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Journal of Alloys and Compounds
Elsevier Science S.A.
Journal of Alloys and Compounds

Elsevier Science S.A.

0925-8388

Journal of Alloys and Compounds/Journal Journal of Alloys and CompoundsSCIISTPEI
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    (162832)Loading Rh single atoms onto hollow cubic Cu_2MoS_4 nanoparticles for decreased electron/hole recombination and increased photocatalytic performance

    Wei WeiHaoyang GongLin Sheng
    11页
    查看更多>>摘要:In this study, hollow cubic Cu_2MoS_4 nanoparticles were synthesized via a facile hydrothermal method. Following that, Rh single atoms were loaded onto the surface of Cu_2MoS_4 nanoparticles to prevent electron/ hole recombination. The cubic morphology of Cu_2MoS_4 nanoparticles and the presence of Rh atoms were investigated by Transmitting Electron Microscope (TEM). The crystal structure of the synthesized Rh-loaded Cu_2MoS_4 was studied by X-ray diffraction (XRD). The shift in Rh X-ray Photoelectron Spectroscopy (XPS) peaks indicated the intimate interaction between Rh and Cu_2MoS_4, providing a pathway for the charge transfer. The photocatalytic efficiency of the synthesized photocatalysts was significantly enhanced by introducing Rh single atoms onto the Cu_2MoS_4 surface. Consecutive photocatalytic dye degradation experiments revealed that Rh-loaded Cu_2MoS_4 nanoparticles could be recycled and reused multiple times with no drop in the photocatalytic efficiency. The improved photocatalytic performance of Rh-loaded Cu_2MoS_4 was attributed to a lower charge transfer resistance, higher charge transfer rate, and longer charge carrier lifetime. The most crucial reactive radical was detected to be O_2~-~ while e~- and h~+ are also playing an essential role in the photocatalytic degradation of RhB on Rh-loaded Cu_2MoS_4. This study highlighted the importance of forming a Schottky junction between Rh and Cu_2MoS_4 to enhance charge carrier separation and improve photocatalytic efficiency.

    (163039)Mxene-TiO_2 composite with exposed {101} facets for the improved photocatalytic hydrogen evolution activity

    Shuang ZongJincheng LiuZhilin Huang
    10页
    查看更多>>摘要:Fabricating Ti_3C_2T_x Mxene based composite with good control of size, morphology and facet for the high-efficiency photocatalytic application is of great potential and highly challenging. In this work, Ti_3C_2-TiO_2 composite are prepared by a simple two-phase assembling method from the Ti_3C_2 Mxene dispersion modified with tetraethyl hydroxyl ammonium (TEHA) and rhombic-shaped TiO_2 nanoparticles with exposed {101} facets. The Ti_3C_2 Mxene acts as a good support to anchor TiO_2 nanoparticles of 15 nm with good facet control. A significantly enhanced photocatalytic hydrogen evolution activity is acquired by the Ti_3C_2-TiO_2 composites. The highest H_2 production rate of 390.92 μmol h~(-1) is gained by the Ti_3C_2-TiO_2 composites with the Ti_3C_2 weight percentage of 6.7%, which is 2.1 times that of pristine TiO_2. The excellent photocatalytic activity can be attributed to the extended light absorption, the boost charge separation efficiency and exposed {101} facets in the TiO_2 nanoparticles. This work provides a new strategy to prepare high quality MXene Ti_3C_2-TiO_2 hybrids with good photocatalytic properties, which could be widely applied to produce other MXene-based composites with excellent properties.

    (163103)One-step synthesis of amorphous NiCoP nanoparticles by electrodeposition as highly efficient electrocatalyst for hydrogen evolution reaction in alkaline solution

    Yanpeng CaoZhichao ChenFeng Ye
    9页
    查看更多>>摘要:Exploring a simple, low-cost preparation method to synthesize excellent catalyst for hydrogen evolution reaction (HER) in alkaline solution is highly meaningful for large-scale electrolysis of water for hydrogen production. Herein, a one-step electrodeposition method with simultaneous electrodeposition and phos-phation was proposed to synthesize the three-dimensional NiCoP/carbon cloth (NiCoP/CC) nanoparticles at room temperature on the conductive carbon cloth (CC). The results showed that the NiCoP nanoparticles covered by nanowires had an amorphous structure. The NiCoP/CC electrode exhibited a good catalytic activity in 1.0 M KOH solution. It required only 74,101,149 mV overpotential for HER in basic solution to obtain current densities of - 10, - 20, - 50 mA cm~(-2), respectively, with a corresponding Tafel slope of 89.5 mV dec~(-1). Furthermore, after 24 h constant voltage test, the current density of NiCoP/CC only showed 2% decay, indicating a good stability. The obtained excellent catalytic activity can be attributed to the amorphous structure, the synergetic effect of Ni and Co, the charge transfer among Ni/Co and P, and nanoparticles in situ grown on carbon cloth. The simple one-step electrodeposition method shows a very promising potential for the preparation of bimetallic phosphides.

    (163111)Understanding the effect of Ni content on microstructure and mechanical properties of A384 HPDC alloy

    Nadendla Hari BabuHiiseyin DemirtasErdem Karakulak
    8页
    查看更多>>摘要:Investigations have been carried out to understand the correlation between Ni content and properties of HPDC cast A384 aluminium alloy in as-cast and heat-treated conditions. Depending on Ni content in the alloy, different Ni-bearing intermetallics were formed. Suitable heat treatment conditions were selected after a series of experiments to obtain optimal mechanical properties. Most of the Ni containing intermetallics found to be stable at solutionizing temperatures which have a dramatic effect on the mechanical properties of alloys after natural and artificial aging. The results showed that, after heat treatment, to achieve higher strength values lower Ni additions are favourable.

    (163088)A strategy for controlling microstructure and mechanical properties of microporous spinel (MgAl_2O_4) aggregates from magnesite and Al(OH)_3

    Junjie YanWen YanZhe Chen
    8页
    查看更多>>摘要:In the present work, a novel strategy is proposed to control the microstructures of microporous spinel aggregates and improve their strengths. This strategy controls the in-situ decomposition behavior of raw material particles and the Kirkendall effect through preheating magnesite and Al(OH)_3, then milling with balls and water. Thus, the expected microstructures of microporous spinel aggregates can be obtained. Four microporous magnesium aluminate spinel aggregates of stoichiometric ratio were prepared using magnesite, Al(OH)_3, calcined magnesite, and calcined Al(OH)_3. The microstructures and strengths of microporous spinel aggregates were analyzed by XRD, SEM, image analysis method, etc. The microporous spinel aggregates prepared from magnesite and Al(OH)_3 had slightly lower apparent porosity (58.2%) than the one (59.2%) synthesized from Al(OH)_3 and calcined magnesite. In addition, the median pore size significantly reduced from 9.5 to 6.8 um, and the compressive strength dramatically increased from 7.3 to 15.2 MPa. These results verify the reliability of this strategy.

    (163011)Effect of laser shock peening without protective coating on the surface mechanical properties of NiTi alloy

    Yuling ChangHao WangSoren Keller
    12页
    查看更多>>摘要:We study the effect of laser shock peening (LSP) without protective coating on the surface mechanical property of NiTi alloy. The Vickers microhardness and wear resistance are measured to determine the mechanical property of NiTi samples treated with different LSP parameters (3 J with 10 ns and 5 J with 20 ns). From the electron backscatter diffraction (EBSD) analysis, it can be found that the laser shock peening does not induce obvious grain refinement in the surface region of NiTi alloy. Both compressive and tensile residual stress in the top layer are determined using the hole drilling method. The results show that the LSP treatment without a protective coating increases the roughness and enhances the surface mechanical properties of NiTi alloy.

    (163071)Facile hydrothermal synthesis of V_2O_5 nanofibers as cathode material for aqueous zinc-ion batteries

    Xiaodong LiuChunyang LiuZhiqiang Wang
    9页
    查看更多>>摘要:Aqueous zinc-ion batteries (AZIBs) are now vigorously explored as a class of novel and competitive candidates for large-scale energy storage in terms of high safety, eco-friendliness and low cost. In order to realize efficient Zn-storage with desirable cycling stability and rate capability, constructing suitable cathode materials that possess reliable host structure and fast Zn~(2+) diffusion kinetics makes a lot of sense. Herein, novel V_2O_5 nanofibers were facilely synthesized via a hydrothermal method and employed as a cathode material for AZIBs. By matching with aqueous Zn(CF_3SO_3)_2 electrolyte, the cathode is able to achieve a specific capacity as high as 264.5 mAh g~(-1) at 200 mA g~(-1). Even conducted at a large current density of 2000 mA g~(-1) a considerable rate capability of 132.6 mAh g~(-1) can also be delivered. In addition, electrochemical reaction kinetics and ion diffusion mechanism were initially conducted to uncover the insights for efficient Zn-storage. This work is anticipated to offer feasible strategy for the design and fabrication of promising vanadium-based cathode materials for rechargeable AZIBs.

    Thermal stability and interfacial structure evolution of Bi_2Te_3-based micro thermoelectric devices

    Hao TangHui BaiXiao Yang
    12页
    查看更多>>摘要:Bi_2Te_3 based thermoelectric device is the only commercialized thermoelectric module. The thermal stability of the interface between the thermoelectric materials and barrier layer or electrode plays pivotal role for the stability and reliability of micro thermoelectric devices especially for power generation. In this work, the thermal stability, bonding strength and structure evolution of the interface between Bi_2Te_3 based materials (both n type and p type materials) and Ni barrier layer were systematically investigated. The interface between Ni and Bi_2Te_3 based materials demonstrates an ohmic contact with the contact resistivity of 3.64 μΩ cm~2 and 5.31 μΩ cm~2 for p-type and n-type element respectively. The bonding strength of p-type and n-type element with electrode is 13.43 MPa and 17.62 MPa, respectively. Upon annealing at 423 K for 7 days, due to the mass diffusion between Ni and Bi_2Te_3 based materials, a thin Ni-Te layer is formed. With further extending the annealing time at 423 K to 42 days, the thickness of the diffusion layer increases to 3 μm. The growth of diffusion layer enhances the bonding strength to 19.81 MPa. However, this is accompanied with a sharp increase in the contact resistivity to 14.48 μΩ cm~2 for n-type element and to 6 μΩ cm~2 for p-type element with Ni barrier. The increase in the contact resistance deteriorates the output power of thermoelectric module especially for the micro-device from 2.60 mW to 2.48 mW under the temperature gradient of 20 K. This work points out that for the application of Bi_2Te_3 based thermoelectric device in power generation above 423 K, appropriate barrier layer is indispensable and plays significant role for the performance of the device.

    (163093)Na~+/Ag~+ substitution induced birefringence enhancement from AgGaS_2 to NaGaS_2

    Yihan YunWenlong XieZhihua Yang
    6页
    查看更多>>摘要:Birefringent materials are of great important as opto-electronic functional devices in solid laser system. Investigations on the design of new birefringent materials with large birefringence is meaningful. In this study, structure-birefringence relationship between AgGaS_2 (AGS) and NaGaS_2 (NGS) was systematically investigated. In the structures, the high ionic Na~+ cations broke the three dimensional (3D) [GaS] network to 2D layers, which results in the regular packing of GaS_4 tetrahedra and further the birefringence (-0.09, nearly twice that of AGS at -1064 nm). Meanwhile, the blue-shift of the UV cutoff edge to 307 nm and a wide band gap of 3.9 eV has been observed in NGS. The property characterizations were carried out using the as-grown NGS single crystal with a size of 4 × 4 × 0.3 mm~3 by high temperature flux method. The results indicate that NGS may be a promising IR birefringent material and the cation substitiition-oriented design strategy could be used to regulate the structure and optical properties of materials.

    (163053)Functional sulfur-doped zinc-nickel-cobalt oxide nanorods materials with high energy density for asymmetric supercapacitors

    Yajie GuoYan WangYu Zhang
    10页
    查看更多>>摘要:Transition metal oxides as the most promising electrode materials for supercapacitors has attracted widespread attention. However, their applications are limited by their sluggish charge transfer kinetics and insufficient active sites. Herein, we report the preparation of sulfur-doped zinc-nickel-cobalt oxides (S-ZNCO) using the synergistic effect of heteroatom doping and defect engineering by hydrothermal treatment and sulfurization method. The morphology and microstructure are characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), selected area electron diffraction (SAED), energy dispersive spectrometry (EDS) mapping, X-ray photoelectron spectroscopy (XPS) and Raman spectra. The results demonstrate the successful doping of sulfur atoms and introduction of oxygen vacancies, which increases the redox reaction active sites and further improves the electrochemical kinetics of the electrode material, giving rise to a high specific capacitance (2919.60 Fg~(-1) at 1 Ag~(-1)) and better electrical conductivity of the S-ZNCO electrode. Furthermore, the assembled S-ZNCO-NF//AC device achieves a high energy density of 72.97 W h kg~(-1) at a power density of 825 W kg~(-1). This work opens up new opportunities to design of advanced transition metal compounds for supercapacitors.