查看更多>>摘要：? 2022Sulfurized poly(acrylonitrile) (SPAN) is an attractive cathode material for lithium-sulfur (Li-S) batteries with demonstrated stable cycling, reduced polysulfide shuttle, and low self-discharge rates. However, the sluggish reaction kinetics of SPAN cathodes greatly limit their capacity output and rate performance. Here, we report novel Se0.03SPAN/CNT-3 nanofibers as sulfur cathode materials, aiming to promote the redox kinetics of sulfur conversion by imparting both electronic conductivity and catalytic activity to SPAN. Specifically, selenium is uniformly distributed in the Se0.03SPAN/CNT-3 composite through Se–S bonds and facilitates the fast transport of Li-ions. While the CNTs embedded in nanofibers enable high electronic conductivity and provide extra contact between electrode and electrolyte, offering smooth transport channels for both electrons and ions. As a result, the Se0.03SPAN/CNT-3 cathode presents a high reversible capacity (791 mAh g?1composite at 0.2 C), superior rate performance (638 mAh g?1composite at 4 C), and extremely stable cycle life over 800 cycles. In particular, when tested in practical conditions of high areal loading (Se0.03S: 5.2 mg cm?2) and lean electrolyte (E/Se0.03S: 10 μL mg?1), this cathode delivers high reversible capacities of 733 mAh g?1composite (0.1 C) and 672 mAh g?1composite (0.2 C), demonstrating its great potential for future application.
查看更多>>摘要：? 2022 Elsevier B.V.This work comprises the development of an ultrasensitive ZnO/SiNWs nanocomposite sensor for detecting formaldehyde (HCHO), an aldehyde whose presence in higher concentrations proves harmful to human health. Herein, ZnO as one of the metal oxide semiconductors (MOS) was used with silicon nanowires (SiNWs) to develop a sensor for precise detection of HCHO. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), Energy Dispersive X-Ray Analysis (EDX), Fourier transform infrared spectroscopy (FTIR), and X-ray Diffraction (XRD) were used to investigate the structural morphology and elemental analyses of the prepared nanocomposite structure. All these characterization studies revealed the uniform composition of ZnO/SiNWs nanocomposite structure. The sensing studies of HCHO at various concentrations were investigated at room temperature. The sensor response was found to be 1.27 with a highly accurate limit of detection (LoD) as (0.01 ppm). The developed ZnO/SiNWs sensor revealed high stability and repeatability, as well as fast response-recovery time. The well depicted sensing results at low concentrations could be attributed to the maximum adsorption of HCHO on the surface of ZnO/SiNWs structure due to high surface area, which was recorded to be 3-fold higher than that of the pristine ZnO based sensor. Hence, the findings and the developed sensor, that are being reported here can be used to reliably and precisely identify infections at an early stage.
查看更多>>摘要：? 2022 Elsevier B.V.Transition metal selenides (TMSes) are promising substitutes for graphite anode for lithium-ion batteries (LIBs). The deficiency of rational strategies to solve the issues of intrinsic activity, synergistic sites deficiency, and structural simplicity for TMSes restricts their application in LIBs. Herein, a hierarchical multi-metal (Fe, Co) modified nanorod-like selenide with nitrogen-coordinated porous carbon support (CoFeSe/NC) is synthesized to intensify the intrinsic activity and structural stability of the derived material via a well-designed Fe-doped ZnCo-based multi-metal organic framework as a precursor. Profiting from the synergistic effect of the N-coordinated porous carbon support, multi-metal components, and well-retained integrated architecture, the CoFeSe/NC anodes exhibit exceptional electrochemical performances with a discharge capacity retention of 775 mAh g?1 after 50 cycles at 0.2 A g?1 and ultralong cycling stability (423 mAh g?1 at 3 A g?1 up to 1000 cycles). Further detailed kinetic analysis and in situ and ex situ characterizations indicate the improved electrochemical kinetics compared to the single-metal selenides and elucidate the lithium storage mechanism of the CoFeSe/NC anodes. This work is expected to offer a guideline to construct the multi-component material with controllable intrinsic activity and induce the rapid kinetic of high-capability anodes.
查看更多>>摘要：? 2022 Elsevier B.V.The well-designed hierarchical nanosheets composed of different components can enhance specific capacitances and cycling stabilities of electrode materials. Herein, Mo-CoP@NiFe layered double hydroxide (LDH) hierarchical nanosheets were prepared by growing NiFe LDH nanosheets on MOF-derived ultrathin Mo-CoP nanosheets fabricated by etching Co-MOF with Mo ions. The hierarchical nanosheet structure can facilitate the transport of electrons/ions and provide numerous electroactive sites. Furthermore, the synergistic effects between the active materials provided more oxidation states for redox reactions. Owing to the hierarchical nanosheets and the synergistic effects between Mo-CoP and NiFe LDH, the Mo-CoP@NiFe LDH electrode exhibited a large specific capacity of 1655 C g?1 (2796 F g?1) and good long-term stability with 79.6 % capacity retention after 8000 cycles. Additionally, the hybrid supercapacitor (HSC) delivered an energy density of up to 48.6 Wh kg?1 at 800 W kg?1 and outstanding cycling stability (90.6 % retention of the initial capacitance over 20,000 cycles).
查看更多>>摘要：? 2022 Elsevier B.V.Au nanoparticle-modified porous TiO2 (Au@TiO2) nanospheres were prepared using a simple hydrothermal route followed by liquid reduction. Au NPs with a diameter of ~12 nm were well anchored on the surfaces of porous TiO2 nanospheres by epitaxial growth as their crystal planes had similar spacings. The sensing behavior of Au@TiO2 nanospheres was investigated using various organic vapors. Au@TiO2 nanospheres show higher responses towards 100 ppm formaldehyde, acetone, ethanol, and isopropanol with respective response values of 45.2, 55, 29, and 50 at a working temperature of 220 °C. The response/recovery times of the Au@TiO2 sensor for 100 ppm acetone vapor were 12 s and 13 s, respectively. These excellent sensing results indicate Au nanoparticle-modified porous TiO2 nanospheres are promising sensing material for the accurate detection of toxic volatile vapors.
查看更多>>摘要：? 2022Lanthanide-based optical ratiometric thermometer is a promising temperature detecting tool for noninvasive temperature measurements. However, owing to the thermal quenching of upconversion luminescence (UCL), the traditional temperature sensing range is limited to less than 600 K. In this work, highly thermally stable UCL is observed through introduced appropriate Cu2+ ions into LiYF4:Yb/Er (20/2 mol%) microcrystals (MCs) and on which are further used for temperature sensing applications. As gradually increases the doping of Cu2+ ions, the octahedron morphology of LiYF4 MCs with smooth surfaces gradually aggregates smaller particles on their surface forming diamond-like micro-clusters. Based on the single-particle spectroscopy technique, the temperature-dependent UCL properties were systematically investigated and demonstrated. Doping of Cu2+ ions can efficiently adjust and enhance the UCL in the LiYF4:Yb/Er (20/2 mol%) MCs. The UCL thermal quenching temperature is less than ~670 K for Cu2+-free MCs. In contrast, the quenching temperature extends to as high as ~870 K when doping with 2 mol% Cu2+ ions. Furthermore, these highly thermal stable MCs are utilized to detect the temperature in a wide temperature ranging from 298 K to 873 K. A maximum relative sensitivity (Sr) of 1.23%K?1 at 298 K is obtained and temperature uncertainty δT< 0.091 K is determined under the measured temperature for the 2 mol% Cu2+-doped MCs. The highly thermally stable UCL properties and excellent thermometer performance of these MCs, particularly conducted at single-particle spectroscopy technique, can be potentially applied to micro-scale thermometers.
查看更多>>摘要：? 2022 Elsevier B.V.Hierarchical microstructures are created when additional γ particles form in γ’ precipitates and they are linked to improved strength and creep properties in high-temperature alloys. Here, we follow the formation and evolution of a hierarchical microstructure in Ni86.1Al8.5Ti5.4 by in situ synchrotron X-ray diffraction at 1023 K up to 48 h to derive the lattice parameters of the γ matrix, γ’ precipitates and γ particles and misfits between phases. Finite element method-based computer simulations of hierarchical microstructures allow obtaining each phase's lattice parameter, thereby aiding peak identification in the in situ X-ray diffraction data. The simulations further give insight into the heterogeneous strain distribution between γ’ precipitates and γ particles, which gives rise to an anisotropic diffusion potential that drives the directional growth of γ particles. We rationalize a schematic model for the growth of γ particles, based on the Gibbs-Thomson effect of capillary and strain-induced anisotropic diffusion potentials. Our results highlight the importance of elastic properties, elastic anisotropy, lattice parameters, and diffusion potentials in controlling the behavior and stability of hierarchical microstructures.
Dreistadt D.M.Thi-Thu L.Capurso G.Bellosta von Colbe J.M....
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查看更多>>摘要：? 2022 Elsevier B.V.This work proposes an effective thermal activation method with low technical effort for industrially produced titanium-iron-manganese powders (TiFeMn) for hydrogen storage. In this context, the influence of temperature and particle size of TiFeMn on the activation process is systematically studied. The results obtained from this investigation suggest that the activation of the TiFeMn material at temperatures as low as 50 °C is already possible, with a combination of “Dynamic” and “Static” routines, and that an increase to 90 °C strongly reduces the incubation time for activation, i.e. the incubation time of the sample with the two routines at 90 °C is about 0.84 h, while ～ 277 h is required for the sample treated at 50 °C in both “Dynamic” and “Static” sequences. Selecting TiFeMn particles of larger size also leads to significant improvements in the activation performance of the investigated material. The proposed activation routine makes it possible to overcome the oxide layer existing on the compound surface, which acts as a diffusion barrier for the hydrogen atoms. This activation method induces further cracks and defects in the powder granules, generating new surfaces for hydrogen absorption with greater frequency, and thus leading to faster sorption kinetics in the subsequent absorption-desorption cycles.
查看更多>>摘要：? 2022 Elsevier B.V.To photodegrade the organic pollution, the Polyimide/Bi2MoO6-OVs p-n type aerogel heterojunction photocatalysts with rich pore structure and large surface area were synthesized by chemical amide reaction and supercritical ethanol drying technique successfully. The introduction of oxygen vacancies can be beneficial to the activation of molecular oxygen, which can inhibit photo-generated charge recombination to improve photocatalytic efficiency. Furthermore, the formation of Mo-N chemical bond between the coordination of N atoms of heptazine units and Mo atoms of Bi2MoO6 is confirmed by structure analysis. And the ability of the heterojunction photocatalyst to degrade RhB is improved significantly, which is due to photogenerated electron-hole pairs can be quickly separated under the internal electric field within the space charge region under visible light. Simultaneously, the SEM images show the flocculent PI polymer is coated on the surface of flower-like Bi2MoO6-OVs microsphere, which can expand the light absorption range and enlarge the surface area. This work provides an innovative perspective to construct polymer aerogel with inorganic materials heterojunction photocatalyst with superior photocatalytic activity.
查看更多>>摘要：? 2022 Elsevier B.V.In this study, BiPO4/CuBi2O4 (BPO-CBO) heterojunctions were prepared via hydrothermal method for singly and simultaneously degrading tetracycline (TC) and reducing Cr(VI) under simulated sunlight. The resultant 30% BPO-CBO heterojunction presented a 0D/1D trepang-like structure with a length of about 4 μm, a diameter about 1.5 μm and a size of 150–200 nm nanoparticles on the surface. It revealed outstanding removal efficiency of 92.0% and 60.3% for TC and Cr(VI) respectively, which were much higher than those results obtained when BiPO4 and CuBi2O4 were used individually. Moreover, the heterojunction displayed outstanding recyclability and reduced no more than 6% of initial time after five cycles. The remarkably enhanced photocatalytic properties were mainly ascribed to the unique trepang-like structure, the built-in electric field between p-n heterojunction and electron transfer the Z-Scheme pathways which was helpful to promote the separation of photogenerated carriers. Additionally, the corresponding reaction pathway and photocatalytic mechanism were further elucidated by the results of capturing experimental, ESR and LC-MS. This research provided a novel perspective for the construction of Z-Scheme p-n heterojunction with 0D/1D trepang-like structure in mixed contaminants purification.
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