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This work proposes an effective design of bioactive 3D-printed Ti-6Al-4V scaffold with the CaO-MgO-SiO 2 glass-ceramic coating to realize a comparable elastic modulus of bone tissue and boost osteogenic differentiation. The improved elastic modulus and stiffness of Ti alloy were achieved via effectively increasing surface area of Ti alloy to reduce stress shielding effect. A hydrophilic surface and bioactive glass-ceramic coating were conducted via chemical etching and heat-treatment under argon atmosphere to enhance cells attachment and boost cell proliferation and osteogenic differentiation. The expression of osteogenic genes in bioactive CaO-MgO-SiO 2 glass-ceramic was evaluated through ALP, OPN, Runx2, and Col1A1 gene markers to explore the mechanism of superior osteogenic differentiation. Significant increase in OPN expression level confirmed the effect of CaO-MgO-SiO 2 coating for the enhancement of osteogenic bioactivity. This work provides a feasible approach through surface etching and bioactive CaO-MgO-SiO 2 glass-ceramic coating on the Ti alloy surface to enhance bioactivity and osteogenesis. [Display omitted] • A compatible bone tissue of 3D-printed Ti-6Al-4V scaffold with the novel bioactive CaO-MgO-SiO 2 glass-ceramic coating. • A superior surface modification to enhance cells attachment and boost cell proliferation and osteogenic differentiation. • This work provides a feasible approach on the Ti-alloy surface to enhance bioactivity and osteogenesis. [ABSTRACT FROM AUTHOR]

Microsheets structural VO 2 (M) was prepared by a hydrothermal and subsequent annealing method in this work. After a system characterization, it is found that VO 2 (M) microsheets obtained by annealing method at 570 °C has a minimum RL value of −45.8 dB and a maximum effective absorption bandwidth (RL < −10 dB) of 3.37 GHz (10.06–13.40 GHz) at 1.9 mm. This result demonstrated that two dimensional (2D) VO 2 (M) have excellent microwave absorption properties. With carefully analysis we concluded that the surface defects and the geometry of the unique 2D geometry of the microsheets VO 2 (M) induces additional polarizations, which improve the microwave absorption properties of samples. A model suggested to explain the enhanced EM wave absorption performance, in which appropriate density of defects induces high defects induced polarization and over high defects density result in the overlap of the bound state around defects and result in the collapse of defects related polarization as illustrated in the abstract graph. Our findings demonstrated that 2D VO 2 (M) can be used as a nice candidate multifunctional infrared/radar stealth materials, thus, extends the application of VO 2 (M). Schematic illustration of the mechanism of EM wave absorption for microsheets VO 2 (M). Image 1 • Two dimensional (2D) VO 2 (M) have excellent microwave absorption properties. • 2D VO 2 (M) is a nice candidate multifunctional infrared/radar stealth materials. • The surface charge resistance could contribute to the resistance loss. • To form surface polarizations, the defects density need to be appropriate. [ABSTRACT FROM AUTHOR]

Plasma electrolytic oxidation (PEO) treatment has been performed on AZ91 Mg alloy in a silicate-containing alkaline electrolyte to disclose the relationship between second phase and resultant coating. The morphology and corrosion behavior were characterized for PEO coatings on three different AZ91 substrates with microstructures altered by heat treatment. In the presence of β phase, both the substrate and PEO coating exhibit enhanced corrosion resistance with finer and more evenly distributed β phase precipitates. In the as-cast AZ91, the anodized coating displays chemically and morphologically discontinuity on α and β phase with very coarse and defective regions on two-phase boundaries. In aged AZ91 with nano-sized β phase precipitates, the PEO coating shows no obvious difference on two-phase boundaries and is more homogenous with fewer pores and defects. The residual stress values given by X-ray diffraction (XRD) analysis indicate that PEO coating on aged AZ91 with finest β phase has the smallest stress which might be the reason for its improved corrosion resistance under synergetic effect of corrosive ions and residual stress. Conversely, in the absence of β phase, i.e. after solid solution treatment, the coating is characterized by the most inhomogeneous microstructure and the worst corrosion resistance, presumably owing to the absence of protective aluminum-containing oxides in the coating and more severe localized oxidation behavior adjacent to AlMn phase. Understanding the effect of second phase on PEO coating will enable us to optimize porous oxide structures for improved corrosion resistance by properly altering the substrate microstructure. [ABSTRACT FROM AUTHOR]

The Cu-4Sn and Cu-4Sn-0.15P alloys with rod diameter of 12.5 mm were prepared and then cold drawn to 2.6 mm via multi-pass drawing. The microstructure evolutions, mechanical properties, and electrical conductivity of Cu-4Sn and Cu-4Sn-0.15P alloys were comprehensively analyzed using optical microscope, scanning electron microscope, tension test and electrical conductivity tester. As compared with the P-free alloy, the addition of P can form a new kind of P-rich phase in the Cu-4Sn alloy, and thus refine the casting microstructure via pinning the grain boundary. The toughening mechanisms of P-rich phases in Cu-4Sn-P alloy wires during cold drawing were investigated. With accumulative drawing strain, the spherical P-rich phase gradually changes into fibrous phases, which thus introduce obvious fiber reinforced strengthening. In addition, the distribution of P-rich phase also enhances the< 111 > texture, and promotes the growth of fragmentation zone. It contributes to an improved ultimate tensile strength and final elongation from 664.5 MPa and ∼ 0 % in Cu-4Sn alloy to 970.5 MPa and 1.53 % in Cu-4Sn-0.15P alloy. Finally, the conductivity for Cu-4Sn-0.15P decreases slightly owing to the intensified electron scattering with high amount of primary phase after the addition of P element. • Adding P to Cu-Sn alloy results in more uniform grain size, while increasing dendrite segregation. • Cu-4Sn-0.15 P alloy wire present more homogeneous distribution of P-rich phases with P content of 9 wt%. • Spherical P-rich phases evolve into fibrous shapes, contributing to higher strength and better elongation. • The addition of P increases the proportion of grain fragmentation during drawing. [ABSTRACT FROM AUTHOR]

A certain amount of silver (Ag)-decorated tin dioxide (SnO 2 ) hollow nanofibers are successfully synthesized by electrospinning technique followed by silver nitrate (AgNO 3 ) treatment at 200 °C for 2 h in air. The crystallization, element composition, microstructure and morphology are investigated using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscope (TEM) and Brunauer-Emmett-Teller (BET) method, respectively. The characterizations show that the crystalline Ag/SnO 2 composites have porous tubular structure with inside diameters of about 220 nm and lengths of several ten microns. The gas-sensing measurements indicate that the Ag-decorated SnO 2 sensor based on the SnO 2 hollow nanofibers shows high response, fast response-recovery capability and excellent selectivity to acetone at low operating temperature of 160 °C. The sensor can effectively detect the low concentration of acetone vapor (about 5 ppm), and the response and recovery time to 50 ppm acetone are around 6 s and 10 s, respectively. The remarkable improvement in gas sensing properties is attributed to the unique 1D hollow nanostructure, the outstanding catalytic oxidation activity of noble metals and p-n hetero interface formed between p-type Ag 2 O and n-type SnO 2 . [ABSTRACT FROM AUTHOR]

Ce/N co-doped TiO 2 /NiFe 2 O 4 /diatomite (CN-TND) hybrid catalyst was prepared via sol-gel method. This ternary composite combined the advantages of three components: adsorption capability of diatomite (Dt), visible-light-driven photoactivity of Ce/N co-doped TiO 2 (Ce/N-TiO 2 ), and magnetic recyclability of ferrite NiFe 2 O 4 . The physicochemical properties of CN-TND were characterized by various analytical methods. The visible-light-driven photoactivity of CN-TND was investigated by the degradation of tetracycline (TC) and disinfection of Escherichia coli ( E. coli ) under visible light irradiation, and the optimal amount of Ce dopant was determined. In addition, the kinetic data of the degradation process were obtained, and the mechanism of this process was proposed. Different scavengers detected the active species involved during the degradation process. CN-TND exhibited ferromagnetism, thus it could be simply separated from the reactor by an external magnet. The reusability test proved its excellent photocatalytic stability and recyclability. We consider it suitable for the application of wastewater treatment. [ABSTRACT FROM AUTHOR]

Novel one-dimensional (1D) magnetic flower-like CoFe 2 O 4 @Bi 2 WO 6 @BiOBr composite photocatalysts were prepared by electrostatic spinning techniques, calcination, solvothermal and precipitation methods. The microscopic morphology and the structure of the photocatalysts were characterized using XRD, SEM, XPS and BET. The photocatalytic efficiency of the photocatalysts was evaluated by measuring the degradation rate of rhodamine B (RhB). The results showed that the efficiency of CoFe 2 O 4 @Bi 2 WO 6 @BiOBr for 3 h is 92.08%. After three cycles, the value remained at 77.71%, showing excellent photocatalytic stability. Furthermore, the possible mechanism of photocatalytic degradation process was proposed by radical trapping experiment and PL test. This work designed and prepared a prospective photocatalyst for degrading organic matters of water environments. • CoFe 2 O 4 was designed as 1D structure to realize the separation and axial transport of photogenerated charges. • CoFe 2 O 4 as the magnetic core facilitated the recycling of the photocatalyst. • Bi 2 WO 6 was designed as flower-like structure to obtain a larger surface area. • BiOBr was combined with Bi 2 WO 6 to construct a heterojunction. [ABSTRACT FROM AUTHOR]

A novel Tm3+: CaY 0.65 Gd 0.35 AlO 4 (Tm3+: CYGA) disordered crystal was successfully grown for the first time, to the best of our knowledge, using the Czochralski method. The optical properties and laser performance were investigated in details. Owing to the addition of Gd3+ ions to the Tm3+: CYA crystal, the Tm3+: CYGA crystal possesses a wider Tm3+ absorption and emission spectra compared with those of the Tm3+: CYA and Tm3+: CGA crystals. In particular, the full width at half-maximum (FWHM) of the emission spectra at approximately 2 µm for the Tm3+: CYGA crystal was 221.3 nm, which is larger than those of the Tm3+: CYA (200 nm) and Tm3+: CGA (151 nm) crystals. Furthermore, an efficient laser operation of the Tm3+: CYGA crystal at 1974 nm was achieved for the first time, with a slope efficiency of up to 31.5 %, corresponding to a maximum output power of 810 mW. The results show that Tm3+: CYGA disordered crystals have the potential to be applied in ∼ 2-μm broadband tunable lasers and ultra-short pulse lasers. [Display omitted] • A novel Tm3+: CaY 0.65 Gd 0.35 AlO 4 (Tm3+: CYGA) disordered crystal has been successfully grown for the first time. • The Tm3+ absorption and emission spectrum has been effectively broadened with the addition of Gd3+. • An efficient laser operation of Tm3+: CYGA crystal at 1974 nm was achieved for the first time. • Tm3+: CYGA crystal could be a promising disordered laser host for ∼ 2 µm broadband tunable laser and ultra-short pulse laser [ABSTRACT FROM AUTHOR]

Donor-π bridge-acceptor (D-π-A) design principle has been widely employed to build functionalized materials with excellent optical properties, whereas its feasibility in electrocatalytic reactions is seldom investigated. We demonstrate the primary study of D-π-A rule in constructing electrocatalysts for oxygen reduction reaction (ORR) purpose by rationally designing three cobalt porphyrins EGZ1–3 with 9H-carbazole, triphenylamine and N,N-diphenyl-[1,1′-biphenyl]-4-amine as the donor substituents, respectively, cobalt porphyrin as the π bridge, and cyanoacrylic acid as the acceptor unit. The electronic properties of the molecules are calculated using the density functional theory and the composite catalysts EGZs/C are characterized by a series of spectroscopic approaches. The electrochemical measurements show that EGZ3/C attains a more positive reduction potential and a greater response current density than EGZ1/C and EGZ2/C, which is possibly due to the optimized electronic structure and the substituent effect. The electron transfer number as well as hydrogen peroxide generation yield values suggest slightly better selectivity of EGZ3/C and EGZ2/C than those of EGZ1/C (i.e., ~ 2.9, ~ 2.9 vs. ~ 2.7 and ~ 54%, ~ 53% vs. ~ 62%, respectively) towards full oxygen reduction. Our result reveals the feasibility of the D-π-A design rule and the importance of molecular electronic state and the substituent feature in constructing ORR electrocatalysts. [Display omitted] • Three donor-π-acceptor cobalt porphyrins are synthesized. • The electronic structure of porphyrins is calculated by density functional theory. • Porphyrin-carbon black composites are studied in oxygen reduction reaction. • The electrocatalyst EGZ3/C attains the best ORR performance. • Both electronic structure and substituents affect the electrocatalytic activity. [ABSTRACT FROM AUTHOR]

• Triphenylamine-porphyrin dyads are synthesized for photocatalysis. • XZP2/TiO 2 exhibits the most efficient charge separation as photoelectrode. • XZP2/TiO 2 performs the best in photodegradation of acid black and tetracycline. • Photocatalytic mechanism and interfacial charge transfer pathways are proposed. [Display omitted] Three triphenylamine (TPA) substituted dichromophoric zinc porphyrins XZP1–3 and a single zinc porphyrin ZP1 have been rationally designed to construct dye-sensitized TiO 2 nanoparticles to explore the feasibility of dichromophoric dye design for photocatalysis. TPA, N,N -diphenyl-(1,1′-biphenyl)− 4-amine and a carbazole-diphenylaniline derivative are attached to the meso -position of porphyrin core as the second chromophore. The electronic structure of the porphyrins is studied by density functional theory (DFT) calculations and the dye-sensitized composites are investigated using couples of spectral and electrochemical techniques. XZP2/TiO 2 exhibits the smallest charge transfer resistance and the longest electron lifetime among the investigated composites. The same catalyst performs the highest efficiency in photodegradation of both acid black (AB1) and tetracycline (TC) polluted water samples. Electronic paramagnetic resonance and radical quenching experiments reveal that the priority reactive species are superoxide radicals (•O 2 −) and holes (h+), suggesting the efficient charge separation at the porphyrin-sensitized TiO 2 interface. This work demonstrates the facilitated interfacial charge separation using dichromophoric dye-sensitized semiconductor particles for photodegradation and, the insights should aid in dyad design for photocatalysis application. [ABSTRACT FROM AUTHOR]

With the seriously environmental pollution, photocatalytic technology has been extensively studied for ensuring the continuous development of society. As a type of appealing semiconductor, bismuth-based materials have become a research hotspot in the field of photocatalysis due to their unique electronic structure, appropriate bandgap energy, high light quantum and outstanding electronic transmission efficiency. However, the separation and recovery of photocatalyst from reaction systems is difficult. The most promising strategy to facilitate separation process is to introduce a magnetic component. This review has mainly involved a classification, current challenges and prospects on the recent progress in fabrication of magnetic bismuth-based photocatalytic materials, as well as the list of their degrade object, dosage, initial concentration and reaction time. [ABSTRACT FROM AUTHOR]

• A single host whit emitting phosphor Ca 3 (SiO 3) 3 :Eu2+, Mn2+ is monodispersed and uniform spherical particles. • The samples are monodispersed and uniform spherical particles with a diameter about 700 nm. • The nonradioactive energy transfer from the lowest 5d levels of Eu2+ to 3d excited levels of Mn2+ was efficient. Eu2+ ions were excited by UV LEDs chip and transmitted energy to Mn2+ ions, then emitted white light. • The color-rendering index and high correlated color temperature of Ca 3 (SiO 3) 3 :Eu2+, Mn2+ x can be adjusted by simply changing the concentration of Eu2+ and Mn2+. A single host phosphor Ca 3 (SiO 3) 3 :Eu2+, Mn2+ (CSO: Eu2+, Mn2+) with good monodispersity has been synthesized by high temperature solid state reaction combined with precursor, using porous silica as template and raw material. The phase, size and surface morphology of the phosphor were measured by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Luminescence properties were characterized by photoluminescence excitation (PLE) and emission spectra from room temperature to 480 K. CSO: Eu2+ has strong excitation band in UV region and emits blue light. To compensate for the lack of orange-red emission region and avoid using multiple phosphors, Mn2+ ions are introduced into the Ca2+ sites. The remarkable enhancements of the orange band attributed to an efficient nonradioactive energy transfer from Eu2+ to Mn2+, which has been testified by the photoluminescence spectra and fluorescence decay dynamics. The emitting light of Eu2+, Mn2+ co-doped CSO could be modulated from cool white to warm white by changing the molar ratio of Eu2+ and Mn2+. [ABSTRACT FROM AUTHOR]

This article has been retracted at the request of the Editor-in-Chief and the corresponding author of this article. The claim of the corresponding author is that, after conducting a series of experiments, they have found that some parts of the published results cannot be repeated. Thus the request of the authors is to retract the published article, due to the rigorous scientific attitude. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal. [ABSTRACT FROM AUTHOR]

Iron-based soft magnetic composites with phosphate-polyimide (PI) insulating layer were successfully fabricated by phosphating and imidization. The effect of phosphoric acid content on microstructure and compressibility of iron powder, and magnetic properties of the cores were investigated. The results demonstrate that the inner inorganic coated layer mainly consists of iron phosphate and ferrous phosphate. With increasing phosphoric acid content, the thickness of phosphate increases gradually, resulting in the reduction of density, maximum permeability and magnetic induction intensity. When the content of phosphoric acid reaches above 0.3 wt%, the bonding strength between the PI coating and iron particles is reduced, leading to the breakage of insulating layer and the augment of core loss. Owing to the excellent thermal stability of PI, magnetic powder cores can be cured at the temperature up to 400 °C. The sample coated with 0.1 wt% phosphoric acid and 1.5 wt% PI exhibits excellent magnetic properties. The maximum permeability reaches 201.4, and the core loss (186.6 mW/g) is less than 15% of monolayer phosphate coated sample (measured at 50 mT and 100 kHz). Additionally, the corrosion resistance of the sample is significantly improved. • Iron-based soft magnetic composites were fabricated by phosphating and imidization. • The phosphate-polyimide coated SMCs can be cured at the temperature up to 400 °C. • The effect of phosphoric acid content on the magnetic properties was investigated. • Magnetic core exhibits lower core loss and higher maximum permeability. [ABSTRACT FROM AUTHOR]

Piezo-catalysis represents a promising and environmentally-friendly technology for dye degradation, but the commonly used BaTiO 3 piezoelectric material still face bottleneck of relative low piezo-catalytic activity. Enhancement of its catalytic activity via diversified means is crucial for improving the degradation efficiency and implementation of water treatment. In this study, we synthesized Ba 1- x Sr x TiO 3 nanoparticles utilizing the sol-gel method. The highest catalytic performance for degrading rhodamine B is at x = 0.15 through the piezo-photocatalytic synergy, displaying a degradation rate of 92.66 % within 18 min and an impressive reaction rate of 14.26 × 10−2 min−1, surpassing most of other BaTiO 3 -based materials. Importantly, the nanoparticles exhibited excellent catalytic degradation performance for a variety of pollutants under different environments. In addition, it is confirmed that Sr2+ doping can enhance the catalytic efficiency via three pathways, i.e. modifying energy band gap, modulating grain size as well as Curie temperature. This work provides a convenient strategy for the rational regulation of catalytic performance in BaTiO 3 -based piezoelectric materials. [Display omitted] • Sr-doping in BaTiO 3 for simultaneous regulation of grain size, T c and energy band. • Piezo-photocatalysis achieves stronger synergic effect than single catalysis. • Various mechanisms work together to improve the catalytic performance. • Maintaining high catalytic activity in various conditions for practical applications. [ABSTRACT FROM AUTHOR]

Abstract The crack-free H13 block was deposited through additive manufacturing with the cold metal transfer technology. The internal 3D pore distribution, the microstructural evolution, and the mechanical performances were explored. A negligible porosity with dispersive-distribution and spherical-shape below 0.001% guaranteed a sound metallurgical bonding within the as-deposited part. The martensite laths growth direction varied dramatically with a very short position variation, as well as the block-like size-inconsistent δ-ferrite presence in the overlap zone, which were mainly generated by the thermal flux direction from the center to margin within a single arc track. Massive second-phase particles with morphology-diversity and size-nonuniformity were precipitated, indicating a strong dependency with the intrinsic heating treatment. The enhanced microhardness in the body zone was attributed to the martensite strengthening mechanism, while slightly low hardness was produced due to the soft δ-ferrite formation. When compared with the other zones, the enhanced ultimate tensile strength was obtained in the body zone at the expense of tensile ductility, revealing a positive relationship with the rise of hard martensite percentage. This work demonstrated that a crack-free H13 block with limited porosity and desirable mechanical properties was deposited using the present technology, despite the nonhomogeneous microstructures. Highlights • A crack-free H13 block part innovatively and firstly deposited using the robotic CMT technology. • A negligible porosity even below 0.001% guaranteed a sound metallurgical bonding behavior. • Varied microstructural evolution with a very short position variation within a single arc track. • Desirable mechanical performances due to martensite strengthening and precipitation strengthening. [ABSTRACT FROM AUTHOR]

Abstract In order to effectively polish the surface of the titanium alloy workpiece, a novel type of iron nitride magnetic abrasives was designed, prepared and characterized. Theoretically, first-principles were used to analyze the effects of phase compositions of iron nitrogen compounds on the mechanical and magnetic properties of the abrasive, and ε-Fe 3 N and γ′-Fe 4 N were determined as the grinding phase compositions with the simultaneously improved properties of hardness, ductility and magnetism. In the experiments, the core-shell structured iron nitrogen compounds were prepared by nitriding the iron powders of about 250 μm with ammonia at 600 °C, and the effects of nitriding time, ammonia pressure and cooling method on the product were investigated. The composition, morphology, magnetic properties and mechanical properties of the product were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), magnetometer and nanoindenter, respectively. Under experimental conditions of ammonia pressure of 0.2 Mpa, nitriding time of 3 h and water quenching, the abrasive was obtained with the external grinding phase of ε-Fe 3 N and γ′-Fe 4 N in a thickness of 35.10 μm and the internal ferromagnetic phase of α-Fe. Its magnetic saturation intensity and hardness were 148.5 A m2 kg−1 and 8.15 GPa, respectively. Grinding with this abrasive, the surface roughness of Ti–6Al–4V alloy plate was effectively reduced from 0.305 μm to 0.077 μm. Highlights • Iron nitride magnetic abrasives were designed by first-principles calculations. • Grinding phase was formed in ferromagnetic phase by nitriding Fe powder with NH 3. • Higher NH 3 pressure and water quenching improved the hardness of the abrasives. • Nanoindenter was used for characterizing the hardness of the abrasives. • The abrasives can effectively polish Ti–6Al–4V plate in MAF process. [ABSTRACT FROM AUTHOR]

Wire arc additive manufacturing (WAAM) technology was adopted to deposite 2Cr13 thin-wall part using robotic cold metal transfer (CMT) equipment; the process stability, phase identification, microstructural evolution, and tensile properties in different layers were investigated. The results showed that a smooth surface was obtained for each layer due to the stable droplet transfer process, which ensured a stable deposition process. Positions in different layers had no significant influence on the structural aspects of the as-fabricated part according to XRD results. Elongated ferrite grains and fine-grained acicular martensite within the matrix in the top layer were recrystallized, instead of a spatial periodicity of martensite laths within equiaxed ferrite grains in the inner layers. Martensite content was increased gradually away from the base metal in the 05–25 th layers except nearly 100% martensite in the first layer. Long axis of martensite laths was randomly distributed in the X-Y plane in the both top and middle regions, while an epitaxial growth parallel to the building direction was found in the X-Z and Y-Z planes. Higher homogeneous ultimate tensile strength (UTS) and strong anisotropy in poorer ductility were obtained for the AM part when compared with the as-solutioned counterpart. Fracture behavior was transformed from ductile to mixed-mode, and finally to brittle from the 01 st layer to the 25 th layer. [ABSTRACT FROM AUTHOR]

Asymmetric-structured La 5.5 W 0.6 Mo 0.4 O 11.25-δ (LWM) ceramic membranes were fabricated by phase-inversion process followed by sintering. Finger-like pores with distributed small pores extend through most bulk of the membrane and reduce the thickness of the dense layer. The hydrogen permeation properties of the LWM asymmetric membranes were investigated as a function of temperature and H 2 partial pressures in feed gas at the temperature range from 800 °C to 1000 °C. The hydrogen permeation flux as a function of time at 900 °C under humid atmosphere was also investigated. Compared with the conventional symmetric dense LWM membrane, the hydrogen permeation flux through the asymmetric membrane is tripled. Furthermore, the chemical stability of LWM oxides after phase-inversion process and H 2 permeation were confirmed by XRD. [ABSTRACT FROM AUTHOR]

In the Co/Cu-ZIF/Fe 2 O 3 p-n junction, the electrons flow from n-type Fe 2 O 3 to p-type bimetallic Co/Cu-ZIF, resulting in the band bending and inner electric field from positive Fe 2 O 3 to negative Co/Cu-ZIF. The density function theory calculation uncovered that such an electronic property change could boost the water oxidation performance. Experiments reveal that the obtained Co/Cu-ZIF(1/1)/Fe 2 O 3 heterojunction achieves a low overpotential of 273 mV and a small Tafel slope of 133.6 mV·dec-1 at 10 mA·cm-2 current density, which are significantly lower than that of monometallic Co-ZIF and FC substrate. Moreover, the p-n conjunction can promote the electrocatalytic degradation of 4-nitrophenol, and the removal rate reaches 80%, current efficiency (23.97%) and low energy consumption (79.5 Wh·L-1) at 50 mA·cm-2. Therefore, it is expected that MOFs-based p-n conjunction with modulation of electron configuration is a promising alternative to boost the electrochemical water oxidation. [Display omitted] • The monolithic electrode of Co/Cu-ZIF/Fe 2 O 3 p-n junction integrated OER and oxidation of 4-NP. • The doping of second Cu center induced the high-valence Co3+ active sites and the O-containing intermediates. • The band bending and Co3+ led to charge redistribution and electron transfer, boosting the electrocatalytic activities. [ABSTRACT FROM AUTHOR]

The stress-induced phase transformation and micromechanical behavior of CuZr-based alloy were investigated by in-situ neutron diffraction. The pseudoelastic behavior with a pronounced strain-hardening effect is observed. The retained martensite nuclei and the residual stress obtained from the 1st cycle reduce the stress threshold for the martensitic transformation. A critical stress level is required for the reverse martensitic transformation from martensite to B2 phase. An increase of intensity for the B2 (110) plane in the 1st cycle is caused by the twinning along the {112}<111> twinning system. The convoluted stress partitioning influenced by the elastic and transformation anisotropy along with the newly formed martensite determines the microstress partitioning of the studied CuZr-based alloy. The reversible martensitic transformation is responsible for the pseudoelasticity. The macro mechanical behavior of the pure B2 phase can be divided into 3 stages, which are mediated by the evolvement of the martensitic transformation. This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( http://energy.gov/downloads/doe-public-access-plan ). [ABSTRACT FROM AUTHOR]

• The radii of the nanoscale precipitates are dramatically smaller in the annealed Cu-2Ag-0.14La alloy than in the annealed Cu-2Ag alloy. • The grain size of annealed Cu-2Ag-0.14La alloy is always smaller than that of the annealed Cu-2Ag alloy from 400 °C to 650 °C. • Precipitation strengthening of nanoscale precipitates in the matrix and grain-boundary strengthening during grain refinement substantially improve the yield strength of the Cu-2Ag-0.14La alloy. [Display omitted] A new Cu–2Ag–0.14La alloy is developed to enhance the mechanical property and electrical conductivity with inducement of Ag-rich primary phases and finer nanoscale Ag precipitates. The microstructural evolution and mechanical properties of Cu–2Ag–0.14La and Cu–2Ag alloys obtained by drawing and annealing were then summarized and analyzed. The results indicate that both the yielding and ultimate tensile strengths of annealed Cu–2Ag-0.14La alloy were reinforced after La modification. The average grain sizes of two alloys increase during annealing, but the size ratio (R Cu-2Ag-0.14La /R Cu-2Ag) dramatically varies with rising the heat temperature, evolving from 70.48% at 400 °C to 43.78% at 650 °C. Meanwhile, it is found that the refined grains sizes in Cu-2Ag-0.14La alloy are closely related to the nano-scale precipitates (~450 nm), which hinder the formation of subgrain boundaries at 400 °C, and impose a stronger pinning effect on boundary migration of recrystallized grains during annealing (≥ 450 °C). Consequently, higher hardness and electrical conductivity are contributed by grain refinement and dispersion strengthening of the nanosized phases. [ABSTRACT FROM AUTHOR]

• MnO 2 was designed as flower-like structure to obtain a larger surface area. • BiOBr and Bi metals were combined with MnO 2 to construct a heterojunction. • The magnetic core facilitated the recycling of the photocatalyst. • The core-shell structure can generate synergistic effects of different components. • Composite materials exhibited excellent dyes degradation capabilities. The flower-like Fe 3 O 4 /SiO 2 /MnO 2 /BiOBr-Bi magnetic composite photocatalyst was prepared in this work. The combination of BiOBr and Bi metal with flower-like MnO 2 constituted a heterojunction structure, which increased the specific surface area of the photocatalyst and promoted the separation of photo-generated carriers, resulting in the enhanced catalytic performance. The morphologies and the compositions of the photocatalyst were characterized in detail. Under simulated light, the degradation of organic dye methylene blue (MB) was used to research the photocatalytic activity. In the case of 15 mg photocatalyst, it was found that the photocatalytic degradation efficiency to the MB solution was 95.23% within 150 min. Moreover, the degradation rate of MB could still reach 81.11% after four cycles. The design of flower-like composites with magnetic core-shell structure provided a new method for fabricating photocatalysts having excellent catalytic performance and cyclic stability. [ABSTRACT FROM AUTHOR]

Metallic lithium (Li) is considered to be one of the most promising anodes for Li-ion batteries due to its high theoretical capacity and low reduction potential. However, dendritic growth and substantial volume variations during battery operation make it difficult for commercialization. Here, a graphene and SiO 2 composites material was presented as a lithiophilic host to enable superior long-term cycling for Li-metal anode. The porous skeleton of graphene with excellent electronic conductivity can effectively reduce the actual current density and suppress the volume expansion. And the SiO 2 particles with excellent ionic conductivity can significantly suppress the growth of Li dendrites and regulate the nucleation sites. So doping SiO 2 nanoparticles between graphene sheets can significantly suppress the growth of Li dendrites and the volume expansion effect of metallic Li deposition, while also providing good electrochemical performance. Benefitting from these synergistic effects, the Li-GF@SiO 2 battery exhibits excellent electrochemical reversibility over 500 cycles depositing 1 mAh cm−2 of metallic Li at a current density of 1 mA cm−2, and the coulombic efficiency of the Li-GF@SiO 2 battery is still as high as 97%, but the Li-Cu battery decays after 75 cycles. So this hierarchical SiO 2 -microsphere-graphene host demonstrates great potential for Li batteries. • The type of graphene and SiO 2 composite material is designed for the stable host of lithium (Li) metal anode because of its lithiophilic character. • The hierarchical silica spheres can effectively reduce the actual current density and guide the nucleation of Li metal. • The superior electronic conductivity and ionic conductivity of composite materials are utilized to suppress the growth of Li dendrites and volume expansion. • The novelty lithiophilic host of Li metal anode can achieve over 500 cycles at a current density of 1 mA cm−2 for Li-metal batteries. [ABSTRACT FROM AUTHOR]

The cyclic stability of hydrogen absorption and desorption is an important indicator of hydrogen storage alloy. The decay mechanism was roundly investigated by controlling the depth of dehydrogenation (DOD) of the V 40 Ti 25.5 Cr 26.5 Fe 8 alloy during the process of hydrogen ab/desorption cycles. The V 40 Ti 25.5 Cr 26.5 Fe 8 alloy exhibits the hydrogen desorption capacity of 2.36 wt% at 323 K in the first cycle. After 30 cycles, the decay rate of the hydrogen desorption capacity is only 4.37 % at 40 % DOD, but rises to 8.74 % at 100 % DOD. The hydrogen desorption capacity (C), plateau pressure (P) and micro-strains (S) all show an "acceleration followed by slowing" exponential variation trend with the increase of cycle number (x). Additionally, any two of C , P and S show linear correlation. It is considered that the micro-strains in the crystal lattice is the main factor for the decay of the hydrogen desorption capacity and the plateau pressure. On the premise of ensuring the valid hydrogen storage capacity to meet the requirements of the application, properly reducing DOD per cycle can effectively reduce the micro-strains accumulation and cell volume expansion, thus improving the cyclic stability of the alloy. Moreover, the application of this alloy in a fuel cell bicycle was investigated, and the total range and mileage per unit weight of the alloy are up to 100.8 km and 15.7 km/kg, respectively. Compared with the lead-acid battery, lithium-ion battery and LaNi 5 -based hydrogen fuel cell, the V-Ti-Cr-Fe-based fuel cell shows significant advantages. ● A bran-new method was proposed to slow down the decay of the dehydrogenation capacity of the V 40 Ti 25.5 Cr 26.5 Fe 8 alloy. ● The alloy decay rate of the dehydrogenation capacity is only 4.37% after 30 cycles at 40% DOD, only half that at 100% DOD. ● Six functions were proposed to explain the influences of the micro-strains in the lattice. ● This alloy fuel cell shows significant advantages compared with other batteries through application in a fuel cell bicycle. [ABSTRACT FROM AUTHOR]

In this work, hierarchical hexagonal nanoplates NiO composite with microcrystalline graphite are successfully synthesized by a hydrothermal process. Carbon nanofibers are disaggregated to the microcrystalline graphite and they are dispersed in NiO hexagonal structure (H–NiO sample). Microcrystalline graphite (1 wt% of the composite) has effect on growth NiO hexagonal nanoplates, improving the sample conductivity and stability. At the first cycle, H–NiO sample presents a high discharge capacity of 1357.2 mAh g−1 and a charge capacity of 1002.6 mAh g−1 with an initial coulombic efficiency of 73.9%. After 45 cycles, H–NiO sample exhibits a high reversible capacity of 1111.6 mAh g−1. The lithium diffusion coefficient of the H–NiO is calculated to be 7.517 × 10−12 cm2 s−1 with faster Li+ diffusion ability than pure NiO sample. The microcrystalline graphite in the composite electrode can effectively decrease the volume change and pulverization of NiO component, meanwhile, it hinders the aggregation in the cycled electrode. The microcrystalline graphite with intrinsic stability has potential application in producing composites with other metal oxides for highly reversible lithium storage capability. The as-produced microcrystalline graphite is in-situ composite with NiO hexagonal plates and play the key role in enhancement of electrochemical properties. The H–NiO nanoplates which is supported by microcrystalline graphite exhibits an excellent cycling stability, with a high reversible capacity of 1111.6 mAh g−1 at a current density of 100 mA g−1 after 45 cycles. Image 1 • Hierarchical hexagonal nanoplates NiO with microcrystalline graphite is synthesized. • Carbon nanofibers disaggregated to microcrystalline graphite and composite with NiO. • Microcrystalline graphite plays the key role in enhanced electrochemical properties. • H–NiO nanoplates presents discharge/charge capacities of 1357.2/1002.6 mAh g−1. • H–NiO exhibit reversible capacity of 1111.6 mAh g−1 after 45 cycles. [ABSTRACT FROM AUTHOR]

Abstract Self-activated phosphors could convert high energy light into visible light from the internal ion groups of host lattice before externally introducing luminescent ions. In this work, we propose a facile route to synthesize self-activated oxyfluorotungstate (Na 2 WO 2 F 4) phosphor. Excited by the UV light, the emission spectrum covers nearly the entire visible light region. After careful analysis of the first principle calculation results and other sufficient investigation, it is believed that the efficient emission of Na 2 WO 2 F 4 phosphor comes from the strong parity-allowed absorption of O-2 p to W-5d charge transfer band. Moreover, the quantum efficiency of Na 2 WO 2 F 4 phosphor reaches up to 76% at room temperature. However, the increase of temperature not only lowers the intensity of the PL emission and the quantum efficiency but gives rise to a blue shift of the emission maxima, due to the phonon interaction with the luminescence center in a vibrating crystalline environment. Graphical abstract Image 1 Highlights • A self-activated phosphor Na 2 WO 2 F 4 was obtained by a facile route. • The emission spectrum of Na 2 WO 2 F 4 covers nearly the entire visible light region. • The quantum efficiency reaches up to 76% at room temperature. • Thermal quenching and high-energy shift of Na 2 WO 2 F 4 were observed and analyzed. [ABSTRACT FROM AUTHOR]

A series of Eu 2+ /Ln 3+ (Ln = La-Lu) co-doped SrS phosphors were successfully prepared by a conventional solid-state reaction. Both red persistent luminescence and near-infrared photo-stimulated red luminescence of Eu 2+ was observed in the Eu 2+ single-doped SrS sample benefited from the existence of intrinsic shallow and deep traps. Importantly, different to other Ln 3+ (Ln = La, Ce, Pr, Nd, Gd, Tb, Dy, Er, Ho, Tm, Yb, Lu) codopants, Sm 3+ ions were demonstrated to play an important role in increasing states/densities of deep traps, being beneficial to significantly enhance photo-stimulated red luminescence of Eu 2+ under the excitation of 808/980/1530 nm laser. Finally, persistent decay kinetics under the irradiation of periodically incident near-infrared laser were investigated to reveal the releasing process of electrons captured in the deep traps of Eu 2+ /Sm 3+ :SrS phosphor. [ABSTRACT FROM AUTHOR]

In this work, the morphology, crystallization process and crystal structure of the phase-change material TiSbTe (TST) alloy have been successfully established, which is essential for applying this alloy in phase-change memory. Specifically, atomic force microscopy (AFM) was employed to characterize the as-deposited and post-annealed thin films, and transmission electron microscopy (TEM) analyses of the films annealed in situ were used in combination with selected-area electron diffraction (SAED) and radial distribution function (RDF) analyses to investigate the structural evolution from the amorphous phase to the polycrystalline phase. Moreover, the presence of structures with medium-range order in amorphous TST, which is beneficial for high-speed crystallization, was indicated by the structure factors S(Q)s . The crystallization temperature was determined to be approximately 170 °C, and the grain size varied from several to dozens of nanometers. As the temperature increased, particularly above 200 °C, the first single peak of the rG(r) curves transformed into double shoulder peaks due to the increasing impact of the Ti Te bonds. In general, the majority of Ti atoms were doped into the SbTe lattice and tended to form structural defects, whereas the remainder of the Ti atoms aggregated, leading to the appearance of TiTe 2 phase separation, as confirmed by the SAED patterns, high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) images and corresponding energy-dispersive X-ray (EDX) mappings. [ABSTRACT FROM AUTHOR]

Lanthanide doped Ba 1-x Sr x TiO 3 (x = 0–1) solid-solution phosphors were successfully prepared by a conventional solid-state reaction. Using Eu 3+ dopants as the structural probe, the variation of 5 D 0 → 7 F 2 / 5 D 0 → 7 F 1 emission intensity ratio with increase of Eu 3+ content and the excitation-wavelength-dependent luminescence in the Ba 1-x Sr x TiO 3 sample were demonstrated to be originated from the different emission behaviors of Eu 3+ in Ba 2+ /Sr 2+ site and Ti 4+ site. Furthermore, upconversion luminescence for the Yb 3+ /Er 3+ co-doped Ba 1-x Sr x TiO 3 samples were investigated, and it was found that the emission intensity of Yb 3+ /Er 3+ : Ba 0.5 Sr 0.5 TiO 3 phosphor was about 5 and 2 times as high as those of Yb 3+ /Er 3+ : BaTiO 3 and Yb 3+ /Er 3+ : SrTiO 3 ones. Using the investigated Yb 3+ /Er 3+ : Ba 0.5 Sr 0.5 TiO 3 solid-solution as the optical thermometric medium, the temperature sensitivity was determined to be 0.76% K −1 at the temperature of 610 K based on the temperature-dependent fluorescence intensity ratio of the thermally coupled 2 H 11/2 and 4 S 3/2 emitting-states of Er 3+ . [ABSTRACT FROM AUTHOR]

It has been a hot research topic to look for inexpensive alternative oxygen evolution reaction (OER) catalysts to replace noble metal-based materials due to their scarcity. Transition metals are ideal candidates because of their high abundance, impressive activities, and easy accessibility. However, a facile method leading to improved performance and stability is still needed. Herein, a highly efficient carbon-encapsulated bimetal catalyst derived from Ni-based metal-organic-frameworks (MOF) was successfully prepared through the low-temperature (350 ℃) pyrolysis of Prussian blue analogue (PBA) precursors under H 2 /Ar atmosphere. Cube-structured PBA as template and precursor，parameters during the pyrolysis process including temperature and calcination atmosphere can be tuned to control the structure and properties of the catalysts. Benefiting from the porous three-dimensional (3D) cubic structure and abundant defect-rich amorphous N-doped carbon shell, Ni 3 Fe@NC-350 exhibits excellent OER activity. The as-prepared catalysts exhibited excellent catalytic performance for OER in 1.0 M KOH with an overpotential of 237 mV to achieve 10 mA cm−2. More importantly, the presented catalyst has an extremely good durability. • A simple low-temperature annealing method was developed to produce alloy encapsulated with N-doping carbon. • The NiFe PBA was employed as nitrogen and carbon source. • The increased activity of OER is due to the synergy of Ni 3 Fe alloy and N-doped carbon layer. • Theoretical calculations revealed that the synergistic effect of NiFe alloy nanoparticles and N-doped carbon layer. [ABSTRACT FROM AUTHOR]

Yb/Tm: YF 3 nanoparticles embedded transparent bulk glass ceramic was successfully prepared to explore its possible application in optical temperature sensors. Specifically, owing to the competition of electron population in the thermally coupled Tm 3+ 3 F 2,3 and 3 H 4 excited states, two upconversion emission bands corresponding to Tm 3+ : 3 F 2,3 → 3 H 6 transition and 1 G 4 → 3 F 4 one exhibited opposite temperature-dependent behaviors, which resulted in monotonous enhancement of the related fluorescence intensity ratio with increase of temperature. As a consequence, Tm 3+ activators in the present YF 3 glass ceramic had advantages of a high sensitivity of 1.84% per K, an avoidable spectral overlapping and a negligible thermal effect for accurate temperature detecting. [ABSTRACT FROM AUTHOR]

Sb–Te alloy is widely considered as one of the important materials for phase change memory (PCM) with fast operation speed. However, the poor amorphous phase stability limits its wide application. In this work, silicon carbide (SiC) doped Sb 2 Te (Sb 2 Te-SiC) nanomaterial was proposed to improve the thermal stability of Sb 2 Te. It was found that the crystallization temperature of Sb 2 Te was remarkably improved from 149 °C to 251 °C. Accordingly, the temperature for 10-year data retention increases from 56.5 °C to 156.4 °C. X-ray diffraction and transmission electron microscope results indicate that the grain size of Sb 2 Te-SiC film was largely reduced with SiC doping. Besides, experimental results show the Sb 2 Te-SiC nanomaterial is very uniform and no phase separation was observed even after 300 °C annealing. Furthermore, the Sb 2 Te-SiC nanomaterial based PCM cells show fast operation speed of 7 ns and good endurance ability of 2.1 × 10 4 cycles. [ABSTRACT FROM AUTHOR]

Lanthanide-activated cubic Na 5 Gd 9 F 32 nanocrystals were precipitated from a borosilicate glass with a specifically designed composition. The precursor glass is already phase-separated after melt-quenching, which is beneficial to the realization of the controllable glass crystallization for affording desirable size, morphology and activator partition. Elemental mapping in the scanning transmission electron microscopy evidenced that the segregation of lanthanide ions into the Na 5 Gd 9 F 32 lattice was in situ formed without the requirement of long-range ionic diffusion. Impressively, such fabricated glass ceramic co-doped with Yb 3+ /Er 3+ ions exhibited intense upconversion luminescence, which was about 500 times higher than that of the precursor glass, and its luminescent color could be easily tuned from red to green by controlling glass crystallization temperature. It is anticipated that such phase-separation synthesis strategy with precise control over nanostructure of glass ceramics offer a great opportunity to design other highly transparent nanocomposites with a wide range of tunable optical properties. [ABSTRACT FROM AUTHOR]

Highlights: [•] We have synthesized the layered LiNi0.5Mn0.5O2−xF x (0⩽ x ⩽0.04) by hydroxide co-precipitation method. [•] The structure, morphology and electrochemical performance of LiNi0.5Mn0.5O2 are influenced by F doping effect. [•] The cations mixing of pure LiNi0.5Mn0.5O2 decreases and Li+ diffusion coefficient increases with doping F. [•] The reversible capacity of LiNi0.5Mn0.5O1.96F0.04 is 155.0mAhg−1 after 50 cycles at 0.2 C, 0.5 C and 1.0 C ratios between 2.8 and 4.6V. [ABSTRACT FROM AUTHOR]

Abstract: A series of lead-free piezoceramics of (1− x)K0.5Na0.5NbO3–xBi0.8La0.2FeO3 [(1− x)KNN–xBLF, 0.005≤ x ≤0.04] were synthesized by conventional solid-state sintering. Crystal structures and microstructures of the ceramics were characterized by X-ray diffraction and transmission electron microscopy. X-ray diffraction substantiates the existence of an orthorhombic-tetragonal morphotropic phase boundary (MPB) near x =0.01. Highest electrical performances were observed near the MPB. The maximum remnant polarization, piezoelectric coefficient, and coupling factor were measured as 22.5μC/cm2, 144pC/N, and 0.34, respectively. The effects of BLF on structures and electrical properties were discussed. Our results might be helpful for developing KNN-based piezoelectric ceramics. [ABSTRACT FROM AUTHOR]

Abstract: In order to improve the properties of Sn–3.8Ag–0.7Cu and Sn–0.5Cu–0.05Ni solders, 0–0.1wt.% of rare earth Ce was added to the base alloys, and the microstructures were studied. Meanwhile, the solderability of solders on Cu substrate was determined by the wetting balance method, the mechanical properties of soldered joints were investigated by the pull-force test and the fracture morphologies were analyzed. It is found that the new solder alloys possess better solderability than the base solder alloys, and the greatest improvement to the solderability of Sn–3.8Ag–0.7Cu–xCe is obtained with around 0.03–0.05wt.% Ce, while the optimal Ce content is in the range of 0.05–0.07wt.% for Sn–0.5Cu–0.05Ni–xCe solders. The results also indicate that the mechanical properties of soldered joints are improved with increasing Ce addition, with peak mechanical properties at Sn–3.8Ag–0.7Cu–0.03Ce and Sn–0.5Cu–0.05Ni–0.05Ce. The grain sizes of solder alloys are refined due to the addition of Ce, thus the mechanical properties of soldered joints are improved simultaneously. [Copyright &y& Elsevier]