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The structural, electronic, optical, mechanical, lattice dynamics, and electronic transport properties of SrCu2O2 crystals were studied using first-principles calculations. The calculated band gap of SrCu2O2 using the HSE hybrid functional is about 3.33 eV, which is well consistent with the experimental value. The calculated optical parameters show a relatively strong response to the visible light region for SrCu2O2. The calculated elastic constants and phonon dispersion indicate that SrCu2O2 has strong stability in mechanical and lattice dynamics. The deep analysis of calculated mobilities of electrons and holes with their effective masses proves the high separation and low recombination efficiency of photoinduced carriers in SrCu2O2. [ABSTRACT FROM AUTHOR]

A highly efficient MgBi2O6 (MBO)/TiO2 heterostructured photocatalyst for the evolution of H2 was successfully prepared using a one-step hydrothermal method. The phase structure, microstructure and optical properties of the MBO/TiO2 composites were investigated by various experimental techniques. A series of H2 production experiments were performed under visible light. The measured results indicated that the nanostructured MBO/TiO2 composite, with a stoichiometric molar ratio of MBO:TiO2 = 0.2%, displayed the best H2 production rate of 3413 μmol h−1 g−1. The excellent photocatalytic performance of the obtained composite material was due to the heterojunction formed between MBO and TiO2, which reduced the charge transfer resistance and accelerated the separation efficiency of the photogenerated electron–hole pairs. The reaction mechanism was also discussed in detail. [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]

The pyrochlore-type (Sr 0.6 Bi 0.305) 2 Bi 2 O 7 (SBO) containing Bi3+ and Bi5+ mixed valent states was first investigated as a photocatalyst in our very recent work. To further improve the photocatalytic performance, SBO/TiO 2 heterostructured composites were successfully fabricated using a single-step hydrothermal method. The photocatalytic activity of as-prepared samples was evaluated by the degradation of methylene blue under visible light irradiation and photocatalytic hydrogen generation using water. SBO/TiO 2 composites exhibited remarkably enhanced photocatalytic activity and high stability. The enhancement of photocatalytic performance is attributed to the increase of light absorption and the separation of photogenerated carriers on the interface of SBO/TiO 2 heterostructured composites. • (Sr 0.6 Bi 0.305) 2 Bi 2 O 7 /TiO 2 composites exhibit excellent photocatalytic activity and high stability in photocatalytic removal of MB and hydrogen evolution. • The mechanism of MB photodegradation and photocatalytic generating hydrogen under visible light on (Sr 0.6 Bi 0.305) 2 Bi 2 O 7 /TiO 2 were explored. • The formation of heterojunction should be directly responsible for the enhancement in photocatalytic efficiency of composites. Accelerating the separation efficiency of photoexcited electron-hole pairs with the help of binary heterojunction structure is considered to be a promising approach for significantly enhancing the photocatalytic hydrogen production performance of TiO 2. Providing more (Sr 0.6 Bi 0.305) 2 Bi 2 O 7 (SBO) catalysts to function as active sites of TiO 2 , together with the ability to construct heterojunction structures, is highly desirable for photocatalytic hydrogen evolution and pollutant photodegradation. To achieve this goal, in this work, (Sr 0.6 Bi 0.305) 2 Bi 2 O 7 /P25 (SBO/P25) binary heterojunction catalyst is formed in situ on the TiO 2 surface by a simple one-step hydrothermal method. To evaluate the feasibility of SBO/P25 as a very efficient photocatalyst for degradation of MB and photocatalytic hydrogen evolution, a series of photocatalytic experimental studies were carried out. The experimental result indicated that the existence of heterojunction structure in the SBO/P25 nanocomposites improves the photocatalytic activity of P25. The photocatalytic performance of H 2 evolution from water splitting and MB degradation for an optimal SBO/P25 photocatalyst reached 3.18 mmol g–1 h−1 and 3.42 × 10−2 min−1, respectively, which were 7.40 and 5.26 times higher than those of pure P25, respectively. The significantly improved catalytic capability on SBO/P25 is mainly ascribed to the enhanced visible light absorption and charge transfer in comparison with P25. In addition, SBO/P25 composites have excellent stability and recyclability, showing great potential for application in wastewater treatment and photocatalytic hydrogen evolution. [ABSTRACT FROM AUTHOR]

[Display omitted] • Heterostructured CaCO 3 /NiS composites were synthesized via the facile hydrothermal method. • CaCO 3 /NiS showed the significantly enhanced photocatalytic bactericidal performance. • The active OH and O 2 – cooperate with vacancies to enhance bactericidal performance of CaCO 3 /NiS. CaCO 3 /NiS heterostructured composites were synthesized via the facile hydrothermal method. CaCO 3 /NiS showed the best photocatalytic bactericidal performance when the addition was 15 mg. Under 10 min visible light irradiation, about 90 % of Staphylococcus aureus was killed by composite, which was 4.5 times and 3 times faster than CaCO 3 and NiS. The addition of CaCO 3 significantly improves the photocurrent response and electron-hole pair separation rate of NiS and effectively increases the yield of active free radical groups. These groups cause the bacterial cell membrane to be destroyed and the internal proteins to be flow out, achieving the effect of killing bacteria. The solitary electron pair in the CaCO 3 /NiS composite absorbs visible light energy, making lots of atoms leave the equilibrium check point and effectively preventing the recombination of photogenerated electrons and holes. The inherent active substances (OH and O 2 –) cooperate with vacancies to enhance bactericidal performance. The design and synthesis of CaCO 3 /NiS composites effectively improve the sterilization effect and its application can be expected. [ABSTRACT FROM AUTHOR]

2D Ti3C2Tx MXene, possessing facile preparation, high electrical conductivity, flexibility, and solution processability, shows good application potential for enhancing device performance of perovskite solar cells (PVSCs). In this study, tetrabutylammonium bromide functionalized Ti3C2Tx (TBAB‐Ti3C2Tx) is developed as cathode buffer layer (CBL) to regulate the PCBM/Ag cathode interfacial property for the first time. By virtue of the charge transfer from TBAB to Ti3C2Tx demonstrated by electron paramagnetic resonance and density functional theory, the TBAB‐Ti3C2Tx CBL with high electrical conductivity exhibits significantly reduced work function of 3.9 eV, which enables optimization of energy level alignment and enhancement of charge extraction. Moreover, the TBAB‐Ti3C2Tx CBL can effectively inhibit the migration of iodine ions from perovskite layer to Ag cathode, which synergistically suppresses defect states and reduce charge recombination. Consequently, utilizing MAPbI3 perovskite without post‐treatment, the TBAB‐Ti3C2Tx based device exhibits a dramatically improved power conversion efficiency of 21.65% with significantly improved operational stability, which is one of the best efficiencies reported for the devices based on MAPbI3/PCBM with different CBLs. These results indicate that TBAB‐Ti3C2Tx shall be a promising CBL for high‐performance inverted PVSCs and inspire the further applications of quaternary ammonium functionalized MXenes in PVSCs. [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]

Antioxidants are molecules that can prevent the harmful effects of oxygen, help capture and neutralize free radicals, and thus eliminate the damage of free radicals to the human body. Persimmon tannin (PT) has excellent antioxidant activity, which is closely related to its molecular structure. We report here a comparative study of four characteristic structural units from PT (epicatechin gallate (ECG), epigallocatechin gallate (EGCG), A−type linked ECG dimer (A−ECG dimer), A−type linked EGCG dimer (A−EGCG dimer)) to explore the structure–activity relationship by using the density functional theory. Based on the antioxidation mechanism of hydrogen atom transfer, the most favorable active site for each molecule exerts antioxidant activity is determined. The structural parameters, molecular electrostatic potential, and frontier molecular orbital indicate that the key active sites are located on the phenolic hydroxyl group of the B ring for ECG and EGCG monomers, and the key active sites of the two dimers are located on the phenolic hydroxyl groups of the A and D' rings. The natural bond orbital and bond dissociation energy of the phenolic hydroxyl hydrogen atom show that the C11−OH in the ECG monomer and the C12−OH in the EGCG monomer are the most preferential sites, respectively. The most active site of the two A−linked dimers is likely located on the D' ring C20′ phenolic hydroxyl group. Based on computational analysis of quantum chemical parameters, the A−ECG dimer is a more potent antioxidant than the A−EGCG dimer, ECG, and EGCG. This computational analysis provides the structure–activity relationship of the four characteristic units which will contribute to the development of the application of PT antioxidants in the future. [ABSTRACT FROM AUTHOR]

Selective recovery of indium has been widely studied to improve the resource efficiency of critical metals. However, the interaction and selective adsorption mechanism of indium/iron ions with tannin-based adsorbents is still unclear and hinders further optimization of their selective adsorption performance. In this study, the epigallocatechin gallate (EGCG) monomer, which is the key functional unit of persimmon tannin, was chosen to explore the ability and mechanism of selective separation/extraction of indium from indium–iron mixture solutions. The density functional theory calculation results indicated that the deprotonated EGCG was easier to combine with indium/iron cations than those of un-deprotonated EGCG. Moreover, the interaction of the EGCG–Fe(III) complex was dominated by chelation and electrostatic interaction, while that of the EGCG–In(III) complex was controlled by electrostatic interactions and aromatic ring stacking effects. Furthermore, the calculation of binding energy verified that EGCG exhibited a stronger affinity for Fe(III) than that for In(III) and preferentially adsorbed iron ions in acidic or neutral solutions. Further experimental results were consistent with the theoretical study, which showed that the Freundlich equilibrium isotherm fit the In(III) and Fe(III) adsorption behavior very well, and the Fe(III) adsorption processes followed a pseudo-second-order model. Thermodynamics data revealed that the adsorption of In(III) and Fe(III) onto EGCG was feasible, spontaneous, and endothermic. The adsorption rate of the EGCG monomer for Fe(III) in neutral solution (1:1 mixed solution, pH = 3.0) was 45.7%, 4.3 times that of In(III) (10.7%). This study provides an in-depth understanding of the relationship between the structure of EGCG and the selective adsorption capacity at the molecular level and provides theoretical guidance for further optimization of the selective adsorption performance of structurally similar tannin-based adsorbents. [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]

Schematic of H permeation of dense metallic membrane. • Interaction between H and V surface and bulk are fully studied. • H coverage (θ) effects the adsorption energy of H/V(1 0 0). • H solubility and diffusivity depend slightly on the H concentration. To investigate the H 2 purification mechanism of V membranes, we studied the adsorption, dissociation, and diffusion properties of H in V, an attractive candidate for H 2 separation materials. Our results revealed that the most stable site on the V (1 0 0) surface is the hollow site (HS) for both adsorbed H atoms and molecules. As the coverage range increases, the adsorption energy of H 2 molecules first decreases and then increases, while that of H atoms remains unchanged. The preferred diffusion path of atoms on the surface, surface to first subsurface, and first subsurface to second subsurface is HS → bridge site (BS) → HS, BS → BS, and BS → tetrahedral interstitial site (TIS) → BS, respectively. In the V bulk, H atoms occupy the energetically favourable TIS, and diffuse along the TIS → TIS path, which has a lower energy barrier. This study facilitates the understanding of the interaction between H and metals and the design of novel V-based alloy membranes. [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]

Vanadium-based materials are considered ideal for hydrogen separation membranes owing to their higher hydrogen permeability and mechanical strength and lower cost compared with other widely used materials such as Pd alloys. However, pure V exhibits severe hydrogen embrittlement, which is often solved by alloying. In the present study, we used first-principles method to systematically calculate the hydrogen solubility, diffusivity, and other mechanical properties of different V-based binary alloys, namely, V–Co, V–Mo, V–Pd, V–Ru, and V–W. The alloys were found to possess stable crystal structures, and on exposure to hydrogen, the H atoms preferentially occupied the tetrahedral interstitial sites (TISs) in both the pure V and alloy within the material matrix, preferentially diffusing between TISs. The hydrogen diffusion coefficients of the different alloys decreased in the order V–Pd > V–Co > V–Ru > V–Mo > V–W. The alloys and their hydrides also exhibited good mechanical properties, with their resistances to hydrogen embrittlement decreasing in the order V–Co > V–Ru > V–Pd > V–Mo > V–W. This revealed that the resistance to hydrogen embrittlement of the alloy increased with decreasing atomic size of the alloying element. The findings of this study promise to facilitate the development of novel V-alloy membranes for hydrogen separation and purification. Image 1 • Hydrogen prefers tetrahedral interstitial sites in V-based alloys. • Hydrogen embrittlement and diffusion depend on doping element for V-based alloys. • Effects of alloying elements explained by elastic and electronic effects. • Pd-doped sample has higher D H values and better mechanical properties. [ABSTRACT FROM AUTHOR]

Herein a novel carbon nitride (CN) homojunction between Co2+, cyanate group spatially co-doped and undoped domain is first designed via the ZIF-67 self-templated doping and polymeric condensation of CN, for efficient photocatalytic H 2 evolution (PHE). The microstructure characterizations on the ZIF-67 amount-dependent crystallinity and modifications confirm the successful construction of CN homojunction between Co2+-concentrated domain and undoped domain (CoCN). As a result, the optimized CoCN shows an improved PHE rate (2512 μmol·g−1·h−1) 2.93 times that of pristine CN, with further 1.7 times increase after 5 rounds of cycling (4305 μmol·g−1·h−1). Steady-transient photoluminescence and photo-electrochemical investigations demonstrate that ZIF-67 self-templated doping enhances visible light absorption and the separation/transfer of photogenerated carriers. Further energy-band analysis suggests that the coupling of the doped and undoped domains facilitates the built-in electric field and band bending, leading to Self-S-Scheme mechanism of photocatalysis. This work provides a new method for the design of CN-based junctions via ZIF-67 templated doping boosting photocatalytic activity. [Display omitted] • g-C 3 N 4 homojunction between Co2+, cyanate doped and non-doped domains is designed via ZIF-67 self-templated doping. • The optimized CoCN shows improved PHE rate (2512 μmol·g-1·h-1), 2.93 times higher than that of pristine CN. • The 40 CoCN exhibits superior stability and improved PHE rate with cycling (to 4305 μmol·g−1·h−1 after 5th cycling). • The Self-S-Scheme mechanism was proposed to explain the superior PHE performance. [ABSTRACT FROM AUTHOR]

Extending visible light absorption range and suppressing the recombination of photogenerated charge carriers are always important topics in developing efficient solar-driven photocatalysts. In this study, the thermal treatment process at 400 °C in a high-pressure hydrogen atmosphere was applied to modify graphitic carbon nitride. Compared to the normal atmospheric hydrogen treatment process, this process has the merit of producing nitrogen deficient graphitic carbon nitride in high-yield. The optimal photocatalytic activity of modified graphitic carbon nitride was demonstrated by controlling the treatment duration in the hydrogen atmosphere. The changes in the crystal structure, microstructure and optical properties of carbon nitrides were investigated by several characterizations. The relationship between the photocatalytic activity and structures of graphitic carbon nitride was preliminarily established. The results obtained in this study could provide some new ways of improving the activity of graphitic carbon nitride based photocatalyst. [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]

High defect tolerance and versatile surface engineering of AgInS 2 (AIS) provide platforms to design donor-band (DB) regulated Zn-alloyed AIS (ZAIS) for effective photocatalytic H 2 evolution (PHE). After that, understanding the correlations among DB-related defects, Zn-alloying, and ZnS shell plays critical roles in the design of effective photocatalysts. Initially, the growth kinetics of GSH-capped AIS QDs involving size and defects evolution and the evolution of the PHE rates for samples corresponding to growth kinetics were investigated. In combination with structural characterization, steady-transient photoluminescence (PL) analysis suggests these planar defects constructed via oriented assembly are responsible for enhanced PHE. TGA-assisted Zn-alloying or ZnS deposition was further developed to stabilize or passivate these defects and led to Zn-alloyed AIS (i.e., ZAIS) QDs, or core-shelled AIS@ZnS and ZAIS@ZnS nanocrystals, respectively. Structural investigations confirmed samples' crystal structures, aggregation-related morphologies, and microstructure. Steady-transient PL and transient photocurrent response suggest improved carriers' separation/transfer in this ZAIS, while a significant decrease in carriers' separation/transfer in the corresponding ZnS-shelled counterpart. As a result, the ZAIS shows superior PHE rates of 2.01 mmol. g−1. h−1, ∼ 3.6 times higher than AIS QDs or 11.8 times higher than AIS@ZnS (0.17 mmol. g−1. h−1). Based on band alignment analysis, the total decrease of PHE of AIS@ZnS or ZAIS@ZnS can be ascribed to the passivation of DB-related defects. This work is expected to provide new insight for designing core-shelled or alloy ternary QDs for effective PHE. The raw/processed data required to reproduce these findings cannot be shared at this time as the data also forms part of an ongoing study. [Display omitted] • AIS QDs with interfacial planar defects were prepared by kinetic control of oriented assembly (OA). • Correlation between growth kinetics and PHE suggest that OA-constructed defects favor electron transfer. • ZAIS QDs with OA-constructed defects exhibit enhanced PHE rate, 11.8 or 9.6 times that of ZnS shelled AIS or ZAIS. • The DB-related defects provide an effective carriers' transportation route for boosting PHE. [ABSTRACT FROM AUTHOR]

In this study, it is reported for the first time that porous Sm-doped CaFe 0.5 Mn 0.5 O 3-δ (CFMO) has good microwave absorption properties. In this paper, Sm x Ca 1−x Fe 0.5 Mn 0.5 O 3-δ (x = 0,0.05, 0.1, 0.15, 0.2) (Sm-CFMO) sample powders were prepared by the sol-gel method after calcination at 750 °C. Sm-CFMO was characterized using XRD, SEM, TEM, XPS and VSM, and mixed with paraffin wax for VNA testing. The addition of Sm elements increased the porous structure of CFMO, increased interfacial polarization and defect polarization, and increased oxygen vacancy content, resulting in enhanced charge polarization and dipole polarization, while greatly optimizing the impedance matching of CFMO, and the compounding with paraffin wax also increased the composite with paraffin also increases the interfacial polarization capacity of the material, thus improving the microwave absorption performance of the sample. Moreover, as a new type of absorbing material, this material has great potential for development in the field of absorbing materials and provides a new direction for the development of absorbing materials in the future. • A new oxide wave absorbing material. • Sm doping modulates the holes and oxygen vacancies thus changing the microwave absorption properties. • There is still much room for development in the field of wave absorbing materials. [ABSTRACT FROM AUTHOR]

Perovskite LaCoO 3 has unique mixed ionic electronic and structural defects, which has high research value in microwave absorption field. LaCoO 3 precursor was prepared by sol-gel method, and LaCo 1− x Fe x O 3 (Fe-LCO, x = 0, 0.05, 0.1 and 0.15) with rhombic symmetric structure was successfully synthesized at 600 °C. By refinement of X-ray diffraction (XRD) (Rietveld analysis), it was found that Fe doping makes LaCoO 3 lattice constant and cell volume increase. As a dielectric loss microwave absorbing material, the electromagnetic attenuation of LaCoO 3 is mainly due to the conduction loss, while the interface and dipole polarization are secondary reasons. It finds that Fe doping can improve the wave absorption performance of LaCoO 3. The best absorbing performance was obtained when Fe content is x = 0.1, with the maximum reflection loss of − 38.99 dB at 10.8 GHz and the effective absorption bandwidth (RL<−10 dB) is 4.48 GHz, while the corresponding thickness was only 3 mm. In summary, LaCoO 3 has broad application prospects in X and Ku bands. • The study focus on rare earth perovskite can expand and popularized of their application in the field of absorption. • LaCo 1- x Fe x O 3 composites have tunable Impedance matching performance and high-performance microwave absorption by ions doping. • The influence of dielectric loss and magnetic loss on material is analyzed in detail. • Composites can still maintain the effective bandwidth at 4–5 GHz when the reflection loss reached − 30 dB and above. • This work develops the application potential of LaCoO 3 in the field of absorption other than photocatalytic field. [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]

[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 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]

Exploring novel sensing materials enabling selective discrimination of trace ambient H 2 S at lower temperature is of utmost importance for diverse practical applications. Herein, heterostructural (Sr 0.6 Bi 0.305) 2 Bi 2 O 7 /ZnO (SBO/ZnO) nanomaterials were proposed. Synergetic effect of promoting analyte adsorption (via multiplying oxygen vacancy defects) and reversible sulfuration-desulfuration reaction induced unique band alignment among SBO/ZnO/ZnS, contributes to the sensitive and selective response toward H 2 S molecules. Novel SBO/ZnO (10%) sensor possesses excellent sensing H 2 S performances, including a high response (107.6 for 10 ppm), low limit of detection of 20 ppb, good selectivity and long-term stability. Together with the merits of low operation temperature of 75 °C and weak humidity dependence (endowed by the hydrophobic SBO), present heterostructural SBO/ZnO sensor paves the way for the practical monitoring of trace H 2 S pollutants in diverse workplaces including petroleum and natural gas industries. [Display omitted] • Heterostructural (Sr 0.6 Bi 0.305) 2 Bi 2 O 7 /ZnO is proposed as a novel H 2 S sensor. • Hydrophobic SBO endows SBO/ZnO sensor excellent humidity resistance performance. • SBO/ZnO sensor has a high response, good selectivity and long-term stability. • Low operation temperature eliminates the explosive risk in real applications. [ABSTRACT FROM AUTHOR]

Hydrogen embrittlement causes deterioration of materials used in metal–hydrogen systems. Alloying is a good option for overcoming this issue. In the present work, first-principles calculations were performed to systematically study the effects of adding Ni on the stability, dissolution, trapping, and diffusion behaviour of interstitial/vacancy H atoms of pure V. The results of lattice dynamics and solution energy analyses showed that the V–Ni solid solutions are dynamically and thermodynamically stable, and adding Ni to pure V can reduce the structural stability of various VHx phases and enhance their resistance to H embrittlement. H atoms preferentially occupy the characteristic tetrahedral interstitial site (TIS) and the octahedral interstitial site (OIS), which are composed by different metal atoms, and rapidly diffuse along both the energetically favourable TIS → TIS and OIS → OIS paths. The trapping energy of monovacancy H atoms revealed that Ni addition could help minimise the H trapping ability of the vacancies and suppress the retention of H in V. Monovacancy defects block the diffusion of H atoms more than the interstitials, as determined from the calculated H-diffusion barrier energy data, whereas Ni doping contributes negligibly toward improving the H-diffusion coefficient. [ABSTRACT FROM AUTHOR]

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 (Sr0.6Bi0.305)2Bi2O7 (SBO), containing Bi3+ and Bi5+ mixed valent states, was recently found to be used as a new visible light responsive photocatalyst. Novel SBO/SnO2 heterostructured composites were synthesized through a facile one-step hydrothermal method. The phase structure, morphology, chemical composition, and optical properties of the obtained samples were characterized by XRD, SEM, TEM, XPS, and UV-vis DRS. Compared to pure SBO and SnO2, the synthesized SBO/SnO2 composites exhibited significantly enhanced photocatalytic efficiency. The results indicated that the photoinduced holes and superoxide radicals play a dominant role and are the main reactive species during the degradation of Methylene Blue (MB) solution under visible light irradiation. Heterojunctions, formed in samples, directly contribute to the improvement of photocatalytic efficiency of SBO/SnO2 composites, since it not only broadens the light response range, but also accelerates the separation of photogenerated carriers. [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]

The pyrochlore-type (Sr0.6Bi0.305)2Bi2O7 (SBO) containing Bi3+ and Bi5+ mixed valent states was first investigated as a photocatalyst in our very recent work. To further improve the photocatalytic performance, AgBr/SBO heterostructured composites were synthesized by using a deposition-precipitation method. The characterization of phase structure, morphology, microstructure, elemental composition, and optical properties of the obtained products were performed using X-ray diffractometer (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM)TEM, X-ray photoelectron spectroscopy (XPS), UV-visible diffuse reflectance spectroscopy (UV-vis DRS). The photocatalytic activity of samples was evaluated by degrading methylene blue under visible light illumination. AgBr/SBO composites possess high stability and significantly enhanced photocatalytic performance. The improvement of photocatalytic activity is due to the enhanced light absorption and the separation of photoinduced electrons and holes on the interface of AgBr/SBO heterostructured composites. [ABSTRACT FROM AUTHOR]