查看更多>>摘要：? 2022 Elsevier B.V.In this work, cyclic oxidation behavior of AlCoCrFeNi2, Al1.5CoCrFeNi2, AlCoCr1.5FeNi2, and Al1.5CoCr1.5FeNi2 High Entropy Alloys (HEAs) has been studied at 1050 °C for 10 cycles to understand the effect of Al and Cr in AlCoCrFeNi2 based HEAs. X-ray photoelectron spectroscopy, X-ray diffraction, electron backscattered diffraction, scanning electron microscopy with energy dispersive spectroscopy were used to study the base metals and oxidized samples. It was found that in all the samples, face centered cubic, and body centered cubic phases were present in different phase fractions. Al1.5CoCrFeNi2 alloy shows lower oxidation rate with oxidation rate constant (Kp) in the order of 10?13 g2cm?4s?1. The lowest oxidation rate of Al1.5CoCrFeNi2 alloy is attributed to the presence of higher Al content as it forms protective continuous thin Al2O3 oxide layer which suppress further oxidation by preventing ingress of oxygen into the substrate. Presence of higher Cr content results in forming protective Cr2O3 oxide layer but eventually it spalls off leading to the exposure of substrate for further oxidation.
查看更多>>摘要：? 2022 Elsevier B.V.Electrocatalytic oxygen evolution reaction (OER) is a critical half reaction for energy conversion and storage technologies such as water electrolysis, rechargeable metal–air batteries, carbon dioxide reduction reaction, and so on. Unfortunately, large overpotential is needed to overcome the sluggish kinetics of OER. With ultra-thin thickness, large specific surface area, rich and adjustable pore structure, and well-defined metal centers, two dimensional (2D) metal-organic frameworks (MOFs) have been widely investigated for OER. By virtue of the desirable chemical composition and diverse structural type, 2D MOFs are also employed as precursors and sacrificial templates to prepare metal-decorated porous carbon, metal oxides, metal hydroxides, metal sulfides, metal phosphides, and so on. These 2D MOFs derivatives with high surface area and abundant metal sites exhibit excellent OER performance. Herein, the current advances on 2D MOFs and their derivatives as (pre)electrocatalysts are summarized, including the synthetic strategy and OER performance. Moreover, the structure-performance relationships and actual active species or sites of 2D MOFs and their derivatives toward OER are discussed. The current scientific and technological challenges and future perspectives related with 2D MOF and their derivatives in practical applications are also mentioned at last.
查看更多>>摘要：? 2022 Elsevier B.V.In this work, core–shell NiCoSe@CoS nanotube arrays directly grown on nickel foam were synthesized via two-step hydrothermal method combined with cyclic voltammetry electrodeposition. In such heterostructures, NiCoSe nanotubes as the core were wrapped by interconnected CoS nanosheets as the shell. Results showed that the obtained NiCoSe@CoS nanotube arrays formed a conductive 3D network by growing CoS nanosheets on the surface of the NiCoSe nanotubes, which increased electroactive sites, shortened ion diffusion pathways, and thus enhanced charge storage. The unique core–shell heterostructures improved the structural stability and accelerated the electrode reaction kinetics of the nanotube arrays. Compared with the single-phase CoS nanosheets and NiCoSe nanotube arrays, the NiCoSe@CoS nanotube arrays as electrodes demonstrated enhanced areal capacitance (3.28 and 2.22 F cm?2 at 3 and 30 mA cm?2, respectively) and cyclic stability (capacity retention rate of 93 % after 5000 cycles at 3 mA cm?2). Furthermore, the NiCoSe@CoS nanotube arrays were used as the positive electrode to assemble hybrid supercapacitor devices with carbon nanotubes as the negative electrode. The fabricated device can deliver an energy density of 36.3 Wh kg?1 at a power density of 801.7 W kg?1 with long-term cycling stability, which indicates that the NiCoSe@CoS nanotube arrays have a greatly practical application value in supercapacitor devices.
查看更多>>摘要：? 2022 Elsevier B.V.Achieving high light absorption efficiency and low photogenerated carrier recombination rates is critical in the production of H2 by photoelectrochemical water splitting. Antimony selenide (Sb2Se3) has recently received much attention due to its favorable optoelectronic properties, low cost and unique nanorod structure. Herein, we constructed coral-like Sb2Se3/SnS2 heterojunction by introducing SnS2 with a nanosheet structure, which contributes to enhanced light absorption and provides more reaction sites. On this basis, synergistic optimization is carried out by the bilayer Sb2Se3 structure and ferrihydrite (Fh) to effectively inhibit charge recombination at the interface and facilitate electron transport. Compared to monolayer Sb2Se3 (1.54%), the IPCE value of bilayer Sb2Se3/SnS2/Fh can reach 20.56% (735 nm). The prepared bilayer Sb2Se3/SnS2/Fh has a maximum photocurrent density of approximately ? 1.0 mA cm?2 at 0 VRHE, continuous testing for 1 h compared to monolayer Sb2Se3 still maintains more than 4 times improvement. This work provides a basis for the development of high efficiency and low cost Sb2Se3-based optoelectronic devices.
查看更多>>摘要：? 2022 Elsevier B.V.As one of the energy storage devices, supercapacitors (SCs) have the advantages of high-power density, short charging time and excellent cycle stability, and have received widespread attention. Therefore, designing and synthesizing a supercapacitor material with high energy density has become a key factor to promote the development of SCs. In this work, the inter-crosslinked Co3S4 nanosheets which derived from ZIF-67 are successfully loaded on Co2(CO3)(OH)2 nanowires (CoCH NWs) can significantly facilitate the diffusion of electrolyte ions and enhance mass/electron transfer. The obtained Co3S4@CoCH composite grows directly on nickel foam (NF) substrates without binder, which improves the conductivity of Co3S4@CoCH/NF electrode. Consequently, the obtained Co3S4@CoCH/NF electrode possesses an excellent capacitance of 2697.1 F g?1 at 2 A g?1 and outstanding rate capability (84.4 % retention at 2–20 A g?1). In the three-electrode system, the capacitance retention is 79.8 % after 8000 cycles at a current density of 10 A g?1. An asymmetric supercapacitor assembled from Co3S4@CoCH/NF and activated carbon as cathode and anode respectively which has fabulous energy density of 42.2 W h kg?1 at 799.0 W kg?1 and stability (74.0 % retention after 8000 cycles). It improves that Co3S4@CoCH/NF is a promising cathode material for supercapacitors.
查看更多>>摘要：? 2022 Elsevier B.V.Cu3SbSe3 is a promising thermoelectric material with ultralow lattice thermal conductivity, especially at temperatures above 450 K at which the order-disorder transition of copper ions takes place. To investigate whether the high-temperature disordered phase can be extended to lower temperature, a series of Ag-alloyed Cu3-xAgxSbSe3 (x = 0, 0.1, 0.2 and 0.3) polycrystalline samples were synthesized and characterized in this work. It was found that the Ag-alloying shifts the order-disorder transition temperature to lower ones, which is beneficial to the thermoelectric application of Cu3SbSe3. For thermal transport, Ag-alloying is effective in suppressing lattice thermal conductivity in the copper-ions-ordered region, while in the copper-ions-disordered region, Ag-alloying barely has any effect on lattice thermal conductivity, as the phonon scattering is dominated by the liquid-like behavior of copper ions. Although Ag and Cu atoms have the same valence electron number, the carrier concentration is slightly increased after Ag-alloying, which suppresses the bipolar effect and increases the Seebeck coefficient at high temperatures. Finally, a maximum zT of 0.34 is obtained at 652 K for the sample Cu2.7Ag0.3SbSe3, which is 161% higher than that of the pristine sample.
查看更多>>摘要：? 2022 Elsevier B.V.Harvesting waste heat into electricity through thermoelectric (TE) material can make a great contribution to reducing energy consumption and environment pollution. Cu2S has proved itself to be a highly promising TE material, whereas the poor electrical property restricts its practical application. Therefore, the way to improve its electrical property by doping elements with high carrier concentration in an environmental-friendly method accelerate its application. Herein, Ag nanoparticles are incorporated into a p-type Cu2S (Ag/Cu2S) by a facile hydrothermal method to improve the thermoelectric properties. The introduction of Ag can effectively tune the carrier concentration, resulting in a high power factor of 1698 μW m?1 K?2; meanwhile, Ag doping can also enhance the phonon scattering, further reducing the thermal conductivity. Eventually, a ZTmax peak value ≈ 1.4 @ 773 K is achieved in the 0.5 wt% Ag-doped Cu2S samples. The design principle for Ag/Cu2S composites opens up a new pathway for the synthesis and application of thermoelectric material.
查看更多>>摘要：? 2022 Elsevier B.V.Nitrogen dioxide (NO2), as a common air contaminant, can cause human asthma and other respiratory diseases under a ppm-level atmosphere. Currently, most metal oxide semiconductors sensors usually work at a high temperature, which hinders its practical application. Therefore, to develop an efficient sensor with good stability and sensitivity is urgent for NO2 detection at room temperature. Herein, we report a FA0.83Cs0.17PbI3 (FACs)-based perovskite sensor via a simple one-step spin-coating method under ambient atmosphere. The FACs-based sensor exhibits a sensitive response to NO2 gas, low detection limit of 0.14 ppm and good reversibility as well as selectivity. The response/recovery time for the detection of 10 ppm NO2 is only 2/22 s, which surpasses the vast majority of sensors. Moreover, the FACs-based sensor also displays excellent stability. No morphological and structural changes occur, when FACs film is successively placed in a high-humidity air (50–60 %) without any encapsulations for three consecutive days. Benefitting from the superior response and stability, the FACs-based sensor in this work may open up a new avenue for high-performance sensor for the practical detection of NO2 at room temperature.
查看更多>>摘要：? 2022 Elsevier B.V.Due to its wide diffusion channels and high electronic conductivity, conversion-type transition metal-based chalcogenide cathode materials are endowed greater potential to implement high capacity in Mg-based batteries. However, large coulombic interactions and sluggish kinetics at high charge density perplex its electrochemical performance, and application of which is also seriously hindered by large volume expansion. Herein, we design a facile approach to in-situ fabricate ultrafine and well-dispersive carbon encapsulated NiS nanoparticles anchored on carbon cloth (NiS@C NPs/CC) through one-step carbonization and sulfuration of benzoate anion-intercalated Ni(OH)2 on CC. The as-prepared NiS@C NPs/CC is employed as the binder-free cathode material for hybrid Mg2+/Li+ batteries (MLIBs), whose energy storage capability is largely enhanced due to well-dispersive NiS nanoparticles. The MLIB assembled with NiS@C NPs/CC cathode implements a superior reversible capacity of 437 mAh g?1 at 100 mA g?1 and exhibits long lifespan. Its small diameter of 13.2 nm greatly shortens the ion transport pathway, and traits of carbon confinement and self-assembly synergistically boost electric conductivity at the same time, which contribute to the impressive electrochemical performance. This work not only realizes favorable synthesis of ultrafine and well-dispersive nanoparticles materials derived from the intercalation of organic-anion, but inaugurates a novel avenue for the rational design of carbon coated binder-free electrode for applications.
查看更多>>摘要：? 2022 Elsevier B.V.A novel yellow-emitting trivalent dysprosium (Dy3+)-activated Na2Y2TeB2O10 (NYTBO) phosphor was synthesized via a traditional solid-state reaction. This paper presents the phase structure, morphological characterization, photoluminescent properties, concentration quenching, and thermal stability. Excitation at the near-ultraviolet (NUV) light of 350 nm gives rise to the blue and yellow emissions, coming from the intra-4f transitions of Dy3+. The optimal Dy3+ doping concentration is determined to be 7 mol%, and the quenching originates from dipole–dipole interaction. The thermal quenching study reveals that the phosphor possesses good thermal stability and excellent resistance to color shifting. The investigation on colorimetric properties suggests that the Dy3+-activated NYTBO yellow phosphor could be promising for the application in NUV-irradiated white light-emitting diode.
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