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Co-ZIF is widely believed as a promising material which shows potential in MOFs based enzyme-free sensors. However, the research of Co-ZIF in glucose sensor filed has been hampered, due to its poor electronic conductivity and slow ion diffusion caused by closed rhombohedral dodecahedron structure. In this work, the obtained Co 0.95 Fe 0.05 -ZIF presents highly opened nanosheet structure on CC, resulting in rich open active sites and ions moving channels. Compared with other reported ZIFs, the Co 0.95 Fe 0.05 -ZIF/CC exhibits excellent sensing performance with a high sensitivity of 3232.30 μA mM−1 cm−2 in the range of 0.20–1.00 mM and a low detection limit of less than 5 μM, due to its highly opened nanosheet structure. The Co 0.95 Fe 0.05 -ZIF/CC also shows excellent selectivity, repeatability and reproducibility for glucose detection. Furthermore, the variation trend of test results measured by this saliva sensor without any sample pre-treatment, is consistent with that of commercial blood glucose meter, indicating its potential in real applications. This synthesis strategy also provides a new direction of structure construction for high performance MOFs in enzyme-free glucose sensor field. [ABSTRACT FROM AUTHOR]

The rapid development of economy and technology caused numerous irreversible effects on the environment, and the rational use and storage of existing resources have became an indispensable process in modern development. Energy storage through supercapacitors can effectively alleviate part of the energy crisis. Here, the effects of heating rates on the morphology of carbonized bacterial cellulose (CBC) carbon and its electrochemical properties were studied and CBC-5 (heating rate of 5 ℃/min) with porous structure was confirmed to be supporting material for loading MnO 2. The specific capacitance of CBC-5@MnO 2 composites was high up to 190 F g−1 at 1 A g−1, and its capacitance retention rate was up to 96.6% after 8000 cycles. The superior electrochemical performance cannot be achieved without the cooperative effect among the metal oxides and carbon materials, which also benefits from the fast transport of ions and electrons in solution. The assembled CBC-5//CBC-5@MnO 2 -6 h hybrid supercapacitors exhibited largest energy density and power density values of 44.5 Wh kg−1 (at 0.2 A g−1) and 11111.1 W kg−1 (at 10 A g−1), respectively. The assembled button cells can light up small LED bulbs for at least 10 min. The porous bacterial cellulose carbon can provided possibilities for high electrode design. [Display omitted] • Morphology change of carbonized bacterial cellulose (CBC) affected by heating rate was clarified. • CBC-5 exhibited a three-dimensional channel structure and large specific surface area. • Homogeneous MnO 2 nanospheres were loaded onto CBC by adjusting hydrothermal time. • The device shows energy density of 44.5 Wh kg−1and power density of 11,111.1 W kg−1. • A button cell was assembled to light an LED lamp for nearly 20 min [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]

Niobium carbide (NbC) membranes have been shown to be an effective catalytic membrane for hydrogen dissociation and desorption. Here, magnetron sputtering method was applied to dope Ni in NbC films to improve the catalytic properties. It is found that the Ni doping largely affects the surface microstructure and electronic structure of the NbC films, which in turn affects the hydrogen permeation performance of the NbC/V composite membranes. By density functional theory (DFT) calculations, it is known that the doping of Ni can modulate the internal electronic structure of NbC, such as d-band center and bader charge, thus improving the catalytic properties of the NbC films. Typically, under the optimal preparation conditions, the hydrogen permeability of the Ni-doped NbC/V composite membranes was 2.59 × 10−8 mol H 2 m−1 s−1 Pa−0.5，at 500 °C, which is higher than that of pure Pd under the same conditions. These findings open up a new way towards the improvement of the catalytic properties for the hydrogen separation membrane materials. • The Ni doping affects the structure and properties of the NbC films. • The Ni doping reduces the dissociation barrier of H 2 of NbC. • H 2 flux first increases and then decreases with increasing Ni doping. • The H 2 permeability of Ni-doped NbC/V membranes is higher than that of Pd. • Ni-doped membranes exhibit high hydrogen permeation stability at 500–650 °C. [ABSTRACT FROM AUTHOR]

Piezocatalysis, which is capable of directly converting mechanical energy into chemical energy, has been identified as a promising strategy for environmental wastewater remediation and clean energy production. Regrettably, the present piezocatalysis is still in the early stage and the piezocatalytic activity is still far from ideal. Thus, exploring and discovering more efficient catalyst design strategies remains a challenge. In this work, a novel and simple method was employed to synthesize a piezocatalytic BiFeO 3 (BFO) using metal-organic frameworks (MOFs) as precursors, and the MOFs derived BFO (MOF-BFO) has excellent piezocatalytic activity. The maximum reaction rate constant (k) for rhodamine B (RhB) can reach 1.70 × 10−2 min−1, which is about 4.7 times that of the sample annealed at 700 °C (BFO-700, 0.36 × 10−2 min−1) and about 10.3 times that of the sample annealed at 450 °C (BFO-450, 0.17 × 10−2 min−1) using conventional one pot co-precipitation method. The MOF-BFO catalyst is also suitable for degradation of other typical dyes, including methylene blue (MB) and methyl orange (MO), dramatically increasing its utility against complex wastewater components. What's more, the analysis indicates that the concentration of oxygen vacancy (O V) may be the primary factor influencing the piezocatalytic performance. Thus, the effect of O V concentration on piezocatalytic activity is further studied, which acts like a double-edged sword, manifesting that creating moderate O V is crucial for regulating piezocatalytic performance. This study not only demonstrates the potential of MOF-BFO as a candidate material for piezocatalytic applications, but also offers insights for the development of efficient piezocatalysts in future. [Display omitted] • The self-made MOF-BFO exhibits superior piezocatalytic activity. • A series of MOF-BFO with varying O V concentrations were synthesized. • MOF-BFO demonstrated notable stability and repeatability. • Appealing insights into the design of high-performance piezocatalysts are revealed. • The potential piezocatalytic mechanism is briefly elucidated. [ABSTRACT FROM AUTHOR]

Hydrogen peroxide (H 2 O 2) is a versatile oxidant that has attracted significant attention in various industrial applications, including water treatment, pulp and paper bleaching, and chemical synthesis. Photocatalytic H 2 O 2 production using semiconductor photocatalysts has emerged as a highly promising approach due to its environmental friendliness and sustainability. Among the various photocatalytic systems, Z-scheme photocatalysts have demonstrated particular promise for efficient H 2 O 2 production owing to their unique electron transfer mechanism. This review article aims to provide a comprehensive overview of the recent progress in the development and application of Z-scheme photocatalysts for efficient photocatalytic H 2 O 2 production. It covers the fundamental principles of photocatalytic H 2 O 2 production and Z-scheme photocatalytic systems, summarizes the achievements of Z-scheme photocatalysts, and discusses the challenges and future prospects. This timely review fills a critical gap in the field by providing a comprehensive understanding of recent progress in Z-scheme photocatalysts for efficient H 2 O 2 production. [Display omitted] • Comprehensive overview of Z-scheme photocatalysts for H 2 O 2 production. • Covers features, mechanisms, and applications of direct and indirect Z-schemes. • Discusses challenges, opportunities, and future research directions. • Valuable resource for researchers in photocatalytic H 2 O 2 production. [ABSTRACT FROM AUTHOR]

Despite of the moderate working temperature and relatively high hydrogen capacity of NaAlH 4 , the slow H 2 absorption and desorption kinetics and poor reversibility pose a major bottleneck hindering its practical application. Herein, porous NiTiO 3 nanorods is constructed to tailor reversible hydrogen storage performance of NaAlH 4. It is theoretically and experimentally demonstrated that the building of NiTiO 3 nanorods effectively promotes the uniform distribution of catalytic Ni-based species and Ti-based species inside of NaAlH 4 matrix that are capable of synergistically weakening Al-H bonds of NaAlH 4. As a result, under the catalysis of porous NiTiO 3 nanorods, the onset temperature for H 2 desorption from NaAlH 4 is decreased down to 89 °C, 91 °C lower than that of pure NaAlH 4. In addition, NaAlH 4 under the catalysis of porous NiTiO 3 nanorods is capable of releasing 4.5 wt% H 2 within 60 min, 3.8 and 0.9 wt% higher than that of NaAlH 4 catalyzed by NiO and TiO 2 , respectively. More importantly, a reversible capacity of 4.6 wt% could be obtained for NaAlH 4 under the catalysis of porous NiTiO 3 nanorods after 5 cycles, corresponding to a capacity retention of 95%, while this value is significantly decreased to 42% for NaAlH 4 without the addition of NiTiO 3 nanorods. This work provides a new perspective for the development and design of high-performance catalysts for realizing reversible hydrogen storage of NaAlH 4 under moderate condition. ● NiTiO 3 nanorods promotes the uniform distribution of catalytic Ni-based species and Ti-based species inside of NaAlH 4. ● Under the catalysis of porous NiTiO 3 nanorods, the onset temperature for H 2 desorption from NaAlH 4 is decreased down to 89 °C. ● A reversible capacity of 4.6 wt% could be obtained for NaAlH 4 under the catalysis of porous NiTiO 3 nanorods after 5 cycles. [ABSTRACT FROM AUTHOR]

The tribological properties of polycrystalline diamond compact (PDC) with different matching pairs (Al 2 O 3 , ZrO 2 , and GCr15 balls) in drilling fluid were studied. The friction coefficient, microstructure, wear rate, three-dimensional surface morphology, and transfer behavior of the friction film of different balls and PDC were analyzed experimentally. The results showed that there are significant differences in friction and wear behavior between PDC and different balls in the drilling fluid environment. In addition, the surface of PDC will form a friction-protective film in the presence of drilling fluid. Different friction pairs exhibit different degrees of damage to the protective film and form a transfer film during the friction process. When the protective film on PDC is destroyed, small particles in the drilling fluid can fill the groove area to repair and prevent further friction and wear. • The friction behavior of PDC is affected by the drilling fluid medium. • Different friction pairs have different extent of damage to the protective film. • The friction pair materials will affect the friction and wear mechanism. [ABSTRACT FROM AUTHOR]

Dielectric capacitors have been extensively studied in electronic and power systems based on their high power density and ultra-fast discharge rates. In this study, the dielectric, energy storage and charge-discharge properties of Sr 0.7 Bi 0.2 TiO 3 -based lead-free relaxor ferroelectric ceramic were investigated. The dielectric breakdown strength was significantly improved by introducing the rare earth element Nd, which was attributed to the rise in resistivity and large band gap. The results show that Sr 0.7 Bi 0.15 Nd 0.05 TiO 3 obtain a high recoverable energy storage density of 2.34 J/cm3 with high efficiency of 92%. In addition, pulsed charge-discharge tests demonstrated that Sr 0.7 Bi 0.15 Nd 0.05 TiO 3 possesses a high power density of 73.5 MW/cm3, a short discharge period of 0.1 μs, and a pulsed discharge energy density of 2.0 J/cm3. Meanwhile, the energy storage performance of Sr 0.7 Bi 0.15 Nd 0.05 TiO 3 exhibits excellent stability of temperature, frequency and cycling. This work provides a systematic study and a new strategy for enhancing the performance of SBT ceramics. • Nd doping broadens the dielectric peak and enhances the relaxor properties. • The improved activation energy and band gap increase the breakdown strength. • Ceramics achieve excellent energy storage density and efficiency at 360 kV/cm. • Ceramics possess excellent charge-discharge performance and thermal stability. [ABSTRACT FROM AUTHOR]

In the present work, the phase equilibria of the Cr-Nb-Ru system at 1100 ℃ were investigated via a combination of diffusion triple and equilibrated alloys. The samples were examined by means of X-ray diffraction and electron probe microanalysis. The isothermal section of the Cr-Nb-Ru ternary system at 1100 ℃ was constructed, which consists of 11 single-phase regions, 19 two-phase regions, and 9 three-phase regions. One new ternary compound τ was discovered. The homogeneity ranges for the phases in this system are established. Three miscibility gaps were observed, corresponding to Cr solid dissolved in HCP(Ru), Nb solid dissolved in HCP(Ru) and Ru solid dissolved in BCC(Cr)，respectively. The miscibility gap of Nb and Cr solid dissolved in HCP(Ru) go through each other. • The isothermal section of the Cr-Nb-Ru ternary system was constructed at 1100 ℃. • One new ternary compound was discovered. • Three miscibility gaps were observed. [ABSTRACT FROM AUTHOR]

Using the ZrO 2 particles as precursor, a novel α -Zr/ β -Zr core-shell structure reinforced Zr-based metallic glass (Zr-BMG) composite was fabricated. The oxygen is mainly concentrated in the α -Zr core, resulting in the very high hardness of α -Zr core. The β -Zr shell contained the relatively moderate amount of oxygen still has good ductility and work hardenability. The α -Zr/ β -Zr core-shell structure reinforced Zr-BMG composite combined the advantages of the soft ductile and hard brittle phase reinforced BMG composites, and thereby exhibits the high strength and good tensile ductility. These findings give a new perspective to adjust the mechanical properties of the BMG composites. Image 1 • The ZrO2 particles were used as precursor induced the formation of α-Zr phase. • A novel α-Zr/β-Zr core-shell structure reinforced Zr-BMG composite was fabricated. • The α-Zr/β-Zr core-shell structure combined the advantages of the soft and hard phase. • The novel Zr-BMG composite exhibits the high strength and good tensile ductility. [ABSTRACT FROM AUTHOR]

A dual interface SiO x /C composite is prepared through a novel, facial, one-step route by redox reaction of organic carbon with silica precursor, using tetraethyl orthosilicate (TEOS) and sucrose as raw material, in which sucrose acts as both a reductant and coated carbon. HRTEM indicates that the composite has a dual interface structure with carbon coating layer and intermediate layer. Crystalline Si approximately 3 nm–20 nm in size is dispersed in amorphous silicon oxide matrix. The SiO x /C is utilized in LIB as anode material and exhibits a high reversible specific capacity of 755 mA h g−1 after 300 cycles at 100 mA g−1 with capacity retention about 91%. Such outstanding cycling stability can be ascribed to the intermediate layer and carbon scaffold, which serve as a buffering to relieve volume change of produced Si upon cycles. • SiO x /C composite with dual interface structure is fabricated by a facial, one-pot synthesis method. • Dual interface structure provides a strong buffering for volume change of SiO x /C. • The dual interface SiO x /C shows high capacity and outstanding cycling performance. • Structure and electrochemical performance analysis of SiO x /C are studied in detail. [ABSTRACT FROM AUTHOR]

Anti-counterfeiting materials development has been raised for a long time to improve the level of security against counterfeiting. Increasing counterfeiting difficulties as well as reducing difficulties of materials preparation are two major concerns in the development of anti-counterfeiting materials. Herein, carbon dots (CDs) and triethyl 1,3,5-benzenetricarboxylate (Et3BTC), both of which show two random lasing peaks located around 325 nm and 450 nm at 265 nm excitation are chosen as two lasing mediums to form hybrids. Moreover, lasing intensity ratio of the two lasing bands from the hybrids can be tuned by changing the working temperature, excitation area, and even bending angle of substrate. As a result, a strategy of dual random lasing medium modulation based high security flexible multi-level anti-counterfeiting technique is developed. Thus, it is suitable for anti-counterfeiting of high-value items due to its high security and excellent waterproofness. This work will provide a perspective to boost the development of high security anti-counterfeiting techniques. [Display omitted] • Lasing at UV-B (325 nm) and visible (450 nm) regimes are realized from carbon dots/ Et3BTC hybrids. • Intensity responses of the two random lasing mediums under different lasing conditions are found to be distinct. • Modulation of the two lasing bands are utilized to realize flexible multi-level anti-counterfeiting. • This development is suitable for anti-counterfeiting on high-value items due to its high security and waterproofness. [ABSTRACT FROM AUTHOR]

In this work, preparation of Cu-Ni/Nano-Al 2 O 3 composite coating with (111)-preferred orientation on the surface of the H64 brass via electrodeposition technique. Variation of the deposition current density was found to play a key role in the control of the microstructure and strongly influence the corrosion resistance of the composite coating. Electrochemical impedance spectroscopy results indicated that the increase of nano-alumina content in composite coating is caused by the change of polarization mode. Under different current densities, the Ni (111) plane is only preferred orientation and the relative texture coefficient reaches the highest value of 54.36% at 5 A•dm−2. The crystallite size of these coatings is about 10–55 nm dependent on current density, and high current density could refine the size. The microstructure of the coating changed from cauliflower to spherical with increasing deposition current density. Moreover, the Cu-Ni/Nano-Al 2 O 3 composite coating obtained at 5 A•dm−2 increased the polarization resistance and coating resistance of the H64 brass by about 50% and 83%, respectively. The corrosion potential (E corr) of Cu-Ni/Nano-Al 2 O 3 composite coating is shifted towards the nobler direction from − 1.191 V to − 0.063 V (Ag/AgCl) with the current density increases. The corrosion mechanism of Cu-Ni/Nano-Al 2 O 3 composite coating has gone through two stages corresponding to two-time and three-time constant of EEC models, respectively. The Cu-Ni/Nano-Al 2 O 3 has large potential merits in field of corrosion. [Display omitted] ● Nodules of coatings become spherical with increase of deposition current density. ● Increasing the deposition potential changes polarization mode of electrodeposition. ● Deposition current density does not change the preferred orientation of Ni (1 1 1). ● The anti-corrosion mechanism of composite coating changes from 5 A•dm−2. ● Nano-alumina distorts the diffusion path of Cl- in the composite coatings. [ABSTRACT FROM AUTHOR]

Abstract A novel cobalt-free cathode Ba 0.95 Ca 0.05 Fe 0.9-x Sn x Y 0.1 O 3-δ -SDC (x ≤ 0.1), with various ratios of Sn was proposed. Here, it is applied for proton-conducting solid oxide fuel cells (H-SOFCs), for the first time. Special attention is paid to the exploration of doping amount of Sn effect on the phase structure, electronic conductivity, thermal expansion coefficient (TEC) and electrochemical properties. Ca, Sn and Y co-doped BaFeO 3-δ is expected to stabilize a single perovskite lattice structure down to room temperature. TEC data shows that doping of Sn can effectively decrease thermal expansion coefficient, the average thermal expansion coefficient decreases from 17.8 × 10−6 K−1 for Ba 0.95 Ca 0.05 Fe 0.9 Y 0.1 O 3-δ to 12 × 10−6 K−1 for Ba 0.95 Ca 0.05 Fe 0.8 Sn 0.1 Y 0.1 O 3-δ at the temperature range of room temperature to 850 °C. The single-cell with Ba 0.95 Ca 0.05 Fe 0.85 Sn 0.05 Y 0.1 O 3-δ -SDC cathode achieves the maximum power density of 949 mW cm−2 at 700 °C. These results demonstrate that Ba 0.95 Ca 0.05 Fe 0.85 Sn 0.05 Y 0.1 O 3-δ -SDC are promising cathodes for proton-conducting solid oxide fuel cells. Highlights • Series of Ba 0.95 Ca 0.05 Fe 0.9-x Sn x Y 0.1 O 3-δ were firstly evaluated as cathode for H-SOFC. • 5% Ca, minor amount of tin and 10% Y co-doping succeeded stabilizing the cubic phase of BaFeO 3-δ down to room-temperature. • At 700 °C, the cell with Ba 0.95 Ca 0.05 Fe 0.9-x Sn x Y 0.1 O 3-δ showed the highest MPD of 949 mW cm−2. [ABSTRACT FROM AUTHOR]

Abstract This work depicts the synthesis of controllable Pd nanoparticles decorated TiO 2 nanowire arrays by electrospray technique. By varying the substrate temperature and volume of precursor solution, Pd/TiO 2 hybrid structure with different sizes and deposition yield was precisely controlled. The highest photocurrent density of the Pd/TiO 2 photoanode was 1.4 mA cm−2 at 1.23 V vs. RHE, which was approximately 5 times higher than the pristine TiO 2. The onset potential with a significant cathodic shift of 80 mV compared to the pristine TiO 2 was also observed. To the best of our knowledge, the obtained photocurrent showed the optimal photocurrent density and high stability compared with previous reports. It is also found that the photoelectrochemical performance is closely related to the size and deposition quantity of Pd nanoparticles. According to the results, the enhanced PEC performance can be attributed to the Schottky junction, charge transfer and the enhancement about the separation efficiency of the photogenerated electrons and holes betweenTiO 2 and Pd NPs. This result demonstrated that this method may design a new and green strategy for synthesizing the well-defined morphologies, compositions, and sizes of the hybrid nanomaterial for photocatalytic hydrogen generation, photocatalytic CO 2 reduction and photosynthesis of organic molecules. Graphical abstract Image 1 Highlights • Pd NPs decorated TiO 2 NWs were synthesized by electrospray technique. • Precisely controllable Pd NPs on TiO 2 NWs about PEC performance were particularly described. • The enhanced PEC performance can be attributed to the Schottky junction betweenTiO 2 and Pd NPs. [ABSTRACT FROM AUTHOR]

Abstract The long-term hydrogen storage performance of a CaCu 5 -type LaNi 4 Co alloy is studied by detailed analysis of its P-C-T curves and structural changes within 1000 cycles. The alloy shows one absorption plateau (α→β phase transition) and two desorption plateaus (γ→β and β→α phase transitions). With increasing cycle number, the plateau pressures for both α→β and β→α phase transitions decrease due to the increase in cell volumes. The increased crystal cells also provide more space to accommodate the simultaneous occupations of 12° and 6 m sites, and thus β→α and β→γ desorption plateaus become less distinguishable. During cycling, partial phase decomposition, crystal grain destruction and surface oxidation occur, resulting in the loss of hydrogen storage capacity. In addition, due to the increase in the atomic disorder and internal microstrains and defects, the average slope factors (SF / H %) of the hydrogen absorption/desorption plateaus are increased. Particularly, the SF / H % value of the γ→β plateau is always higher than those of the α→β and β→α plateaus, and it also increases faster with cycling, reaching about 4 times of the other two plateaus at the 1000th cycle. It is considered that the improvement of the γ→β phase transition process is significant to promote the cycling behavior and practical applications of this alloy system. Graphical abstract Image 1 Highlights • Hydrogen storage properties of the LaNi 4 Co alloy within 1000 cycles are studied. • Changes in PCT curves with double desorption plateaus are investigated in detail. • Phase decomposition, lattice expansion, crystal damage and surface oxidation occur. [ABSTRACT FROM AUTHOR]

Abstract In this work, various amounts of (La,Mg) 5 Ni 19 phase is successfully produced in a A 2 B 7 -type La 0.75 Mg 0.25 Ni 3.5 alloy by zone heating the as-cast alloy at the peritectic reaction temperature of the (La,Mg) 5 Ni 19 phase (1203 K) for different durations. The formation process, electrochemical effects and functioning mechanism of the (La,Mg) 5 Ni 19 phase are studied. The as-cast alloy contains (La,Mg) 2 Ni 7 and LaNi 5 main phases, and (La,Mg) 5 Ni 19 minor phase. During zone heating, the peritectic reaction between the LaNi 5 solid phase and the melted (La,Mg) 2 Ni 7 liquid phase occurs, forming (La,Mg) 5 Ni 19 phase. Thus the (La,Mg) 5 Ni 19 phase abundance increases from 9.8 wt% (as-cast) to 46.2 wt% (heated for 24 h). The hydrogen desorption plateau pressure of the alloys increases with increasing (La,Mg) 5 Ni 19 phase abundance, contributing to fast hydrogen desorption and large current dischargeability. In addition, the (La,Mg) 5 Ni 19 phase network in the alloy matrix has a good structural stability against repeated hydrogen absorption/desorption, keeping the alloy from serious lattice destruction and crystal defects. Moreover, the discrete expansion/contraction between the LaNi 5 phase and the superlattice phases during cycling decreases with the consumption of the LaNi 5 phase, which relives the alloys' pulverization, and thus enhancing the oxidation resistance. Thereby, the cycling stability of the alloy electrodes of the 150th cycle increases from 65.4% (9.8 wt% (La,Mg) 5 Ni 19 phase) to 80.4% (46.2 wt% (La,Mg) 5 Ni 19 phase). Graphical abstract Image 1 Highlights • Various amounts of A 5 B 19 phase is produced in-situ in an A 2 B 7 -type alloy. • HRD is increased due to high plateau pressure and Ni content of A 5 B 19 phase. • S 150 increases a lot due to enhanced structural stability and oxidation resistance. [ABSTRACT FROM AUTHOR]

Abstract This paper mainly describes a sacrificial template synthetic approach for the fabrication of the Ag-nanosheet-assembled hollow tubular array by using an electrochemical deposition in the mixed solution of silver nitrate and citric acid on gold layer pre-coated ZnO nanorods. The tubular array is formed by an outer shell of Ag-nanosheet blocks and corresponding an inner hollow structure, this internal hollow structure is attributed to the completely corroded ZnO nanorods. Such Ag-nanosheet-assembled hollow tubular array exhibits excellent surface-enhanced Raman scattering (SERS) performance including rich surface activity, good selectivity and high sensitivity. Using this array as sensitive SERS substrate with good signal uniformity and reproducibility, it has been revealed that the detecting limit of R6G solution can be to10−12 M, presenting the potential applications of the SERS substrate materials in rapid detection of environmental organic pollutants. Graphical abstract Image 1 Highlights • A sacrificial template approach for the synthesis of the Ag hollow tubular array. • The synthesis of Ag hollow tubular array was two-step electrodeposition method. • The hollow tubular array was form of an outer shell of Ag-nanosheet blocks. • The Ag array was used as SERS substrate with surface activity and sensitivity. • The substrate detecting limit was 10−12 M, using detection of organic pollutants. [ABSTRACT FROM AUTHOR]

Abstract As an emerging p -conjugated materials, graphitic carbon nitride (g-C 3 N 4) has captured worldwide attention due to impending energy crisis and increasingly serious environmental contamination. In this work, the two-dimensional (2D) MgFe mixed metal oxide (MMO) derived from the layered double hydroxides precursor was employed to construct 2D/2D nanosheet heterojunction with g-C 3 N 4. The formed CN/MgFe-30 nanosheet heterojunctions exhibited the optimal photocatalytic hydrogen production about 6.64 times (1.26 mmol/g−1·h−1) than that of pure g-C 3 N 4 under the visible light irradiation, which were attributed to unique inter-plane 2D/2D structure and excellent synergistic effect between g-C 3 N 4 and MgFe MMO. The experiment characterization proved that MgFe MMO nanosheet not only suppressed the overgrowth of g-C 3 N 4 , resulting in the formation of nanoscale g-C 3 N 4 , but also facilitated the photoinduced carrier separation and transfer based on 2D/2D CN/MgFe-X nanosheet heterojunctions. This proposed synthesis strategy pave a way to realize the large-scale production of nano-g-C 3 N 4 based 2D/2D nanosheet heterojunctions photocatalysts for hydrogen production. Graphical abstract Image 1 Highlights • MgFe MMO was employed to construct 2D/2D nanosheet heterojunction with g-C 3 N 4. • The existence of MgFe MMO impeded the overgrowth of g-C 3 N 4. • The photocatalytic activity of nano-CN/MgFe-30 was 6.64 times than that of g-C 3 N 4. • This strategy supported large-scale production of nano-g-C 3 N 4 based heterojunction. [ABSTRACT FROM AUTHOR]

Iron hexacyanoferrate (FeHCF) is regarded as a promising cathode material of sodium-ion batteries (SIBs) due to the merits of easy preparation, low cost and three-dimensional open framework. However, the practical application of FeHCF is highly restricted by the intrinsic [Fe(CN) 6 ]4- vacancy and coordinated water as well as nanoscale particles. Herein, sodium citrate is introduced to mediate the drawbacks of FeHCF, resulting in microscale particles with less water content. Accordingly, the modified sample, FeHCF-3, achieved the performance of 92 mA h g−1 at 100 mA g−1 and 80 % capacity retention after 300 cycles. Furthermore, an optimal iron hexacyanoferrate (FeHCF-H-2) with high-salt-concentration preparation is designed and performs a good reversibility of 96 mA h g−1 after 700 cycles at 100 mA g−1. Such strategy may drive the application of high-tap, low-defect and stable cathode for SIBs. • The sodium citrate in FeSO 4 solution helps to adjust the growth of FeHCF. • High-salt-concentration solution preparation toward high stability and ∼μm size • High capacity of 116 mA h g−1 and good capacity retention of 80 % after 700 cycles. [ABSTRACT FROM AUTHOR]

Electrical conductivity between substrate and catalyst is a key factor restricting the OER (oxygen evolution reaction) catalytic activity of transition metal oxides. Herein we report a facile and direct route for synthesizing spinel NiCo 2 O 4 nanostructure on conductive substrates by electrospray technique. By simply altering the substrate temperature, film thickness and voltage, NiCo 2 O 4 with different morphology and electrocatalytic performance was obtained. The optimal performance showed a low overpotential of 375 mV at 10 mA/cm 2 and an excellent stability over 15 h. This work proved that electrospray technology is an effective strategy to fabricate the binder-free catalysts with high activity and stability for OER. [ABSTRACT FROM AUTHOR]

Tin-based materials are considered to be next-generation anode materials for lithium-ion batteries (LIBs) due to their high theoretical capacity and safety, but their large volume expansion results in rapid capacity fading. In this work, the heterostructure of Sn|SnO 2 submicron particles supported by carbon fibers and amorphous carbon layers (CF/Sn|SnO 2 @C) is successfully synthesized by hydrothermal and thermal treatments. Sn|SnO 2 submicron particles are uniformly grown on CF and encased in the CF network. Herein, CF together with a layer of amorphous carbon not only buffers the volume change of Sn|SnO 2 to prevent its pulverization and dissolution but also improves the electric and lithium ionic transportation capabilities during the lithiation/delithiation cycle. The CF/Sn|SnO 2 @C film can directly act as a binder-free anode for LIBs, exhibits a stable capacity of 657.6 mAh g −1 at a current density of 0.1 A g −1 after 50 cycles and presents better rate capacities than the Sn|SnO 2 @C comparison sample. Taking advantage of the stabilization and conductive channels of CF, this work demonstrates potential applications in the preparation of CF-based, binder-free anodes for LIBs in which metal oxide submicron particles can be effectively supported by a CF network. [ABSTRACT FROM AUTHOR]

Selective laser melting (SLM), as a powder-bed-based additive manufacturing technology, is a promising technology for manufacturing metal parts with high geometric complexity. The prediction of the SLMed microstructure, a key approach to manipulate the microstructures and performances, is challenging due to the complex heat history involving multiple thermal cycles. In the work, the microstructural simulation of solidification and solid-state phase transformation processes under various spatially variable thermal cycles of SLM was investigated by a developed two-dimensional cellular automaton (CA) model considering the temperature distribution and transient thermal history. The morphology and size of the β grain and martensite simulated by the model agree well with the experimental results in single-layer, thin-wall and multi-track multi-layer samples. Based on the simulated results, there are three zones (powder melting, remelting and reheating zones) and four stages (powder melting, mushy, multi-phases and solid-state phase transformation stages) during SLM depositing Ti 6Al 4V alloy. The morphology, growth direction and size of prior β grains depend mainly on the direction of heat flux and overlapping of adjacent deposited tracks. Six evolutional types of β grains exist including disappearance, morphological change, size increasing to be a stable value, growing, size decreases to be a stable value, and no evolution. The prediction of microstructure in SLMed alloy can be realized by the developed CA model. [ABSTRACT FROM AUTHOR]

LaNi 5 -based hydrogen storage alloys have a strong application potential in many areas such as gaseous hydrogen storage, hydrogen compressing, Ni/MH batteries etc. But the cycling stability is always an important issue of concern. In this study, the changes in the hydrogen storage performance of the LaNi 4 Al alloy at 403, 423 and 443 K during 1000 hydrogen absorption/desorption cycles are studied, and the degradation mechanism is explored using EXAFS as a main study method. It is found that with increasing cycle number, the P-C-T plateau first becomes flattened then steepened, the plateau pressure and the hysteresis are decreased, the entropy change for both hydrogen absorption and desorption first increases and then decreases, and the hydrogen storage capacity decreases. Testing temperature does not have notable influence in the variation trend of the long-term hydrogen storage properties. The degradation is mainly reflected by the tilted P-C-T plateau and the reduced hydrogen storage capacity. Structural analysis results suggest that the strain-induced nanocrystalization and the atomic mis-location during hydrogen absorption/desorption might cause a high disorder state and a partial destruction in LaNi 5 crystal lattice, resulting in the degradation in the hydrogen storage properties. [ABSTRACT FROM AUTHOR]

The nonlinear electrical properties of ZnO ceramic-epoxy composite materials with different ZnO filler concentrations were studied and the mechanisms were analyzed in this work. The electric field dependence of leakage current density was measured, which indicates that composites with ZnO filler concentration from 10 vol% to 20 vol% exhibit nonlinear electrical properties. However, the mechanisms about their nonlinear electrical properties are different. Nonlinear conductivity of composite with 10 vol% ZnO fillers appears after multiple partial discharges, which is ascribed to combination of partial discharge and tunneling effect. In order to further understand the mechanism, series resistance model of ZnO fillers and epoxy resin for conduction channel is put forward. Whereas, for the composites with 15 vol% and 20 vol% ZnO fillers, nonlinear conductivity directly appears with increasing electric field, without partial discharge, which is attributed to tunneling effect. Besides, as filler concentration increases from 10 vol% to 20 vol%, the switching field significantly drops from 380 V/mm to 56 V/mm, while the nonlinear coefficient sharply increases from 9.60 to 16.08. These results are important to clearly understand the electrical performance and mechanisms of composites for field grading materials. [ABSTRACT FROM AUTHOR]

A nanocomposite containing three-dimensional (3D) flower-like MoS 2 nanosheets and two-dimensional (2D) interconnected carbon nanosheets was successfully prepared by a facile hydrothermal method. The nanocomposite (MC-2) containing 6% surface-functional carbon nanosheets are beneficial to inhabit the restacking of MoS 2 nanosheets and form curved MoS 2 nanosheets, which are grown along the vertical orientation on the carbon nanosheets. The curved MoS 2 nanosheets could provide more suitable ion transport channels. The carbon nanosheets can enhance the electronic conductivity and keep the integrity of the nanocomposites. MC-2 exhibits the highest specific capacitance of 381 F/g at the current density of 1 A/g, as well as superior cyclic stability with 92% capacitance retention over 3000 cycles in KOH electrolyte. The excellent electrochemical performance of MC-2 as supercapacitor electrode is attributed to the 3D/2D structure and the synergistic effects between MoS 2 nanosheets and carbon nanosheets. [ABSTRACT FROM AUTHOR]

Polyvinyl Butyral (PVB)/Co 2 Z/reduced graphene oxide (RGO) layered composite was successfully prepared by a simple casting process in order to enhance impedance match. PVB acts as a matrix in this composite. The layered structure makes electromagnetic wave pass through the two layers successively, thereby resulting in the attenuation of electromagnetic wave. The results show that the hybrid PVB/Co 2 Z/RGO composite exhibits a highly efficient microwave attenuation property compared with the PVB/Co 2 Z and PVB/RGO composite in a wide frequency range due to the dielectric loss caused by the introduction of RGO. For the as-prepared PVB/Co 2 Z/RGO composite, an optimal reflection loss (RL) as low as −35.2 dB can be observed at 14.7 GHz with an absorber thickness of only 2 mm and the effective absorption bandwidth corresponding to the reflection loss below −10 dB is 4.24 GHz. Findings indicate that the layered PVB/Co 2 Z/RGO composite might be a promising candidate for a lightweight electromagnetic wave absorbing material. [ABSTRACT FROM AUTHOR]

Molybdenum carbide is a promising material as electrocatalyst for hydrogen evolution reaction (HER). Herein, a facile strategy was proposed to prepare Mo-precursor by coordination of Mo with polysaccharide from natural biomass (jujube) at room temperature, which also acted as carbon and chelating agent. After the Mo-polysaccharide complex is carbonized, Mo 2 C nanoparticles (NPs) are highly dispersed on N-doped carbon matrix. In this process, nitrogen self-doping, lamellar carbon formation and molybdenum carbonization were achieved simultaneously, and particle aggregation is avoided. The results show that 2D carbon nanosheets-embedded Mo 2 C NPs is an excellent electrocatalyst for HER in alkaline medium. An overpotential of 124 mV at j = 10 mA cm−2 can be reached when the optimum Mo 2 C/NC-1.0 material as electrode material, and it is better than other Mo 2 C materials reported recently. The exceptional HER performance is originated from the 2D lamellar structure and rich-N atom from jujube source, which can accelerate electron transfer and change the electron density of Mo 2 C. This study opens a new avenue to design biomass-derived C/Mo 2 C used as catalyst in hydrogen-evolving reactions. [Display omitted] • Polysaccharide from jujube acts as chelating agent and provides anchor point of Mo. • Nitrogen self-doping and formation of carbon nanosheets/Mo 2 C was achieved in-situ. • The as-obtained Mo 2 C/NC exhibited exceptional HER electrocatalytic performance. • Jujube-derived C/Mo 2 C is a promising non-noble metal catalyst for energy applications. [ABSTRACT FROM AUTHOR]

The large intrinsic band gap in Ta 2 O 5 photocatalyst has essentially hindered its potential applications in visible light irradiation. Doping non-metal elements into semiconductors is found to be an effective strategy for narrowing the band gap. In this study, we investigated the influence of non-metal atoms X (X C, N, F, Si, P, S, Cl, Se, Br, and I) on the band gap and photocatalytic ability of λ-Ta 2 O 5 by means of first-principles calculations. As to the reported N-doped and S-doped Ta 2 O 5 , our calculations well explained experimental observations on the band gap narrowing and photocatalytic redox capability. Based on the computed formation energies, we found that the preferred doping site of a non-metal atom is mostly related to the size and common valence of dopant. Our results predict that C-, P-, Si- and Se-doped Ta 2 O 5 are promising visible-light-responsive photocatalysts. The former two systems can be used in photocatalytic decompositions of organics, and the latter two systems may be applied to overall water splitting reactions. Further experimental studies are highly demanded to explore the promising applications of these four systems in the photocatalytic field. [ABSTRACT FROM AUTHOR]

In this study, Ce-doped ZnO photocatalysts are successfully prepared by using a simple and facile one-pot water bath method. The as-prepared samples are characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), ultraviolet–visible (UV–Vis) diffuse spectroscopy and Brunauer-Emmett-Teller (BET) surface area analysis. It is found that the as-synthesized Ce-doped ZnO possessed hollow porous structure, high surface areas and large pore volumes. The photocatalytic degradation efficiency (99%) of methyl orange (MO) with an optimal molar ratio of 0.3% Ce-doped ZnO is realized. The separation behavior of photogenerated electrons-holes pairs was investigated by surface photovoltage (SPV) and transient photovoltage (TPV) technique. The results illuminate that Ce element in Ce-doped ZnO tremendously promotes the separation of charges and inhibits the recombination of photogenerated charge carriers, corresponding to the excellent photocatalytic performance. [ABSTRACT FROM AUTHOR]

Metal organic framework MIL-101(Cr) nanoparticles were successfully HF- free synthesized via hydrothermal method and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and Nitrogen adsorption-desorption technology. Then resistive humidity sensor was fabricated to investigate humidity sensing properties. The results indicate that the sensor shows high sensitivity and rapid response-recovery time. The impedance changes more than three orders of magnitude in the range of 33–95% RH at 100 Hz. The response time and recovery time are 17 s and 90 s respectively. Finally, the humidity sensing mechanism was discussed through complex impedance analysis. The results illustrate that porous MIL-101(Cr) nanoparticles have great potential to be used as humidity sensing materials. [ABSTRACT FROM AUTHOR]

Au nanoparticles modified branched TiO 2 (Au/B-TiO 2 ) arrays were synthesized and the crystallization and morphology of the branches could be well controlled by simply altering the reaction times. The B-TiO 2 array composed of ultra-thin nanorod with thickness of ∼5 nm showed enhanced photoelectrochemical performances compared to TiO 2 nanorod array due to decreased resistance and increased carriers' transfer efficiency. Further, after the modification of Au nanoparticles, the photocurrent density was ∼2.5 mA/cm 2 at 1.23 V vs RHE, which was much higher than that of B-TiO 2 and TiO 2 nanorod array due to enhanced light harvesting ability, enhanced carriers' density that resulted from the synergistic effect of branched structure of TiO 2 and SPR surface plasmon resonance (SPR) effect of Au nanoparticles. [ABSTRACT FROM AUTHOR]

Cobalt sulfide (CoS) has a high theoretical capacity as an anode materials for lithium ion batteries (LIBs), however it suffers from poor cyclability and weak retention. Therefore, a lot of efforts have been devoted to overcome these defects. In this work, cobalt sulfide/carbon nanotubes (CoS/CNTs) nanocomposites were prepared by a simple and effective solvothermal method. The nanocomposites were constructed by CoS nanoparticles coated on the carbon nanotubes and the electrochemical performances of the CoS/CNTs nanocomposites were investigated as anode materials for LIBs. The results showed that the materials had superior cycle stability and kept a high discharge capacity of 780 mAh g −1 after 50 cycles at the current density of 100 mA g −1 . The excellent electrochemical performances are due to the good combination of the hybrid structure and better electron transportation originated from CNTs. The CoS/CNTs nanocomposites with excellent rate capabilities and super capabilities could be promising anode material for lithium ion battery. [ABSTRACT FROM AUTHOR]

The construction of a Z-scheme heterojunction favors the improvement of the photocatalytic activity of photocatalysts. Herein, the LaVO 4 /Bi 3 O 4 Cl Z-scheme heterojunction was designed reasonably by the method of in situ growth. The obtained heterojunction was further used as a photocatalyst for the degradation of ofloxacin (OFX), an antibiotic, in wastewater. The degradation efficiency of OFX by the optimal sample (LBC-2) was 94.3 % and the values of k were about 114.7 and 2.4 times those of LaVO 4 and Bi 3 O 4 Cl, respectively. In addition, LBC-2 maintained high activity after 4 cycles. The significantly reduced recombination rate of carriers in LBC-2 was reflected by the results of the photoluminescence (PL), photocurrent (PC), and electrochemical impedance spectroscopy (EIS) studies. The degradation pathways of OFX were proposed accounting to the intermediates detected by liquid chromatography-mass spectroscopy (LC-MS). Toxicity estimations showed that the toxicity of some intermediates decreased. This work provides new insight into the development of Z-scheme photocatalysts for the removal of antibiotics as pollutants. • Novel Z-scheme LaVO 4 /Bi 3 O 4 Cl composite photocatalysts were synthesized. • LaVO 4 /Bi 3 O 4 Cl composites exhibited excellent activity for ofloxacin degradation. • The apparent rate constant for ofloxacin degradation was about 114.7 and 2.4 times as that of LaVO 4 and Bi 3 O 4 Cl. • Z-scheme heterojunction boosted the fast transfer of charge carriers. • The degradation pathway of ofloxacin was deduced. [ABSTRACT FROM AUTHOR]

A novel Z-scheme BiOCl/Bi 24 O 31 Br 10 heterojunction with hierarchical structure was firstly fabricated, in which BiOCl nanosheets grew in-situ and vertically on the surface of Bi 24 O 31 Br 10 nanosheets. The obtained BiOCl/Bi 24 O 31 Br 10 composites exhibited favorable photocatalytic activity for RhB degradation under simulated sunlight irradiation. Especially, BB-0.3 (mass fraction of Bi 24 O 31 Br 10 , 30%) composite performed the best photocatalytic activity, and its degradation rate constant (k) for RhB was nearly 4.1 and 7.7 times higher than that of pure BiOCl and Bi 24 O 31 Br 10 , respectively. Larger specific surface area, wider photo-response range and efficient separation of photogenerated carriers were the main reasons for improving photocatalytic activity, which could be proved by Brunner-Emmett-Teller (BET) analysis, UV–vis diffuse reflectance spectra (UV–vis DRS), photoluminescence spectra (PL), transient photocurrent response and electrochemical impedance (EIS). Meanwhile, the effects of the catalyst dosage, pollutant concentration, initial solution pH and inorganic ions were discussed. Free radical scavenging experiments and electron spin resonance (ESR) measurement indicated that •O 2 - and h+ made significant contributions to the photocatalytic degradation of RhB. And recycling tests showed that the BB-0.3 heterojunction had a good stability. The possible photocatalytic mechanism of the Z-scheme heterojunction between BiOCl and Bi 24 O 31 Br 10 was proposed. [Display omitted] • BiOCl/Bi 24 O 31 Br 10 heterojunction is firstly fabricated by solvothermal method. • BiOCl nanosheets grow in-suit and vertically on the surface of Bi 24 O 31 Br 10. • BiOCl nanosheets and Bi 24 O 31 Br 10 nanosheets form a 3D hierarchical structure. • BiOCl/Bi 24 O 31 Br 10 heterojunction exhibits good photocatalytic activity. [ABSTRACT FROM AUTHOR]

An efficient Ho:SrF 2 single-crystal fiber (SCF), lightly Ho-doped to a concentration of 0.5 at%, was successfully grown using the temperature gradient technique, and its laser characteristics were studied. Several optical parameters of the Ho:SrF 2 SCF were determined using the Judd-Ofelt (J-O) theory, including the J-O intensity parameters, radiative lifetimes, and fluorescence branching ratios. In addition, the continuous-wave (CW), tunable, and passive Q-switched (PQS) laser operations of Ho:SrF 2 SCF pumped by a thulium-doped fiber laser were demonstrated in this study. While the CW laser was operating, average output power greater than 1 W and a continuous tuning range of 62 nm were obtained. For the PQS operation, a minimum pulse duration of 779 ns with a repetition rate of 36.27 kHz was achieved using silver nanorods as saturable absorbers. These results indicate that the Ho:SrF 2 SCF has potential application in tunable or ultrafast laser at 2.1 µm. • The Ho-doped SrF 2 single-crystal fiber (Ho:SrF 2 SCF) was first grown using the temperature gradient technique. • A systematic study of the Ho:SrF 2 SCF spectral characteristics has been carried out. • We presented the first experimental demonstration of CW, tunable, and PQS operations of in-band pumped Ho:SrF 2 SCF laser. [ABSTRACT FROM AUTHOR]

Chemical bath–deposited cadmium sulfide (CBD-CdS) is the most widely used buffer layer material for antimony selenosulfide (Sb 2 (S,Se) 3) photovoltaic devices, but its medium band gap, large band gap offset with transparent conducting oxides, and surface defects must be addressed to improve its applicability. Hexagonal CdS films (60 nm thick) prepared using the thermal evaporation method were used as the buffer layers of Sb 2 (S,Se) 3 photovoltaic devices. Compared with CBD-CdS (60 nm thick), thermal evaporation–deposited CdS (TED-CdS) films have a larger band gap and fewer surface defects. The Sb 2 (S,Se) 3 film deposited on TED-CdS is more compact, and its 1D ribbons are stacked more vertically to the substrate. The band gap offset between CdS and fluorine-doped tin oxide glass decreases from 0.76 eV (CBD-CdS) to 0.60 eV (TED-CdS). Therefore, suppressed electron trap density and charge recombination, as well as improved light harvesting, are achieved. By replacing CBD-CdS with TED-CdS, the best device efficiency increases from 6.14 % to 7.16 %, with the open circuit voltage, short-circuit current density, and fill factor increasing from 0.660 V, 15.96 mA/cm2, and 58.37 % to 0.664 V, 17.39 mA/cm2, and 62.85 %, respectively. The device stability and reproducibility are also improved. [Display omitted] • Hexagonal CdS buffer layer was prepared by thermal evaporation (TED-CdS). • TED-CdS has larger band gap than chemical bath deposited CdS (CBD-CdS). • TED-CdS is conducive to the growth of [221]-oriented Sb 2 (S,Se) 3 grains. • TED-CdS decreases the band gap offset between CdS and FTO. • Improved light harvesting and suppressed charge recombination are achieved. [ABSTRACT FROM AUTHOR]

The bifunctional catalysts which can improve both oxygen evolution (OER) and oxygen reduction reaction (ORR) activity are highly desirable for fuel cells, metal-air batteries and water splitting. Here, we report a perovskite structure Sr 0.9 M 0.1 RuO 3-δ (SMRO, M=K, Na, Ag) synthesized via sol-gel method performing excellent bifunctional catalytic activity. With the metal ion (M+) doping in A-site, X-ray photoelectron spectroscopy analysis reveals that oxygen vacancy and lattice oxygen are introduced into the structure, which is confirmed as the primary reason for the improvement of catalytic activity. The highest OER and ORR activity among these four samples is observed in Sr 0.9 Ag 0.1 RuO 3 (SARO). This work may shed light on the designing of high-efficiency bifunctional OER/ORR electrocatalysts. • With the metal ion (M+) doping in A-site, XPS analysis reveals that oxygen vacancy and lattice oxygen are introduced into the perovskite structure, leading to the OER/ORR activity improved efficiently. • Sr 0.9 Ag 0.1 RuO 3 (SARO) performs the highest bifunctional OER and ORR activity among the four samples investigated in this paper. • The high catalytic activity in SARO can retain at least 8 hours for OER and 2000 potential cycles for ORR in long-term stability tests. [ABSTRACT FROM AUTHOR]

Layered lithium-rich manganese-based materials with high voltage stability and high energy density are used to modify the surface of spent LiCoO 2 materials (LCO) for designing high-performance Li+-storage structures with high specific capacity and high voltage cycling stability. In this typical regeneration process, Mn2+, Co2+, Ni2+, and Li+ acetates were introduced as raw materials for coating Li 1.20 Mn 0.54 Co 0.13 Ni 0.13 O 2 (LLO) on the surface of spent LCO particles uniformly via a sol-gel method. The structural, morphological, and elemental-chemical-state characterisation results indicate that the recycled LLO@LCO materials exhibit a typical core-shell structure, with a layer-structured-Li 1.20 Mn 0.54 Co 0.13 Ni 0.13 O 2 layer ~ 10 nm thick as the high-voltage-stable-shell and a well-ordered layer-LiCoO 2 as the high-capacity-core. As expected, the regenerated LLO@LCO composites show an upgraded Li+-storage performance compared to bare LCO. The optimised LLO@LCO materials show an initial capacity of 197.1 mAh g−1 at 0.1 C, and ~ 95.8% retention after 100 cycles under 3.0–4.5 V at a rate of 1 C. All results indicate that this highly efficient, LLO assisted modification regenerate strategy can be easily extended to regenerate other spent cathodes to synthesise advanced energy storage materials with high voltage cycle stability and high specific capacity. • LLO was introduced for regenerating spent LCO. • LLO@LCO compounds were synthesized via sol-gel method. • Recycled LLO@LCO shows upgraded high-voltage stability. [ABSTRACT FROM AUTHOR]

AB y compounds with superlattice structures are considered as new generation materials for hydrogen storage and very promising as negative electrode for Ni- M H batteries. These compounds can be considered as the stacking of two fundamental layers along the c crystallographic axis: [ A 2 B 4 ] and [ AB 5 ]. Binary R Ni x (R = rare earths) compounds adopting stacking structures absorb large quantity of hydrogen but show poor reversibility. The superlattice structures are built by constraining the ab planes of the [ A 2 B 4 ] subunit to that of the more stable [ AB 5 ] one. The volume mismatch between the two subunits is the main cause of the multi-plateau behavior of the binary R Ni x (R = rare earths) compounds. The multi-element compounds show often improved hydrogen storage properties. In this review we highlight the structural evolution with the element substitution and the correlation between the subunit volume matches and the hydrogenation properties. • AB y compounds are promising as negative electrode for Ni- MH batteries and hydrogen storage. • The superlattice structures are built by constraining the ab planes of the [ A 2 B 4 ] to that of the more stable [ AB 5 ] one. • The volume match between the two subunits is an important parameter controlling the hydrogen storage properties. [ABSTRACT FROM AUTHOR]

Microcomposite particles of aluminum (Al) dotted by ammonium dinitramide (ADN) (Al@ADN) are successfully prepared by an in-situ crystallization growth method. The morphologies, structures and thermal behavior of Al@ADN are characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and simultaneous thermogravimetry and differential scanning calorimetry. The compositions and morphologies of Al@ADN after heating are characterized by X-ray photoelectron spectroscopy (XPS) and SEM. A high-speed camera is used to record the combustion performances of Al@ADN in a transparent quartz tube. Furthermore, the morphologies and structures of the residues are analyzed by SEM and XRD. The results show that ADN is deposited on the surface of Al to form Al@ADN. The decomposition of ADN increases the total oxidation degree of the Al particles. Under heating, the acids decomposed by ADN corrode the surficial alumina layer and the internal aluminum react with HNO 3 to form Al(NO 3) 3 , which makes the combustion of Al easier. Under an oxygen atmosphere, the pure Al could not be ignited. In contrast, Al@ADN could be ignited and Al@ADN 5:1 has a shorter ignition and burning time compared with Al@ADN 10:1. After burning, the Al@ADN composites are completely converted to α- and γ-Al 2 O 3. For Al@ADN 10:1, the residues show a cube-like stacking, while a ribbon-like stacking is presented for Al@ADN 5:1. [Display omitted] • Core-shell energy storage materials of aluminum dotted by ammonium dinitramide. • Shorter ignition time and burning time with increasing ammonium dinitramide. • Thermal oxidation interaction mechanism of aluminum and ammonium dinitramide. • Aluminum shells are corroded by decomposition of ammonium dinitramide to form Al(NO 3) 3. • Morphologies and structures after aluminum combustion. [ABSTRACT FROM AUTHOR]

Lutetium-doped Bi 2 Te 3 flower-like nanopowders were synthesized by hydrothermal method. The flower-like nanopowders were hot pressed into bulk pellets and the doping effects of lutetium on the thermoelectrical properties were investigated. The results show that the doping of lutetium can reduce the electrical resistivity greatly, while does not reduce the Seebeck coefficient too much, therefore results in a high power factor. Because the mass of the lutetium atom is close to the mass of the bismuth atom, replacing bismuth by lutetium will not increase the frequency of phonons greatly, which is helpful to remain a lower thermal conductivity. As a result of the combining effect of the lutetium doping and nanostructure of the sample, figure of merit ( ZT ) for the Lu 0.1 Bi 1.9 Te 3 sample can reach a high value 1.7 at 373 K. [ABSTRACT FROM AUTHOR]

The microstructure and electrochemical properties, especially the degradation in discharge capacity and kinetics performance of La 0.80 Mg 0.20 Ni 2.95 Co 0.70− x Al x ( x = 0, 0.05, 0.10, 0.15) alloys were studied. The alloys mainly contained (La,Mg) 2 Ni 7 and LaNi 5 phases. Al element tended to enter LaNi 5 phase rather than (La,Mg) 2 Ni 7 phase, leading to the increase in LaNi 5 phase abundance and decrease in (La,Mg) 2 Ni 7 phase abundance. Moreover, the cell volumes of both phases increased with increasing Al content. The alloys were seriously pulverized and oxidized during cycling, causing serious degradation in both discharge capacity and electrochemical kinetics. The addition of Al relieved the alloy pulverization by decreasing the cell volume expansion rate after hydrogenation. The alleviated pulverization together with the Al oxide layer on the alloy surface retarded the alloy corrosion/oxidation during charge/discharge cycles in alkaline electrolyte. Thus, the capacity cycling retention and the HRD 1500 cycling retention at the 150th cycle were increased from 61.9% ( x = 0) to 81.3% ( x = 0.15) and from 88.3% ( x = 0) to 95.7% ( x = 0.15), respectively. [ABSTRACT FROM AUTHOR]

CuO–Cu 2 O/graphene composite has been successfully prepared by the combination of a microwave-assisted process and subsequent annealing. X-ray diffraction and electron microscopy reveals that copper oxide nanospheres with a size of 120–200 nm are uniformly anchored on graphene nanosheets. The copper oxide nanospheres are composed of numerous CuO and Cu 2 O nanocrystals of ∼10 nm. These nanospheres are hollow and the thickness of the shells is around 50–70 nm. The CuO–Cu 2 O/graphene composite shows a highly reversible capacity and excellent rate performance as anode for Li-ion battery. The reversible capacity of the composite retains 487 mA h g −1 after 60 cycles at 200 mA g −1 . Even when cycled at various rate (200, 500, 1000, 2000, 5000 mA g −1 ) for 60 cycles, the capacity can recover to 520 mA h g −1 at the current of 200 mA g −1 . The enhanced electrochemical performances are ascribed to the hollow spherical architectures, excellent conductivity of graphene sheets, and possible synergistic effects between CuO, Cu 2 O and graphene that enhance the intrinsic properties of each component. [ABSTRACT FROM AUTHOR]

Highlights: [•] Diffusion coating treatment for Mg alloys in Al-containing molten salts. [•] The diffusion coating process was carried at lower temperatures (280–400°C). [•] The diffusion kinetics of the formed intermetallic coatings were investigated. [•] The interdiffusion coefficients and activation energies for each phase were obtained. [ABSTRACT FROM AUTHOR]

Highlights: [•] Interconnected agglomerates of nanoparticles are assembled into a porous network. [•] Both bulk insertion and interfacial storage contribute to the high capacity. [•] The enlarged voltage window of 0.01–3.0V is employed firstly. [•] An ultrathin carbon layer (1nm thick) helps to avoid the structure instability. [•] The obtained nanoparticles have a high capacity of 270mAhg− 1 at 300th cycle. [ABSTRACT FROM AUTHOR]

Highlights: [•] The 320°C isothermal section of the Mg–Nd–Zn system was well established. [•] Eight ternary phases (τ1–τ7 and T-NdMg12) were found at 320°C. [•] T-NdMg12 is the Nd-stabilized NdMg12 phase. [•] T-NdMg12 and τ5–τ7 can be regarded as the newly found ternary phases. [ABSTRACT FROM AUTHOR]

• Sputtering conditions largely affect the structure and properties of the NbC films. • The NbC phase in the NbC films is the key factor affecting the catalytic activity. • The highest hydrogen permeability of NbC/V membranes is ~1.9 times that of pure Pd. • NbC exhibits high potential as catalysts for H 2 dissociation in membrane applications. Niobium carbide (NbC) catalytic films were deposited on vanadium (V) foils by magnetron sputtering to prepare the NbC/V composite membranes for high temperature hydrogen separation. It is found that the sputtering power and substrate bias largely affect the structure and catalytic activity of the NbC films, and thus the hydrogen permeability of the NbC/V composite membranes. Optimized conditions for membrane preparation were obtained, which generated a pronounced high hydrogen permeability, particularly ~5.85 × 10−8 mol H 2 m−1 s−1 Pa−0.5 at 650 °C. This is 1.9 times that of pure palladium (Pd). The high hydrogen permeability of the NbC/V membranes can be attributed to the high catalytic activity of the NbC films towards hydrogen dissociation, as the cubic NbC phase in the films exhibits preferential growth along the catalytically dominated crystalline plane and a relatively high percentage. This work demonstrates that the NbC/V system shows high potential as a new non-precious metal membrane for hydrogen separation and purification at high temperatures. [ABSTRACT FROM AUTHOR]

• Mn-Cu alloys are fabricated by laser powder bed fusion based on mixed element powders. • The optimal processing windows for the dense Mn-Cu alloys is discovered. • The as-fabricated Mn-Cu alloys present good tensile properties. Mn-Cu alloys with high Mn contents have good damping capacity but poor workability and mechanical properties. In this research, laser powder bed fusion (LPBF) was applied to fabricate the Mn-Cu alloys (Mn 63 Cu 37 , Mn 73 Cu 27 , and Mn 82 Cu 18) based on mixed element powders. The printability, microstructure and mechanical properties of the as-fabricated Mn-Cu alloys were investigated through a series of characterization methods. The results indicate that the Mn-Cu alloys with high relative densities (99.76–99.85%) can be fabricated using the optimal processing parameters. The as-fabricated Mn-Cu alloys show higher strengths (537.5–589.6 MPa) and yield strengths (404.0–440.1 MPa) than those of commercial Mn-Cu alloys fabricated by conventional methods. The tensile strength presents an overall downward trend with increasing Mn content. Thus, LPBF can be considered as a promising method to fabricate Mn-Cu alloys with high Mn contents. [ABSTRACT FROM AUTHOR]