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Abstract MoS 2 shows promising potential in the application of lithium ion batteries (LIBs) or sodium ion batteries (SIBs), however, suffering from the sluggish kinetics and terrible volume expansion. Here we fabricate interlayer-expanded VMo 2 S 4 nanosheets onto RGO and exhibit excellent electrochemical properties for lithium and sodium storage. The 2D nature and interlayer-expanded feature assure the shortened ion transfer path and improved diffusion kinetics. RGO substrates enhance the electric conductivity and preserve the material integrity. Based on such benefits, the present sample serves as advanced anode for both LIBs and SIBs, delivering reversible capacities of 1081 mAh g−1 for LIBs and 254 mAh g−1 for SIBs after 200 cycles at 1 A g−1. Graphical abstract Image 1 Highlights • Interlayer-expanded VMo 2 S 4 nanosheets on RGO are developed. • V dopants induce enlarged interlayer and synergism between V and Mo. • RGO improves conductivity and buffers the volume variation. • 2D feature shortens ion diffusion path. • High and fast lithium/sodium storage are obtained. [ABSTRACT FROM AUTHOR]

The AlN/Y nanocomposite and nanomultilayered films with different Y contents were fabricated by the magnetron sputtering technique. The microstructures and mechanical properties of the AlN/Y nanocomposite and nanomultilayered films were characterized and measured, respectively. The AlN/Y nanocomposite film is composed of equiaxed AlN nanocrystallites encapsulated by the Y interfaces. When the Y:Al ratio is 2:23, Y interfaces can exist as the crystallized state and keep the epitaxial growth with the adjacent AlN nanocrystallites. Accordingly, the crystallization degree and mechanical properties are improved. The AlN/Y nanomultilayered film consists of the evident multilayered structure with distinct interfaces. When the Y-layer thickness is no more than 0.7 nm, Y layers are inclined to grow epitaxially with the adjacent AlN layers, leading to the improvement of crystallization degrees and mechanical properties. The interfacial evolutions and mechanical properties variations between AlN/Y nanocomposite and nanomultilayered films have the common feature as the Y content grows. It has been experimentally and theoretically verified that the AlN/Y nanocomposite and nanomultilayered films have the same coherent-interface strengthening mechanism. [ABSTRACT FROM AUTHOR]

Herein, we reduced PdCl 4 2− ions on the synthetized cuprous phosphide/reduced graphene oxidation (Cu 3 P/RGO) hybrids to improve the catalytic activity and durability of Pd nanocrystals. In comparison with commercial Pd/C and Pd/RGO catalysts, the Pd/Cu 3 P/RGO exhibit high electroactivity and durability toward alcohol oxidation in alkaline medium. The enhanced catalytic performance of Pd/Cu 3 P/RGO is due to the high electrochemically active surface area, which can be ascribed to the interactions between Cu 3 P/RGO and Pd nanocrystals. The investigation of Cu 3 P/RGO as a promoter in alcohol electrooxidation will offer an opportunity in the field of direct alcohol fuel cells (DAFCs). [ABSTRACT FROM AUTHOR]

Pure and Ag-doped ZnO nanofilms with four morphologies, namely nanocone, nanocrystal, nanochips and nanoleaves, have been successfully synthesized by magnetron sputtering method. The composition of the Ag-doped ZnO (AZO) nanostructures was explored by X-ray diffraction (XRD) and energy-dispersive spectroscopy (EDS). The XRD patterns revealed that the samples exhibited the hexagonal wurtzite structure with preferential orientation along the (002) crystal plane, although the c-axis as preferred orientation decreased with Ag doping. Moreover, we report the photoluminescence, field-emission (FE) and ultrafast nonlinear optical behavior of AZO films. A blue-shift was demonstrated in the UV region of photoluminescence results for the AZO nanostructures. The resulting FE showed that the superior FE properties were attributed to the better morphologies. The ultrafast time resolved optical Kerr gate experiment results showed that AZO was a good candidate for an optical Kerr gate medium due to its ultrafast response and large third-order nonlinear susceptibility. The result of time-resolved photoluminescence showed that the first decay time was about several picoseconds for films, and the slow relaxation process had the lifetime longer than hundred picoseconds. By analyzing the experimental results of the time-resolved photoluminescence experiment, we found the fast decay process could be attributed to the exciton migration and the slow decay to the recombination process of the relaxed excitons. [ABSTRACT FROM AUTHOR]

The present work aims at evaluating the effect of cerium nitrate on corrosion resistance of mild carbon steel coated by Dacromet in 3.5% NaCl solution. The scanning electron microscope (SEM) and energy dispersive X ray spectroscope (EDX) analysis were carried out to compare the surface structure and the composition of Dacromet coating and Dacromet+Re coating. The results of the electrochemical measurement showed that, compared with Dacromet coating, Dacromet+Re coating had a longer controlled sacrificial anodic protection function to steel substrate, a lower corrosion current density (i corr ) and a higher corrosion potential (E corr ). The modulus values of |Z| of Dacromet+Re coating is about 1 order of magnitude higher than that of Dacromet coating at low-frequency region. [ABSTRACT FROM AUTHOR]

The creation of considerably effective electrocatalysts to reduce overpotentials is essential for speeding up the sluggish oxygen evolution reaction (OER) processes, which is imperatively required for the practical exploitation of electrochemical water-splitting. Herein, we prepared a unique composite structure, uniformly spherical Ni-MOF decorated with NiMoO 4 nanorods on Ni foam (NF), and assessed its performance toward oxygen evolution reaction. The synergistic effect between NiMoO 4 and Ni-MOF remarkably promoted the OER intrinsic activity. Moreover, introducing NiMoO 4 endowed the composite structure with enhanced electrical conductivity and exposed more active sites. The NiMoO 4 /Ni-MOF/NF electrode exhibited exceptional electrocatalytic activity in 1.0 M KOH aqueous solution, with a low overpotential of 218 mV to drive the current density of 10 mA cm−2 and a low Tafel slope (67.75 mV dec−1), surpassing the benchmark RuO 2. The presented strategy opens a promising candidate for preparing novel non-precious metal OER electrocatalysts derived from MOF materials for sustainable energy applications. [Display omitted] • The composite exhibits OER activity with an overpotential of 218 mV at 10 mA cm−2. • The introduction of NiMoO 4 enhanced the electrical conductivity of the composite. • Uniform active sites and high porosity for pristine Ni-MOF were retained. • The superior OER activity was due to more active sites and the heterostructure. [ABSTRACT FROM AUTHOR]

● A facile sol-gel method is first proposed to synthesize NASICON-type Li 2 Zn 2 (MoO 4) 3 and Li 2 Cu 2 (MoO 4) 3. ● Rietveld refinement indicated the structure evolution in Cu-doped Li 2 Zn 2−x Cu x (MoO 4) 3. ● The Li 2 Zn 2 (MoO 4) 3 and Li 2 Cu 2 (MoO 4) 3 electrode display excellent lithium storage performance. ● In-situ XRD confirmed the existence of mesophase Li 4 MoO 5 in Li 2 M 2 (MoO 4) 3 (M=Zn, Cu) during the initial lithium insertion. NASICON (Na superionic conductor) type electrode materials are known for their wide range of electrochemical potentials, high ionic conductivity, and most importantly their structural and thermal stabilities. Li 2 M 2 (MoO 4) 3 (M=Zn, Cu), belonging to molybdenum-based NASICON family, are successfully synthesized by simple sol-gel method. The structure evolution caused by the substitution of Zn2+ by Cu2+ within Li 2 Zn 2- x Cu x (MoO 4) 3 (0 ≤ x ≤ 2) has been investigated. Rietveld refinement results reveals that the priority order of copper atoms replacing zinc atoms in Li 2 Zn 2 (MoO 4) 3. Furthermore, both Li 2 Zn 2 (MoO 4) 3 and Li 2 Cu 2 (MoO 4) 3 electrodes deliver excellent electrochemical performance, and high reversible capacities of 864 mAh g−1 and 747 mAh g−1 can be acquired at a current density of 0.1 A g−1, respectively. In addition, the in-operando X-ray diffraction measurements indicate the formation of cubic mesophase Li 4 MoO 5 both in Li 2 Zn 2 (MoO 4) 3 and Li 2 Cu 2 (MoO 4) 3 during the initial lithium insertion, which irreversibly converts into the amorphous phases on further discharge at subsequent discharge and charge process. [ABSTRACT FROM AUTHOR]

Highlights: [•] The non-equilibrium microstructures of Fe40Ni40B20 alloy were obtained. [•] The duplex structure were obtained by futher heat treatment. [•] The mechanical properties of the samples with duplex structure were largely enhanced. [•] We provide an effective method to improve the properties of eutectic alloy. [Copyright &y& Elsevier]

• A multidimensional nanosheets/nanowires P-Co 3 O 4 electrode for Zn-ion batteries and supercapacitors was constructed. • The conductivity and interface reaction activity of Co 3 O 4 were improved by phosphating to obtain enhanced specific capacity. • The assembled P-Co 3 O 4 //Zn exhibited a specific capacity of 119.4 mAh g−1 and a capacity retention of 111% after 5000 cycles. Here, a surface phosphating Co 3 O 4 electrode materials with multidimensional nanostructure and oxygen-deficient have been fabricated and applied to aqueous Zn-ion batteries and asymmetric supercapacitors. The multidimensional nanostructure is beneficial to the full contact between active materials and electrolyte. Moreover, the oxygen vacancies can enhance electrical conductivity and further increases the concentration of active sites, consequently accelerating their interface reaction activity and kinetics. Therefore, the combination of structural and compositional advantages endows the P-Co 3 O 4 nanosheets/nanowires electrode a specific capacity of 244.9 mAh g−1 at 4 A g−1. Furthermore, the assembled P-Co 3 O 4 //Zn battery showed fascinating electrochemical performance, including a high specific capacity of 119.4 mAh g−1 at 1 A g−1 and a high energy density of 193.7 Wh kg−1 at a power density of 1.6 kW kg−1 and excellent stability of 111% capacity retention after 5000 cycles. The assembled P-Co 3 O 4 //AC ASC device also achieved an energy density of 24.87 Wh kg−1 and excellent cycle stability. Outstanding performance advantages make it possible for P-Co 3 O 4 electrode to be applied in the fields of new energy storage devices and wearable electronic devices. [ABSTRACT FROM AUTHOR]

Halide perovskite quantum dots have attracted considerable research interest as excellent candidate for photonic and optoelectronic applications due to their unique optoelectronic properties. Stability is prerequisite and therefore is of critical importance. Here we demonstrate highly stable luminescent CsPbBr 3 quantum dots (QDs) can be achieved in different glass matrices via the high temperature melting process and melt-quench method. The microstructure of CsPbBr 3 QDs glass as well as their optical properties are systematically characterized by microscopic techniques and time-resolved spectroscopic techniques. We conclude the surface passivation is the key aspect for the high stability and high luminescence by embedding the quantum dots in the glass matrix. This study provides technical method to form highly stable luminescent solid devices and detailed physical understanding which is critical for the practical applications. • Luminescence in CsPbBr 3 QDs glass were study. • CsPbBr 3 QDs precipitated in 3 kinds of glass matrices. • Exciton recombination is confirmed as the dominant radiative mechanism. • the QDs glass could be flexibly fabricated into various device. [ABSTRACT FROM AUTHOR]

Abstract: Anatase TiO2 nanoparticles of about 16nm in crystal size have been successfully synthesized via a sol–gel method. Thermal treatment of the precursor at 500–600°C results in the formation of different TiO2 phase compositions. The samples were characterized by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Effects of the pH value of the solution, H2O2 addition, TiO2 phase composition and recycled TiO2 on the photocatalytic degradation of methyl orange (MeO) in TiO2 suspensions under ultraviolet (UV) illumination were primarily investigated. The results indicate that a low pH value, proper amount of H2O2 and pure anatase TiO2 will facilitate the photocatalytic oxidation of the MeO solution. The photodegradation degree decreases with increasing the pH value of the solution and varies with different amounts of H2O2. Pure anatase TiO2 shows better photocatalytic activity for MeO decolorization than biphase TiO2. The photocatalytic mechanism of the as-synthesized TiO2 nanoparticles was discussed. [Copyright &y& Elsevier]

The microstructure and properties of Cu-0.42Cr (wt.%) and Cu-0.45Cr-0.14Ti (wt.%) alloy subjected to cold rolling and aging treatment are investigated through tensile testing, electrical conductivity measurement, scanning electron microscopy, and transmission electron microscopy. Results show that the tensile strength of Cu-0.45Cr-0.14Ti (wt.%) alloy enhances as the degree of deformation increases, but the degree of deformation slightly influences electrical conductivity. When deformation is changed, electrical conductivity is basically unchanged. The good combination of strength and electrical conductivity, which reach 610 MPa and 55.4% IACS, respectively, can be obtained in the Cu-0.45Cr-0.14Ti (wt.%) alloy after 80% cold rolling and aging at 450 °C for 15 min. Ti inhibits the growth of the Cr precipitation phase and enhances the precipitation strengthening effect. Ti mainly exists in the matrix in the form of solute atoms, which do not form a separate lattice structure after aging treatment. • The alloy material is prepared by a process method combining solid solution aging treatment and deformation treatment. • Ti element enhances the effect of age hardening and significantly improves the mechanical properties of the alloy. • Titanium atoms segregate around the Cr phase to slow down the rate of precipitation coarsening. • Ti atoms have never formed a separate lattice structure in the Cu-0.45Cr-0.14Ti (wt.%) alloy. [ABSTRACT FROM AUTHOR]

Glasses doped with CsPbBr 3 quantum dots (QDs) were prepared by a conventional melt-quenching process followed by heat treatment, which exhibit good thermal stabilities and optical properties. A narrow visible photoluminescence (PL) emission (508–528 nm) band with a shift in luminescence peak position and a significant change in emission intensity was observed, depending on the B 2 O 3 concentration. Transmission electron microscopy (TEM) showed changes in the size and number of QDs with change in glass composition. The PL decay time was about 0.92–1.58 us, and it showed an increasing trend with increasing size of the QDs. With decreasing concentration of B 2 O 3 , the network structure of the glass exhibit a high aggregated state, thus providing sufficient growth space to the QDs. The luminescence of the QDs glass was found to be controlled by changing glass topology. The tunable narrow band emission of CsPbBr 3 QDs doped glass may have potential applications in new generation of display materials. Image 1 • The CsPbBr3 QDs doped glass were successfully prepared. • Successfully regulate the glass topology by adjusting the glass component. • The photoluminescence intensity and peak position of the glass samples were controlled by changing topology. [ABSTRACT FROM AUTHOR]

The slow kinetics and high cost of noble metal catalysts greatly hinder the oxygen evolution reaction (OER) in the application of large-scale oxygen production, as well as water splitting. In order to overcome this burgeoning issue, worldwide research efforts have been carried out to find alternative, and efficient electrocatalysts. Due to its cheap and abundant sources, FeCo-based materials are considered as better candidate electrocatalysts for OER. Herein, a nanocomposite catalyst consisting of FeCoSe 2 nanoparticles and Co 0.85 Se nanosheets was synthesized via a one-pot hydrothermal method. The resultant FeCoSe 2 /Co 0.85 Se heterostructure catalysts can further used as a self-supported catalytic electrode to drive the OER, which exhibits the overpotential of 0.33 V at a current density of 10 mA cm−2 and Tafel slope of 50.8 mV dec−1. Raman spectroscopy was employed to explore the intrinsic active species of as-prepared hybrid catalyst during the OER process, and test result shows that metal selenides was acting as the precursor of the real reaction species. This work provides a possibility to develop cheap and effective OER electrocatalysts to replace the costly noble metal catalysts for OER in electrochemical devices. • FCS/CS nanocomposites are synthesized by one-pot method. • 5% FCS/CS nanocomposite exhibits the best OER performance. • The real reaction species of CoOOH is formed during the OER process. [ABSTRACT FROM AUTHOR]

The design of cost-efficient catalysts for the electrooxidation of liquid fuel is now highly desirable for the commercial application of direct fuel cells. In spired by this, we herein reported our tremendous efforts in the fabrication of core-shell PdAu convex nanospheres via a green method. Different from the previously reported PdAu core-shell nanostructures, the present PdAu convex nanospheres integrated the benefits of core/shell, many granular protuberances, alloy and electronic effect as well as high surface area. All of these favorable properties embody them to exhibit greatly enhanced electrocatalytic activity and long-term stability towards ethylene glycol oxidation as compared with commercial Pd/C. This work emphasizes the significance of shape-controlled of PdAu nanostructures over the electrocatalytic performances for the ethylene glycol oxidation. [ABSTRACT FROM AUTHOR]

p-type YbCd 2-x Mg x Sb 2 (x = 0.1, 0.2, 0.4, 0.6, 0.8) Zintl phases have been synthesized via melting reaction followed by suitable cooling, annealing, grinding, and spark plasma sintering (SPS) densification processes. The effects of isoelectronic substitution of Mg for Cd on thermoelectric properties have been investigated. Electrical conductivity, Seebeck coefficient, and thermal conductivity measurements have been performed as a function of temperature from 300 to 650 K. The XRD patterns show that the solubility limit x of Mg in the YbCd 2-x Mg x Sb 2 is less than 0.8. With increasing Mg content x, the cell parameters a and c of the YbCd 2-x Mg x Sb 2 compounds decrease. The isoelectronic substitution of Mg for Cd leads to a remarkable decrease in total thermal conductivity and an increase in Seebeck coefficient, though a slightly decease in electrical conductivity. As a result, the maximum dimensionless figure of merit ZT of 1.08 is obtained at 650 K for YbCd 1.9 Mg 0.1 Sb 2 . Compared with the ZT of 0.78 at 650 K in the unsubstituted YbCd 2 Sb 2 , it is improved greatly by 38%. [ABSTRACT FROM AUTHOR]

ZrN and TiNiN nanolayers are alternately deposited on silicon substrate by magnetron sputtering. A series of ZrN/TiNiN nano-multilayer films with different Ni contents are prepared by varying the Ni:Ti volume ratio of the targets. The effects of Ni content on the microstructures and mechanical properties of ZrN/TiNiN nano-multilayer films are studied by X-ray diffractometer (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and nanoindentation instrument. The results show that with the increase of Ni content, the crystallization degree of ZrN phase first increases and then decreases. Besides, the hardness, elastic modulus and toughness of the films also increase first and then decrease with Ni content increasing. When Ni:Ti= 1:24, the ZrN/TiNiN nano-multilayer films obtain the highest hardness, elastic modulus and fracture toughness, which are 23.2 GPa, 317.8 GPa and 2.29 MPa·m1/2, respectively. This is mainly attributed to the best columnar crystal growth of the ZrN/TiNiN nano-multilayer film. The TiNiN layer changes into face centered cubic structure under the template of ZrN layer, and grows in coherent epitaxy with ZrN layer. ● A series of ZrN/TiNiN nano-multilayer films with different Ni contents are prepared by magnetron sputtering. ● When Ni:Ti= 1:24, the ZrN/TiNiN nano-multilayer films simultaneously obtain the highest hardness and fracture toughness. ● The high hardness and toughness are due to that the TiNiN layer grows in coherent epitaxy under the ZrN layer template. [ABSTRACT FROM AUTHOR]

The base cooling effect was improved by imposing the continuous water flow on the back of the substrate during the laser additive manufacturing of Inconel 718 (IN718). The dendritic microstructure, crystal orientation and hot cracking behavior were studied by using optical microscopy (OM), scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD) techniques. The results showed that the crystal orientation was increased by increasing the base cooling effect during the deposition. Also, highly ordered columnar dendrites were established, and mono-crystalline texture was constructed in the final clad. It was fund that the effect of solidification cracking on the properties of final clad was negligible since it was only generated at the top region of the deposit, while liquation cracking was produced and remained in the heat affected zone (HAZ) and needed to be carefully controlled. The susceptibility to the liquation cracking showed a high dependence on the grain boundary misorientation, which was considered to be attributed to the stability of interdendritic liquation films, as well as the magnitude of local stress concentration in the last stage of solidification. [ABSTRACT FROM AUTHOR]

• WC-Co composite powder is synthesized by employing successive liquid methanol. • Carbon nanolayers loaded on the intermediates prevent particle aggregation of WC-Co. • WC-Co composite powder with clean surface is no need for washing with water or acid. • WC-Co composite powder possesses controllable carbon content. Tungsten carbide-cobalt (WC-Co) mixtures is the most critical material for cemented carbide. However, traditional preparation methods by using various carbon sources (e. g. carbon black, glucose, methane, carbon monoxide) cause severe carbon deposition. Consequently, traditional WC-Co mixtures exhibits uncontrollable carbon content. To address the challenge, we investigate the in-situ synthesis of WC-Co mixtures by supplying successive liquid methanol as a carbon source and nitrogen gas as a diluent. The as-prepared WC-Co mixture possesses clean surface and controllable carbon content, which are no need for removing excess carbon deposition by washing with water. The carbon nanolayers derived from methanol cracking gas appear on the surface of the intermediates, which can effectively prevent particle aggregation, efficiently increase the intimate contact probability of WC particles and Co particles, and greatly reduce the appearance of excess carbon deposition during subsequent carbonization processes. The present study offers insights on employing quantitative methanol cracking gas as reductive and carbonaceous atmosphere to mediate carbon content in the WC-Co composite powder, which presents a more economical and efficient pathway for large-scale synthesis of high-quality WC-Co mixtures with clean surface and controllable carbon content. [ABSTRACT FROM AUTHOR]

This paper aims to investigate the effects of stress aging treatment on the microstructure, mechanical properties and corrosion behavior of Al-Zn-Mg-Cu alloy. The alloys were subjected to SAT and stress-free aging treatment (SFAT) at 175 °C under different aging stress and aging time conditions. Various analytical techniques, including scanning electron microscopy (SEM), electron back-scatter diffraction (EBSD), transmission electron microscopy (TEM), slow strain rate tensile, X-ray Diffraction (XRD) and potentiodynamic polarization, were employed to obtain results. The findings demonstrate heightened strength, improved corrosion resistance under SAT conditions in contrast to SFAT. The alloys subjected to SAT exhibit higher strength compared to SFAT, attributed to the diffusion of stress-induced dislocations and extensive nucleation of matrix precipitates. Furthermore, the presence of large-sized and discontinuous grain boundary precipitates impedes the anodic dissolution of grain boundaries and the expansion of stress corrosion, contributing to the enhanced corrosion resistance of the alloy. • The strength of the alloys showed an increasing and then decreasing trend with increasing applied stress, the correct application of SAT can improve the strength of alloys. • SAT results in lower I corr values compared to SFAT. S100 exhibits a larger capacitance arc in the Nyquist plots, indicative of superior corrosion resistance. • SAT improves the mechanical properties of the alloy. Applied stress facilitates dislocation diffusion and aggregation, creating additional nucleation sites that promote the nucleation and growth of precipitated phases. • SAT improves the corrosion resistance of the alloy. Applying aging stress beyond a specific threshold and extending the aging time both facilitated Gbps growth and widened the PFZ. Thereby enhancing the alloy's corrosion resistance. [ABSTRACT FROM AUTHOR]

Lithium-sulfur batteries (LSBs) have attracted widespread attention because of their advantages such as high discharge capacity and high energy density. Although LSBs have good development potential, there are still many obstacles, such as poor conductivity, volume expansion etc., especially shuttle effect which seriously limit the application of LSBs. To restrain the shuttle effect, we proposed a novel Co 3 O 4 /ZnO dodecahedral heterojunction as a separator blocking layer which was derived form ZIF-67/ZIF-8 bimetallic MOF. Since the bimetallic oxide heterojunction contains more abundant oxygen vacancies, it has better adsorption and catalytic performances than monometallic oxides. Co 3 O 4 /ZnO coated on the PE separator can effectively block the lithium polysulfides (LiPSs) shuttle due to its good adsorption ability, furthermore, the catalytic effect will accelerate the reaction of LiPSs and improve the electrochemical performances. Consequently, the initial discharge specific capacity of the Co 3 O 4 /ZnO modified separator battery at 0.5 C rate reaches up to 875.5 mAh g−1 when the cathode sulfur areal density is 3 mg cm−2, and still keep 500.9 mAh g−1 after 400 long cycles. Even when the cathode sulfur areal density is 5 mg cm−2, it still shows good cycle stability. • Co 3 O 4 /ZnO dodecahedral heterojunction is derived from ZIF-67/ZIF-8 bimetallic MOF. • Co 3 O 4 /ZnO heterojunction is used as a separator coating material for Li-S battery. • Co 3 O 4 /ZnO heterojunction show excellent absorption and catalytic effect for polysulfides. [ABSTRACT FROM AUTHOR]

Abstract: Synthesis of WO3/TiO2 nanocomposites by a sol–gel method was investigated using differential thermal analysis (DTA), X-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques. Thermal treatment of the precursor at 400°C in air resulted in the formation of WO3/TiO2 nanocomposites with a particle size of about 60nm. The c-axis parameter of TiO2 in the WO3/TiO2 nanocomposites, lower than that of pure TiO2, increased with increasing calcination time. Doping TiO2 with WO3 can lower its band gap and shift its optical response to the visible region. This nanocomposite should be effective as a visible-light-driven photocatalyst. [Copyright &y& Elsevier]

Titanium (Ti) and its alloys have great application potential. However, their relatively poor surface hardness, wear resistance, corrosion resistance, and biological activity greatly limit their effectiveness in practical applications. As a surface treatment method, the micro-arc oxidation (MAO) process has attracted much attention because it does not require expensive production equipment and is simple to operate. This paper discussed and summarized the mechanism of micro-arc oxidation and some classic models, which require development to provide better understanding and guidance for future research. Subsequently, the influencing factors of the formation of the micro-arc oxidation coating during micro-arc oxidation process were analyzed in detail. In addition, common applications of micro-arc oxidation coatings, including biomedical applications, wear resistance, corrosion resistance properties, and decoration, were summarized independently. Finally, existing problems and future prospects of the titanium alloy micro-arc oxidation process were discussed to facilitate the wide application of titanium alloy MAO process. [ABSTRACT FROM AUTHOR]

In this work, Ti matrix composite reinforced with 5 vol % TiC ceramic was prepared using in situ technologies, then various microstructures of the composite were obtained after it was treated with thermo-mechanical treatments applied in different temperature ranges with different deformation amplitudes. Widmanstatten, bimodal or fined α laths microstructure was obtained after it was treated by thermo-mechanical treatment performed in β phase field, in α+β phase field or in upper α phase field, respectively. The measured β transfuse temperature of the composite rises about 100 K compared to that of the monolithic matrix alloy, which resulted from the carbon solid solution of the matrix. The results of tensile tests showed that the composite strength was increased after the thermo-mechanical treatment, and the increase may be attributed to the effects of the load transfer from matrix to TiC particles and the refinement of the matrix microstructure. The TEM observation shows that the size of α colonies takes an important role to the equivalent grain size of the matrix, but the size of the thickness of α plates has minor effect on it. [ABSTRACT FROM AUTHOR]

Because of its high theoretical specific capacity, lithium-sulfur batteries are regarded as one of the most promising secondary batteries. However, there are still a series of problems, which seriously affect the commercial application of lithium-sulfur batteries. Therefore, a magnetic porous carbon material was developed in this work for the modification of lithium-sulfur battery separators, which may reduce the shuttle effect of polysulfides and increase its electrochemical performances. The solvothermal preparation of Ni-Zn bimetallic MOF precursors was followed by a high-temperature carbonization in nitrogen environment to sublimate Zn ions and produce porous structures, achieving Ni@C(Zn) composite. In order to improve the electrochemical performances of lithium-sulfur batteries, the Ni@C(Zn) composite was coated on one side of the polyethylene (PE) separator. Ni@C(Zn) composite displays good physisorption and chemisorption properties, and it can also operate as a secondary current collector to promote the usage of active materials as well as inhibiting shuttle effect of polysulfides. By using Ni@C(Zn) coated PE separator, the initial discharge specific capacity of lithium sulfur battery is as high as 1278.6 mAh g−1 at a current density of 0.05 C when the S cathode is loaded with 3 mg cm−2 active materials. Furthermore, the discharge specific capacity in the first cycle at 0.5 C is 749.4 mAh g−1, which remains at 461 mAh g−1 after 500 long cycles, and the capacity retention rate is as high as 61.5%. Even when the S loading is as high as 5 mg cm−2, it can still experience a stable cycle of 100 cycles at 0.2 C. • Ni@C(Zn) composite was derived by bimetallic Ni-Zn MOFs. • Ni@C(Zn) composite was used as separator modification layer of lithium sulfur battery. • larger specific surface area and higher porosity can better block the shuttle of polysulfides. • Ni@C(Zn) composites have good catalytic effect which can promote the redox conversion of polysulfides. [ABSTRACT FROM AUTHOR]

Because of its high theoretical specific capacity, lithium-sulfur batteries are regarded as one of the most promising secondary batteries. However, there are still a series of problems, which seriously affect the commercial application of lithium-sulfur batteries. Therefore, a magnetic porous carbon material was developed in this work for the modification of lithium-sulfur battery separators, which may reduce the shuttle effect of polysulfides and increase its electrochemical performances. The solvothermal preparation of Ni-Zn bimetallic MOF precursors was followed by a high-temperature carbonization in nitrogen environment to sublimate Zn ions and produce porous structures, achieving Ni@C(Zn) composite. In order to improve the electrochemical performances of lithium-sulfur batteries, the Ni@C(Zn) composite was coated on one side of the polyethylene (PE) separator. Ni@C(Zn) composite displays good physisorption and chemisorption properties, and it can also operate as a secondary current collector to promote the usage of active materials as well as inhibiting shuttle effect of polysulfides. By using Ni@C(Zn) coated PE separator, the initial discharge specific capacity of lithium sulfur battery is as high as 1278.6 mAh g−1 at a current density of 0.05 C when the S cathode is loaded with 3 mg cm−2 active materials. Furthermore, the discharge specific capacity in the first cycle at 0.5 C is 749.4 mAh g−1, which remains at 461 mAh g−1 after 500 long cycles, and the capacity retention rate is as high as 61.5%. Even when the S loading is as high as 5 mg cm−2, it can still experience a stable cycle of 100 cycles at 0.2 C. • Ni@C(Zn) composite was derived by bimetallic Ni-Zn MOFs. • Ni@C(Zn) composite was used as separator modification layer of lithium sulfur battery. • larger specific surface area and higher porosity can better block the shuttle of polysulfides. • Ni@C(Zn) composites have good catalytic effect which can promote the redox conversion of polysulfides. [ABSTRACT FROM AUTHOR]

TiB reinforced titanium matrix composite with a near alpha alloy matrix was fabricated using in situ technologies. The Widmanstatten microstructure evolution of the composite and the TiB whiskers realignment effect during thermo-mechanical processing were investigated, and the mechanical properties of the composite were measured. It was found that the microstructure of the composite is refined significantly by the thermo-mechanical processing due to the recrystallization of beta grains. With the increase in deformation amplitude, the value of probability density of small orientation angles of TiB whiskers along extension direction increases sharply. Strength of the composite was increased significantly by the thermo-mechanical processing, which results from the increase in the strengthening effect of TiB whisker and the microstructure refinement. The value of the thickness of alpha plates (b) without precipitated sillicide has minor effect on the strength of the composite but it becomes a non-ignorable strengthening factor after sillicide precipitation due to its dislocation hindering effect. [ABSTRACT FROM AUTHOR]

A series of TiN/Ni nanocomposite films with different Ni content were synthesized by reactive magnetron sputtering. The microstructural evolution, mechanical properties and strengthening mechanism of TiN/Ni nanocomposite film were studied. When Ni:Ti ratio is less than 1:24, the small amount of Ni can be dissolved in the TiN matrix, leading to the slight decrease of the hardness and elastic modulus. When Ni:Ti ratio rises to 4:21, Ni inclines to separate from TiN due to the thermodynamic incompatibility as an interfacial phase and grow coherently with adjacent TiN crystallites. As a result, the TiN/Ni film was remarkably strengthened with the maximal hardness and elastic modulus of 33.3 GPa and 373 GPa. As Ni:Ti ratio further increases to 5:20, Ni interface transforms into amorphous state, leading to the destruction of the epitaxial growth structure and the rapid decrease of hardness and elastic modulus. The strengthening effect of TiN/Ni nanocomposite film can be attributed to the coherent interface between Ni interfacial layers and TiN crystallites. [ABSTRACT FROM AUTHOR]

Due to the increasing demand of new energy vehicles and large-scale power grids for high energy density devices, lithium-sulfur batteries (LSBs) have attracted more and more researchers' attention stemming from their advantages of high theoretical specific capacity, low cost of active substances and environmental friendliness. However, there are still some intractable problems hindering the commercialization of LSBs, among which the most serious problem is "shuttle effect" of polysulfides. For the purpose of solving this problem, this paper prepared hollow structure molybdenum sulfide/cobalt sulfide mixed with amorphous carbon (MoS 2 /Co 9 S 8 /C) (HMCC) nanoparticles using ZIF-67 as the precursor and coated on the side of ordinary PE separator facing the positive electrode by a simple scraper coating process. The combination of MoS 2 and Co 9 S 8 bimetallic sulfides can not only adsorb and catalyze the rapid transformation of intermediates, but also effectively conduct lithium ions mainly because of the exposure of many active sites of layered MoS 2 in the outermost layer. In addition, a small amount of carbon inside can enhance electrical conductivity of the coating, increasing the utilization of active substances, and the stable hollow structure can act as a "transfer station", greatly inhibiting the large amount of polysulfides to run off. The dual advantages of structure and composition make the modified separator have excellent performance in different current densities. Reversible specific capacities of 930.4 mAh g−1 and 690.7 mAh g−1 are released at 0.5 C and 1 C, and capacity retention of 72 % and 64 % after 500 and 600 cycles, respectively. In addition, due to the rapid conduction of lithium ions, the growth of lithium dendrites is greatly inhibited, which maintains the high safety of the battery. This provides a new research direction for the application of other new bimetallic sulfides in the separator modification of LSBs. • A hollow bimetallic sulfide composite MoS 2 /Co 9 S 8 /C is derived from ZIF-67. • MoS 2 /Co 9 S 8 /C is used as a separator coating layer for lithium polysulfides. • The hollow MoS 2 /Co 9 S 8 /C show both physical confinement and catalytic effect on lithium polysulfides. [ABSTRACT FROM AUTHOR]

The NiCr/Al nanomultilayered films with different Al thicknesses (t Al) were prepared by magnetron sputtering. The structural evolution of the Al nanolayer with the increase in t Al was investigated. When the Al layer thickness changed from 1.2 nm to 2.4 nm, the Al layer could keep the co-epitaxial growth with the adjacent NiCr layer. Accordingly, the crystallization degree improved. When the Al layer thickness changed from 2.4 nm to 3.0 nm, the transformation from the coherent to incoherent interfaces took place between the NiCr and Al layers. Meanwhile, the co-epitaxial growth with the adjacent NiCr nanocrystallites was destroyed, the crystallinity and the grain size decreased, leading to the increase of the resistivity under the combined effects of the grain boundary scattering and interface scattering. The interfacial evolution of NiCr/Al nanomultilayered films was closely related to the changes of electrical properties. When the Al layer thickness changed from 3.0 nm to 3.6 nm, the surface quality of the film was improved, which effectively reduced the scattering of defects and vacancies during the electron transport, resulting in the decrease of the resistivity of the NiCr/Al nanomultilayered film. [Display omitted] • Al films inserted NiCr nanolayers with different thickness were synthesized. • The microstructure structure of NiCr was damaged with insertion of Al nanolayers. • The resistivity was renewedly increased with the change of interface structure. • The resistivity later deteriorates with the improvement of the surface quality. [ABSTRACT FROM AUTHOR]

Through introducing the CrAlSiN modulation layers consisted of CrAlN and SiN x phases, a series of TiN/CrAlSiN nanomultilayered films with different Si content were synthesized by reactive magnetron sputtering. The effect of Si content on microstructural evolution and superhardness effect of TiN/CrAlSiN nanomultilayered film was investigated by XRD, HRTEM and nanoindentation techniques. When inserted by CrAlSiN nano-layers with Si:CrAl ratio less than 4:21, TiN layers can force CrAlSiN layers to transform into fcc structure and grow epitaxially with them, leading to appearance of the superhardness effect. The columnar crystal structure of TiN/CrAlSiN nanomultilayered film can be effectively refined by insertion of the CrAlSiN layers due to thermodynamic incompatibility of CrAlN and SiN x . As the Si content further increases, the amount of amorphous SiN x phase increases, which makes the CrAlSiN layers present amorphous feature and blocks the epitaxial growth structure within the TiN/CrAlSiN nanomultilayered film, resulting in the decrease of hardness and elastic modulus. [ABSTRACT FROM AUTHOR]

Highlights: [•] LiFePO4/C and LiFe1−2xTi x PO4/C are prepared by carbothermal reduction method. [•] Phenol–formaldehyde resin is used as reducing agent and carbon source. [•] Mechanism of carbothermal reduction reaction is presented on the basis of TG–DSC. [•] The electrochemical performances of samples are systematically investigated. [Copyright &y& Elsevier]

Heterojunction has been considered to be one of the most effective methods for efficient hydrogen evolution reaction by photocatalytic water splitting. In this work, nanostructured Cu 7 S 4 /MnIn 2 S 4 heterojunction was successfully fabricated via a simple two-step method, which was much simpler than most heterojunction synthesis. Firstly, Cu 7 S 4 nanoparticles were synthesized by oil bath stirring, and then the Cu 7 S 4 /MnIn 2 S 4 heterojunctions were synthesized by the hydrothermal method. The prepared Cu 7 S 4 /MnIn 2 S 4 composite exhibited significantly improved hydrogen evolution activity with a rate of 13.81 μmol h−1 (10 mg catalyst), which was approximately 18 times higher than that of pristine MnIn 2 S 4. This result could be attributed to the construction of p-n heterojunction for promoting the separation of photogenerated charge carriers and inhibiting their recombination. Possible electron transfer mechanism was proposed by the related characterization. This work will inspire the simple fabrication of nano-heterojunctions in the future. [Display omitted] A facile and effective method was developed to fabricate nanostructured Cu 7 S 4 /MnIn 2 S 4 p-n heterojunction via oil bath mixing and hydrothermal methods by using p-type Cu 7 S 4 and n-type MnIn 2 S 4 nanoparticles, which exhibited significantly improved hydrogen evolution activity and stability. The construction of p-n heterojunction inhibits the recombination of carriers and holes. • The heterojunction was prepared by a simple oil bath mixing and hydrothermal method. • Photocatalytic hydrogen evolution rate reached 13.81 μmol h−1 (10 mg catalyst). • Cu 7 S 4 /MnIn 2 S 4 is a typical p-n heterojunction, which was successfully fabricated for the first time. The function of p-n junction and the mechanism were also discussed in detail. [ABSTRACT FROM AUTHOR]

• Urchin-like Nb 2 O 5 @N-C microspheres are prepared by two simple steps. • Polydopamine was served as carbon and nitrogen source. • Nb 2 O 5 @N-C microspheres exhibit outstanding rate and cyclic performances. [Display omitted] Orthorhombic Nb 2 O 5 is a promising material for the anodes of lithium-ion batteries (LIBs) owing to its pseudocapacitive features, stability, and safety. However, the practical applications for Nb 2 O 5 are limited due to its poor electrical conductivity. In this work, three-dimensional (3D) urchin-like microspheres coated with N-doped carbon were synthesized by hydrothermal synthesis and then polymerized in dopamine. When evaluated as anode for LIBs, the 3D urchin-like Nb 2 O 5 @N-C composites exhibited excellent high-rate capability (146 mAh g−1 at 20 C) and stability (78 mAh g−1 at 10 C after 2900 cycles). The remarkable electrochemical performance of the Nb 2 O 5 @N-C composites was ascribed to their unique structure and the N-doped carbon coating, which prevents the electrode from structural damage, mitigates volume expansion during the charge/discharge process, and enhances the conductance of the active material. [ABSTRACT FROM AUTHOR]

The (AlCrTiZrHf)N high-entropy alloy nitride films were synthesized by reactive magnetron sputtering. The effects of different N 2 flow rates on the microstructures and mechanical properties of (AlCrTiZrHf)N films were studied by the X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), nanoindentation, coating friction and wear tester. The results show that the AlCrTiZrHf high-entropy alloy film presents an amorphous state. With the increase of the N 2 flow rate, the (AlCrTiZrHf)N high-entropy alloy nitride films transform to a face-centered-cubic (FCC) structure. When the N 2 :Ar ratio is 5:4, the hardness and elastic modulus of the films reach 33.1 GPa and 347.3 GPa, respectively. The strengthening effect is mainly attributed to the formation of saturated metal-nitride phases and the solid-solution strengthening of various elements. Meanwhile, the (AlCrTiZrHf)N film exhibits the low friction coefficient and superior wear resistance. Based on the excellent properties of high-entropy alloy nitride films, the (AlCrTiZrHf)N film presents a potential application in protective coating. Image 1 • The (AlCrTiZrHf)N high-entropy alloy nitride films with different nitrogen content were produced. • The (AlCrTiZrHf)N films transform to a face-centered-cubic (FCC) structure with the increase of the N 2 flow rate. • When the N 2 :Ar ratio is 5:4, the hardness and elastic modulus of the film reach the maximum of 33.1 GPa and 347. • GPa.4.The friction coefficient was 0.5. [ABSTRACT FROM AUTHOR]

In this work, graphene nanoplates/copper (GNPs/Cu) composites with a multi-layer structure were prepared through electrostatic self-assembly and electroless copper plating, enabling the uniform dispersion of GNPs in Cu matrix and thus improve the interfacial wettability of GNPs in Cu matrix. GNPs were arranged parallelly in the prepared Cu matrix composites, and GNPs in the same horizontal surface interweaved to form GNPs protective layers, which inhibited the splash and evaporation of molten Cu in the arc erosion tests. The arc erosion resistance of the composites enhanced with the increase of GNPs content. Meanwhile, the wettability and interface bonding strength of GNPs and Cu matrix has been improved, and GNPs were not easily separated from Cu matrix in the wear tests under electric current. The GNPs protective layers improved the wear resistance of the composites under electric current and inhibited the formation of erosion pits. • GO were adsorbed on the surface of flake Cu powders by electrostatic self-assembly. • Cu nanoparticles coated on the surface of GO by electroless Cu plating. • The surface-coated Cu nanoparticles improved the interfacial wettability of GNPs. • GNPs protective layers improved the arc erosion resistance of composites. • The electric wear resistance of GNPs/Cu composites were improved. [ABSTRACT FROM AUTHOR]