查看更多>>摘要：Cobalt-nickel (Co-Ni) free Lithium-rich cathode material (1 - x)Li2MnO3 center dot xLiFeO(2) is more environmental friendly and cheaper than other traditional cathode materials. However, the complex synthesis method limits its large-scale practical application. This work explores a simple dry synthesis route to directly obtain 0.7Li(2)MnO(3)center dot 0.3LiFeO(2) with good electrochemical performance. Calcination temperature is a key factor controlling the phase growth. With the calcination temperature increasing, the crystallization and ordered layered structure are improved, but the LiFe5O8 spinel phase appears in X-ray diffraction (XRD) patterns from 600 degrees C. The results of selected area electron diffraction (SAED), element mapping (EDS) and vibrating sample magnetometer (VSM) demonstrate convincingly the growth progress of LiFe5O8 as the temperature rises. The spinel phase deteriorates the electrochemical performance. Furthermore, it is proved that the crystallization and activity of Li2MnO3 precursor are effective to retard the formation of LiFe5O8 and enhance the electrochemical performance. The sample calcined at 600 degrees C exhibits a high initial capacity above 200 mAh g(-1), but capacity fades quickly to 120 mAh g(-1) after 50 cycles at 0.2 C. The sample calcined at 650 degrees C with a little LiFe5O8 delivers a low initial capacity about 160 mAh g(-1), but stabilizes at 160 mAh g(-1) after 50 cycles. Therefore, how to control the formation of thermally stable phase LiFe5O8 is an important issue, and it needs further investigation to achieve Co-Ni free Li-rich cathode materials with excellent performance. Significantly, the simple synthesis and acceptable electrochemical properties make the practical application of Fe-Mn based Li-rich material possible. (C) 2022 Published by Elsevier B.V.
查看更多>>摘要：In order to further improve the oxidation resistance of CoCrFeNiAlx (x = 0.1, 0.5, and 1) high entropy alloys (HEAs), the surface of CoCrFeNiAl(x )prepared by vacuum arc melting is controlled by laser surface remelting (LSM) and the high-temperature oxidation properties of CoCrFeNiAlx before and after LSM is systematically studied. The results revealed that, with the increase of Al content, the parabolic velocity constant k(p )value gradually decreased after LSM treatment. Moreover, CoCrFeNiAl0.1 formed a continuous Cr2O3 oxide layer, CoCrFeNiAl0.5 formed an outer layer of Cr2O3 oxide film and an inner layer of Al2O3 precipitation, and CoCrFeNiAl1 formed a uniform and dense Al2O3 oxide layer on the entire area. After 100 h of oxidation, the oxide film thickness of three alloys is around 5 mu m, 4 mu m, and 3 mu m, respectively. The improvement in oxidation resistance after LSM can be ascribed to the formation of a dense re-melted layer, uniform distribution of the elements, refinement of the re-melted layer.(c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Si(3)N(4 )nanowires doped with rare earth ions (such as Ce3+, Tb3+, Eu2+ and Eu3+) were synthesized by plasma assisted direct nitridation method using Si, rare earth oxides and N2 as raw materials. The prepared doped Si(3)N(4 )nanowires were characterized by XRD, EDS, XPS, SEM and TEM. The obtained single-crystal doped Si(3)N(4 )nanowires have uniform diameters of about 50-100 nm and lengths of more than 10 mu m. The photoluminescence (PL), PL decay curves as well as thermal quenching behaviors of doped Si3N3 nanowires were systematically investigated. This work provides an effective strategy for doping large-size functional atoms in Si(3)N(4 )nanowires. (C) 2022 Elsevier B.V. All rights reserved.
Ysea, Nadia B.Llorente, Victoria BenaventeLoiacono, AntonellaMarquez, Lucrecia Lagucik...
13页
查看更多>>摘要：It is critical to minimize the cost of materials and inputs used in hydrogen production and to create solutions for large-scale generation to reduce the cost of hydrogen produced. Seawater is a natural low-cost electrolyte with high Na+ and Cl- concentrations, among other soluble salts. Chloride ions allow a highly corrosive media to the materials typically used as electrodes. In this work, we have prepared and tested different Ni-based catalysts for hydrogen evolution in NaCl-containing solutions. NiMo alloy, Ni(WO3), and Ni(Nb2O5) composites are compared and studied from a critical point of view to find a viable solution for catalysis in seawater electrolysis. The NiMo catalyst presents a higher dissolution rate in the NaCl medium than all synthesized catalysts. Furthermore, Ni-based composites showed improved durability due to a decrease in dissolution, and an increase in catalytic activity when using Nb2O5 as the dispersed phase. The Ni(Nb2O5) electrodes presented the higher catalytic activity in NaCl solution, even higher than that found in NiMo catalyst. (C) 2022 Published by Elsevier B.V.
查看更多>>摘要：The application of transition metal dichalcogenides (TMDs) in many optical devices has been seriously limited by its narrow band-gap and high electron-hole recombination rate. Therefore, more studied are desired for exploring the novel TMDs/Ga2O3 heterostructures with excellent photoexcitation properties and interfacial dynamics. Herein, the WSe2/Ga2O3 and MoS2/Ga2O3 heterostructures were successfully prepared by a two-step radio frequency magnetron sputtering method. The growth mechanism and interfacial charge transfer of the wide and narrow TMDs/Ga2O3 heterostructures are considered. The X-ray diffraction results show that the (002) orientation of the WSe2 and MoS2 was suppressed, which can be attributed to interfacial interaction. Compared to pure TMDs, the A1 g was blue-shifted in the Raman spectrum for the proposed heterostructures, which is related to the decrease of the electron density. The photoluminescence emission of TMDs/Ga2O3 heterostructures was enhanced mainly due to the transition from trions recombination to exciton recombination. Meanwhile, the transmission properties of electrons under the builtin electric field are further confirmed by the transient absorption spectroscopy. Effective charge separation not only reduces radiation emission rate but also significantly enhances the nonlinear optical response of TMDs. An open-aperture Z-scan measurement was carried out to confirm that Ga2O3 is a promising candidate for enhancing the saturable absorption or reverse saturable absorption of TMDs.(c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Ferroelectric (FE) materials, owing to their remarkable photovoltaic effects, are one class of the most promising materials candidates for self-powered photodetectors. Here, with the pronounced rectification ratio as large as 10(3) at electric bias of & PLUSMN; 1.0 V and a low dark current of 12 pA, the self-polarized Bi0.9Eu0.1FeO3 (BEFO)/Nb-doped SrTiO3 (NSTO) p-n heterojunctions are synthesized. It is revealed that the BEFO/NSTO p-n heterojunctions achieve the excellent photovoltaic effect with a short-circuit current as high as 0.23 mu A and an open-circuit voltage of 0.41 V under the light illumination of 405 nm in wavelength and intensity of 151.7 mW/cm(2). More importantly, the built-in potential in the as-prepared heterojunctions offers the self-powered photo-detecting functionality, with the high light-on/off current ratio of 2.0 x 10(4), high responsivity of 0.64 mA/W and sensitive detectivity D* of 1.63 x 10(10) Jones, and fast response speed of 50/44 ms without external bias voltage. In particular, the super-performance with R ~ 1.97 mA/W and D*~ 5.0 x 10(10) Jones in the weak incident light intensity (1.4 mW/cm(2)) are demonstrated, better than most previously reported FE-based self-powered photodetectors. Moreover, the devices possess good ambient stability and reproducibility. This work provides a demo for optically driven high-performance electronic devices based on self-polarized ferroelectric materials. (c) 2022 Elsevier B.V. All rights reserved.
Kim, Hoe JoonRajaitha, P. MaryHajra, SugatoPadhan, Aneeta Manjari...
9页
查看更多>>摘要：The high dielectric constant and lower dielectric loss make NdFeO3 materials ideal for potential use in many several applications. Specifically, NdFeO3 is a promising candidate for electrochemical sensing applications owing to its high thermal stability, and non-toxicity. In this present study, multiferroic NdFeO3 particles are synthesized using a solid-state reaction at a higher temperature. Structural studies confirm that NdFeO3 crystallizes in an orthorhombic symmetry. Elemental color mapping of the NdFeO3 sample reveals there is no impurity, and that the sample comprises Nd, Fe, and O elements. In addition, the Nyquist plot suggests the contribution of grain and grain boundary effect towards the resistive and capacitive characteristics of NdFeO3. Magnetic measurements at room temperature indicated an antiferromagnetic nature of the sample with a weak ferromagnetic component arising due to the canted nature of Fe3+. The non-collinear magnetic structure of NdFeO3 promotes the ferroelectric loop. Single-phase room temperature NdFeO3 multiferroics were coated upon the glassy carbon electrode with the aim of sensing hydrogen peroxide (H2O2) using a three-electrode electrochemical setup. The cyclic voltammetry technique showed an increase in the peak current with an upsurge in the concentration of H2O2 between 1 mM and 10 mM. The limit of detection, the limit of quantification, and sensitivity was calculated to be 0.87 mu M, 2.92 mu M, and 52.6 mu A mM(-1) cm(-2) respectively. The correlation coefficient R-2 was found to be 0.9792. The value of linearity with regression coefficient was calculated to be R-2 = 0.9922 from the effect of scan rate. NdFeO3 showed an excellent selectivity towards H2O2 in the presence of H2SO4, KCl, HCl, and NaOH, and good sensitivity for monitoring H2O2 in a real milk sample. The sensitivity of modified Glassy carbon electrode (GCE) in milk was calculated to be 46.58 mu A mM(-1) cm(-2). (C) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：The hot deformation behavior and microstructural evolution of Inconel 625 superalloy sheet under different conditions were investigated. The hot tensile tests under the temperature ranging from 800 degrees C to 950 degrees C with the increment of 50 degrees C and the strain rates between 0.001 and 0.1 s-1 were performed on a Gleeble 3500 machine. The experimental results indicated that the plastic flow behavior of the Inconel 625 sheet changes from work hardening to hot softening with the rise of experimental temperature and the decline of strain rate. Furthermore, the elongation is decreased with the rise of deformation temperature and decline of strain rate. According to the principle of dynamic material model (DMM), the process maps at various strains were constructed, and the optimal domain with the highest power dissipation was determined. The optimal domain appears at the temperature range of 925 and 950 degrees C and the strain rate between 0.001 and 0.1 s-1 with the power dissipation efficiency of about 46.5%. The grain size, grain boundary and texture of the deformed samples under typical conditions was analyzed by electron backscatter diffraction (EBSD) and transmission electron microscope (TEM), which reflected that the dynamic recrystallization (DRX) occurs in the optimal hot working window, and the preferred orientation for DRX nucleation of the Inconel 625 superalloy sheet is the < 001 > direction. The deformation behavior of Inconel 625 sheet under the longterm service temperature range is affected by the coupled effect of DDRX and CDRX. (c) 2022 Elsevier B.V. All rights reserved.
Paul, ShiddarthaSchwen, DanielShort, Michael P.Erickson, Anna...
10页
查看更多>>摘要：Multimetallic layered composites (MMLCs) have shown an excellent potential for application under extreme environments, e.g., accident-tolerant fuel cladding, because of their low oxidation tendency and high corrosion resistance. Interfacial phases or complexions in nanocrystalline materials accelerate the annihilation of defects and enhance the radiation resistance of materials, making MMLCs with engineered interlayer phases compelling to deploy in extreme conditions. However, implementation of MMLCs in full capacity remained a challenge due to a lack of fundamental understanding of the underlying mechanisms governing the characteristics of the interface between the metallic layers. The precise role of interlayer phases in MMLCs and their interaction with defects, specifically under extreme conditions, is still unexplored. Pursuing atomistic simulations for various Inconel-Ni MMLCs model materials, we revealed accelerated defect mobility in interlayers with larger crystalline misorientation and the inverse relationship between the interface sink strength to the misorientation angle. Furthermore, we found a linear relation between interlayer misorientation angle with the density of radiation-induced defects and radiation enhanced displacements. Finally, our results indicate that radiation-induced material degradation is accelerated by the higher defect formation tendency of MMLCs with a high-angle interlayer interface.(c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Hydrophobic AlCoCrFeNi high-entropy alloy (HEA) was prepared by electrochemical dealloying using 5% of weight percent H2SO4 aqueous solution at low temperature. The results of energy-dispersive spectrometer (EDS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses revealed that the element contents of Al and Ni were greatly reduced after dealloying treatment, leading to the increase of body centered cubic (BCC, Fe-Cr) phase and consequently, the achievement of the protective barrier of Cr- enriched oxide film on the substrate surface. The static water contact angle increased with the extension of dealloying period and reached a maximum value of 127 +/- 1 degrees, showing pronounced hydrophobic performance after dealloying treatment. Meanwhile, the AlCoCrFeNi HEA specimens showed excellent mechanical properties involved compressive strength and micro-hardness. Compared with the as-cast AlCoCrFeNi HEA, the HEA specimens after dealloying treatment exhibited superior corrosion resistance in an acidic aqueous solution of 3-nitro-1, 2, 4-triazole-5-one (NTO) aqueous solutions confirmed by potentiodynamic polarization tests and electrochemical impedance spectra (EIS) analyses, which was credited to the Cr- and Fe-enriched oxide and hydrophobic surface. Data Availability: The raw/processed data required to reproduce these findings cannot be shared at this time as the data also forms part of an ongoing study. (c) 2022 Elsevier B.V. All rights reserved.
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