查看更多>>摘要：Electrochemical deposition of rhenium-iron alloy from water-in-salt electrolytes containing a super-high concentration of lithium chloride is investigated. Different techniques, including cyclic voltammetry, chronoamperometry, X-ray fluorescence, scanning electron microscope, X-Ray diffraction, and electrical measurements at cryogenic temperature are used to characterize the alloy electrochemical system and the deposited films. The catalytic effect of iron on rhenium deposition is observed, where the deposition rate of rhenium significantly increases in the presence of iron. Alloying rhenium with iron significantly inhibits the recrystallization of the as-deposited amorphous films. At the same time, it also greatly suppresses the superconductivity of rhenium.(c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：A novel sensor based on Schottky junction inducing avalanche breakdown effect in TiO2-Sn3O4 nanoheterojunctions is assembled. High sensitivity for NO2 gas sensing is demonstrated at room temperature. TiO2- Sn3O4 nanocompositewas synthesized as the gas sensing layer and Schottky contact was formed by Au electrodes. The Schottky contact functions as a "gate " which can trigger the avalanche breakdown effect in the TiO2- Sn3O4 heterojunctions. By tuning the Schottky barrier height through the responsive variation of the surface chemisorbed gas and the bias on the device, NO2 at a concentration from 5 to 50 ppm can be detected with an average response time of 8 s at room temperature. This nanostructured device is a promising candidate for application in high-sensitivity and high-speed NO2 gas sensor. The methodology and working principle illustrated in this paper present a new sensing mechanism that can be readily and extensively applied to other gas sensing systems. (C)& nbsp;2022 Published by Elsevier B.V.
查看更多>>摘要：Recent trends in the aluminum industry toward increasing the recycling rate of aluminum alloys have led to difficulties in controlling the formation of intermetallic compounds (IMCs). The up-to-date investigations have revealed that ultrasonic irradiation is a promising tool to refine and modify the intermetallic compounds formed in the melt before or during casting, and the reported mechanisms include ultrasound assisted nucleation and fragmentation of compounds. This work presents results concerning the modification effect of ultrasound on model Al3Zr compounds with emphasis on the effect of vibration amplitudes. The results reveal that needle-like Al3Zr compounds can be significantly modified to thicker shape when amplitude increases from 38 mu m to 48 mu m, and then change to more rounded shape with the further increase of amplitude. Theoretical consideration and numerical simulation show that in addition to the above-mentioned mechanisms, cavitation-induced heat generation and mircrojet-driven mass transfer are also of prime importance in controlling the morphology and growth of IMCs. (C)& nbsp;2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：A novel p-n heterostructure Ag-Ag2MoO4/polyaniline (Ag-Ag2MoO4/PANI) composite was synthesized via a facile oxidation polymerization followed by co-precipitation. The surface morphology, structure, optical and photoelectrochemical properties of the as-prepared composites were determined using various techniques, and the photocatalytic activity was evaluated using chromium (VI) [Cr(VI)] and methyl orange (MO) as target inorganic and organic pollutants under visible-light irradiation. The results showed that the p-n heterostructure was formed between Ag-Ag(2)MoO(4)and PANI, which could effectively promote the rapid transfer and separation of the photogenerated electron-hole pairs. At the same time, the metallic Ag nanoparticles on the surface harvested visible-light photons and generated extra plasmonic hot electrons to enhance the photocatalytic activity. As expected, the optimal Ag-Ag2MoO4/PANI(0.10) exhibited high photo catalytic activity in the Cr(VI) reduction and MO degradation owing to the fast separation and transfer of the electron-hole pairs. Moreover, trapping experiment revealed that center dot OH and center dot O-2(-) played a vital role during the MO degradation process. Based on various characterizations and experimental results, the possible photocatalytic mechanisms were proposed. This work gave a simple method to construct p-n heterostructure photocatalysts for environmental restoration. (C) 2022 Elsevier B.V. All rights reserved.
Egbu, JamesOhodnicki Jr, Paul R.Baltrus, John P.Talaat, Ahmed...
10页
查看更多>>摘要：We report on a systematic investigation of newly developed (Fe70Ni30)(80)Nb4B14Si2 metal amorphous nanocomposites (MANCs) and the factors affecting their surface roughness, including oxide formation and phase evolution during the nanocrystallization process. Analysis of surface roughness using atomic force microscopy (AFM) revealed an average roughness of 9.33 nm after heat treatment compared with as-cast amorphous ribbons, which exhibited a roughness of 4.21 nm. A surface oxide layer thickness has been determined using X-ray photoelectron spectroscopy (XPS). For samples annealed at 400 degrees C for 1 h, 450 degrees C for 1 h, and 550 degrees C for 3 h in air, the average surface oxide layer thickness was determined to be 10.9, 11.7, and 54.4 nm, respectively. It was observed that oxygen is enriched at the outermost surface and decreases rapidly as the XPS sputtering depth increases. Fe-oxide appeared as a predominant metal oxide at the top surface, followed by the presence of Nb oxide. A boron content increase was observed at the interface between the top surface oxide layer and the bulk of the sample. A protective surface oxide layer on FeNi-MANCs, such as observed in this work, can provide sufficient electrical insulation to reduce interlaminate eddy current losses and lower overall losses in magnetic components. (C) 2022 The Author(s). Published by Elsevier B.V.
查看更多>>摘要：Despite high entropy alloys (HEAs), phase formation rules as a simple method have been seldom used to predict the solid solution phases in light high entropy alloys (LHEAs). Some terms and thermodynamic based parameters are calculated via programing and all 4833 possible quintuple alloys out of proper elements are extracted and categorized in seven alloy groups and fifteen alloy systems with a density less than or equal to 5 g cm(-3) defined for LHEAs in this research. As expected, most alloys had low-density elements like Li, Mg, Al, and Ti in their chemical composition. Al14Li11Mg35Ti15Zr25 alloy was identified as the lightest alloy (3.36 g cm(-3)). Various alloys can be obtained and designed with optimizing values for the atomic size difference, electronegativity difference, and other respective terms. All alloy groups and systems are discussed and limitations for alloying methods are described. Al19Li7Mg6Ti35Nb33 LHEA was chosen as a candidate alloy to fabricate by melting and characterization of the as-cast alloy showed the formation of a high hardness single-phase BCC solid solution structure. Acceptable uniformity in the chemical composition of the alloy with a density of 5.31 g cm(-3) confirms the relative reliability of phase formation rules. (C)& nbsp;2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：In recent years, bimetallic oxides have been widely researched as promising anode materials of Li-ion batteries due to their superior electrochemical capacities compared with single transition metal oxides. However, the low interior conductivity and volume change upon cycling result in poor cycling stability. Here, carbon nanotubes (CNTs) have been employed in a solvothermal method to successfully boost the high capacity and superior cycling stability of ZnFe2O4/C nanoparticles. The effect of CNTs content on the structure, morphology, and electrochemical property of the composite has been investigated. At 200 mA g-1, ZnFe2O4/C/CNTs composite shows a high first discharge specific capacity of 1375.7 mAh g-1. After 100 cycles, the specific capacity can be still maintained at 1430.4 mAh g-1. The excellent electrochemical performance of ZnFe2O4/C/CNTs is attributed to the protective shell of carbon coating layer and three-dimensional channel constructed by high-conductive CNTs, which can alleviate volume change upon cycling and accelerate the transfer of electrons and lithium ions. This work provides a feasible idea for improving the properties of carbon-modified bimetallic oxide anode materials of secondary rechargeable batteries.(c) 2022 Published by Elsevier B.V.
查看更多>>摘要：Recently, Metal-Organic Frameworks-derived carbide catalysts draw lots of attention because of their low price, abundant reserves and superior stability. However, the metal element tends to form particles at a high temperature still a challenge to achieving high Oxygen Reduction Reaction (ORR) activity. Herein, a kind of Zeolitic imidazolate frameworks (ZIFs) based carbon nanosphere with well-dispersed Co-N-x active sites (Co and N co-doped holey Hollow Carbon nanospheres, hHCS) are prepared by using Polyvinylpyrrolidone as the surfactant to realize the well dispersion of Cobalt. Then KOH activation is used to enlarge specific surfaces area (SSA). In an alkaline medium, the obtained sample shows excellent ORR catalytic performance with a half-ware potential of 0.80 V and a limiting current density of 6.53 mA cm(-2), which are even comparable with that of commercial Pt/C. Further, the simple also exhibits remarkable stability during long-term working and better tolerance of methanol. According to the Density Functional Theory (DFT), the outstanding ORR activity can be ascribed to the favorable dispersed Co-N-x. It can be also attributed to the high SSA, hierarchically pore structure and N-base active sites. (C)& nbsp;2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Antimony selenide (Sb2Se3) is a very handy light-absorbing material in photochemical devices based on TiO2 nanotube arrays (TNT), but it has some problems with anisotropy and agglomeration. Large particles of antimony selenide instead impede photon transport and are susceptible to photocorrosion instability, making it crucial to develop a strategy for the directional growth of rod-shaped Sb2Se3 arrays. Herein, we successfully achieved the deposition of Sb2Se3 inside the tube of TNT by pulsed electrodeposition strategy to obtain the oriented Sb2Se3 nanorod arrays for efficient photoelectron transport. The conductive atomic force microscopy indicates the enhanced electron transfer performance. The UV spectral conclusion shows that the deposition of rod-shaped Sb2Se3 enhances the UV-vis diffuse absorption of TiO2, meanwhile, TNT acts as a shell to protect antimony selenide and effectively prevents its photocorrosion phenomenon. Therefore, the photocurrent density of TNT/Sb2Se3 NRs is 6.79 times as that of bare TNT. The Pt/TNT/Sb2Se3 NRs electrode exhibits a photocurrent density of 2.6 mA cm(-2) (-0.2 V RHE) and considerable hydrogen evolution per-formance. In addition, the Surface-Enhanced Raman effect (SERS) originated from this Sb2Se3 array, is first observed, which is expected to reduce the cost of SERS technology. (C)& nbsp;2022 Published by Elsevier B.V.
查看更多>>摘要：Laser-arc hybrid additive manufacturing (LAHAM) of Cu-Cr-Zr alloy was studied. The microstructure evaluation and mechanical properties of the samples fabricated by LAHAM were analyzed compared with those prepared by wire arc additive manufacturing (WAAM). Columnar crystals growing along the building direction in both LAHAM and WAAM samples was observed. In the LAHAM sample, the grain size was refined and the maximum texture index and pole density intensity were reduced by 32.9% and 25.8% respectively compared with those in the WAAM sample. Meanwhile, it was found the uniform Cr precipitation, and the orientation relationship of precipitated Cr with Cu-matrix followed N-W relationship: (111) fcc.Cu // (110)bcc.Cr, [011]fcc.Cu //[001]bcc.Cr, which was conducive to the improvement of tensile properties of the LAHAM copper alloy. Compared with the WAAM sample, the ultimate strength and elongation of LAHAM sample increased by 11.6% and 13.1%, to 258.7 MPa and 41.8%, respectively. The improvement in ultimate strength was attributed to grain refinement and precipitation strengthening, and it was found the precipitation strengthening accounted for about 75% of the total strength enhancement and was the primarily strengthening mechanism in the LAHAM copper alloy.(c) 2022 Elsevier B.V. All rights reserved.
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