查看更多>>摘要：? 2022 Elsevier B.V.In this study, high-aspect-ratio (~1250) curved copper nanowires (CuNWs) composed of formate (FA) as the surface passivation layer were synthesized by the solvothermal method using sodium formate (HCOONa). Experimental data and density functional theory (DFT) simulations suggest that the growth of CuNWs-FA was due to the high chemisorption energy of FA on the [100] plane of Cu. The relative resistance ratio of CuNWs-FA increased by 1.67 and 1.72 after aging at 25 °C for 60 days and 60 °C for 5 days, showing FA passivation greatly improved the oxidation resistance of CuNWs. The transparent conductive electrodes (TCEs) fabricated from CuNWs-FA showed high transmittance (89.19%), low sheet resistance (Rs = 44.54 Ω sq?1), and excellent mechanical stability against 10,000 bending cycles. The TCEs-based transparent flexible heaters (TFHs) exerted a fast heating rate and a uniform temperature distribution within the 20 s response time, which is a testament to the CuNWs-FA in applications such as electrochromic and optoelectronic devices. This passivation approach sheds light on solving the major drawback of CuNWs oxidation and promotes its use in flexible electronic devices.
查看更多>>摘要：? 2022 Elsevier B.V.In order to improve the thermal stability of anodized TiO2 nanotube arrays, this paper proposed to fabricate the hybrid TiNb oxide nanotube arrays (TiNb ONA) on β-phase TiNb alloy plates by anodic oxidation. Then, TiNb ONA precursors were transformed into conductive nitride nanotube arrays (TiNb NNA) by nitridation at 800 °C. Introducing Nb contributes to the higher structural stability and easier nitridation of TiNb ONA compared with TiO2 nanotube arrays. After that, the spinel CuFe2O4 and nanosized Re-Ni alloy were respectively loaded on TiNb ONA and TiNb NNA to form CuFe2O4/TiNb ONA and Re-Ni/ TiNb NNA composite electrodes, and their performances in the photoelectrochemical reduction of CO2 and hydrogen evolution reactions were assessed respectively. Results showed that the well-maintained TiNb ONA improved the photo-response performance of the thermally-synthesized CuFe2O4, and TiNb NNA support also boosted the hydrogen evolution reaction because of the conductivity and catalytic activity of TiNb nitrides.
查看更多>>摘要：? 2022 Elsevier B.V.In this study, Cu-Cr-Mg alloy wires were prepared by up-drawing continuous casting and multi-pass drawing. The effect of the solid solution process on the strength and electrical conductivity of the Cu-Cr-Mg alloy was investigated. The solid solution degree of Cu-Cr-Mg alloys with different solid solution processes was evaluated by XRD. The types and morphologies of nanoprecipitates of the two alloys during different thermomechanical treatments were compared by selected area electron diffraction in TEM, and the degree of recrystallization of the peak-aged Cu-Cr-Mg alloy was analyzed by EBSD. The results showed that the degree of supersaturated solid solution of the as-cast Cu-Cr-Mg alloy was comparable to that of the as-cast Cu-Cr-Mg alloy after holding at 950 ℃ for 1 h and water quenching. Meanwhile, the strength of the as-cast Cu-Cr-Mg alloy was 52.2 MPa higher than that of the solution-treated Cu-Cr-Mg alloy, and the decrease in conductivity was only 6.3% IACS. The microstructure results showed that a large number of dispersed nanoscale precipitates existed in the matrix of both alloys, and the precipitates were close in size. The results of the strengthened model calculations are also close to the experimental results.
查看更多>>摘要：? 2022 Elsevier B.V.Due to wide applications in imaging and optical communications, how to develop novel high quality and low-cost candidate materials for near-infrared (NIR) photodetectors has become a hot research topic in recent years. Here, the self-powered NIR photodetector based on novel diamond randomly staggered α-Fe2O3 nanorod array is reported, which exhibits a dark current of 1.0 nA and photocurrent of 0.85 μA at 1.8 W @ 1 V, 40 ℃ with an NIR light irradiation on the novel α-Fe2O3 film. The experimental curve of photocurrent with light intensity is fitted based on equation of Iph= C1Pα, and the exponent α is estimated to have a value of 4.0, implying that there exists a four-photon excitation process under irradiation with wavelength of 808 nm. Furthermore, the J-V characteristics at different substrate temperatures are investigated, and the Arrhenius plot of current density vs temperature shows that the activation energy is about 0.58 eV under dark, but is reduced to 0.32 eV under NIR illumination. Above characteristic of the obtained high NIR photoelectric response can be probably attributed to the synergetic effect of strong light absorption and oxygen vacancies.
查看更多>>摘要：? 2022 Elsevier B.V.Overuse of antibiotics has given rise to drug resistant pathogens, while functional nanomaterials have emerged as a new antimicrobial way to replenish traditional antibiotics. In this work, we reported hybridized Ag/Co3O4 nanosheet composites using a combined synthetic strategy. Using adsorptive sites of 2-dimensional hydroxide, the synthesized α-Co(OH)2 ultrathin nanosheets used as initial materials captured Ag ions, which were then thermally decomposed into dense Ag nanoparticles assembled on the in-situ formed Co3O4 nanosheets, which were endowed with highly-concentrated Ag nanoparticles, long-acting antimicrobial activity, and more catalytic active centers. The targeted nanocomposite afforded excellent catalytic reduction of toxic para-nitrophenol to aminophenol. Furthermore, hybridized Ag/Co3O4 nanosheets showed the prolonged inhibitory effect (96 h) on microbial growth as typified by Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, and Candida albicans compared with that of silver- and cobalt-based counterparts. Furthermore, the MIC values of Ag/Co3O4 nanosheets against the above-mentioned microbes and Mycobacterium tuberculosis ranging from< 4–32 μg/mL were at least 8- to 32-folds lower than sole Ag or Ag-free Co-200 composites, validating the synergetic antimicrobial effect between silver and cobalt oxide. More importantly, we uncovered that the resulting nanocomposite obtained superior antimicrobial activity by sustained release of Ag and Co ions and superoxide anions against pathogens, which provides the great potential for antimicrobial application on special hospital occasions.
查看更多>>摘要：? 2022 Elsevier B.V.Potassium ion hybrid capacitors (PIHCs) have attracted widespread attention as combining the advantages of potassium ion batteries (PIBs) with supercapacitors. However, the sluggish kinetics caused by the large radius of K+ hinder the practical application of PIHCs. Herein, we synthesized a boron and fluorine co-doping interlaced network porous carbon nanofibers (BF-PCNFs), which was used as the freestanding anode of PIHCs the freestanding anode of PIHCs to alleviate large volume expansion and increase conductivity. Benefiting from the B, F co-doping and porous interlace nanostructure of BF-PCNFs, the anode shows 185 mA h g?1 under a load of 12.6 mg cm?2, a reversible capacity of 176 mA h g?1 at 1000 mA g?1 after 6000 cycles, and the capacity retention from 100 mA g?1 to 5000 mA g?1 is 62%. Furthermore, the PIHCs based on BF-PCNFs as anode and activated carbon as cathode exhibit an energy density of 87 Wh kg?1 and a power density of 393 W kg?1. The capacity retention is as high as 78% over 4000 cycles. Considering the exceptional rate performance, long cyclability and high-mass-loading, our work may supply a new strategy for designing novel energy storage devices with outstanding performance.
查看更多>>摘要：? 2022 Elsevier B.V.We report on the fabrication of an all-vanadium based Li-ion hybrid supercapacitor whose performance is highly enhanced compared to either batteries or supercapacitors via prelithiation process. Orthorhombic vanadium oxide nanoparticles and amorphous vanadium phosphate nanosheets implemented with carbon nanotubes are applied to battery-type and capacitive electrode, respectively. By utilizing vanadium-based electrodes with different charge-storage mechanisms in one device, advantages of both supercapacitors and batteries can be achieved. After a simple short-circuit prelithiation, the fabricated hybrid supercapacitor exhibits a high electrochemical performance with a capacitance of 111.6 F g?1 at 10 mA g?1, operation voltage window of 3.2 V, energy density of 160.2 Wh kg?1 and power density of 4.484 kW kg?1. Furthermore, it retains 98.3% of its initial capacitance after 2000 charge-discharge cycles. Due to its high operation voltage, a single, fully-charged hybrid supercapacitor successfully lights up variously colored LEDs for longer than one hr. With energy stored in the hybrid supercapacitor, a fragmentized graphene foam based strain sensor is powered to monitor various body-movements. This study demonstrates the high potential of the vanadium-based Li-ion hybrid supercapacitor as a powerful energy storage device obtained via deliberate selection of materials and prelithiation process.
查看更多>>摘要：? 2022 Elsevier B.V.The enhanced effect of metal catalysts is crucial to achieve advanced performance of hydrogen storage system. Rational design of catalysts with superior catalytic activity is significant to regulate the re-/hydrogenation kinetics of MgH2. Herein, Ti3C2-supported praseodymium(III) fluoride (PrF3) nanoparticles (PrF3/Ti3C2) composite was prepared by hydrothermal method, which exhibited superior catalytic activity toward hydrogen storage of MgH2. The onset temperature of dehydrogenation was reduced to 180 °C after adding 5 wt% PrF3/Ti3C2, corresponding to a reduction of 107 °C compared with pristine MgH2. About 7.0 wt% hydrogen was rapidly desorbed within 3 min at 260 °C and 6.6 wt% hydrogen was absorbed within 36 s at 200 °C for MgH2-5 wt% PrF3/Ti3C2. Moreover, MgH2-5 wt% PrF3/Ti3C2 exhibited an excellent capacity retention of 92.5% even after 10 cycles. Experimental results reveal that the electron transfer among Ti-species (Ti0, Ti2+, and Ti3+) occurred due to the striking enhanced effect of PrF3 on Ti3C2 MXene during the reaction process, and the synergistic action between Ti-species and PrF3 are responsible for the markedly enhanced hydrogen storage properties of MgH2. This study is helpful to the design and optimization of hydrogen storage materials for mobile application.
查看更多>>摘要：? 2022 Elsevier B.V.Cu3N layers prepared by annealing, under NH3:O2 flow, of Cu sputtered on Si, fused SiO2, and soda-lime-glass were studied by Raman and N-K-edge Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy. The annealing temperatures were ranging from 300° to 800°C. Benefiting from resonance effects on the Raman peak intensities when different excitation wavelengths are used, the contribution in the Raman signal of copper oxides, which provide peaks lying close to those of Cu3N, is more easily discriminated. The formation of Cu2O surface oxide is observed in almost all the samples even for annealing at low temperatures. CuO is generally formed at higher temperatures with the onset depending on the amount of O2 in the NH3:O2 mixture. However, high temperature is necessary to grow larger crystallites, as it is deduced from the decrease in the width of the high-frequency Raman peak (at ca. 650 cm?1) of Cu3N, in accordance with Scanning Electron Microscopy observations. The formation of CuO is accompanied by the creation of N2 trapped in the sample, which is directly detected by the NEXAFS measurements. N2 is most probably formed by the N atoms originating from the dissociation of the Cu-N bonds.
查看更多>>摘要：? 2022 Elsevier B.V.In this study, Al-Cu alloy suitable for laser powder bed fusion (LPBF) is rapidly developed through casting and laser remelting. The microstructure of as-cast Al-Cu alloy is consisted of equiaxed grains, and it was significantly refined after remelting. The Vickers hardness in the remelted zone improved by approximately 33.7% compared with that of as-cast Al-Cu alloy. The effects of different element content on Al-Cu-Mg-Zr alloy were analyzed, and optimum alloy composition was obtained with Al-5Cu-2Mg-1Zr-0.3Mn-0.15Ti through comparing microstructure, the hardness and other properties after remelting. The nano-indentation hardness and Young's modulus of remelted Al-5Cu-2Mg-1Zr-0.3Mn-0.15Ti alloys were 1.86 and 86.7 GPa, respectively. The microstructure was dense without obvious crack after LPBF forming, and the tensile strength, yield strength and elongation values reach 483 MPa, 365 MPa and 13.4% after solution treatment.
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