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In this study, the successful construction of a novel AgVO 3 /BiVO 4 heterojunction photocatalyst via a facile two-step method was reported. The organic dye Rhodamine B (RhB) was chosen as a simulative pollutant to investigate the photocatalytic performances of the samples. The results showed that the AgVO 3 /BiVO 4 heterojunction possessed remarkably enhanced photocatalytic activity under visible-light irradiation compared with individual components. The AgVO 3 /BiVO 4 heterojunction possessed the highest rate constant, which was about 17.2 and 3.1 times higher than those of pure BiVO 4 and AgVO 3 , respectively. Such an enhancement was mainly ascribed to the formation of suitable heterojunction structure with intimate interfacial contact between AgVO 3 and BiVO 4 , resulting in the effective separation of photogenerated electron-hole pairs. The possible photocatalytic mechanism was also proposed based on the trapping experiments of active species, indicating that h + and OH played a key role in the photocatalytic degradation process. [ABSTRACT FROM AUTHOR]

Single-atom based photocatalysts have been widely used in the degradation of organic pollutants due to their excellent activity, nearly 100 % atomic utilization efficiency and well-defined active centers. Here, we propose a single Co atom cocatalyst coordinated by nitrogen-doped graphene (Co-NG) to enhance the photocatalytic activity of perylene diimide (PDI) toward bisphenol A (BPA) degradation. Firstly, the self-assembled PDI on the surface of Co-NG exhibits a uniform dispersion state, which facilitates electron transport across the interface. Secondly, Nitrogen-doped graphene can act as a charge transfer bridge to facilitate charge migration from PDI to single Co atom catalytic center. Therefore, in the photocatalytic degradation of BPA, the Co-NG/PDI composite photocatalyst showed a significant increase in activity. 7 % Co-NG/PDI composite possesses the best photocatalytic performance, and the apparent rate is 6.64 times and 7.6 times higher than those of self-assembled PDI and Co-NG. The excellent activity is due to its high photogenerated carrier migration and transfer efficiency. Furthermore, the results of free radical capture experiment and ESR test confirm that singlet oxygen, superoxide radical, hydroxyl radical and hole are the main active species in the degradation process of BPA. We detected the intermediate products and proposed the degradation by LC-MS analysis. This study may provide a promising sunlight-driven photocatalyst for the treatment of the BPA in wastewater. [Display omitted] • The spatial stereo structure PDI was synthesized and the migration distance of optical carriers was shortened effectively. • Co-NG/PDI was synthesized by anchoring Co single atom of cobalt on nitrogen-doped graphene as a cocatalyst for PDI. • The Co-NG/PDI compositehas better visible light photocatalytic degradation BPA activity than self-assembled PDI. [ABSTRACT FROM AUTHOR]

Photocatalytic reduction of nitrate ( NO 3 − ) is a green and potentially inexpensive technique for reducing NO 3 − pollution in ground water. TiO 2 -based photocatalysts have been studied extensively for this purpose. In the present study, the semiconducting catalyst CuFe 0.7 Cr 0.3 S 2 was applied to NO 3 − reduction. Loading this catalyst with metal co-catalysts (Ru, Au, Cu, Ag, Pt, and Pd) greatly increased the rate of NO 3 − reduction and the N 2 selectivity. In addition, there was a synergistic enhancement of the photocatalytic performance when the catalyst was loaded two co-catalysts. For example, the catalyst loaded with Pd and Au at mass fractions of 0.75% and 3%, respectively, could photocatalyze the complete reduction of NO 3 − in a 100 ppm N aqueous solution with 100% N 2 selectivity in less than 5 h with UV irradiation. However, with an inner irradiation from a full-arc Xe lamp, the NO 3 − conversion rate reduced to 0.065 mg N/h, probably because of the low density of the photoexcited electrons. The results show the potential of metal sulfides for photocatalytic reduction of NO 3 − , and the possibility of use of visible light. [ABSTRACT FROM AUTHOR]

Ni60 cladding layers added with different amounts of rare-earth CeO 2 , Y 2 O 3 , and La 2 O 3 were prepared on the surface of 6063 aluminum alloys through laser cladding. The effects of such cladding layers on the macroscopic morphology, section morphology, micro-hardness, phase composition, microstructure, and composition distribution of the laser clad Ni-based coating were investigated by performing metallographic microscopy, X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, and micro-hardness test. Cladding layers with the optimum rare-earth contents were 4% CeO 2 + Ni60 cladding layer, 5% Y 2 O 3 + Ni60 cladding layer, and 5% La 2 O 3 +Ni60 cladding layer. The main phase composition of the cladding layers included β-NiAl (Cr), Al 3 Ni, AlNi 3 , and Al. The Ni60 cladding layers added with rare-earth oxides produced a chemical reaction that was involved in the cladding process to form stable rare-earth compounds. Ni60 cladding layers added with 4% CeO 2 , 5% Y 2 O 3 , and 5% La 2 O 3 were preferable over those without rare-earth oxides, as the former displayed smoother micro-morphologies without obvious pores and cracks. The dendritic structures of the Ni60 cladding layers were coarse; moreover, many grain segregations that were accompanied by a large number of pores were observed in the local area. By contrast, the Ni60 cladding layers added with rare-earth oxides displayed compact dendritic structures, and the grains were obviously refined. The hardness of the cladding layers from the surface to the substrate was gradually decreased as the cladding layer depth increased. Compared with Ni60 cladding layer, the transitions of Ni, Al, Cr, and other elements in the Ni60 cladding layers added with different amounts of CeO 2 , Y 2 O 3 , and La 2 O 3 were became more observable with increasing depth, and the dilution rate of the cladding layer was reduced. [ABSTRACT FROM AUTHOR]

A series of 2.1 GHz surface acoustic wave filters with Al/Ti/Cu/Ti four-layer electrode using different Cu thickness were fabricated. Power durability test show an improvement from 24.5 dBm to 28 dBm by electrode with Al (111 nm)/Ti (5 nm)/Cu (15 nm)/Ti (5 nm) to widely used Al (155 nm)/Ti (5 nm). The different frequency response, electrode morphologies before and after power durability test indicate different failure mechanism of these samples. By checking the microstructures and distribution of elements in those conditions, the enhanced power durability can be attributed to: 1) using of Cu layer, 2) fine grain strengthening, 3) solution strengthening. Concurrently, Increased resistance of electrode induced by electrode structure design and atoms diffusion will deteriorate filter performance and accelerate atoms migration. In this work Al (111 nm)/Ti (5 nm)/Cu (15 nm)/Ti (5 nm) made a compromise in the above factors and achieved higher resistance to acoustomigration, which is promising for higher power surface acoustic wave filters. [ABSTRACT FROM AUTHOR]

To obtain spherical MoNbTaWZr powders, porous agglomerated MoNbTaWZr particles prepared by spray granulation were subsequently processed by plasma spheroidization. The microstructure, morphology, particle size distribution, purity and property of each step during process were systematically investigated. Results show that the obtained spherical MoNbTaWZr powder has dense structure, smooth surface, and good sphericity in shape. It also has narrow particle size distribution, while D 10 , D 50 , D 90 and D av were 32.0 µm, 42.3 µm, 56.0 µm and 43.2 µm, respectively. The powder has a high purity, and the concentration of oxygen, hydrogen, carbon, and nitrogen were all at ppm. In addition, excellent flowability (8.89 s/50 g) and apparent density (7.27 g/cm3) are benefit from high spheroidization ratio (98.4 %) and dense structure. The spherical powder also exhibits a high nano-hardness due to solid solution strengthening and refinement in dendritic structures. ● Spherical MoNbTaWZr powder was successfully prepared by spray granulation combined with plasma spheroidization. ● Morphology, microstructure, particle size, and purity during preparation were systematic investigated. ● The obtained powder has narrow size distribution, high purity, and good flowability. ● High purity benefits from deoxidation during spheroidization process. [ABSTRACT FROM AUTHOR]

Stretchable supercapacitors with simultaneously high energy/power densities and long life can enrich integrated power options for ever-increasing wearable electronics. However, supercapacitors with high electrochemical performances while maintaining high stretchability are still challenging. Herein, we report stretchable sodium ion capacitors (S-SICs) based on multi-dimensionally and hierarchically elastomeric composite electrodes, and stretchable high voltage gel polymer electrolyte (3.0 V). The elastomeric composite electrode is constructed by stretchable 3D electrospun polyurethane (PU) fibrous mat and conductive 1D Ag nanowire network. 2D MoSe 2 /MXene and 3D AC/MXene as anodic and cathodic materials are embedded in this conductive and stretchable mat. This hierarchical structure enables multi-dimensional conductive connections under tensile condition. The pre-strain treatment on PU fibrous mat further increases the relatively stretching distance before losing conductive connection among hierarchical components. The electrodes exhibit superior sodium ion storage performances (420 mAh g−1 at 5 A g−1), as well as good stretchability and stability (95% after 1000 cycles at 2 A g−1). Based on this, the S-SICs with high operating voltage demonstrate high energy/power densities (max. 5.44 mWh cm−3, 493.55 mW cm−3) and good stretchability. This prototypical exhibition of S-SICs indicates a promising design direction of stretchable supercapacitors with high electrochemical performances and tolerance of stretchability. • Stretchable sodium ion capacitors (S-SICs) are promising. • Multi-dimensionally and hierarchically composite enable superior electrodes. • Pre-strain increases tolerances of stretchability and electrochemical activity. • S-SICs demonstrate high energy/power densities and good stretchability. [ABSTRACT FROM AUTHOR]

A diffusion-modified HfC/HfC SiC bilayer system was innovatively designed and synthesized onto cemented carbide (WC-Co) substrate by reactive double glow plasma surface alloying (DGPSA) technique for adherent diamond deposition. The microstructure, phase composition and adhesion of the bilayer system were investigated, as well as its effect on the diamond coating system. The results showed that the bilayer system was made up of a 1.0-μm-thick nanostructured HfC-dominant inner layer and a 0.7-μm-thick HfC SiC mixed outer layer. As the gradient element distributions existed at the bilayer/substrate interface, the bilayer system displayed a superior adherence to the substrate. And the surface microhardness improved from 1802 HV 0.1 to 2857 HV 0.1 after the reactive DGPSA treatment. Subsequently, a uniform and dense nanocrystalline diamond coating with thickness of 4.0 μm was successfully deposited onto the HfC/HfC SiC interlayered substrate. Benefit from the effective suppression of Co diffusion by the interlayer and the reasonable design in its hardness and thermal expansion coefficient (TEC), the obtained diamond coating possessed an excellent adhesion. Therefore, the diffusion-modified HfC/HfC SiC bilayer systems synthesized via reactive DGPSA technique can be considered as a novel interlayer option for depositing adherent diamond coatings on WC–Co substrates. [ABSTRACT FROM AUTHOR]

The high-performance LiNi 0.5 Mn 1.5 O 4 has been prepared by an improved solid-state method, which is calcined in nitrogen at the first stage and in air at the second stage. The reaction process between nickel atoms and manganese atoms was changed by the improved solid-state method. The final product is a high purity cubic spinel structure (Fd3m) with high crystallinity, little impurities and excellent electrochemical performances. The EDX demonstrates that there is slightly lower nickel content and carbon content on the crystal surfaces. It shows a discharge capacity of 138 mAh/g at the first cycle and 133.9 mAh/g after 100 cycles at 0.1C rate. It also can deliver a discharge capacity of 111.3 mAh/g at 5C rate. The discharge capacity of the cathode at 55 °C is up to 124 mAh/g with capacity retention of 96.1% after 100 cycles. These results show that the improved solid-state method has potential application for the large-scale synthesis of LiNi 0.5 Mn 1.5 O 4 in high power Li-ion batteries. [ABSTRACT FROM AUTHOR]

LiNi 1/3 Co 1/3 Mn 1/3 O 2 is successfully coated with MnO 2 by a chemical deposition method. The X-ray diffraction (XRD), scanning electron microscope (SEM) and high resolution transmission electron microscope (HRTEM) results demonstrate that MnO 2 forms a thin layer on the surface of LiNi 1/3 Co 1/3 Mn 1/3 O 2 without destroying the crystal structure of the core material. Compared with pristine LiNi 1/3 Co 1/3 Mn 1/3 O 2 , the MnO 2 -coated sample shows enhanced electrochemical performance especially the rate capability. Even at a current density of 750 mA g −1 , the discharge capacity of MnO 2 -coated LiNi 1/3 Co 1/3 Mn 1/3 O 2 is 155.15 mAh g −1 , while that of the pristine electrode is only 132.84 mAh g −1 in the range of 2.5–4.5 V. The cyclic voltammetry (CV) and X-ray photoelectron spectroscopy (XPS) curves show that the MnO 2 coating layer reacts with Li + during cycling, which is responsible for the higher discharge capacity of MnO 2 -coated LiNi 1/3 Co 1/3 Mn 1/3 O 2 . Electrochemical impedance spectroscopy (EIS) results confirmed that the MnO 2 coating layer plays an important role in reducing the charge transfer resistance on the electrolyte–electrode interfaces. [ABSTRACT FROM AUTHOR]

Photocatalytic nitrogen (N 2) fixation provides a green avenue for the production of ammonia (NH 3), which is extremely significant for global biogeochemical cycle. However, there is still lack of highly efficient catalyst to improve the N 2 photofixation efficiency. In this work, oxygen vacancy engineered perovskite SrTiO 3 materials have been prepared by post reduction using lithium alkylamine solution and served as effective catalysts for visible-light-driven N 2 -to-NH 3 conversion. The formation and concentration of oxygen vacancies were confirmed by electron paramagnetic resonance, X-ray photoelectron spectroscopy and thermogravimetric analyses. The SrTiO 3 catalyst with optimized oxygen vacancies concentration exhibited improved photocatalytic N 2 reduction rate of 306.87 μmol·g−1·h−1, which is approach ten-fold higher than that of pristine SrTiO 3. Electrochemical impedance spectroscopy and photoluminescence measurements reveal that optimum amount of oxygen vacancies can promote the effective adsorption of N 2 molecules and improve the photocatalytic performance by facilitating the fast separation of photo-generated charge carriers. Moreover, the as-fabricated defective SrTiO 3 exhibited outstanding stability, which makes it emerge the promising potential for further practical applications. This work offers a feasible method for the design of high performance photocatalysts through defect engineering. • Synthesized defective SrTiO 3 catalysts by lithium alkylamine solution reduction. • Oxygen vacancies regulation to improve the photocatalytic NRR activity for SrTiO 3. • About ten-fold NH 3 formation rate (873.48 μmol·g−1·h−1) to original SrTiO 3. • Defective SrTiO 3 suppressed the recombination of the photogenerated carriers. [ABSTRACT FROM AUTHOR]

• The (Fe x , Co y)-NG/mpg-C 3 N 4 materials exhibited excellent activity due to the synergistic effect of well-defined dual sites. The photocatalytic hydrogen evolution reaction is a promising and powerful approach to replace traditional fossil fuels. Herein, we have fabricated Fe, Co dual single atoms dispersed on nitrogen-doped graphene ((Fe x , Co y)-NG) by freeze-drying method, which can as a highly efficient co-catalyst. The (Fe x , Co y)-NG loaded mesoporous graphitic carbon nitride (mpg-C 3 N 4) exhibits an excellently high performance for photocatalytic hydrogen evolution. The high activity can belong to two ways: (i) the ultrathin mpg-C 3 N 4 not only increases the absorption and active sites but also shortens the charge migration distance; (ii) The nitrogen functional groups from NG can provide abundant coordination sites to evenly bind Fe and Co atoms. The photocatalytic hydrogen evolution performances (Fe x , Co y)-NG co-catalyst with different content ratios of Fe atoms and Co atoms were also investigated. The optimized hydrogen production rate (1958 μmol g−1) of 5 wt% (Fe 0.2 , Co 0.8)-NG/mpg-C 3 N 4 is obviously higher compared to the monometallic counterparts (5 wt% Fe-NG/mpg-C 3 N 4 or 5 wt% Co-NG/mpg-C 3 N 4). The higher photoactivities are due to the synergistic effect between Fe and Co. [ABSTRACT FROM AUTHOR]

The discovery of phosphor with efficient red emission is a crucial step in the development of the white light-emitting diodes (wLEDs). Herein, based on the regulation of the W/Zn ratio, the Eu3+-activated ZnWO 4 -WO 3 ∙0.5H 2 O-WO 3 multiphase phosphor was designed successfully via the one-step hydrothermal treatment route. The effects of the W/Zn ratio on the phase structure, composition, morphology, luminescence property and lifetime of the obtained samples were systematically and comparatively investigated. The obtained product not only maintains the multi-wavelength excitation feature of ZnWO 4 :Eu3+ phosphor, but also sharply improves the characteristic emission intensity of Eu3+ ions. It is found that the WO 3 ∙0.5H 2 O crystal has a special 3D interconnected channel structure, which is a relatively much access to the chemical behavior and permits the ready insertion of part of Eu3+ ions, and this coordination environment can obtain strong pure red light emission. Further, the ZnWO 4 -WO 3 :Eu3+ phosphor obtained after dehydration treatment can be excited more efficiently in the deep-ultraviolet (DUV), near-ultraviolet (NUV) and blue light regions, and its quantum efficiencies reach 18%, 22% and 21.2%, respectively. Besides, it also exhibits better CIE chromaticity coordinate, higher color purity than commercial Y 2 O 2 S:Eu3+ phosphor. Therefore, the ZnWO 4 -WO 3 :Eu3+ is promising for the application in red phosphor with different wavelengths for wLEDs. • The ZnWO 4 -WO 3 :Eu3+ multiphase phosphor was obtained by tailoring the W/Zn ratio. • The WO 3 ·0.5H 2 O with 3D interconnected channel structure allows the insertion of Eu3+. • The ZnWO 4 -WO 3 :Eu3+ phosphor can be efficiently excited by multi-wavelength bands. • Meritorious CIE, QE and high color purity was obtained. [ABSTRACT FROM AUTHOR]