHOR]

The insertion of a graphene (or h-BN) layer in a two-dimensional (2D) MoS2–metal interface to de-pin the Fermi level has been a common strategy in experiments. Recently, however, the 2D material space has expanded much beyond transition metal dichalcogenides, and it is not clear if the same strategy will work for other materials. Here, we select a family of twelve emerging, commercially available 2D semiconductors with the work function range of 3.8–6.1 eV and study their interfaces with metals in the presence and absence of the graphene buffer layer. Using the density functional theory, we show that the graphene buffer layer preserves the ideal Schottky–Mott rule to a great extent when the interfaces are made with Ag and Ti. However, the h-BN buffer layer does not yield a similar performance since its electrons are not as localized as graphene. It is further observed that even graphene is not very effective in preserving the ideal Schottky–Mott rule while interfacing with high work function metals (Au, Pd, and Pt). The quantum chemical insights presented in this paper could aid in the design of high-performance electronic devices with low contact resistance based on newly developed 2D materials. [ABSTRACT FROM AUTHOR]

In this paper, ultra-thin nanofiber PDI was obtained by self-assembly dispersion of commercial PDINH. A novel Co/Ni-MOF-74@PDI Z-scheme heterojunction photocatalyst material was constructed by a simple solvothermal method. XRD, SEM, TEM, FT-IR and other characterization techniques proved the successful preparation of the Co/Ni-MOF-74@PDI Z-scheme heterojunction photocatalyst material. By degrading chlortetracycline hydrochloride, it was found that the photocatalytic activity of Co/Ni-MOF-74@PDI was much higher than that of pure Co/Ni-MOF-74 and PDI. Subsequently, Co/Ni-MOF-74@PDI was used to activate H2O2 to further improve the degradation efficiency of chlortetracycline hydrochloride. It was found that the photocatalytic performance was greatly improved after the addition of 19.6 mM H2O2 to the system, and the degradation rate of chlortetracycline hydrochloride was 87% within 90 min. The electron transfer pathway and H2O2 activation mechanism of the Co/Ni-MOF-74@PDI composite photocatalyst were proved by free radical quenching experiments, electron paramagnetic resonance analysis and X-ray electron spectroscopy. Finally, the easy exfoliation point and degradation pathway of chlortetracycline hydrochloride were studied using density functional theory, UPLC-MS and toxicity evaluation software. It was found that the main active substances were h+, ˙O2, 1O2 and ˙OH, and the toxicity of chlortetracycline hydrochloride and its intermediates was evaluated. [ABSTRACT FROM AUTHOR]

In this paper, the water dissociation abilities of transition metals Cr, Co, Ni, Cu, and surface Cr incorporated into Co, Ni, and Cu matrix were estimated using density functional theory. The calculations indicate that the transition metal matrix can markedly affect the ability of surface Cr to promote H2O dissociation. The barriers of the H2O dissociation step on Cr, Co, Ni, and Cu increase in sequence. After introducing Cr into a transition metal matrix, the H2O dissociation ability of Cr reduces. Compared with pure metals, doping the Co surface with Cr is less favorable for H2O dissociation and introducing Cr onto Ni and Cu surfaces can accelerate the H2O dissociation reaction and Cr–Ni has stronger H2O dissociation ability than Cr–Cu. The electron distribution calculations show that the electron deviation levels from Cr to the metal matrix are a key factor in affecting the H2O dissociation ability of surface Cr, and strong electron deviation is advantageous. The adsorption calculations reveal that the OH-binding energy of catalyst cannot relate to its H2O dissociation ability and follows a rough volcano relationship with its alkaline HER performance. [ABSTRACT FROM AUTHOR]

The development of productive and sustainable bifunctional electrocatalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) plays an important role in the commercial evolution of metal–air batteries. In this paper, a low-temperature molten salt template method was adopted to synthesize the composite of CoS2 and nitrogen-doped carbon (CoS2/NC) without the protection of inert gas. The structural characterization studies show that the specific surface area (SSA) and crystal growth kinetics are increased and effectively improved, respectively, by the composite of CoS2 and NC. The as-synthesized CoS2/NC composite demonstrates outstanding bifunctional catalytic activity in alkaline electrolytes and exhibits a half-wave potential (E1/2) of 0.854 V (vs. RHE) and an overpotential of only 220 mV for the OER at a current density of 10 mA cm−2 (η10). Simultaneously, CoS2/NC also exhibits excellent electrochemical stability. Additionally, density functional theory (DFT) calculations have manifested that the synergistic effect of CoS2 and NC results in a remarkable enhancement in the bifunctional catalytic performance of the composite materials. This study offers a new pathway and theoretical guidance for the fabrication of efficient bifunctional electrocatalysts. [ABSTRACT FROM AUTHOR]

Context: Since 1991 when Grätzel et al. improved the conversion efficiency of dye-sensitized solar cells to 7.1% by applying nano technology as the first time, the researches on dye-sensitized solar cells have received widely attentions. The organic dye without precious metals has a lower cost, which is easily to get synthesized and its structure is easily decorated, owing a higher photoelectric conversion efficiency at the same time. Therefore, in recent years, the organic dye has attracted people's attentions more and more. In order to better understand the relationship between structure and properties of dye molecules, with ZL003 as a prototype, molecular modifications are then made and a scheme, with rigid fused π-bridge comprising electron-rich and deficient segments. The calculated results indicate that the π-bridge containing dithienopyrrolobenzothiadiazole and dipyrrolo-dithienobenzothiadiazole as π-bridge has been demonstrated to be successful to significantly redshift the absorption maximum wavelength, extend the lifetime of the first excited state, and decrease the energy gap between the highest occupied molecule orbital (HOMO) and the lowest unoccupied molecule orbital (LUMO). It is hoped that the calculation result of this paper would provide theoretical basis for the experimental synthesis of more efficient dye molecules. Method: All calculations were performed in Gaussian 09 program package. The ground state geometries (S0) and the first excited state (S1) were optimized using density function theory (DFT) with the hybrid function B3LYP functional, coupled with the 6-31G(d, p) basis set for optimization of molecule ground state conformations. TD-DFT calculations of excited state energies and absorption spectra were performed using MPWPW91 functional combined with the 6–31 + G (d) basis set. [ABSTRACT FROM AUTHOR]

In many photocatalytic reaction paths, the breaking of the first CO bond in a CO2 molecule is often the key step that becomes the rate‐controlled reaction step. In this paper, a graphitic carbon nitride (g‐C3N4) supported nickel single‐atom catalyst (Ni@g‐C3N4) was successfully constructed, and the mechanism of CO2 catalytic reduction was systematically studied based on density functional theory (DFT). The introduction of nickel promotes the adsorption of small molecules, especially for the CO2 activation. According to density of states (DOS) and frontier orbital analysis, the photogenerated carriers tend to jump from nitrogen atoms to carbon atoms, forming an electron transfer in real space, after g‐C3N4 is excited by light. With the appearance of nickel‐doped levels, the DOS of Ni@g‐C3N4 is no longer symmetric with respect to the spin up and down, especially around the original band gap of g‐C3N4. Single‐atom nickel has abundant frontier orbitals and high activity and is a favourable place for chemical reactions. The presence of surface hydrogen can promote the recovery of CO2, and the energy barrier of Ni@g‐C3N4 with hydrogen is only 15% of the clean g‐C3N4 surface. This paper provides a new idea for the development of efficient single‐atom catalysts for CO2 reduction. [ABSTRACT FROM AUTHOR]

In this paper, a cyclic (CuIpz)3·CH3CN (1) precursor and a mixed-valence pentanuclear complex Cu I3 Cu II2 (OH)pz6·CH3CN (2) have been synthesized and structurally characterized by single-crystal X-ray diffraction, where pzH = 4-chloro-3,5-diphenylpyrazole. The excellent catalytic activity of 2 has been demonstrated in the chemical fixation of CO2 into value-added cyclic carbonates, which can be carried out at ambient pressure and room temperature along with ultra-high yield and perfect steric hindrance tolerance. Based on density functional theory (DFT) calculations and comparison with the catalytic performance of 1, it is proposed that the coordinatively unsaturated CuII atoms of 2 are probably the active sites for this catalytic reaction. [ABSTRACT FROM AUTHOR]

In this paper, the geometric structures and electron-optical properties of AlAs/GaS heterojunctions and Se-doped AlAs/GaS heterojunctions are calculated based on first-principles of density functional theory (DFT). At the same time, the influence of the AlAs layer's 5° rotation stacking method on the AlAs/GaS heterojunction is discussed. The results show that the AlAs/GaS heterojunction is a type-II van der Waals heterojunction (vdWH) with a direct bandgap of 0.974 eV, and the Z-scheme electron transfer mechanism is more conducive to the separation of photogenerated electrons and holes. Both semiconductor-to-metal transitions can be achieved by applying an external electric field and strain. Under the action of an external electric field and uniaxial strain, AlAs/GaS maintains the type-II energy band alignment throughout the process. When biaxial strain is applied, the heterojunction is accompanied by a direct–indirect bandgap transition. It is worth mentioning that the optical absorption of the AlAs/GaS heterojunction is significantly higher than that of the two monolayers, and the absorption range is wider. The above characteristics indicate that the AlAs/GaS heterojunction has wider applications in fields such as photodetectors. [ABSTRACT FROM AUTHOR]

Context: In the paper, the ORR/OER on graphene-supported nitrogen coordinated Ru-atom (Ru-N-C) is simulated. We discuss nitrogen coordination influences electronic properties, adsorption energies, and catalytic activity in a single-atom Ru active site. The over potentials on Ru-N-C are 1.12 eV/1.00 eV for ORR/OER. We calculate Gibbs-free energy (ΔG) for every reaction step in ORR/OER process. In order to gain a deeper understanding of the catalytic process on the surface of single atom catalysts, the ab initio molecular dynamics (AIMD) simulations show that Ru-N-C has a structural stability at 300 K and that ORR/OER on Ru-N-C can occur along a typical four-electron process of reaction. AIMD simulations of catalytic processes provide detailed information about atom interactions. Methods: In this paper, we use density functional theory (DFT) with PBE functional to study the electronic properties and adsorption properties of graphene-supported nitrogen coordinated Ru-atom (Ru-N-C) Gibbs-free energy and Gibbs-free energy for very reaction step. The structural optimization and all the calculations are carried out by Dmol3 package, adopting the PNT basis set and DFT semicore pseudopotential. Ab initio molecular dynamics simulations (AIMD) were run for 10 ps. The canonical (NVT) ensemble, massive GGM thermostat, and a temperature of 300 K are taken into account. The functional of B3LYP and the DNP basis set are chosen for AIMD. [ABSTRACT FROM AUTHOR]

Phagraphene is a newly proposed two-dimensional allotrope of carbon. Its structure resembles that of a defective graphene sheet. The unit cell structure of phagraphene consists of a 5–6–7 ring sequence due to which it possesses lower energy than most carbon allotropes. Phagraphene has properties, namely thermal conductivity of 218 ± 20 W/mK and 285 ± 29 W/mK, along armchair and zigzag directions, respectively, a tensile strength of 85 ± 2 GPa, the elastic modulus of 870 ± 15 GPa along armchair and 800 ± 14 GPa along zigzag direction, and fracture strain of the same order as that of pristine graphene. Density functional theory and molecular dynamics simulations have proved the unique electronic properties of phagraphene, namely direction-dependent Dirac cones, tunable Fermi velocities, quasi-direct band gap, to be comparable with pristine graphene. Based on molecular dynamics and density functional theory investigations, phagraphene is capable of being used in Li-based batteries and thermoelectric devices as anode material due to its good adsorption properties and remarkably good doping characteristics. Such characteristics can lead to a future trend of analyzing such allotropes because phagraphene can provide potential applications in atmospheric pollutant-detecting and drug-carrying properties in ailments like cancer. This paper is a nascent one discussing all the previous works on molecular dynamics simulations of phagraphene and tries to serve as the leading one for researchers interested in this field. This paper summarizes the mechanical and thermal properties of phagraphene estimated using molecular dynamics simulations as studied in previous works. The study shows that molecular dynamics has a good application in studying such a novel carbon allotrope. The discussions made in this paper thematize phagraphene's properties as a next-generation material and can help the researchers in a qualitative overview. [ABSTRACT FROM AUTHOR]

In this paper, a pioneering study of the electronic and optical properties of QPHT-graphene after adsorbing three types of alkali metal atoms (Li/Na/K) was conducted using first-principles calculations based on density functional theory. The electronic properties study covers TDOS, PDOS, and Bader charge analyses, in addition to charge density difference. The optical properties study considers the complex dielectric function, complex refractive function, absorption coefficient, reflection coefficient and energy loss function under three types of polarization. The results show that all configurations exhibit a good optical response within a wide energy range of 0–25 eV and are anisotropic under all three polarization types. Under E x and E y polarizations, the adsorption of alkali metal atoms significantly enhances the absorptivity, reflectivity, and refractivity of the pristine QPHT-graphene. As the atomic number increases, it shows a regular oscillatory behavior. Under E z polarization, the QPHT-graphene optical response is concentrated in the high-frequency ultraviolet region, i.e., higher than 10 eV, and alkali metal atom adsorption has little effect on its optical properties. These results show that alkali metal atom adsorption can effectively modulate the optical properties of QPHT-graphene. This research can help to further understand the electronic and optical properties of QPHT-graphene and is instructive in promoting the application of new two-dimensional nanocarbon materials in the field of optoelectronics. [ABSTRACT FROM AUTHOR]

One of the major characteristics of high-molecular-weight polymerization is its poor water solubility. Because of the significant impact this situation has on the usage of corrosion inhibitors, it is imperative to research low-molecular-level green amino acid corrosion inhibitors, particularly at the molecular level. Therefore, in this paper, we studied the effect of density functional theory (DFT) and molecular dynamics (MD) on the adsorption performance of aspartic acid (Asp) and glutamic acid (Glu) on the iron surface. We theoretically evaluated the adsorption energy by analyzing the formation of chemisorption of amino acid molecules with different polymerization degrees through electron transfer. The results showed that the optimum degree of polymerization was 8 for Asp that of Glu was 6, because the peptide bond and carboxylic acid root were attached to the d orbital of the iron atom. The adsorption energies at the optimum degree of polymerization were -304.457939 kcal/mol and -286.312175 kcal/mol for Asp and Glu, respectively, which demonstrated that Asp is a better corrosion inhibitor than Glu. This paper provides a theoretical approach for the design of subsequent corrosion inhibitors and the selection of polymerization degree. [ABSTRACT FROM AUTHOR]

Sensing nitroaromatic explosives has gained significant attention due to both increased terrorist threats and a need for environmental protection. In this regard, a fluorescent chemosensor, 1-benzyl-3,5-di(thiophen-2-yl)pyrazin-1-ium bromide (BTPyz), was synthesized and characterized via spectroscopic methods. The photophysical properties were investigated using absorption and emission spectral analysis. As a fluorescent chemosensor, BTPyz exhibited a selective response towards 2,4,6-trinitrophenol (TNP) with a detection limit of 11.6 nM and quenching constant (KSV) of 3.8 × 104 M−1. The fluorescence quenching mechanism was attributed to ground-state charge-transfer complex formation and resonance energy transfer, as evident from Uv-visible, fluorescence and NMR spectroscopy, single-crystal XRD studies, and density functional theory calculations. BTPyz was also employed for the contact mode detection of TNP on paper strips. The detection of TNP in real water and soil samples demonstrated BTPyz to be a promising detection tool toward environmental specimens. [ABSTRACT FROM AUTHOR]

In this paper, based on density functional theory (DFT), the adsorption and cracking mechanism of CH3OH on the Cu@CnB8 (n = 24, 40, 88) surface is studied. There are three possible paths of C–H, C–O and O–H for the initial cracking of CH3OH on the surface of Cu@CnB8. In this paper, the adsorption energy of CH3OH and intermediates on the Cu@CnB8 surface is calculated, and the related reaction energy and activation energy under the possible cracking path are calculated. The calculation results show that CH3OH is physically adsorbed on the Cu@CnB8 surface. The main path of CH3OH cracking is CH3OH → CH3O → CH2O → CHO → CO. The activity of CH3OH cracking decreases with the increase of Cu@CnB8 size, that is, the small size Cu@CnB8 can be used as an effective catalyst for the cracking of CH3OH. [ABSTRACT FROM AUTHOR]

As one of the varieties of magnet wire, the enameled wire has excellent mechanical properties, heat resistance, ageing resistance, dimensional stability and chemical stability. This is one of the keys affecting the development of the electrical industry, especially the development of new motors. Different varieties of enameled wire insulating varnishes have advantages and disadvantages, in addition to their general properties. In order to improve the service life and reliability of the electrical coil of the motor, it is necessary to select the appropriate enameled wire reasonably according to different purposes. Molecular simulation technology can play a guiding role in the relationship between the molecular structure and properties of resins, help to understand the microscopic mechanism, shorten the experimental period, improve efficiency and save costs. In this paper, based on density functional theory (DFT) and molecular dynamics (MD), the microscopic properties of four insulating resins, polyamide–imide (PAI), polyester (PET), polyesterimide (PEI), and polyimide (PI), were studied. We also studied the influence mechanism of the insulating resin microstructure on the macroscopic properties of enameled wires, including adhesion, insulating properties and flexibility. The calculation results show that the polyester insulating enameled wire paint has good insulation performance and flexibility, the polyamide–imide paint has the best adhesion, and the polyimide insulating paint has very reliable insulation performance and flexibility. The performance research in this paper lays a foundation for the preparation of insulating resin coatings with better comprehensive properties. The performance research in this paper lays a foundation for preparing insulating resin paint with excellent comprehensive performance. [ABSTRACT FROM AUTHOR]

In this paper, we study the nuclear gradients of heat bath configuration interaction self-consistent field (HCISCF) wave functions and use them to optimize molecular geometries for various molecules. We show that HCISCF nuclear gradients are fairly insensitive to the size of the "selected" variational space, which allows us to reduce the computational cost without introducing significant errors. The ability of the HCISCF to treat larger active spaces combined with the flexibility for users to control the computational cost makes the method very attractive for studying strongly correlated systems, which require a larger active space than possible with a complete active space self-consistent field. Finally, we study the realistic catalyst, Fe(PDI), and highlight some of the challenges this system poses for density functional theory (DFT). We demonstrate how HCISCF can clarify the energetic stability of geometries obtained from DFT when the results are strongly dependent on the functional. We also use the HCISCF gradients to optimize geometries for this species and study the adiabatic singlet–triplet gap. During geometry optimization, we find that multiple near-degenerate local minima exist on the triplet potential energy surface. [ABSTRACT FROM AUTHOR]

In this paper, the quantum effects of fine scaling on the buckling behavior of carbon nanotubes (CNTs) under axial loading are investigated. Molecular mechanics and quantum mechanics are respectively utilized to study the buckling behavior and to obtain the molecular mechanics coefficients of fine-scale nanotubes. The results of buckling behavior of CNTs with different chiralities with finite and infinite dimensions are given, and a comparison study is presented on them. The differences between finite and infinite nanotubes reflect the quantum effects of fine scaling on the buckling behavior. In addition, the results show that the dimensional changes highly affect the mechanical properties and the buckling behavior of CNTs to certain dimensions. Moreover, dimensional changes have a significant effect on the critical buckling strain. Beside, in addition to the structure dimensions, the arrangement of structural and boundary atoms have a major influence on the buckling behavior. [ABSTRACT FROM AUTHOR]

2-(3-Bromophenyl)-1-(4-morpholinyl)ethanone belongs to one of morpholine derivatives. In this paper, 2-(3-bromophenyl)-1-(4-morpholinyl)ethanone was synthesized by a two-step synthesis method. In order to determine the structure of the target compound, FT-IR,1H NMR,13C NMR and MS were used for detection. Meanwhile, X-ray diffraction was used to detect the single crystal and obtain the crystal structure data of the target compound. The molecular crystal structure was compared with that determined by density functional theory. The frontier molecular orbitals and molecular electrostatic potential energy were used to further study the physical properties of the compounds. [ABSTRACT FROM AUTHOR]

Electrocatalytic water splitting is considered as a green and efficient way of hydrogen production. How to promote the performance of electrode and develop stable non-precious metal catalysts has caused extensive research. One of the effective strategies is combining two or more catalytic materials to build heterogeneous structures. In this paper, a series of Co 0.3 -Ni 3 S 2 /Ni 3 Sn 2 S 2 heterostructured materials were synthesized to in-situ grow Ni 3 S 2 /Ni 3 Sn 2 S 2 on Ni foam with a 3D porous structure by modulating the substance ratio of elemental cobalt and elemental sulfur through a one-step hydrothermal process. The materials have superior oxygen evolution reaction (OER) properties and urea oxidation reaction (UOR) performance. Under an alkaline electrolyte of 1 M KOH, for OER, Co 0.3 -Ni 3 S 2 /Ni 3 Sn 2 S 2 only requires overpotential of 251 mV to obtain a current density of 10 mA cm−2. In an alkaline solution of 1 M KOH +0.5 M urea, for UOR, only the potential of 1.326 V was demanded for the catalyst to reach a current density of 50 mA cm−2, but its stability over 15 h was average. Density Functional Theory (DFT) analyses suggest that Co–Ni 3 S 2 has better metallic properties and promote the dynamics in catalysis. This study put forward a new thought for future research on nickel-tin binary metal sulfide hybrid electrocatalysts with excellent freshwater, seawater and urea oxidation properties. In this paper, a series of Co x -Ni 3 S 2 /Ni 3 Sn 2 S 2 materials was in situ grown on Ni foam by a one-step hydrothermal method, and the synthesized Co 0.3 -Ni 3 S 2 /Ni 3 Sn 2 S 2 material present excellent water and urea oxidation properties. [Display omitted] • Co 0.3 -Ni 3 S 2 /Ni 3 Sn 2 S 2 materials were successfully synthesized by hydrothermal processes. • Co 0.3 -Ni 3 S 2 /Ni 3 Sn 2 S 2 electrode shows excellent catalysis in the cathode reaction of water and urea. • Co 0.3 -Ni 3 S 2 /Ni 3 Sn 2 S 2 requires only potential of 1.326 V to achieve a current density of 50 mA cm−2 for UOR. [ABSTRACT FROM AUTHOR]

Given the superior performance of SF6 in arc extinguishing and its wide application in high voltage fields, the search for new adsorbent materials for SF6 and its main decomposition products holds significant importance in mitigating greenhouse gas potential and its implications for the environment and energy sectors. We chose ZIF-67, an organic framework with a high specific surface area and distinctive pore size structure, to address this important issue. Using the grand canonical Monte Carlo simulation approach, we investigated the adsorption of SF6 and its main decomposer gases by ZIF-67 at GPa. The interaction of ZIF-67 with SF6 and its main breakdown products was then examined at the level of atomic orbital interactions, with the adsorption energy and density of states estimated using density functional theory. The findings reveal that ZIF-67 has the best ability to capture H2S, with a saturation capacity of 3.2 mmol g−1 at room temperature. Its adsorption capacity for SOF2 and SO2F2 is about five to seven times higher than that of industrial adsorbents kdhF-03, and the working conditions are milder. The molecule radius and adsorption capacity are tightly correlated. An innovative method for the widespread recovery and treatment of SF6 and its byproducts is presented in this research. This paper aims to provide new insights and solutions to promote sustainable development in the power industry. [ABSTRACT FROM AUTHOR]

Currently, a promising direction of study is the use of biologically active coordination compounds in the pharmacopoeia and the creation of effective bactericidal drugs, biomaterials, and enzyme modulators on that basis. The paper considers a coordination germanium compound with 2-amino-3-hydroxybutanoic acid. The prospects for the use of the compound in medicine are outlined. This work is aimed at solving the problems regarding the synthesis of biologically active compounds with a wide spectrum of actions. The structure and composition of the coordination compound have been established through calculation and experimental methods. The biocidal (bactericidal and fungicidal) activity of germanium-containing compounds against a number of bacteria and microscopic fungi has been studied. Using the quantum-chemical method with density functional theory (DFT, B3LYP/6–311++G(2d,2p)), the theoretical IR spectrum of the compound was calculated. The structure of the coordination compound and the structure of the intermediates at all stages of the synthesis process were established by calculation. [ABSTRACT FROM AUTHOR]

Perovskite materials have attracted much attention in recent years due to their high performance, especially in the field of photovoltaics. However, the dark side of these materials is their poor stability, which poses a huge challenge to their practical applications. Double perovskite compounds, on the other hand, can show more stability as a result of their specific structure. One of the key properties of both perovskite and double perovskite is their tunable band gap, which can be determined using different techniques. Density functional theory (DFT), for instance, offers the potential to intelligently direct experimental investigation activities and predict various properties, including band gap. In reality, however, it is still difficult to anticipate the energy band gap from first principles, and accurate results often require more expensive methods such as hybrid functional or GW methods. In this paper, we present our development of high-throughput supervised ensemble learning-based methods: random forest, XGBoost, and Light GBM using a database of 1306 double perovskites materials to predict the energy band gap. Based on elemental properties, characteristics have been vectorized from chemical compositions. Our findings demonstrate the efficiency of ensemble learning methods and imply that scientists would benefit from recently employed methods in materials informatics. [ABSTRACT FROM AUTHOR]

Superconductivity enhancement is often associated with phonon softening by doping or external pressure. In this paper, we report L 1 2 -type trialuminides Al3V as a typical example belonging to this scenario. The electronic, phononic and superconducting properties have been studied by using the first-principle method. Under uniaxial compression, the superconducting transition temperature Tc of Al3V can be increased from ≈1.5 K to its maximum at ≈7.3 K when the lattice approaches the structural instability. A detailed investigation of Al3V reveals that the (V: d)-(Al: p) hybrid bands are strongly coupled to the phonon modes with lower frequency. The uniaxial compression induces a significant softening of the phonon mode with non-zero phonon line-width, and yet keeps the electron density of states near the Fermi level unchanged. This leads to a stronger electron–phonon coupling (EPC) and therefore a higher Tc. On the contrary, the L 1 2 structure is more stable against the hydrostatic pressure and the phonon energy actually grows up when the hydrostatic pressure is increased. As a result, EPC becomes weaker and Tc can be reduced to ⩽ 0.3 K under high hydrostatic pressure. Our results present an interesting example that superconductivity can enhanced by tuning the softened phonon via pressure or doping. [ABSTRACT FROM AUTHOR]

In this paper, we studied the magnetic stability, structural, elastic and electronic properties of Ir2FeAl full Heusler compound in the regular phase (Cu2MnAl, prototype L2 1) , by using the first principle of density functional theory, with the generalized approximation of the GGA gradient. We found that the ferromagnetic state of Ir2FeAl is more stable than the nonmagnetic configuration at their lattice parameters equilibrium. This result was confirmed by the calculation of the cohesive energy. The stability is asserted by the elastic constants and the conditions of the mechanical stability criterion. The band structure and the calculated densities of states (DOS) of this alloy show a semi-metallic behavior. The ferromagnetic performance of Ir2FeAl is confirmed by the total magnetic moment of 4.28 μ B , where its major contribution comes from Fe atoms. We estimated the Debye temperature of Ir2FeAl from the average speed of sound. This is the first quantitative theoretical prediction of the elastic properties of the Ir2FeAl compound, and it still awaits experimental confirmation. [ABSTRACT FROM AUTHOR]

Oil-immersed transformers play a pivotal role owing to their environmentally friendly characteristics, compact footprint, and cost-effectiveness. Ensuring the online monitoring of oil-immersed transformers is a fundamental measure to ensure the secure and stable operation of modern power systems. In this paper, metal particle cluster-doped SnS is firstly used in the adsorption and sensing of decomposition components (CO, C2H2) under fault conditions in oil-immersed transformers. The study comprehensively analyzed band structure, differential charge density, density of states, and molecular orbital theory to unveil the adsorption and sensing mechanisms of target gases. The findings suggest that the modification of metal particle clusters can enhance the surface electronic properties of single-layer SnS. In the regions of metal particle clusters and the gas–surface reaction area, electronic activity is significantly heightened, primarily attributed to the contribution of d-orbital electrons of the metal cluster structures. The modified SnS exhibits adsorption capacity in the following order: Ru3-SnS > Mo3-SnS > Au3-SnS. Additionally, the modified material demonstrates increased competitiveness for C2H2, with adsorption types falling under physical chemistry adsorption. Different metal elements exert diverse effects on the electronic distribution of the entire system, providing a theoretical foundation for the preparation of corresponding sensors. The findings in this work offer numerical insights for the further preparation and development of SnS nanosensors, concurrently shedding light on the online monitoring of faults in oil-immersed transformers. [ABSTRACT FROM AUTHOR]

The complex theoretical analysis of the density of states, band structures, and Fermi surfaces, based on predictions of the density functional theory methods, unveils the unique electronic properties of the LaZn1−xBi2 system. In this paper, the Zn vacancies (for x = 0.5 ) were modeled using a modified unit cell of lower symmetry than that for a fully stoichiometric one (for x = 0 ). The existence of several Dirac-like features in the electronic band structures was found. Some of them were found to be intimately associated with the nonsymmorphic symmetry of the system, and these were investigated in detail. The calculated Fermi surface shapes, as well as the Fermi velocity values (up to ∼1.2 × 10 6 m/s), are in good agreement with other analogous square-net Dirac semimetals. The combination of charge-carrier uncompensation, relatively small band splitting, and the tolerance factor for square-net semimetals t ≤ 0.95 for LaZn0.5Bi2, constitutes a very promising indicator of the topological features of this system, warranting further experimental studies. [ABSTRACT FROM AUTHOR]

The capacity to manipulate magnetization in 2D dilute magnetic semiconductors (2D‐DMSs) using light, specifically in magnetically doped transition metal dichalcogenide (TMD) monolayers (M‐doped TX2, where M = V, Fe, and Cr; T = W, Mo; X = S, Se, and Te), may lead to innovative applications in spintronics, spin‐caloritronics, valleytronics, and quantum computation. This Perspective paper explores the mediation of magnetization by light under ambient conditions in 2D‐TMD DMSs and heterostructures. By combining magneto‐LC resonance (MLCR) experiments with density functional theory (DFT) calculations, we show that the magnetization can be enhanced using light in V‐doped TMD monolayers (e.g., V‐WS2, V‐WSe2). This phenomenon is attributed to excess holes in the conduction and valence bands, and carriers trapped in magnetic doping states, mediating the magnetization of the semiconducting layer. In 2D‐TMD heterostructures (VSe2/WS2, VSe2/MoS2), the significance of proximity, charge‐transfer, and confinement effects in amplifying light‐mediated magnetism is demonstrated. We attributed this to photon absorption at the TMD layer that generates electron–hole pairs mediating the magnetization of the heterostructure. These findings will encourage further research in the field of 2D magnetism and establish a novel design of 2D‐TMDs and heterostructures with optically tunable magnetic functionalities, paving the way for next‐generation magneto‐optic nanodevices. [ABSTRACT FROM AUTHOR]