查看更多>>摘要：With the progress of society, people have higher and higher requirements for energy battery anode materials. Commercial graphite electrode is limited by its specific capacity and can no longer meet people's needs. As a result, it is urgent to study high-performance anode materials for lithium-ion batteries. In this work, the sea urchin-like Co-Co Prussian blue analogue@Ni-1,3,5-Benzenetricarboxylate (Co-Co PBA@Ni-BTC) assembled from one-dimensional nanorods is prepared by a flexible one-step hydrothermal method using Co-Co PBA and Ni-BTC metal-organic frameworks as templates. Hierarchical microspheres constructed by nitrogen-doped carbon layer coated NiCo2O4/NiO composite nanorods (NiCo2O4/NiO@C) are further prepared by two-step calcination. After 200 cycles at a current density of 1 A g(-1), the capacity can be maintained at 1432.8 mAh g(-1) and the coulombic efficiency is up to 98.1%. When the current density reaches 5 A g(-1), its capacity can still be maintained at 894.3 mA h g(-1). The excellent electrochemical performance comes from the one-dimensional nanostructure and highly uniform nitrogen-doped carbon coating. This work provides new ideas for the application of metal-organic framework materials in lithium-ion battery anode materials. (C) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Magnetite and magnetite/ceria composites prepared by chemical procedures in various mutual ratios were exposed to calcination treatment in a temperature interval between 473 K and 1073 K. A combination of several experimental methods has provided detailed structural, phase, and magnetic properties utilisable for selection of optimal compositions and calcination conditions from the viewpoint of degradation ability tested using parathion methyl and paraoxon. It was shown that the ceria content, selected between 5 wt% and 50 wt%, influences magnetic properties. Its optimal amount was determined to be above 20 wt% and the calcination temperature of 773 K when the highest rate constant, slightly above 0.06 min-1, was obtained for parathion methyl in acetonitrile using a degradation test.
查看更多>>摘要：Water electrolysis for hydrogen production requires highly active and inexpensive catalysts. Herein, we combine ultrasonic impact nanocrystallization (UIN) technology with nital etching method to rapidly prepare highly efficient self-supporting Cu electrode with abundant low-angle grain boundaries. When used as a catalyst for hydrogen evolution reaction (HER), the as-prepared electrode exhibits an overpotential of 353 mV at a current density of 10 mA cm-2, which is about 200 mV lower than that of the blank Cu plate. Moreover, the overpotential decreased to 246 mV after the stability test of 100 h, indicating a self-optimizing property. This work paves a new way for the preparation of self-supporting electrode with high performance.
查看更多>>摘要：A novel high entropy silicide (NbMoTaWV)Si-2 coating was prepared on a NbMoTaWV high entropy alloy by silicon pack cementation. The single-phase structure of (NbMoTaWV)Si-2 was obtained due to the high entropy effect and sluggish effect of NbMoTaWV refractory high entropy alloy. The processing parameters could affect the coating structure and thickness. Low temperature favored the formation of single-layer (NbMoTaWV)Si-2 layer while high temperatures (1200 ? and 1300 ?) produced two layers coating, (NbMoTaWV)Si-2 layer and (NbMoTaWV)Si-2/(NbMoTaWV)(5)Si-3 mixed interdiffusion layer. Coating with reasonable thickness and minimized cracks could be obtained under proper processing parameters. The oxidation test of coating specimens was conducted at 1200 ? for up to 96 h. The high entropy of (NbMoTaWV) Si-2 suppressed the generation of metallic oxides and promoted the formation of dense and intact SiO2 layer, which largely improved the oxidation resistance of NbMoTaWV. Failure in corners was observed in most coating specimens after exposed for 48 h, and the failure mechanism was also discussed. (C) 2022 Published by Elsevier B.V.
Lazurenko, D. V.Petrov, I. Yu.Mali, V. I.Esikov, M. A....
13页
查看更多>>摘要：Ti-Al3Ti metal-intermetallic laminate (MIL) composites are known as promising structural materials due to the unique combination of their specific properties. However, their application is still limited due to the extremely high brittleness of the Al3Ti phase. In this study, we attempt to address this issue by changing the D022 crystal structure of Al3Ti to the more ductile L12 structure by alloying it with silver. To select the best fabrication regimes of Ti-Ti(Al1-xAgx)3 composites, in situ synchrotron X-ray diffraction analysis was performed to reveal the chemical reactions occurring upon heating the Ti-Al-Ag sample. The analysis showed that the highest amount of Ti(Al1-xAgx)3 phase with the L12 structure appears at 930 degrees C. This temperature was chosen for subsequent spark plasma sintering experiments. Scanning electron microscopy, energy dispersive X-ray analysis, and X-ray diffraction analysis revealed that the sintered sample consisted mainly of Ti, Ti(Al1-xAgx)3, and a minor fraction of the Ag-Al compound distributed in the central parts of the intermetallic layers and at the grain boundaries. Modification of the titanium trialuminide crystal structure positively affected the properties of the composite, providing a 60% increase in fracture toughness. The Ag-Al phase also contributed to toughening, causing an additional crack deflection effect. (c) 2022 Published by Elsevier B.V.
查看更多>>摘要：Through site selective substitution engineering, the (Ba2Ca)(1-2x)/3Bi(x)B(2)Si(4)O(14)(BCBSO: xBi(3+)) phosphors were prepared by high-temperature solid-phase synthesis. BCBSO: xBi(3+) phosphors show two obvious emission peaks at 330 and 500 nm, which are derived from the Bi3+ ions occupying Ba and Ca sites, respectively. The emission of the BCBSO: xBi(3+) phosphors is tunable by varying the Bi3+ content. Through XRD and XPS, the crystal structure and element composition of the samples have been determined. The emission and decay curves confirm that the two emissions come from different luminescent centers. The two emission bands of the BCBSO: Bi3+ phosphor have distinctive thermal responses to temperatures. The Sm3+ ion activated BCBSO phosphor has a bright emission mainly at 601 nm. The temperature-dependent emission of BCBSO: 0.08Bi(3+), 0.1Sm(3+) indicates an optical thermometer which is designed with high relative sensitivity at 510 K (S-r = 2.3206% K-1). (C) 2022 Published by Elsevier B.V.
查看更多>>摘要：Zinc-ion batteries (ZIBs) have become potential energy storage devices due to its low cost, environmentally friendly and high safety. The development of ZIBs is facing huge challenges especially in cathode materials. Here, we report a strategy of doping Co into MoS2 to get CoxMo1-xS2 nanosheets with rich dislocation-defects and expanded layer spacing. MoS2 itself has poor Zn2+ diffusivity and low specific capacity due to small layer spacing. The diffusion of Zn2+ is greatly improved by doping of Co. When CoxMo1-xS2 nanosheets are used as positive electrode in ZIBs, the capacity increased from 31.3 mA h g(-1) to 164.1 mA h g(-1), which is increased by more than five times. What's more, even if the current is increased ten times, it still has high capacity (about 40% capacity retention). In addition, the peaks of the Zn2+ intercalation/deintercalation in the CoxMo1-xS2 electrode have been effectively improved, which indicates a much more efficiency Zn2+ intercalation kinetic. Therefore, its capacity has been greatly improved. This research provides a general and effective strategy to reduce the embedding energy barrier of Zn2+ to increase the diffusion rate of Zn2+ and the capacity of ZIBs. (c) 2022 Elsevier B.V. All rights reserved.
Trang, Ton Nu QuynhDoanh, Tieu TuTrinh, Nguyen Thi PhuongThu, Vu Thi Hanh...
14页
查看更多>>摘要：Semiconductor/metal hybrid nanostructures-based finely tuning the charge transfer as a promising approach has been identified for photocatalytic activity recently towards renewable hydrogen (H2) evolution reaction (HER) and environmental remediation. Engineering surface-active facets of the metal cocatalyst on the surface of 3-dimensional (3D) structured photocatalysts not only efficiently promotes charge separation and transfer but also serves as reaction active sites for the further development of advanced photocatalysts. Herein, taking 3D SrTiO3 (STO) as a model, we introduce a plasmonic photocatalyst involving the adjusted loading of well-defined Ag active components as a cocatalyst deposited on the surface of 3D STO nanocubes to form the binary Ag/STO nanostructures for photocatalytic behavior driven by light at wavelengths of 365 nm and 420 nm. After the incorporation of the functional cocatalyst, the photocurrent response of STO was substantially increased, while its photoluminescence emission significantly declined, which could be due to the Schottky channel and enrichment of surface reactants: (i) the enhancement of the interfacial separation and inhibition of the recombination process of the photogenerated electron-hole pairs; and (ii) the Ag arrangement on the 3D structure could not only promote the enhanced light absorption but also provide a large surface area with highly active sites for the photocatalytic reaction. The as-synthesized hybrid photocatalyst with a loading content of 1 wt% Ag displays a high photocatalytic H2 evolution and RhB degradation reaching 30 mu mol g-1 h-1 (H2 gas) and a rate constant (k) of 0.027 min-1 (RhB dye), which was 2.5, and 3.4 times higher than that of the pristine STO specimen (12.5 mu mol g-1 h-1 and k = 0.008 min-1, respectively, at 385 nm). Under a wavelength of 420 nm, the binary Ag/STO structures exhibited excellent performance for the H2 production (17.5 mu mol g-1 h-1) and RhB degradation (k = 0.0134 min-1) in comparison with the pristine STO specimen. They also demonstrated remarkable stability for H2 evolution and dye degradation performance in continuous cycles. Based on the experimental outcomes, an energy band outline and a plausible mechanism have been proposed to describe the charge transfer and separation process for enhanced HER activity and RhB degradation.
查看更多>>摘要：In this study, flame-made Rh-doped SnO2/electrochemically exfoliated graphene hybrid materials were developed and systematically investigated for gas sensing towards H2S. Structural characterizations by various microscopic and spectroscopic techniques demonstrated the dispersion of graphene sheets on Rhsubstituted polycrystalline SnO2 nanoparticles with improved specific surface area. The effects of Rh dopants and graphene on gas-sensing behaviors of the hybrid sensors were systematically evaluated towards H2S, H2, CH4, C2H2, C2H4, CH3SH, CO2, C2H5OH, C3H6O and NO2 at 200-400 degrees C in dry and humidified air with 20-80% RH. It was found that Rh doping at the optimal amount of 0.5 wt% considerably enhances the response and selectivity of flame-made SnO2 nanoparticles toward H2S and additional graphene loading further increases the H2S-sensing performance with the optimum graphene content of 0.5 wt%. Accordingly, the 0.5 wt% graphene-loaded 0.5 wt% Rh-doped SnO2 sensor provided the highest responses of similar to 439 and the shortest response time of 6.5 s to 10 ppm H2S with high selectivity against CH3SH, H2, CH4, C2H2, C2H4, CO2, C2H5OH, C3H6O and NO2 at the optimal working temperature of 350 degrees C. The mechanisms of H2S response enhancement were described by the combinative effects of catalytic p-type substitutional Rh dopants and active graphene-Rh-doped SnO2 junctions.
查看更多>>摘要：With excellent compressive mechanical properties, FeNiCrAl medium entropy alloys with multi-principal components have attracted extensive attention in recent years. However, the limited tensile ductility of FeNiCrAl medium entropy alloys is the bottleneck for their industrial applications. In this work, dual phases of FCC + B2 and BCC + B2 were modulated in FeNiCrAl medium entropy alloys for excellent tensile behaviors. In the as-cast state, the tensile yield strength and ultimate tensile strength are 1140 MPa and 1423 MPa, respectively, with a uniform elongation of 6.0%. (c) 2022 Elsevier B.V. All rights reserved.
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