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Highlights • Spray drying method is an original method for preparing BiOCl photocatalyst. • The crystallinity of BiOCl prepared by the spray drying method is good. • The BiOCl photocatalyst synthesized by spray drying has a special morphology with hollow spherical structure. • BiOCl with large specific surface results an efficient separation and transport of photogenerated electron-hole pairs. • BiOCl has an efficient visible-light-driven photocatalysis. Abstract Hollow microspheres of BiOCl assembled with nanosheets were successfully synthesized using a facile spray drying method. The phase structure, morphology, composition, oxidation state, and optical property of samples were characterized by XRD, FE-SEM, TEM, BET, XPS, EIS and UV–vis-DRS. The experimental results revealed that the decomposition efficiency of Rhodamine B (RhB) of BiOCl prepared by the spray drying method is four times as fast as that of BiOCl with solid spheres synthesized using the traditional solvothermal method. And the reaction in the presence of BiOCl-2 prepared by the spray drying method includes photodegradation and adsorption The better crystallinity and larger specific surface for the as-prepared BiOCl photocatalyst with hollow microspheres structure assembled with nanosheets are undoubtedly favorable for drastically enhancing its photocatalytic activity, which can largely enhance the efficient separation and transport of photo-generated electron-hole pairs. In addition, the degradation mechanism of BiOCl photoctalyst synthesized by spray drying method over RhB was analyzed and founded that the superoxide radical (O 2 −) and the hole (h+) played the pivotal role in RhB photocatalytic degradation instead of hydroxyl radical (OH). [ABSTRACT FROM AUTHOR]

AgBr/MgBi 2 O 6 heterostructured photocatalysts were synthesized by the deposition-precipitation method. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL), and UV–Visible diffuse reflectance spectroscopy (UV–Vis DRS) were employed to examine the phase structure, morphology and optical properties of the as-prepared samples. The photocatalytic activity was investigated by decomposing methylene blue (MB) solution under visible light irradiation (λ > 420 nm). AgBr/MgBi 2 O 6 composites exhibited significantly enhanced visible-light-driven photocatalytic properties in comparison with pure MgBi 2 O 6 and AgBr. When the molar ratio of AgBr to MgBi 2 O 6 was 3:1, the composite catalyst showed the optimal photocatalytic activity and excellent stability. The enhanced photocatalytic activity of AgBr/MgBi 2 O 6 composites was attributed to the formation of p-n heterojunction between AgBr and MgBi 2 O 6 , thereby resulting in the effective separation and transfer of photogenerated electrons-hole pairs. [ABSTRACT FROM AUTHOR]

Electronic structure, thermodynamics, and thermoelectric properties of β -BaCu 2 S 2 with naturally layered structure have been systematically investigated by using first-principles calculations and the Boltzmann transport theory. Our calculated results show that the Ba–S bonding interactions play an important role in determining the structural stability of β -BaCu 2 S 2 considering the Cu–S and Cu–Cu antibonding states at the top of valence band. Thermoelectric transport properties of β -BaCu 2 S 2 are significantly anisotropic depending on the crystallographic orientation. The slow carrier mobility, especially that along the c axis, would be responsible for its relatively low thermoelectric figure of merit. Metal doping is expected to be an effective route to improve the thermoelectric properties of β -BaCu 2 S 2 significantly through enhancing its electrical conductivity. [ABSTRACT FROM AUTHOR]

In this study, porous Ce-doped CaFe 0.5 Mn 0.5 O 3–δ (CFMO) with good microwave absorption properties is reported for the first time. Herein, Ce x Ca 1−x Fe 0.5 Mn 0.5 O 3−δ (x = 0, 0.05, 0.1, 0.15) (Ce-CFMO) sample powders were prepared by sol–gel method after calcination at 750 °C. Ce-CFMO was characterized by XRD, SEM, TEM, XPS, and VSM, and the Ce-CFMO was also mixed with paraffin wax for VNA. The addition of Ce led to enhanced porosity, enhanced interfacial polarization, enhanced defect polarization, and higher oxygen vacancy content in the CFMO. This resulted in enhanced charge polarization and dipole polarization as well as significant optimization of the impedance matching of CFMO. The unique pore structure of the CFMO is the main reason for its microwave absorption performance. Moreover, the preparation method of this material is simple and its cost is low, providing it with wide application prospects. CFMO has not yet been applied in the field of microwave absorbing materials, and there is still a lot of room for development in the future. [ABSTRACT FROM AUTHOR]

Abstract: The pressure-induced phase transformations in LiNH2 have been studied by using ab initio total-energy calculations and evolutionary structure prediction simulations. Two stable high-pressure polymorphs of LiNH2 are found: β-LiNH2 (orthorhombic, NaNH2-type, Fddd) and γ-LiNH2 (orthorhombic, P21212). The β→γ structural transition occurs at 10.7GPa, which is in good agreement with experimental observation. Further analysis of the structural properties, charge density distribution, and calculated phonon density of states indicates that the possibility of the N–H⋯N hydrogen bond occurring in the high-pressure γ-LiNH2 is extremely high. The existence of hydrogen bond weakens the N–H polar covalent bonds within NH2 groups, which can facilitate the hydrogen desorption. [Copyright &y& Elsevier]

Given the remarkable performances of rare earth multiferroic ortho-ferrites with magnetic optical and dielectric properties, the Y 1- x Sr x FeO 3 (x = 0, 0.05, 0.1, 0.15) perovskite structure microwave absorbing ferrite materials was successfully synthesized by Sr2+ ions A-site doping based on sol-gel technology in this paper. The XRD of all samples was refined with FullProf software, which confirmed the formation of the orthogonal perovskite structure (SG: Pnma). The SEM and TEM results display the average particles size of the samples is distributed between 110 and 160 nm. The increase of Sr doping concentration leads to the increase of particles size, which may be related to the growth of preferred orientation and incomplete substitution. The XPS analysis shows that Fe3+ was accompanied by the presence of Fe2+ with the doping of Sr2+ ions and oxygen vacancies increased significantly. The samples change from weak ferromagnetic state to paramagnetic state with the increase of Sr content. The minimum reflection loss (RL) of the Y 0.95 Sr 0.05 FeO 3 samples at 12.2 GHz reached −30.87 dB with thickness of 2.2 mm, where its effective absorption bandwidth (EAB, RL ≤ −10 dB) reached 2.4 GHz (11.3–13.7 GHz). Moreover, the EAB of the Y 0.85 Sr 0.15 FeO 3 samples reached 2.64 GHz, and the corresponding range is 9.0–11.6 GHz (X-band). [ABSTRACT FROM AUTHOR]

The group VB metals (V, Nb, Ta) are referred to as one of the most valuable hydrogen separation membrane materials because of their advantages over Pd. To evaluate the hydrogen-permeation performance of the three metals, their structure stability, H-solubility, H-diffusivity, H-permeability, and elastic stiffness tensors have been investigated using the first-principles method. Our results reveal that the tetrahedral interstitial site (TIS) is favorable position for H-occupying, but mainly because H-solution enthalpy is the lowest. H-diffusion coefficient follows the order of V > Nb > Ta, H-permeability and H-permeation flux follow the order of Nb > V > Ta. The attractive interactions between H atoms are weak, so it is impossible to form H 2 molecules inside the metals, and all metal hydride phases present good ductility. The calculated Debye temperature is basically consistent with the experimental value. These results provide fundamental data for the further design of alloy membranes based on VB metals. • H-permeation in VB metals (V, Nb, Ta) was systematically studied and compared. • Zero point energy was considered to ensure the accuracy of the calculations. • The preferred adsorption site and diffusion path of H atom was determined. • The calculated results agreed well with literature data. [ABSTRACT FROM AUTHOR]

Heterostructured AgBr/Bi 2 Sn 2 O 7 photocatalysts were synthesized successfully via the ultrasonic-assisted chemical precipitation method. XRD, FT-IR, FE-SEM, TEM, XPS, UV–vis-DRS and PL spectroscopy were used to characterize the phase structure, morphology, chemical composition, oxidation state, and optical properties of AgBr/Bi 2 Sn 2 O 7 heterojunction. The photocatalytic activity of as-prepared catalysts was evaluated by the degradation of RhB under visible light irradiation. The obtained AgBr/Bi 2 Sn 2 O 7 composite with the 1:1 molar ratio exhibited significantly enhanced photocatalytic performance. Further first-principles calculations indicated that the hybridization interaction between Ag and O atoms at AgBr/Bi 2 Sn 2 O 7 interface is expected to be beneficial for enhancing the charge transfer and improving the photocatalytic activity of heterostructured composites. [ABSTRACT FROM AUTHOR]

[Display omitted] • A machine learning and Python assisted method was proposed to predict six kinds magnetic properties of Fe-based amorphous and nanocrystalline alloys. • Artificial Neural Network algorithm showed the best predictive ability with determination coefficient of>0.90. • An alloy Fe 83 B 9 P 3 C 4 Nb 1 with desired magnetic properties was designed and verified experimentally. • The predicted magnetic properties by Artificial Neural Network are in very good agreement with experimental measured ones. We report a machine learning (ML) and Python assisted strategy to accelerate the design and verification of Fe–based amorphous and nanocrystalline alloy with desired properties. Linear Regression (LR), Support Vector Regression (SVR), Decision Tree Regression (DTR), Artificial Neural Network (ANN) and Random Forest Regression (RFR) are employed to build prediction models of soft magnetic properties, such as saturation magnetic flux density (B s), coercivity force (H c), magnetization (M s), Curie temperature (T c), maximum permeability (µ max) and effective permeability (µ e). It is found that ANN has the excellent fitting ability with largest coefficient of determination (R2) to predict the soft magnetic properties of new designed alloys. Then, Python screening is used to find the alloy compositions with best soft magnetic properties of Fe–B–P–C–Nb system. Finally, Fe 83 B 9 P 3 C 4 Nb 1 alloy with good soft magnetic properties has been designed and prepared to verify. It is indicated that the soft magnetic properties of Fe 83 B 9 P 3 C 4 Nb 1 amorphous and nanocrystalline alloy predicted by ML are in agreement with the experimental measured results. These findings indicate that ML and Python assisted approach can accelerate the design of Fe–based alloys with desired properties accurately. [ABSTRACT FROM AUTHOR]

The glass transition kinetics of melt-spun La 65 Al 20 Co 15 amorphous alloy ribbons has been investigated using differential scanning calorimetry (DSC) technique with continuous heating of the sample at different heating rates. The dependence of the glass transition temperature ( T g ) on the heating rate ( β ) has been determined by Lasocka’s relationship. The activation energy ( E ) of the glass transition has been obtained by employing Moynihan and Kissinger methods, respectively. It is found that the glass transition process cannot be described in terms of single activation energy. The variation of E with the extent of conversion ( α ) is further analyzed by using two iso-conversional methods. It is observed that the E of glass transition demonstrates a significant increase with the extent of conversion from amorphous to supercooled liquid phase of La 65 Al 20 Co 15 metallic glass. [ABSTRACT FROM AUTHOR]

The 2LiBH 4 –MgH 2 reactive hydride composite is a promising hydrogen storage system due to the combined high hydrogen capacity and relatively moderate reaction enthalpy. However, the sluggish de/rehydrogenation kinetics severely impedes its practical applications. In this study, graphitic carbon nitride (C 3 N 4 ) as a metal-free additive was added to the 2LiBH 4 –MgH 2 composite and examined with respect to the promoting effect on the hydrogen storage properties of the composite. Our study found that mechanically milling with small amount of C 3 N 4 additive can eliminate the incubation period between two dehydrogenation steps and thus markedly enhance the dehydrogenation kinetics of the LiBH 4 –MgH 2 composite. Further cyclic study found that the composite with C 3 N 4 additive exhibits improved cyclic dehydrogenation property although it also shows capacity loss upon cycling, particularly in the second cycle. Combined dehydrogenation property, phase analysis and a series of designed experiments suggested that the C 3 N 4 additive could react with both LiBH 4 and MgH 2 in heating process, and the resulting products may improve the reversible dehydrogenation property of the composite system. [ABSTRACT FROM AUTHOR]

Abstract: In this study, activated carbon (AC) was added to the 2LiBH4–MgH2 composite and examined with respect to its effect on the hydrogen storage properties of the system. Our study found that AC is an effective additive for promoting the reversible dehydrogenation of the 2LiBH4–MgH2 composite. A series of control experiments were carried out to optimize the sample preparation method, milling time and addition amount of AC. In comparison with the neat LiBH4–MgH2 system, the LiBH4–MgH2–AC composite prepared under optimized conditions exhibits enhanced dehydrogenation kinetics, improved cyclic stability and particularly, eliminated incubation period between the two dehydrogenation stages. A combination of phase/microstructure/chemical state analyses has been conducted to gain insight into the promoting effect of AC on the reversible dehydrogenation of the 2LiBH4–MgH2 system. Our study found that AC exerts its promoting effect via tailoring nanophase structure of the 2LiBH4–MgH2 composite. [Copyright &y& Elsevier]

The phase equilibrium relationships of the Ho-Fe-B system at 800 °C were investigated using diffusion couples and aided by the application of equilibrium alloys. This is critical for the design of high performance multiphase rare earth permanent magnetic materials. The experimental data were obtained from diffusion couples using scanning electron microscopy (SEM) and electron probe microanalysis (EPMA),and the isothermal section of the Ho-Fe-B system at 800 °C was established. The X-ray diffraction was used to analyze eight essential equilibrium alloys at 800 °C to further determine the reliability of the diffusion couple determination phase diagram. Experimental results clearly show the applicability of the diffusion couples' approach in determining such complex phase diagrams as Ho-Fe-B. The isothermal section at 800 °C was constructed from the results obtained from diffusion couples which contains 17 three-phase equilibrium regions and three stable ternary compounds Ho 2 Fe 14 , Ho 5 Fe 17 B 17 and HoFeB 3. • The phase equilibrium relationship of Ho-Fe-B ternary system is determined by diffusion couple method. • Intermetallic compounds: Ho 2 Fe 14 B, Ho 5 Fe 17 B 17 and HoFeB 3. • High performance multi-phase rare earth permanent magnetic materials. [ABSTRACT FROM AUTHOR]

To improve the resistance to hydrogen embrittlement and hydrogen permeation performance of vanadium (V) membranes, first-principles calculations were employed to study the stability, dissolution, and diffusion properties of H in transition metal (M = Mo, W)-doped V membranes, as well as their mechanical and thermodynamic properties, as alternative candidates for H 2 separation. Our results revealed that the doping percentage of Mo/W alloying can significantly improve the mechanical and thermodynamic properties of pure V. The most stable location for adsorbed H atoms is the tetrahedral interstitial site (TIS) in the body-centered cubic structure of the V 1- x M x (x = 0.0625, 0.125, 0.1875, and 0.25) alloys. Additionally, the hydrogen migration path should preferentially follow TIS → nearest-neighbor TIS. An M content of 0.25 yields the best anti-hydrogen embrittlement and the highest hydrogen-diffusion properties. The addition of individual Mo or W as doping elements into the V-based system greatly enhanced the hydrogen diffusion coefficient, and the addition of both Mo and W significantly improved the anti-hydrogen embrittlement of V-based alloys. Our results also showed that hydrogen concentration markedly influenced the solubility and diffusivity of hydrogen in V-based alloy membranes. These results provide a basis for the design of V-based alloy hydrogen permeation membranes. Image 1 • Mo/W-doped V solid solutions present a better mechanical strength. • H-diffusion coefficient of V metal is greatly improved by 25 at.% Mo/W doping. • V 0.5 Mo 0.25 W 0.25 solid solution has a better resistance to H-embrittlement. [ABSTRACT FROM AUTHOR]

The pyrochlore-type (Sr 0.6 Bi 0.305) 2 Bi 2 O 7 containing Bi3+ and Bi5+ mixed valent states was first investigated as a new photocatalytic material in this work and successfully synthesized by using a facile hydrothermal method. Our experimental measurements combining with the first-principles calculations show that (Sr 0.6 Bi 0.305) 2 Bi 2 O 7 is n-type semiconductor with a band gap of 1.25 eV. The as-prepared (Sr 0.6 Bi 0.305) 2 Bi 2 O 7 exhibits high photocatalytic efficiency and stability under visible light irradiation. The calculated electronic density of states indicates that Bi and O atoms close to the Sr vacancy probably possess higher activity and are helpful for its photocatalytic performance. • (Sr 0.6 Bi 0.305) 2 Bi 2 O 7 containing Bi3+ and Bi5+ mixed valent states was first investigated as a new photocatalytic material. • The experimental measurements combining with the first-principles calculations show that (Sr 0.6 Bi 0.305) 2 Bi 2 O 7 is n-type semiconductor with a band gap of 1.25 eV. • (Sr 0.6 Bi 0.305) 2 Bi 2 O 7 exhibits high photocatalytic efficiency and stability under visible light irradiation. • Electronic structure calculations indicate that Bi and O atoms close to the Sr vacancy probably possess higher activity and are helpful for its photocatalytic performance. The pyrochlore-type (Sr 0.6 Bi 0.305) 2 Bi 2 O 7 containing Bi3+ and Bi5+ mixed valent states was first investigated as a new photocatalytic material in this work and successfully synthesized by a facile hydrothermal method. The phase structure, morphology, microstructure, elemental composition, and optical properties of samples were characterized in details. The experimental measurements combining with the first-principles calculations show that (Sr 0.6 Bi 0.305) 2 Bi 2 O 7 is a n-type semiconductor with a band gap of 1.25 eV. The photocatalytic activity of (Sr 0.6 Bi 0.305) 2 Bi 2 O 7 was evaluated by the degradation of various organic dyes. Our results show that (Sr 0.6 Bi 0.305) 2 Bi 2 O 7 exhibits high photocatalytic efficiency and stability under visible light irradiation. The calculated electronic density of states indicates that Bi and O atoms close to the Sr vacancy probably possess higher activity and are helpful for its photocatalytic performance. [ABSTRACT FROM AUTHOR]