查看更多>>摘要：? 2022 Elsevier B.V.The heterostructure of metal oxide and other materials is one of the important ways for the development of electronic devices. The Bi2MoO6 (BMO)/ZnO composites were synthesized by secondary hydrothermal method. The morphology and crystal structure of the compound were characterized by scanning electron microscopy, EDS mapping, X-ray photoelectron spectroscopy, transmission electron microscopy, nitrogen physical adsorption and X-ray diffraction. The synthesis technology and gas sensitivity of BMO and BMO/ZnO composites were discussed. The results showed that BMO and BMO/ZnO had better butanol gas sensitivity, faster response rate, lower working temperature, and good stability. Compared with methanol, benzene, methyl alcohol, ethanol, and acetone, BMO/ZnO sensor showed good selectivity to butanol at 270 ℃. The response time and recovery time for 100 ppm butanol were about 6 s and 33 s, respectively, the response value up to 128. The n-n type BMO/ZnO composites with unique microstructure has abundant diffusion channels, and the research work provides a valuable reference for the low-cost preparation of high-performance butanol sensors. The energy band, potential barrier and charge transfer of BMO/ZnO composites are discussed, and the optimization of their gas sensitivity is analyzed in detail.
查看更多>>摘要：? 2022 Elsevier B.V.The coupling of piezoelectric and plasmonic effects is an effective strategy to enhance the photocatalytic performances. Here we prepared the new piezoelectric composites composed of Na0.5Bi0.5TiO3 nanoplates coated with Ag particles, which exhibited excellent piezo-photocatalytic performances. The plasmonic effect of Ag nanoparticles widened the catalysts’ spectral absorption range, and the electric field from the deformation of Na0.5Bi0.5TiO3 piezoelectric nanoplates can largely enhance the separation and migration efficiencies of photo-generated charge carriers in Ag@Na0.5Bi0.5TiO3 composites. With full-spectrum lights and ultrasonic excitation simultaneously, the piezo-photocatalytic activity of Ag@Na0.5Bi0.5TiO3 degraded 98.8% RhB in 30 min, and the corresponding rate constant k value reached as high as 0.146 min?1, 7.6 times that of pure Na0.5Bi0.5TiO3 photocatalysis. This work suggests a novel method to design and develop efficient piezoelectric photocatalysts.
查看更多>>摘要：? 2022 Elsevier B.V.Glass-coated amorphous magnetic microwires (GAWs) typically have a glass skin and amorphous metal alloy inner core, giving them special electromagnetic (EM) properties. GAWs not only exhibit multiple EM losses and suitable impedance matching but also have a conductive core with magnetic properties. In this study, GAW filament fibers (LFs) and short fibers (SFs) were prepared, and they exhibited completely different EM performance. LFs with filaments closely arrayed reflected EM waves and could thus act as an EM shielding material, whereas SFs with randomly distributed fibers demonstrated excellent microwave-absorbing (MA) properties. Single-layer SFs of just 3 g/m2 and a length of 5 mm had a minimum reflectivity (RL) of ?20.4 dB at 12.3 GHz, and the effective absorption bandwidth (EAB) of RL< ?10 dB was 5.36 GHz with a thickness of just 1 mm. Moreover, the MA properties of the SFs were obtained and controlled by adjusting the length, content, and lamination of the SFs in accordance with their multiple MA mechanisms. Double-layer SFs with a thickness of 2 mm could also achieve an EAB (RL< ?10 dB) above 10 GHz. The novel and effective strategy proposed in this study can thus produce SFs GAWs from ultralight MA fabric that exhibit excellent MA properties and broadband.
查看更多>>摘要：? 2022 Elsevier B.V.A novel magnetic CoFe2O4/g-C3N4/Bi4Ti3O12 composite photocatalyst has been successfully prepared via an ultrasonic-assisted heat treatment method for the degradation of malachite green (MG) dye in wastewater. The crystal structure, element composition, morphology, and optical properties of the as-prepared samples are investigated by a series of characterization techniques. The maximum degradation rate for MG reaches 98.05% over 40%-CoFe2O4/g-C3N4/Bi4Ti3O12 composite after optimizing the dosage and concentration, which is better photocatalytic activity than pure Bi4Ti3O12 and g-C3N4/Bi4Ti3O12. In addition, CoFe2O4/g-C3N4/Bi4Ti3O12 can be conveniently separated from the reaction system by the external magnetic field and reused multiple times. The characterization shows that the enhanced activity of CoFe2O4/g-C3N4/Bi4Ti3O12 is mainly due to the formation of heterojunction, promoting the separation efficiency of photogenerated electron-hole (e-/h+) pair. The capture experiments and EPR spectra show that the main active substances are h+ and ?O2? for decomposing MG in the reaction system. Then, a dual Z-scheme heterojunction electron-transfer mechanism is proposed. This study provides an idea for cycle stable magnetic photocatalysts for the treatment of MG solution.
查看更多>>摘要：? 2022 Elsevier B.V.Low-dimensional (LD) materials show great potential in sensing applications due to their attractive properties. Herein, Co@N-doped carbon nanorods (CoN-CRs) were prepared via the pyrolysis of a rod-like Co-ZIF-L precursor, which was synthesized using polyvinylpyrrolidone (PVP). The fabricated CoN-CRs were characterized by a series of techniques, and their electrochemical sensing behavior towards nitrite was subsequently evaluated. Compared with Co@N-doped carbon sheets (CoN-CSs), CoN-CRs exhibited enhanced performance for nitrite detection due to their higher surface area and more accessible active sites. Under optimized conditions, the CoN-CRs-based sensor was able to determine nitrite concentration in two linear ranges (0.5–4000 and 4000–8000 μM), with corresponding sensitivity values of 1.03 μA μM?1 cm?2 and 0.82 μA μM?1 cm?2, respectively, and a detection limit of 0.17 μM. Moreover, this sensor exhibited good selectivity, stability and reproducibility, and provided satisfactory feasibility for the analysis of nitrite in sausage samples and tap water. This work demonstrates that CoN-CRs are promising sensing materials for nitrite monitoring.
查看更多>>摘要：? 2022 Elsevier B.V.Crystal surfaces play significant role in controlling the photocatalytic properties of a semiconductor material. In this work, we report the controlled synthesis of various BiFeO3 nanostructures and validate the influence of various crystal surfaces towards photocatalytic properties for water oxidation. The synthesis of BiFeO3 nanostructures including hexagons, rectangular cuboids and nanoplates is achieved in NaOH aqueous solutions with various concentrations via a facile hydrothermal method. High-resolution transmission electron microscopy (HRTEM) revealed NaOH concentration dependent growth direction of various BiFeO3 nanostructures. BiFeO3 rectangular cuboids dominated with (102) crystal facets exhibited higher surface photovoltage (SPV) response confirming efficient charge carrier separation compared to hexagons and nanoplates. Furthermore, the photoelectrochemical measurements also confirmed the improved photocurrent density and positive shift in flat band potential for BiFeO3 rectangular cuboids studied via Mott-Schottky plots. Resultantly, BiFeO3 rectangular cuboids demonstrated superior photocatalytic O2 evolution activity of 82.2 μmol h?1 g?1 compared to 42.6 μmol h?1 g?1 and 53 μmol h?1 g?1 for hexagons and nanoplates, respectively, without any cocatalyst under visible light irradiation.
查看更多>>摘要：? 2022 Elsevier B.V.The performances of nanothermometers based on visible light are inevitably degraded in biological applications because visible light is greatly weakened after passing through tissues. Herein, in view of the second biological optical transparency window, a type of tailored core-multishell lanthanide-doped nanocomposite was synthesized with facile one-pot coprecipitation method to supplant complex method demanding stepwise thermal decomposition. Proved to have excellent dispersibility, crystallinity, stability and luminous efficiency, the nanocomposite is capable of enhanced NIR-II emissions and a broad temperature detection scope based on three kinds of spectral parameters relevant to its unique core-multishell structure. The maximum absolute and relative sensitivity of luminescence intensity ratios in low temperature range can reach up to 11.3% K?1 and 1.27% K?1, respectively, and a theoretical derivation is provided to address the peculiar V-shaped trend of NIR-II luminescence lifetime. The prepared nanocomposite can serve as a promising candidate for optical thermometer in the fields of cryoablation of diseased tissues and industrial applications in strong magnetic or radiofrequency fields.
查看更多>>摘要：? 2022 Elsevier B.V.Recently, wire-shaped supercapacitors (WSCs) with the benefits of being flexible, lightweight, and wearable, have attracted great attention as portable and wearable power sources, though still, they face critical challenges of inadequate energy density and electrochemical stability under mechanical deformations. Therefore, we report the fabrication of the asymmetric WSC constituting surface-modified Ni wire as current collectors, PVA-KOH electrolyte, and hydrothermally grown Mn3O4 nanoflakes and dip-coated PEDOT: PSS-MWCNT nanocomposites as positive and negative electrode active materials, respectively. Owing to surface modification of Ni wire and active materials with approximate mass matching, mesoporous nanostructured surface morphology, and improved surface areas, the twisted asymmetric WSC exhibits excellent volumetric capacitance of 7.55 F/cm3, 2.69 mWh/cm3 energy density, and 95 mW/cm3 power density at 25 μA with a 1.6 V voltage window. In addition, considering the recent trend of developing multi-functional self-powered systems integrating energy harvesters, storage entities, and functional components, ultraviolet photodetector (UV PD) in metal-semiconductor-metal (MSM) configuration was fabricated by hydrothermal growth of Cu-doped ZnO nanorods onto interdigitated electrode printed glass substrate, and hence for the first time a self-powered UV-light detection system with a fast response and high on/off ratio were successfully demonstrated by connecting solar-charged parallel asymmetric WSCs and UV PD.
查看更多>>摘要：? 2022 Elsevier B.V.Rechargeable aqueous zinc ion batteries (ZIBs) have attracted increasing interest in large-scale energy storage systems due to their low cost, high safety, and high volumetric energy density. Manganese-based materials are one of most promising aqueous zinc ion battery cathode materials while their practical applications in ZIBs are limited by their low electrical conductivity, poor cycling stability and controversial energy storage mechanism. In this work, Ag0.8Mn8O16, a kind of manganese-based cathode material with combination displacement/intercalation reaction was prepared by using a hydrothermal method. Due to combination displacement/intercalation reaction mechanism, the generation of metallic silver during the discharge process greatly enhances the electronic conductivity of the material and thus the Ag0.8Mn8O16 exhibits excellent rate performance and a reversible capacity of 198 mA h g?1 at 2 A g?1 after 1000 cycles. In addition, Ag0.8Mn8O16 shows an interesting capacity rise at low current density and through a series of comparative experiments, the existence of deposition dissolution mechanism in Zn/Ag0.8Mn8O16 battery was confirmed to be a critical factor of capacity increase.
查看更多>>摘要：? 2022 Elsevier B.V.A2BB’ X6 double perovskite has recently been considered as a potential substitute for lead-based halide perovskite. In particular, the lead-free Cs2AgInCl6 material possesses excellent moisture and thermal stability. However, the wide bandgap of the Cs2AgInCl6 host limits its optical properties. Doping with active elements is a unique avenue to endow Cs2AgInCl6 with excellent optical properties. Here, a strategy is proposed to explore the efficiency of near-infrared (NIR) emissions in Ln3+ (Ln[dbnd]Nd, Yb) ions doped Cs2AgInCl6 microcrystal by the codoping of Sb3+ ion for the first time. The incorporation of Sb3+ ion emerges a new optical absorption channel at a longer wavelength (>350 nm) and reduces the electron bandgap. Under the excitation at 365 nm, Sb3+ and Ln3+ (Ln[dbnd]Nd, Yb) co-doped Cs2AgInCl6 show the efficient NIR emission peaking at around 1000 nm, attributing to the effective energy transfer from Sb3+ to Yb3+ or Nd3+ f-electrons. Accordingly, the photoluminescence mechanism and environmental stability of Sb3+ and Ln3+ (Ln[dbnd]Nd, Yb) co-doped Cs2AgInCl6 microcrystal were also discussed in detail. This work demonstrates the availability of the Sb3+ doping tactics to realize efficient NIR emission in Ln3+ (Ln[dbnd]Nd, Yb) doped Cs2AgInCl6 microcrystal.
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