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Red LEDs excited by blue light have a wide range of applications in plant growth due to their simple structure. The preparation of efficient red phosphors has attracted much attention from researchers. In this paper, Cs 2 NaGdCl 6 :Ho3+ Sb3+ phosphors were synthesized by the solvothermal method, which produced the characteristic emission of Ho3+ 5 F5→ 5 I8 at 655 nm under 460 nm excitation. The red light at 655 nm is further enhanced after the introduction of Sb3+, and the quantum efficiency can reach 39.85 %. The luminescence mechanism and energy transfer of Sb3+ and Ho3+ were further investigated. The produced phosphor was encapsulated with a 460 nm blue chip into an LED to realize red and blue dual emission, which meets the demand for blue and red light for plant growth. • A double perovskites phosphor Cs 2 NaGdCl 6 :Ho3+ Sb3+ was synthesized. • The emission spectrum excited by the blue light chip matches well with the plant absorption spectrum. • Synthesis of a halide double perovskites with good thermal stability. • The materials show promising application in the field of plant cultivation. [ABSTRACT FROM AUTHOR]

Two crucial elements that aid in the development of supercapacitors are the usage of distinctive components and the creation of optimal structures. In view of this, polyphenylene sulfide (PPS) non-woven fibers prepared by melt-blast process are used as carbon precursor, and oxidized polyphenylene sulfide (O-PPS) was prepared by an innovative and environmentally friendly oxidation method, which overcame the melting and shrinkage of PPS at high temperatures. After carbonization, flexible carbon fibers (SCFs) with high specific surface area were formed by O-PPS. Then, polypyrrole (PPy) and metal-organic framework material (Co-MOF) are successively grown on the SCFs, and the Co-MOF is transformed into layered double hydroxide (NiCo-LDH) ultra-thin nanosheets (ca. 4 nm) with rich electrochemical active sites under nickel nitrate etching, which obtains the "skin-core" structure composite electrode. This materials' high specific capacitance of 1705.6 F g−1 at 1 A g−1, and the electrode reaction process is governed by the pseudocapacitance characteristic. Asymmetric supercapacitors assembled with porous carbon possesses 46.96 Wh kg−1 at 725 W kg−1, and the capacitance retention rate is 81.47% after 8500 cycles. This research provides a new combination of ultra-thin NiCo-LDH nanosheets with carbon fiber for energy storage while improving the energy density of supercapacitors. [Display omitted] • A greener and milder polymer oxidation process. • This material owns "skin-core" structure with ultra-thin nanosheet loaded. • The assembled asymmetric supercapacitor exhibits superior capacitance behavior. [ABSTRACT FROM AUTHOR]

In this paper, a novel modified graphene oxide sheets (GOSs) has been synthesized based on pyromellitic acid (PMA) depositing on the surface of GOSs via noncovalent approach. Fourier Transform Infrared spectra (FT-IR), X-ray diffraction patterns (XRD) and scanning electron microscopy (SEM) were adopted to investigate its structure. The as-prepared materials are dispersed in Rhodamine-B (RB) solutions which show highly efficient fluorescence. This phenomenon suggests the quenching effect of graphene oxide can be effectively weakened via rational structural modification. Moreover, this dispersion serving as a fluorescent probe still has a relatively high selectivity and sensitivity (Stern-Volmer constant K SV = 4.58*10 4  L mol −1 ) to Fe 3+ ions. [ABSTRACT FROM AUTHOR]

The crystal phase and energy band adjustment of halide perovskites have become the focus of research. Sb3+ doped lead-free indium-based perovskites A 2 InX 5 ·H 2 O:Sb3+ (A=Cs+, Rb+; X = Cl-, Br-) are synthesized at room temperature. Through changing the crystal phase structure, an intelligent anti-counterfeiting material is used to monitor water vapor and high temperature. Moreover, the Rb 2 InBr 5 ·H 2 O:Sb3+ achieves broadband near-infrared (NIR) emission with a high photoluminescence quantum efficiency (PLQY) of 54.3%. The NIR light-emitting diode shows that the device can effectively achieve NIR imaging. Theoretical calculations further clarified that the regular changes in luminescence originate from energy band modulation. This work provides a broader sight for the synthesis, luminescence mechanism and application of indium-based perovskite. • Indium-based perovskite with controllable luminescence properties was synthesized at room temperature. • The reversible change of crystal phase is used for smart anti-counterfeiting. • High-efficiency quantum yield of Rb 2 InBr 5 ·H 2 O:Sb3+ is used in near-infrared light-emitting diodes. • Theoretical calculation combined with experiments prove that broadband emission originate from band gap adjustment. [ABSTRACT FROM AUTHOR]

• The microstructure evolution along the building direction of LDED HX block sample was studied. • It is found that the liquation cracks at grain boundaries can be propagated into solidification cracks. • The Scheil model was used to explain the reason for the formation of continuous liquid film at grain boundaries. • The theory of dendrite coalescence was used to explain why the hot cracking always occurs at HAGBs. Hastelloy X (HX) block was fabricated by laser directed energy deposition (LDED). Microstructure evolution and cracking behavior of the as-deposited LDED HX were investigated. The results showed that the microstructure of LDED HX was composed of columnar grains with interior fine columnar dendrites, and some of the second phases (Laves, M 6 C, σ, M 23 C 6) caused by micro-segregation can be observed at the inter-dendrite and grain boundary. From the bottom to the top of the sample, the grain size became coarser and the micro-segregation intensified due to the decreasing cooling rates. The formation of continuous γ-M 23 C 6 eutectic at the grain boundaries led to the hot cracking at the middle and top of the sample. Hot cracking was determined to be caused by a stable liquid film and thermal stress. The liquid film was caused by continuous γ-M 23 C 6 eutectic, and the stability of the liquid film was depended on dendrite coalescence undercooling, Δ T b , which was related to the misorientation angle θ. When the misorientation angle exceeds 11.6°, the dendrite coalescence undercooling, Δ T b > 0. The liquid film was stable at the grain boundary. Therefore, cracking always occurred at high angle grain boundaries (HAGBs). The stress concentration at the grain boundaries was intensified at the middle and top of the sample and provided the driving force for crack initiation and propagation. Carbide particles at the grain boundary promoted a pinning effect on the liquid feeding, which led to the liquation cracking propagating to solidification cracking. [ABSTRACT FROM AUTHOR]

Exploring a facile and cost-efficient approach to synthesize electrocatalysts that promoting the interconversion between H 2 O and O 2 remains a crucial challenge. In this work, we report a convenient and effective strategy to synthesis Co metal and MnO immobilized on carbon nanotubes (MnO/Co-CNTs) vis strong metal-support interaction (SMSI). The CNTs support anchored abundant MnO/Co nanoparticles (NPs) in a small size of ~2 nm, when the strong interaction between them suppressed the homogeneous nucleation of MnO/Co during high temperature sintering. Thus, enormous well-dispersed catalytic active sites are produced on the conductive CNTs. Together with the boosted charge transfer between MnO/Co and support, the catalytic activity of MnO/Co-CNTs is eventually significantly promoted. The catalyst shows an efficient oxygen reduction reaction (ORR), oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline solution. Furthermore, SMSI alleviate the agglomeration of NPs and secure the active sites during electrochemical reactions, which account for the enhanced catalytic durability for ORR, OER and HER. In consequence, the MnO/Co-CNTs catalyst shows excellent performance for rechargeable Zn-air battery, and can be utilized to catalyze overall water splitting to produce hydrogen and oxygen. This work manifests a promising approach for optimizing the catalytic performance of the NPs. Superior nonprecious MnO/Co-CNTs bifunctional oxygen electrocatalyst was successfully fabricated through strong metal-support interactions. The extremely outstanding catalytic activities of the as-developed MnO/Co-CNTs were ascribed to the enormous well-dispersed catalytic active sites and the boosted charge transfer between MnO/Co and carbon nanotubes support. Impressively, the as-fabricated rechargeable Zn-air battery afforded an extremely high charge/discharge stability. [Display omitted] • MnO/Co-CNTs oxygen electrocatalyst was obtained by strong metal-support interaction. • Well-dispersed catalytic active sites, geometric and electronic modification gave rise to superb electrocatalytic activity. • MnO/Co-CNTs afforded excellent performance for rechargeable Zn-air battery. [ABSTRACT FROM AUTHOR]

Ternary composites involved graphitic carbon nitride (g-C 3 N 4) have gained scientific interest in recent years. Herein, we report a series of ternary composites containing AgCl nanoparticles, Au nanoparticles, and g-C 3 N 4 (AgCl/Au/CN) via a two-step chemical deposition method. In this semiconductor−metal−semiconductor structure, AgCl nanoparticles can absorb organic anions, as well as form a Z-scheme heterojunction combined with g-C 3 N 4 ; Au nanoparticles can play a role in the separation of photogenerated carriers. These features allow AgCl/Au/CN to exhibit excellent photocatalytic degradation performance for anionic dyes. When the molar ratios of AgCl and Au to g-C 3 N 4 are 1% and 0.5%, respectively, the optimal AgCl/Au/CN sample can achieve effective degradation for Rhodamine B within 25 min under visible-light irradiation of relatively low intensity. • AgCl/Au/g-C 3 N 4 ternary composites are prepared via a two-step chemical deposition method. • 15 min, 40 min, AgCl/Au/g-C 3 N 4 is efficient for anionic dye degradation due to its absorption ability for organic anions. • Kinetic rate constant of the optimal AgCl/Au/g-C 3 N 4 for Rhodamine B degradation is 3.68 times higher than that of g-C 3 N 4. • A Z-scheme, fast transfer of carriers, and absorption lead to the enhanced photocatalytic performance of AgCl/Au/g-C 3 N 4. [ABSTRACT FROM AUTHOR]

As a kind of cheap and easily available organic molecular with Faradic redox activity, quinones can well combined with carbon-materials by non-covalent π–π conjugation and remedy its shortcomings possessing relatively low specific capacitance. However, in previous studies, the combination of quinones and carbon-based materials often requires toxic organic solvent or high energy-consuming and interminable process, greatly hindering their practical application. Here we use water-soluble sodium anthraquinone-2-sulfonate (AQS) and graphene oxide (GO) solution as raw materials to directly obtain AQS composite reduced GO (AQS/rGO) hydrogels by chemical reduction, the whole process of which is performed at relatively low temperature and normal pressure, and only takes a short time, resulting in great promotion in sustainability and efficiency. The AQS/rGO hydrogel exhibiting a high specific capacitance of 387.43 F g−1 at 1 A g−1 and an excellent cycling stability of 91.11% after 10000 cycles at 10 A g−1, has a prodigious improvement for the pure graphene in all aspects. Besides, the maximum energy density of the asymmetric supercapacitor assembled by AQS/rGO-1 hydrogel reaches 15.98 W h kg−1 at the power density of 325.02 W kg−1. This work provide a new idea for the green and efficient preparation of graphene organic quinones composite and has an important significance for its practical application. • AQS can be combined with graphene sheet by non-covalent π-π conjugation. • The process of preparing AQS/rGO hydrogels is utrla-simple, green and efficient. • The AQS/rGO hydrogels exhibits superior electrochemical performance to pure graphene. • The asymmetric supercapacitor delivers high energy density. [ABSTRACT FROM AUTHOR]

Ti-6Al-3Nb-2Zr-1Mo (Ti6321) alloy, as a new type of marine metal, has excellent corrosion resistance and mechanical properties, but its application is restricted by the traditional manufacturing processes. Wire-arc directed energy deposition (DED) has some incomparable advantages in the efficient and customized fabrication of large/extra-large components, which makes it become a potential manufacturing process for the fabrication of Ti6321 alloy components. However, the formability and corresponding performance evaluation of wire-arc DEDed Ti6321 alloy remains unknown. Here, for the first time, the microstructure, mechanical properties and corrosion resistance of wire-arc DEDed Ti6321 alloy was characterized and compared with rolling, and the relationship between process-microstructure-properties was established. Results show that the full lamellar α+β structure of the DEDed specimens demonstrated better corrosion resistance than the near equiaxed α p + lamellar α s /β structure of rolled specimens. This is owed to the higher grain boundary density, more content of β phase and slighter element segregation of the DEDed specimens, resulting in a more uniform and stable passivation film on its surface. Meanwhile, the grain morphology and low dislocation density of the DEDed specimens causing in lower tensile strength (decrease by ∼15.6 %) but higher elongation (increase by ∼41.5 %) than the rolled specimens. Due to the presence of coarse prior-β grains, the DEDed specimens show expected anisotropy in building direction and traveling direction, but overall exhibits sufficient mechanical properties, which exceed the execution standard. This study verified the feasibility of fabricating Ti6321 alloy with idea properties by wire-arc DED, and provides a potential strategy for the production and practical application of large-size Ti6321 alloy components. [Display omitted] • The fabrication of Ti6321 alloy by wire-arc DED was conducted in-depth and systematic research for the first time. • Comparison between the mechanical properties and corrosion resistance of rolled and DEDed Ti6321 alloy was conducted. • Relationship between the process, microstructure and properties of DEDed Ti6321 alloy were studied. [ABSTRACT FROM AUTHOR]

Far-red phosphors with higher thermal stability and exhibit excellent spectral compatibility with the far-red light phytochrome (P FR) absorption spectrum. They are currently a research hotspot and widely applied in plant growth lamps. In this study, we have prepared a Mn4+-activated Sr 2 ScNbO 6 far-red phosphor by using the high temperature solid phase method in air. The strongest excitation center of the Sr 2 ScNbO 6 : Mn4+ phosphor was located at 365 nm. Due to the 2E g →4A 2 g transition, this phosphor generates strong deep-red light at 703 nm, which significantly overlaps with the absorption spectrum of plant phytochrome P FR. The variable temperature photoluminescence (PL) emission spectra from 303 K to 503 K confirmed this phosphor possesses relatively good thermal stability. In addition, the concentration quenching effect and the thermal quenching mechanism are studied in detail. The results demonstrate that Sr 2 ScNbO 6 : 0.4 % Mn4+ phosphor provides a novel choice for the far-red phosphor required for short-day plant cultivation. • A double perovskite phosphor Sr 2 ScNbO 6 : Mn4+ was synthesized. • Sr 2 ScNbO 6 : Mn4+phosphor shows relatively good thermal stability, I 423 K /I 303 K ≈ 44 %. • The Mn4+ far-red emission matches well with the absorption spectral of P FR. • The materials show promising application in the field of short-day plant cultivation. [ABSTRACT FROM AUTHOR]

The synthesis of nano-sized ternary delafossite oxides with pure crystal phases is of great challenge. We present a novel hydrothermal method for the synthesis of AgCrO 2 nanocrystals with ultrafine size of 10–20 nm at relatively low temperature range (190–230 °C). It is the first time to report that AgCrO 2 nanocrystals can be hydrothermally synthesized at such a low temperature (190 °C) and applied as photocathode in dye sensitized solar cells (DSSCs). The as-synthesized AgCrO 2 nanoproducts, including their crystal phases, morphologies, element compositions, valence state information, thermal stability, electrical and optical properties, have been systematically studied. This facile method employed metal nitrates (AgNO 3 and Cr(NO 3 ) 3 ) as the starting materials and NaOH as the mineralizer, where Cr(NO 3 ) 3 undertook the dual functions of Cr 3+ source material and weak reducing reagent. The in-situ oxidation–reduction reaction between Cr 3+ and Ag + /Cu 2+ during the hydrothermal crystal growth is the noteworthy feature of this general method. The crystal formation mechanism disclosed in the synthesis of chromium based delafossite oxides will certainly be benefit for the preparation of other delafossite oxides. [ABSTRACT FROM AUTHOR]

Abstract The development of facile, inexpensive and large-scale methods to prepare carbon scaffolds with high sulfur content is crucial to the practical applications of Li-S Battery. Herein, Nitrogen, Oxygen and Cobalt multiple-doped graphitized mesoporous carbon sulfur composites (N-O-Co-C/S) with high sulfur content (90%) are developed via inexpensive carbonization methods. The composites exhibit superior performance with a capacity of 610 mAh g−1 at a current of 0.5 C after 200 cycles and 302 mAh g−1 at a current of 2 C after 1400 cycles. The superior performance of N-O-Co-C/S composites can be attributed to the enhanced electrical conductivity and ionic conductivity of Co-N-O-C/S composites, which can be supported by electrochemical impedance spectroscopy measurement. The polysulfide-trapping was mainly attributed to the strong O-S, N-S and Co-S interactions, thus improving the e electrochemical performance. Highlights • Nitrogen, Oxygen and Cobalt multiple-doped mesoporous graphitized carbon are been synthesized. • Its composites with sulfur show excellent electrochemical performances. • N and Co co-doped graphitized carbon can facilitate charge transfer and suppress the shuttle phenomenon. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) nanomaterials have become a new class of microwave absorption (MA) materials due to their high specific surface area and peculiar electronic properties. In this study, MoS 2 /graphene 2D hybrid nanosheets with isomorphic hetero-structures are prepared by liquid exfoliation and hydrothermal reaction. Their chemical composition and morphology are characterized and their MA properties are also investigated comprehensively. The minimum reflection loss (RL) value of an absorber containing wax and 20 wt% MoS 2 /graphene hybrid nanosheets (MoS 2 /GN) is −55.3 dB at a thickness of only 1.6 mm. The largest effective absorption bandwidth is up to 5.6 GHz for an absorber containing wax and 15 wt% MoS 2 /GN at a thickness of 2.2 mm. The enhanced MA performance of MoS 2 /GN is attributed to the high electrical conductivity of graphene and the multiple MoS 2 /graphene interfaces in the heterogeneous structures. The results suggest that those light-weight MoS 2 /graphene hybrid nanosheets are very promising materials for electromagnetic wave absorbing, which can exhibit broad effective absorption bandwidth in the absorber containing low loadings of MA materials at a small thickness. Besides, the facile preparation of MoS 2 /graphene hybrid nanosheets reported in this work provides a feasible and effective approach in the synthesis of high-performance 2D MA nanomaterials. [ABSTRACT FROM AUTHOR]

Multiferroics have broad application prospects in various fields such as multi-layer ceramic capacitors and multifunctional devices owing to their high dielectric constants and coupled magnetic and ferroelectric properties at room temperature. In this study, cobalt ferrite (CFO)/barium calcium titanate (BCT) composite fibers are prepared from BCT and CFO sols by an electrospinning method, and are then oriented by magnetic fields and sintered at high temperatures. The effects of magnetic fields and CFO contents on the nanostructures and magnetoelectric properties of the composites are investigated. Strong coupling between magnetic and ferroelectric properties occurs in CFO/BCT composites with magnetic orientation. More interestingly, the dielectric constants of CFO/BCT composites with magnetic orientation are found to be enhanced (by ∼1.5–3.5 times) as compared with those of BCT and CFO/BCT without magnetic orientation. The boost of dielectric constants of magnetic-field orientated CFO/BCT is attributed to the magneto-electrical coupling between CFO and BCT, where the polar domains of BCT are pinned by the orientated CFO. Therefore, this work not only provides a novel and effective approach in enhancing the dielectric constants of ceramic ferroelectrics, which is of tremendous value for industrial applications, but also elucidates the interaction mechanisms between ferromagnetic phase and ferroelectric phase in multiferroic compounds. [ABSTRACT FROM AUTHOR]

SiC- based nanomaterials possess superior electric, thermal and mechanical properties. However, due to the tricky synthesis process, which needs to be carried out under high temperature with multi-step reaction procedures, the further application is dramatically limited. Herein, a simple as well as a controllable approach is proposed for synthesis of SiC- based nanostructures under low temperature. Phenyl-bridged polysilsesquioxane was chosen as the starting material to react with magnesium at 650 °C, following which SiC@C nanocomposites were finally obtained, and it maintains the original bent rod-like architecture of polysilsesquioxanes. The possible formation process for the nanocomposites can proposed as well. The electrochemical behaviour of nanocomposites was accessed, verifying that the synthesized SiC@C nanocomposites deliver good electrochemical performance. Moreover, SiC@C also shows to be a promising scaffold in supporting Si thin film electrode in achieving stable cycling performance in lithium ion batteries. [ABSTRACT FROM AUTHOR]