查看更多>>摘要：Glass containing magnetic nanocrystals are attractive to provide high optical linear and nonlinearity properties. In this study, we reported the synthesis of perovskite La0.8Sr0.2FeO3 nanocrystals in heavy metal oxide glass under the AlO3 tailoring. The influence of AlO3 amount to the formation of La(0.8)Sr(0.2)FeO(3 & nbsp;)nanocrystals and the influence of nanocrystals to glass structure, optical linear & nonlinear properties were thoroughly investigated. The 10 nm-nanocrystals of orthogonal La0.8Sr0.2FeO3 were synthesized by melting quenching followed with subsequent crystallization process at 400 ? for 30 min under the tuning of AlO3. The formed La0.8Sr0.2FeO3 were well distributed in matrix without aggregation. Structure and chemical valence study revealed the aluminum abnormality effect and the Sr2+ induced multi-valence states of Fe ions and oxygen vacancies in La0.8Sr0.2FeO3 lattice. Such modification clearly influenced the optical ab-sorption, refractive index, polarizability, energy band gap shrinkage and nonlinearity. Physical parameters such as oxygen packing density, free volume etc. were calculated to confirm the influence of AlO3 tailored La0.8Sr0.2FeO3 crystallization to glass. The glass with 10%AlO3 amount exhibited a large thermal stability (132 ?), low thermal expansion coefficient (10.2 x10(-6)/K) and high BO4/AlO4 units, providing suitable environment for La0.8Sr0.2FeO3 crystallization. About 20 nm nanocrystals were formed and well distributed in glass which contributed to large nonlinearity absorption coefficient (5.19 x10(-10) m/W) and FOM (13.6 x10(3 )esu cm) which much superior than from relative literatures. The obtained glass with extremely good optical linear and nonlinearity performances can be promising candidate for photonics device applications. (C) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：A dual-phase reinforced Cu-0.75 wt% Al2O3-0.75 wt% TiB2 composite ingot was prepared by liquid phase in-situ reaction casting method and then processed by hot rolling and cold rolling. The microstructure and property evolution of the composite during processing were investigated, and the strengthening mechanism was determined. Spherical Al2O3 particles with a size of 50 ~ 500 nm and irregular polygonal TiB2 particles with a size of 50 nm ~ 1.5 mu m were formed in the Cu matrix. When the cold rolling reduction exceeded 80%, the strengthening particles flowed with the plastic flow of the Cu matrix. The violent shear action between the particles and the Cu matrix made the particle agglomerations separate, which enhanced the uniform dispersion of strengthening particles. For the reduction of 90%, the tensile strength, yield strength, hardness, elongation and electrical conductivity were 477 MPa, 452 MPa, 158 HV, 5.7% and 80.0% IACS respectively. The strengthening mechanisms were dislocation strengthening, dispersion strengthening and subgrain strengthening in descending order. Liquid phase in-situ reaction casting combined with large-deformation rolling is a promising process for the preparation of dual-phase reinforced dispersion strengthened copper matrix composite. (c) 2022 Published by Elsevier B.V.
查看更多>>摘要：Hydrogen production from water splitting is a green and efficient technology for storing clean energy. Herein, cerium-incorporated Ni2P nanosheets are designed as trifunctional electrocatalysts to generate hydrogen by hydrothermal self-oxidation of surface nickel foam (NF) in pure water to in-situ form Ni(OH)2 nanosheets, followed by incorporation of Ce and phosphorization. The prepared material exhibits excellent electrocatalytic performance in hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and urea oxidation reaction (UOR). When the current density is 100 mA cm-2, the UOR potential of Ce-Ni2P is 1.473 V lower than that in the OER (1.731 V), suggesting a great potential to replace the sluggish OER for overall water splitting. Moreover, the Ce-Ni2P/NF can be applied to the electrochemical treatment of real urine electrolysis with similar performance to the urea electrolysis. Such remarkable performance is attributed to the incroporation of Ce with "Ce3+/Ce4+ redox pairs", which can not only provide abundant reactive sites by the charge transfer appearance of defect sites, but also offer an effective buffering space for the pre-oxidation process from Ni2+ to Ni3+. It is thus beneficial for overall water splitting and coupled urea electrolysis, providing a promising candidate for urine wastewater treatment and clean energy production. (c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：One-dimensional rod-shaped Ag2Mo2O7/BiOI composite photocatalysts were prepared via a facile hydro-thermal-calcining method. The structure, morphologies, and elemental nature of the photocatalysts were characterized. Ag2Mo2O7/BiOI was formed through the attachment of BiOI nanosheets on the surface of Ag2Mo2O7 rods, resulting in a 1D/2D heterojunction with larger interface area, more surface-active sites, and faster charge transfer channel. The Ag2Mo2O7/BiOI heterogeneous exhibited excellent and stable photodegradation performances for Rhodamine B (RhB) and Tetracycline (TC) under visible light irradiation. At the optimum composition of 15 wt% BiOI, the Ag2Mo2O7/BiOI heterojunction exhibited a highest de-gradation rate for RhB and TC, which were 70 times and 16 times higher than those of Ag2Mo2O7, re-spectively. The improved photocatalytic performance can be attribute to the efficient separation of photoinduced charges caused by the formation of the n-n heterojunction between Ag2Mo2O7 and BiOI. Additionally, the dominant active species of photocatalytic reaction were determined to be .O-2- and h+ by free radical capture experiments and ESR test. In addition, a toxicity test with E. coli was carried out, which shows that the photodegraded Tetracycline solution is basically harmless to E. coli. Based on the experimental results and hybrid density functional theory calculation, a plausible photocatalytic mechanism of n -n heterojunction was proposed. (c) 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：Rational design of advanced cobalt oxides/carbon nanocomposites toward electrocatalytic oxygen reduction has received increasing research attention largely due to the potential synergism between cobalt oxides and carbon support. An efficient CoO/Co-N-C hybrid electrocatalyst has been prepared by high-temperature pyrolysis of ZIF-8 (ZIF = Zeolitic Imidazolate Framework) involving cage-encapsulation of CoCl2 followed by KOH treatment. In the alkaline solution (0.1 M KOH), the optimal CoO/Co-N-C hybrid catalyst (namely C-Co (OH)(2)@ZIF-8-10%-100 0) delivers a half-wave potential (E-1/2) of 0.84 V (vs. RHE), and a high four-electron reduction selectivity. The control experiments reveal that the superb ORR activity with C-Co(OH)(2)@ZIF-8-10%-1000 is jointly contributed by strongly coupled CoO NPs and Co-Nx moieties. Compared to the Pt/C benchmark, C-Co(OH)(2)@ZIF-8-10%-100 0 exhibits comparable ORR performance but better methanol tolerance and electrochemical stability. Besides, the home-made zinc-air battery with C-Co(OH)(2)@ZIF-8-10%-1000 as the air-cathode catalyst displays an open-circuit voltage of 1.43 V and a maximal power density of 96 mW cm(-2). (c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：In this work, Al-0.88Er-0.78Zr (wt%) alloy was fabricated via laser powder bed fusion (LPBF). The microstructure, precipitates distribution, electrical conductivity and hardness of as-built and aging treatment specimens were carefully characterized. Results show that LPBF process greatly expand the solid solubility of Er and Zr in Al. The addition of Er can significantly refine the grain size and form a bimodal grain structure consisting of fine equiaxed grains (grain size ~0.53 & PLUSMN; 0.15 mu m) at the boundary of molten pool together with coarse columnar grains (width 2.57 +/-& nbsp;0.84 mu m) at the center of molten pool. After 375 celcius for 3 h aging treatment, the particles on the grain boundary inhibit the grain growth; at the same time, a large number of Al3(Er,Zr) particles with L12 structure and size of 2.25 +/-& nbsp;0.3 nm are precipitated, which plays a major role in enhancing the hardness with the peak hardness of about 89.24 & PLUSMN; 3.77 HV. Er and Zr elements are proved to be an alternative way of the additive elements for developing a new 3D printing high-strength aluminum alloy.(C)& nbsp; 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：We investigate the baroentropy change on manganites (delta S-b(M) and delta S-b(M)-rho) using modified form of Maxwell's equation through magnetization and magnetization-resistivity measurements. Hence, we choose two Mnsite doped pervoskite manganites Pr0.6Ca0.4Mn0.96Co0.04O3 and Pr0.6Ca0.4Mn0.96Co0.04O3 due to strong correlation between magnetic and electrical properties. The two external perturbations such as magnetic field and hydrostatic pressure have a similar influence on magnetic and transport properties of manganite systems due to its strong coupling between spin, charge, and orbital degrees of freedom. Baroentropy change, similar to magneto entropy change, could be estimated by replacing magnetic field in Maxwell's equation by pressure in perovskite manganites. The estimated values of & UDelta;SbM and & UDelta;SbM-rho using proposed equations well agree with each other, justifying the use of these equations. As these values are deduced from pressure dependent magnetization and resistivity measurements, this method of baroentropy change estimation is very useful as well as reliable in order to select application-oriented systems from the manganites family. (C)& nbsp;2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Spin polarized van der Waals (vdW) heterostructures have attracted considerable interest owing to the spin splitting manipulation. In this paper, first-principles calculations are employed to explore the two-dimensional arsenene/CrI3 vdW heterostructure as a promising spin polarized material, as well as the spin polarization under strain and electronic field are investigated. The most stable stacking configuration and ferromagnetic (FM) property of the arsenene/CrI3 vdW heterostructure have been confirmed. The detailed calculations show that the Curie temperature (Tc) of the FM coupling CrI3 layer in the heterostructure can be enhanced up to 61 K, which is attributed to both superexchange interaction and proximity exchange effect. The electronic structures suggest that this heterostructure possess an intrinsic type-II band alignment and diluted magnetic semiconductor property. Interestingly, we found a transition from diluted magnetic semiconductor to half-metal and gradually to metal induced by the biaxial strains, and the extra electronic field can modulate the "maxican hat" of the valance band maximum (VBM) of arsenene. Our work provides not only application prospects of the arsenene/CrI3 vdW heterostructure nanodevices but also theoretical effective support for the research and development of the spin electronics and flexible electronics. (c) 2022 Elsevier B.V. All rights reserved.
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