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 plate-like Fe-rich intermetallics phases in the recycled Al-Si alloys significantly deteriorate the mechanical properties. In this study, the effect of Mn addition on Fe-rich phases formation and the properties of the Al-7Si-1.2Fe alloys were systematically studied by optical microscopy, scanning electron microscopy, differential scanning calorimetry, thermodynamic calculations, synchrotron X-ray radiography and tomography. The results show that with the addition of Mn, the two-dimensional (2D) morphology of the Fe-rich phase change from plate-like to Chinese-script and star-like. The synchrotron X-ray tomography results indicate that the three-dimensional (3D) morphology of Fe-rich phases change from interconnected platelike to separated hollow polyhedron with increasing Mn content. The in-situ synchrotron X-ray radiography results reveal that the formation temperature, size, and area fraction of the primary Fe-rich phase in the Al7Si-1.2Fe-1.09Mn alloy gradually decreased, but the number density increased as the cooling rate increased. The thermodynamic calculation results indicate that beta-Al5FeSi could be eliminated when the Mn content exceeded 1.06%, which was consistent with the experimental results. However, excessive Mn addition caused the formation of large primary Fe-rich phases, resulting in a significant reduction in the elongation of the alloys. Reducing the equilibrium partition coefficient difference of Mn and Fe and reducing the formation of primary Fe-rich phases with high Mn/Fe ratios are good strategies to neutralize the negative effect of Fe-rich phases. (C) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：To meet the rapid development of flexible supercapacitors with both high energy density and power density, hybrid ion capacitors like lithium and sodium ion capacitors have attracted more and more at-tention. However, the hidden danger associated with the using of organic electrolytes limit their practical application. In this regard, a new configuration flexible zinc-ion hybrid supercapacitor (ZHSC) based on free-standing films of RGO-V2O5 (RGV) battery-type cathode and RGO-MXene (RGM) capacitor-type anode in aqueous electrolyte has been designed. The RGM/RGV system consists of specific layered structure, short ion diffusion pathway, high electrical conductivity and exceptional structural stability. As a result, the ZHSC based on RGM/RGV exhibits excellent electrochemical performance, including a large specific capacity of 175 F g-1 at 0.5 mV s-1, a maximum energy density up to 107.2 Wh kg-1 (321.6 W kg-1) and a high capa-citance retention of 81% of its initial capacitance (10,000 cycles). Additionally, the ZHSC displays a high specific capacity of 125 F g-1 at 0.5 mV s-1 even in an aqueous gel electrolyte. More importantly, super -capacitors based on the composite films exhibit stable flexibility electrochemical performance. The in-vestigation provides an essential strategy to synthesize composite films for application in high performance flexible hybrid supercapacitors.(c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：The localized surface plasmon resonance effect (LSPR) with kinetic energies and interfacial transfer dynamics can highly improve the separation of photo-generated carriers. We demonstrate here that a plasmonic catalyst Au-Pt-SiC has been prepared by a facile reduction-photo-deposition technique. The Pt-Si bond is formed on the SiC surface to construct an excellent channel for accelerating photo-electrons transfer from SiC to Pt. The LSPR of Au with electrons-deficiency property further activates the anchored Pt-Si bond, and motivates an oriented high-efficient photo-electrons transport channel among the Au, Pt and SiC. This channel accelerates the excited electrons in SiC to transfer to cocatalysts and thus improves the photo-generated charge carriers separation. The LSPR of Au also harvests light energy efficiently to broaden the light absorption range. Consequently, the rate of photocatalytic water reduction for H-2 is enhanced to 2248.5 mu L h(-1) g(-1) in Au-Pt-SiC, 2.1 times higher than that of the individual Pt loading. (C) 2022 Elsevier B.V. All rights reserved.
Stringe, MarkSpangenberg, KatharinaPinto, Manoel Wilker da SilvaPeterlechner, Martin...
9页
查看更多>>摘要：Reproducible thermodynamic sample states of a Pd40Ni40P20 bulk metallic glass are realized via differential scanning calorimetry by repeated quenching from the supercooled liquid state to temperatures well below the glass transition. Annealing treatments at 0.81 Tg and 0.96 Tg are embedded in the calorimetric method, changing the energetical state of the system. Varying the annealing times, a detailed and reproducible picture of the reversible relaxation dynamics with separated alpha- and beta-relaxation is obtained. An endothermic signature before Tg can either be provoked or depressed depending on the annealing temperature. The activation energy related to this process is obtained via Kissinger analyses yielding about 30 RTg. A large number of annealing cycles at 0.96 Tg irreversibly alters the response of the alpha-relaxation, while the mechanism of beta-relaxation is interestingly not influenced by this alternation. In order to extend the calorimetric response of the relaxation spectra to spatial resolution, the sample states were additionally analyzed using electron correlation microscopy providing information on the glass dynamics on an atomistic scale. The thus obtained kinetic parameters of local dynamics do not show an alteration of room temperature dynamics for different levels of alpha-relaxation, which is consistent with the results obtained via kinetic analyses of calorimetric data.
查看更多>>摘要：Superior electromagnetic (EM) wave absorption properties in 8.2-12.4 GHz (X-band) can be obtained via the effective combination of polyaniline (PANI) and SnO2 nanoparticle cluster. In this work, SnO2 nanoparticle cluster@PANI (SnO2@PANI) core-shell microspheres were firstly fabricated via a hydrothermal process followed by in-situ polymerization, and the EM wave absorption properties of SnO2@PANI coreshell microspheres in X band were studied. The related structure and morphology analyses indicated SnO2@ PANI core-shell microspheres were successfully synthesized with PANI coated on the surface of SnO2 nanoparticle cluster. The minimum reflection loss (RLmin) of - 69.1 dB (thickness of 2.78 mm) and effective absorption bandwidth (EAB) covering the whole X-band (when the thickness was from 2.5 to 3.1 mm) was achieved. Remarkable EM wave absorption properties of SnO2@PANI core-shell microspheres were mainly attributed to the outstanding impedance matching characteristic and dielectric loss capability (conduction loss, interfacial polarization loss and dipole polarization loss).
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.
Sharma, Pradeep KumarSenguttuvan, T. D.Sharma, V. K.Patro, Pankaj...
10页
查看更多>>摘要：Thermoelectric materials are promising as they found numerous applications in electrical power generation and solid-state cooling. In the last decade, Lead Telluride (PbTe) has emerged as a potential thermoelectric candidate for electrical power generation in the medium temperature range. In the present work, we demonstrate nearly 78% enhancement in thermoelectric figure of merit (zT) of nanostructured PbTe compound through doping with bismuth and dispersing 50 nm SiC nanoparticles. Bismuth doping induces n-type conduction and improves the electrical conductivity, while the SiC nanoinclusions modulate the Seebeck coefficient by carrier energy filtering, in addition to suppressing the lattice thermal conductivity. The significant phonon scattering at multi-scale scattering centers resulted in a minimum lattice thermal conductivity (kappa(L)) of 0.69 W/m-K in Bi-0.02-Pb0.98Te-8% SiC nanocomposite sample. Finally, the reduced lattice thermal conductivity in conjunction with moderate electrical conductivity and high Seebeck coefficient leads to a zT(max) value of 0.32 at 590 K in the sample with 6% SiC content. Hence, the partial substitution of the host atom and the presence of a secondary phase can be another promising strategy to enhance the thermoelectric performance. (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.
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.
NSTL
Elsevier