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Due to the suitable bandgap and valence band for photoelectrochemical (PEC) water oxidation, BiVO 4 has been regarded as a promising photoanode material. However, poor charge-separation and -transport behavior as well as sluggish surface oxygen evolution reaction (OER) kinetics caused the BiVO 4 photoanode for water splitting to be significantly lower than its theoretical value. In this study, the synergistic effect of constructing an n-BiVO 4 /p-CuCoO 2 heterojunction and NiCo 3 -LDH as an OER cocatalyst was designed to enhance the PEC performance of BiVO 4 photoanode. The resultant BiVO 4 /CuCoO 2 /NiCo 3 -LDH demonstrates a maximum photocurrent density of 6.95 mA/cm2 at 1.8 V vs. RHE, which is approximately 24.8 times that of BiVO 4 (0.28 mA/cm2) and 5.5 times that of BiVO 4 /CuCoO 2 (1.27 mA/cm2) with good stability (70 % remained after 2 h of operation). This work broadens the construction strategy of photoanode heterojunctions to enhance PEC performance. [Display omitted] • Combination of p-n junction and OER cocatalysts to enhance PEC performance. • Modification of BiVO 4 with CuCoO 2 and NiCO 3 -LDH cocatalyst to enhance the PEC performance. • Optimum molar ratio of Ni and Co was investigated to enhance the OER catalytic performance of NiCo 3 -LDH. • Photocurrent density of BiVO 4 /CuCoO 2 /NiCo 3 -LDH is about 24.8 times compared with that of BiVO 4. • Simple routes have been adopted for the fabrication of BiVO 4 /CuCoO 2 /NiCo 3 -LDH photoanodes. [ABSTRACT FROM AUTHOR]

Multi-principal element alloys (MPEAs) have garnered significant attention due to their exceptional mechanical properties and resistance to irradiation. The changes in microstructures under irradiation are influenced by the primary damage state and the diffusion and interaction of defects over a prolonged period, presenting a problem that spans several scales. In this work, we present a multiscale modeling of defect evolution in body-centered cubic (BCC) MPEAs by combining molecular dynamics (MD) and cluster dynamics (CD) for the first time, which enables us to link the microscopic scale defect process with the experimentally observable defect structures at a mesoscopic scale and to analyze the critical factors affecting the irradiation performance of MPEAs. In contrary to previous reports on face-centered cubic (FCC) MPEAs, our MD simulations show that the random arrangement of different elements in MPEAs strongly suppresses intra-cascade cluster formation, even compared with their corresponding averaged alloy models (AAM). We then utilize the primary damage states from MD simulations to feed into a CD model and show that cluster growth in random MPEAs is inhibited during the reaction-diffusion stage due to the slower and three-dimensional defect dynamics compared with their corresponding AAMs. Our results elucidate the unique irradiation resistance mechanism of BCC MPEAs and provide essential guidelines for alloy design with controllable defect dynamics. [Display omitted] • Multiscale modeling of the nucleation and growth mechanism of defect clusters. • Lattice distortion leads to small-sized clusters during defect nucleation stage. • Heterogeneity broadens the cluster size distributions and reduce the size. [ABSTRACT FROM AUTHOR]

Abstract In this work, ultrathin 2D SnS 2 nanosheets were coupled with 2D MoS 2 nanolayers as face-to-face 2D/2D heterojunction photocatalysts. Compared with pristine SnS 2 , this face-to-face 2D/2D SnS 2 /MoS 2 heterojunction exhibited obvious improvement in photocatalytic and photoelectrochemical performance. The highest heterojunction composite activity was nearly two times and 12 times than that of pristine SnS 2 in photocatalytic activity and photoelectrochemical performance, respectively. The good performance was ascribed to the face-to-face 2D/2D heterojunction structure and suitable energy band matching. In this face-to-face 2D/2D heterojunction structure, the migration distance between the photoinduced carriers' separation site to the heterojunction interface was very short, but the contact surface was large. Furthermore, the conduction band position of MoS 2 was more positive than that of SnS 2. Therefore, the photoinduced electrons at the conduction band of SnS 2 could flow into the conduction band of MoS 2. The transmission between the SnS 2 /MoS 2 heterojunction prolonged the carriers' life and improved the carriers' separation efficiency. In this way, photoinduced carriers produced in SnS 2 and MoS 2 could flow across the heterojunction quickly, which increased the carriers' separation efficiency. This work successfully developed a new structure to improve the heterojunction property for photocatalytic applications. Graphical abstract Image 1 Highlights • 2D/2D SnS 2 /MoS 2 heterojunction photocatalysts were obtained. • The photocatalytic and photoelectrochemical activity of the composite are enhanced. • The 2D/2D heterojunction structure is suitable for carriers' transmission. [ABSTRACT FROM AUTHOR]

Abstract Nano-MnS were coupled with ultrathin two-dimensional MoS 2 nanolayers as heterojunction photocatalysts. The well heterojunction contact can be confirmed by high resolution TEM images. The heterojunction composites display higher absorption intensity of visible light and the S XPS peaks show obvious shift. Compared with pristine MnS, this MnS/MoS 2 heterojunction exhibited vast enhancement in photocatalytic and photoelectrochemical performance. The heterojunction composite with highest activity displayed 161% enhancement in photocatalytic activity, 2.6–11.5 times increase of photocurrent density. This vast improvement can be assigned to the energy band matching of MnS/MoS 2 heterojunction. Both the conduction band and valence band of MnS are more negative than those of MoS 2 , the photo-induced electrons at the conduction band of MnS will transfer into the conduction band of MoS 2 while the photo-induced holes at the valence band of MoS 2 will transfer into the valence band of MnS. In this way, the photo-produced carriers will flow into different semiconductors and the carriers' separation efficiency is enhanced. The work develops a new approach to improve the heterojunction property for photocatalytic and photoelectrochemical application. Graphical abstract Image 1 Highlights • MnS/MoS 2 heterojunction photocatalysts were obtained. • The photocatalytic and photoelectrochemical activities of the composite are enhanced. • The MnS/MoS 2 heterojunction structure is suitable for carriers' transmission. [ABSTRACT FROM AUTHOR]

Abstract The γ′/γ evolution in nickel superalloys under different stress states and stress values at 1223 K was simulated through the phase-field method to study the 45°-type rafting mechanism and the influence of orientation deviation on the γ′/γ evolution. The simulation results demonstrate that for the shear stress case, 45°-type rafting appears under the external shear stress of 137 MPa. In 45°-type rafting, the equivalent stress inhomogeneity in the γ channel induces a directional diffusion of γ′-forming elements into the low-equivalent-stress areas which are distributed along the diagonal directions. Based on the simulations, a model for the 45°-type rafting mechanism has been proposed. In addition, the influence of orientation deviation on γ′/γ evolution originates from the introduction of shear stress components. With increasing external stress, the shear stress component is increased, which causes the rafting direction to approach the 45° direction. Furthermore, the existence of orientation deviation accelerates the process of γ′ rafting. Highlights • Distribution of equivalent stress in γ′/γ phases under shear condition is studied. • 45o-typed rafting mechanism is discussed with the corresponded mechanism map. • Existence of orientation deviation accelerates the process of γ′ rafting. [ABSTRACT FROM AUTHOR]

Abstract A co-precipitation combined with hydrothermal method is adopted for synthesizing Li 0.9 Na 0.1 Mn 1-x Ni x PO 4 /C (x = 0, 0.05, 0.1, 0.15, 0.2, 0.3) nanocomposites, using high specific surface area Li 2.7 Na 0.3 PO 4 precursor, MnSO 4 ·H 2 O, Ni(NO 3) 2 ·6H 2 O as raw materials. The X-ray diffraction analysis results shows doping ions have not destroy the crystal structure of olivine LiMnPO 4 /C composites. It can be also seen from the scanning electron microscope that the primary particles connect with each other on the surface at the nanometer scale. In all doping ratios, the obtained Li 0.9 Na 0.1 Mn 0.9 Ni 0.1 PO 4 /C composite shows excellent rate capability with the discharge capacity of 157.9 mAh/g and 150.5 mAh/g at 0.05 C and 1 C, respectively. With the increasing of cycle numbers, the capacity fades slightly. In conclusion, dual ion doping can significantly improve the lithium ion diffusion rate by broaden the transport channel. Highlights • Hollow structure Li 2.7 Na 0.3 PO 4 precursor with high specific surface area is prepared. • A simple hydrothermal method to synthesize co-doped Li 0.9 Na 0.1 Mn 0.9 Ni 0.1 PO 4 /C composite is present. • The initial discharge capacity of Li 0.9 Na 0.1 Mn 0.9 Ni 0.1 PO 4 /C is 157.9 mAh/g and 150.5 mAh/g at 0.05 C and 1 C, respectively. • Li 0.9 Na 0.1 Mn 0.9 Ni 0.1 PO 4 /C shows good rate performance. [ABSTRACT FROM AUTHOR]

The achievement of high polarization nonpolar III-nitrides has been hindered by high density of defects, large surface fluctuations and in-plane strains. Here, we show that these critical challenges can be improved by manipulating the growth time of SiN x interlayers. The discolation density of nonpolar a -plane Al 0.1 Ga 0.9 N has been effectively reduced by introducing the in-situ deposited SiN x interlayer, as the nonpolar a -plane Al 0.1 Ga 0.9 N can only nucleate at open pores of SiN x nanomask. During the growth process, the lateral overgrowth will occur from the openings with the dislocation bending and annihilation. Furthermore, the strip distributed nanomask can change the anisotropy of in-plane strains and optical properties of nonpolar a -plane Al 0.1 Ga 0.9 N. When the growth time of SiN x increased from 0 min to 2 min, the in-plane strain along m- axis and c- axis direction changed from −0.2250% and −0.5145% to −0.0638% and −0.2728%, respectively. More importantly, the optical degree of polarization of nonpolar a -plane Al 0.1 Ga 0.9 N has been changed from 0.4385 to 0.8129 along with the increase SiN x deposition time by polarized photoluminescence. By simplely changing the SiN x growth time, high polarization nonpolar a -plane devices may be fabricated on this high quality strain-modulatable nonpolar AlGaN template, which is desirable for high efficiency liquid crystal displays or other polarization sensitive photodetectors. [ABSTRACT FROM AUTHOR]

A facile and novel method of growing nickel hydroxide nanoparticles on polypyrrole nanotubes (Ni(OH) 2 /PNTs) is presented using methyl orange and ferric chloride formed fibrillar complex as self-degrading tubular template coupled with hydrothermal synthesis. The Ni(OH) 2 /PNTs samples were characterized by SEM, TEM, FTIR, XRD and XPS. As pseudocapacitors, the obtained Ni(OH) 2 /PNTs in three-electrode configuration display a significantly enhanced specific capacitance (864 F/g at 1 A/g), better rate performance, lower charge-transfer resistance and higher cycling performance (91.1% of the initial capacitance retention at 5 A/g over 2000 cycles) compared to the individual Ni(OH) 2 and PNTs, and previously reported composite electrodes based on Ni(OH) 2 or PNTs. Besides, the symmetric supercapacitors of Ni(OH) 2 /PNTs in two-electrode configuration show a maximum energy density of 18.8 Wh/Kg at the power density of 414.6 W/Kg and a maximum power density of 3.4 kW/kg at the energy density of 8.4 Wh/Kg. The high electrochemical performance of Ni(OH) 2 /PNTs can be attributed to the synergistic effect of both components and the unique nanostructure. These encouraging results reveal that the Ni(OH) 2 /PNTs can be used as promising electrode materials for supercapacitors in energy storage. In addition, the method described in this paper provides a generalized route for the construction of transition metal oxides (hydroxides)/PNTs-based composite nanostructures with improved electrochemical performance. [ABSTRACT FROM AUTHOR]

A modified thermally controlled solidification using melt superheating treatment has been designed to an IN718C superalloy to achieve grain refinement and further improve mechanical properties. It is found that the applied melt treatment can refine grain size from 6420 to 89 μm and greatly reduce the amount of porosity from 15.22 to 0.015%. The morphology of the microstructure is evolved from dendritic to granular structure. Meanwhile, the melt superheating treatment has no obvious influence on the dendrite segregation of Cr and Fe, but reduce the dendrite segregation of Nb and Ti. The amount of Laves phase decreases with increasing of melt superheating temperature from 1380 to 1680 °C. Corresponding to this, the stress rupture property under 650 °C/620 MPa is significantly improved. [ABSTRACT FROM AUTHOR]

Olivine structure LiMnPO 4 /C cathode is synthesized by a hydrothermal method with high specific surface area Li 3 PO 4 precursor in PEG400-H 2 O mixed solution system. The synthetic conditions are systematically optimized and statistical analysis using orthogonal experiments. The physical and electrochemical properties of Li 3 PO 4 and LiMnPO 4 /C samples prepared under the optimized conditions are investigated in detail. The XRD and SEM results show that Li 3 PO 4 powders are pure phase with uniformly hollow spherical morphology. The Nitrogen adsorption-desorption isotherm exhibits the specific surface area of Li 3 PO 4 powders are 79.19 m 2 /g. LiMnPO 4 reveals a well ordered olivine structure and possess small and unagglomerated particles, which generates from the Li 3 PO 4 precursor structure. The electrochemical measurements show that pure LiMnPO 4 /C sample prepared under the optimal conditions delivers a maximum discharge capacity of 121.3 mAh/g at a 0.1 C rate. After 100 cycles, the discharge capacity decreases to 115.1 mAh/g with the capacity retention of 94.89%. [ABSTRACT FROM AUTHOR]

One-dimensional cube-shape Co x Zn 1−x O nanowires have been fabricated through vapor-solid deposition process. Scanning electron microscopy observations reveal that the products consist of a large quantity of cube-shape nanostructures with typical lengths in the range of several tens to several hundreds of micrometers. The room-temperature Raman spectra of Co x Zn 1−x O exhibited the presence of lattice defects in the system. The photoluminescence properties of Co x Zn 1−x O nanowires under 10 K–110 K were investigated. The results show that there is an intensive ultraviolet multi-peaks emission under low temperature. The multi-peak emissions are mainly attributed to longitudinal optical phonon replicas of free exciton. The multi-peaks emission in ultraviolet region will exhibit redshift with the increasing temperature. A U-shaped behavior of the full width at half maximum (FWHM) value of the FX-1LO emission peaks at 10 K–110 K was shown. [ABSTRACT FROM AUTHOR]

Semiconductor heterostructure is usually constructed to separate carriers, and the energy band structures of component semiconductors are mainly considered to achieve the separation. However, the interface of heterostructure also has a great influence on the transmission of carriers which is always neglected. Here, we employed {001} and {101} facets of anatase TiO 2 as substrate to composite with two-dimension MoS 2 and compared the photocatalytic activity. The results show that MoS 2 /TiO 2 (001) composite with optimal ratio demonstrates a large enhancement of photocatalytic activity as much as 3.4 times than that of pristine TiO 2 nanosheets with exposed {001} facets. As compared, P25 with main exposed surface of anatase {101} facets was composited with MoS 2 , and the composite only exhibits 31% boost of photocatalytic activity than pristine P25. This contrast confirmed that {001} facets of anatase TiO 2 are the key to construct carrier exchange heterostructure between MoS 2 and TiO 2 to enhance the photocatalytic activity. The HRTEM images show that the two-dimension MoS 2 grown on the {001} facets of TiO 2 nanosheets to show a face-to-face contact. This contact is an ideal transmission channel for photo-induce carriers with less scattering. Moreover, due to the higher valence band compared with {101} facets, the photo-induced holes will transfer to {001} facets and finally be extracted by MoS 2 for photocatalysis degradation. The strategy that employs different crystal faces to regulate heterostructure interface can also be applied in other fields such as solar cell and electron device. [ABSTRACT FROM AUTHOR]

Photocatalysts with exposed specific active facets usually exhibit desirable photocatalytic activity. These active crystal facets offer various advantages that are often ignored. In this work, we employed specific exposed crystal facets as substrate to construct an excellent heterostructure for high-efficiency photocarrier transformation channel. The (001) face of anatase TiO 2 was selected to fabricate the composite (001) Bi 2 WO 6 as Bi 2 WO 6 (001)/TiO 2 (001) heterostructure. The lattice spacing of {110} facets of TiO 2 (0.26741 nm) in the heterostructure was very close to that of {020} (0.27180 nm) or {200} facet (0.27285 nm) of Bi 2 WO 6 . Thus, (001) Bi 2 WO 6 grew on the (001) faces of anatase TiO 2 with little lattice compression between the {020} and {200} facets. Bi 2 WO 6 nanocrystal could not grow on the (101) faces of P25, which confirms that the {001} facet of the substrate is the critical factor for constructing the heterostructure. The Bi 2 WO 6 (001)/TiO 2 (001) heterostructure was confirmed to be an ideal transmission channel that extended the separation time of photocarriers and enhanced the photocatalytic activity. Thus, an improved strategy that employs specific crystal facet substrate is proposed to construct a heterostructure for high-efficiency photocarrier transformation channel. [ABSTRACT FROM AUTHOR]

Iron sulfide (FeS) was supposed to be a suitable substitute for the commonly used graphite anode in lithium-ion batteries due to its higher specific capacity. However, its electrochemical property was severely limited due to its weak conductivity and evident volume change. To address these issues, we successfully construct controllable self-assembled flower-like with N-doped carbon coating FeS anchored on S-doped reduced graphene oxide (FeS/C@rGO) nanocomposites, used the synthesized octahedron iron-based metal-organic framework and graphene oxide composite (Fe-MOF@GO) as the precursor and thioacetamide as the sulfur via high-temperature calcination. The flower-like structure was generated by the controllable self-assembly of FeS nanosheets following an octahedral collapse, which enhanced the contact area between the active material and the electrolyte and improved Li+ transmission efficiency. Furthermore, the N-doped carbon and rGO efficiently inhibits the volume growth and aggregation of FeS nanosheets, resulting in the fabrication of controllable self-assembled flower-like FeS/C@rGO with a stable structure and outstanding rate performance. The discharge capacities of the FeS/C@rGO electrode were 1446.3, 1379.4, 1266.7, 1179.2, 1097.5 and 980.7 mAh g−1 at different current densities of 0.1, 0.2, 0.5, 1.0, 2.0 and 5.0 A g−1, respectively. When the current density returns to 0.1 A g−1, the reversible capacity is restored to 1629.7 mAh g−1. Moreover, the reversible specific capacity of FeS/C@rGO anode was 1428.2 mAh g−1 (130 cycles) at 0.1 A g−1 current density, showing excellent cycling performance. [Display omitted] • Flower-like FeS/C@rGO was prepared by solvothermal and calcination process using Fe-MOF as self-sacrificing template. • Flower-like structure was generated by the self-assembly of FeS nanosheets following an octahedral collapse. • The addition of rGO increases electrical conductivity of material and effectively mitigates the volume growth. [ABSTRACT FROM AUTHOR]

The development of stable, efficient photocatalyst for environmental antibiotics degradation is great significant and remains a major challenge. Herein, novel 2D/0D n-MoSSe/p-Co 3 O 4 Z-scheme heterojunction catalysts (MSCO) are developed to combine the advantages of n-type MoSSe nanoplates and p-type Co 3 O 4 nanoparticles. With an optimized Co 3 O 4 loading ratio, the MSCO2 sample exhibited 7.8 and 28.8 times of photocurrent density more than that of pure MoSSe and Co 3 O 4 , and likewise showed 2.54 and 8.91 times of photocatalytic tetracycline hydrochloride removal rate more than that of pure MoSSe and Co 3 O 4. Moreover, the heterojunction displayed outstanding recyclability after five cycles. The remarkably enhanced catalytic properties were mainly ascribed to the 2D/0D structure, 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 the electron spin resonance (ESR) and high-pressure liquid chromatography-mass spectrometry (HPLC-MS). This research provided a new idea for the construction of Z-Scheme p-n heterojunction with 2D/0D structure in photocatalysis, photoelectrochemistry, and electrocatalysis. novel 2D/0D n-MoSSe/p-Co 3 O 4 Z-scheme heterojunction catalysts (MSCO) are developed to combine the advantages of n-type MoSSe nanoplates and p-type Co 3 O 4 nanoparticles, which displayed a much higher photocatalytic and photoelectrochemical performance than pure MoSSe and Co 3 O 4. [Display omitted] • Novel 2D/0D n-MoSSe/p-Co 3 O 4 Z-scheme heterojunction catalysts (MSCO) were obtained. • The photoelectrochemical and photocatalytic activity of the MSCO catalyst were largely enhanced. • The photocurrent of the MSCO catalyst has an enhancement of 27.8 times. • The photocatalytic degradation rate of the MSCO catalyst has an enhancement of 7.91 times. [ABSTRACT FROM AUTHOR]

High-entropy alloys (HEAs) have received extensive interest owing to their unusual mechanical properties as a result of the extreme compositional complexity. Understanding the dislocation behavior under the influence of chemical disorder, especially chemical short-range ordering (SRO), which is commonly found in HEAs, is fundamental to the rational design of high-performance alloy systems. Here, we systematically investigate the effect of disorder and SRO on the regulation mechanism of dislocation nucleation and cross-slip in HEAs through a combination of Monte Carlo methods, molecular dynamic (MD) simulations, and theoretical analysis. Our results demonstrate that the incipient plasticity of HEAs under nanoindentation is mainly controlled by the nucleation and cross-slip of Shockley partial dislocation loops, which are found to be highly dependent on SRO. In contrast to traditional strengthening, SRO leads to a significant increase in the stable nucleation radius of the dislocation loop and cross-slip resistance. Strengthening is then achieved due to the extension of the dislocation nucleation period and the high resistance for dislocation cross-slip. Aided by the transition path analysis and theoretical model, we show that the local compositional changes originating from SRO, specifically for strong Co-Cr pairs, are the dominant factors governing the dislocation properties and accordingly, the strengthening effects. Finally, the SRO strengthen effect is further validated against different alloy systems with different SRO types. These findings suggest that the elasticity and strength of HEAs can be improved through the prolonging of the nucleation period of dislocations resulting from SRO, dictating an avenue for enhancing the mechanical properties of HEAs. • The incipient plasticity of HEAs under nanoindentation is controlled by the nucleation and cross-slip of partial dislocation loops. • Strong SRO increases the nucleation energy barriers and the stable nucleation length is longer simultaneously. • Dislocation cross-slip is inhibited by SRO. • SRO increase the critical transition radius from dislocation slip to cross slip. • Strength originating from the interaction between solute and dislocation is enhanced by strong SRO. [ABSTRACT FROM AUTHOR]

Designing novel and highly efficient photodetectors is a significant work as well as full of challenges. Herein, 2D SnSSe (SSS) porous nanoplates (Sn: S: Se=1: 1: 0.5) with atom-level heterojunctions were obtained from optimized hydrothermal synthesis, and a novel SSS-based photoelectrochemical detector was constructed accordingly. The morphology, microstructure, chemical states and light absorption performance of the SSS sample were clearly revealed by various characterization methods. Further analysis showed that there was an internal electric field in the SSS sample, which resulted from no coincide centers of the positive and negative charge. Due to the internal electric field and porous structure, the SSS sample had lower internal resistance (0.3 KΩ), which was conducive to the transmission of internal carriers, and could enhance the photoelectrochemical (PEC) activity eventually. In addition, a possible schematic illustration of the SnSSe-based photodetector was accordingly proposed. This SnSSe-based photodetector exhibited a higher photocurrent density (262.8 μA/cm2) that was 28.9 and 4.8 times of the SnS 2 and SnSe 2 and showed a higher photo-responsivity (0.24 mA/W) with a higher response speed. Moreover, the conduction band position of the SSS sample was higher than the O 2 /•O 2 − and H+/H 2 from band structure analysis, revealing it could also be used as a photocatalyst in photocatalytic degradation and photocatalytic hydrogen production. This pioneering work put forward a new scheme for the preparation of ternary SnSSe and revealed its potential application in the field of photodetection. [Display omitted] • novel atom-level heterojunction 2D SnSSe porous nanoplates were obtained. • The photoelectrochemical activity of the SnSSe-based photodetector is largely enhanced. • The photocurrent of the SnSSe-based photodetector has an enhancement of 28.88 times. • The photo-responsivity and response speed of the SnSSe-based photodetector has a large enhancement. [ABSTRACT FROM AUTHOR]

Designing highly efficient photocatalysts for the degradation of overused levofloxacin (LEV) antibiotics is an important and challenging task. Herein, novel atom-level heterojunction 2D MoSSe nanoplates (MSS) with various S:Se molar ratios were obtained by hydrothermal synthesis. XRD studies indicated lattice constants of these MSS catalysts were intermediate between the values for MoS 2 and MoSe 2 , and their internal lattice distortion energy increased due to the interaction between the two types of lattice structures. Further analysis revealed the appearance of the internal electric fields in MSS catalysts, which appeared as the centers of the positive charge and the negative charge did not coincide. Due to the internal electric field, MSS catalysts had lower internal resistances, which were conducive to the transmission of internal carriers, and eventually enhanced the photoelectrochemical activity. The photocatalytic LEV degradation rate (k) of the MSS1 was 7.5 and 8.1 times superior to that of MoS 2 and MoSe 2 , respectively. The photocurrent densities of MSS1 and MSS4 were 3.5 and 18.2 times higher than that of MoS 2. In addition, the conduction band position of MSS1 shifted to the higher than O 2 /•O 2 − and that of MoS 2 , which could generate •O 2 − for LEV degradation. Moreover, Electron Spin Resonance (ESR) analysis further revealed that the main active species in photocatalytic LEV degradation were photo-generated •O 2 – and •OH that generated from the transformation of the •O 2 −. Finally, a possible photocatalytic mechanism for LEV degradation was proposed. These results confirm the advantage of the developed ternary compound. [Display omitted] • Novel atom-level heterojunction 2D MoSSe nanoplates with tunable S:Se molar ratio were obtained. • The photocatalytic and photoelectrochemical activity of the MoSSe is largely enhanced. • The photocurrent of the MoSSe photocatalyst has an enhancement of 17.26 times. • The photocatalytic activity of the MoSSe photocatalyst has an enhancement of 6.58 times. [ABSTRACT FROM AUTHOR]

Anatase nano-TiO 2 with exposed highly active curved surface was obtained via a simple hydrothermal route with the assistance of citric acid and HF. In this progress, exposed percentage of curved surface can been directly tuned by controlling the mole ratio of citric acid and HF. Such anatase nano-TiO 2 with exposed curved surface shows a unique truncated biconic morphology and has large specific surface area. The nano-TiO 2 shows higher photocatalytic activity than that of TiO 2 nanosheets with exposed {001} facets which confirms the curved surface have higher activity than {001} facets. The higher photocatalytic activity of curved surface can be ascribed to the fact that some high index facets such as {112} and many crystal edges contained on the curved surface may have higher activity than {001} facets. A synergistic effect between curved and {001} facets is confirmed that nano-TiO 2 with a optimal coexposed ratio between curved and {001} facets has higher photocatalytic activity than that of TiO 2 with exposed curved or {001} facets. The optimal coexposed ratio is affected by degradation molecules. The present work demonstrates a explore of hydrothermal synthetic method for controlling preparation of nano-materials. [ABSTRACT FROM AUTHOR]

In this work, specific exposed crystal facets were employed to construct epitaxial heterostructure for high efficiency carriers transmission channel. The (001) face of anatase TiO 2 was chosen to composite (001) Bi 4 Ti 3 O 12 for two reasons. First, as the lattice spacing of (110) faces of anatase TiO 2 (0.26741 nm) is very close to that of (020) (0.27240 nm) or (200) (0.27080 nm) faces of Bi 4 Ti 3 O 12 , (001) Bi 4 Ti 3 O 12 will epitaxial grow on the (001) faces of anatase TiO 2 . Second, due to the high surface energy, the chemical reaction between TiO 2 and Bi(NO 3 ) 3 will occur at a low Bi:Ti mole ratio to form well crystallographic Bi 4 Ti 3 O 12 nanocrystals. Compared with Bi 4 Ti 3 O 12 /P25 composite, this epitaxial heterostructure is confirmed to be an ideal carriers exchange channel to extend the separation time of photo-induced carriers and enhance photocatalytic activity. This study demonstrates the importance of crystal facets choice of substrate for constructing high efficiency carriers transmission channel. [ABSTRACT FROM AUTHOR]

In this work, a template CVD method to produce graphene nanoribbons (GNRs) was developed with Cu nanoribbons as catalyst. Appropriate temperature, growth time and cooling rate were investigated and displayed the great importance for obtaining GNRs. The morphology, thickness and crystalline quality of the GNRs were characterized by the SEM, AFM, TEM (HRTEM and TEM diffraction), and Raman spectroscopy respectively, which indicated the GNRs had much narrower width, less layer numbers, smooth edges and higher crystalline compared to previous ones. Moreover, the electrical properties of the GNRs were measured and the mobilities reach 80–300 cm 2 V −1 s −1 . This research provides a new type of GNRs experimentally, which is of great importance for the graphene applications. [ABSTRACT FROM AUTHOR]

The effects of strain rate and temperature on the uniaxial tension responses of Ti-6.6Al-3.3Mo-1.8Zr-0.29Si alloy are systematically investigated over a wide range of strain rates, 0.001–1150 s −1 , and initial temperatures, 293–573 K. Dynamic tension and recovery tests are conducted using a split-Hopkinson tension bar to obtain the adiabatic and isothermal stress-strain responses of the alloy at high strain rates. The experiments reveal that the tension behavior of the alloy is dependent on the strain rate and temperature. The value of initial yield stress increases with increasing strain rate and decreasing temperature, whereas the isothermal strain-hardening behavior changes little with strain rate and temperature over the full ranges explored. The adiabatic temperature rise is the main reason for the reduction of strain hardening rate during the high-rate deformation process. SEM observations indicate that the tension specimen is broken in a manner of ductile fracture. The phenomenologically based constitutive model, Johnson–Cook model, is suitably modified to describe the rate-temperature dependent deformation behavior of Ti-6.6Al-3.3Mo-1.8Zr-0.29Si alloy. The model correlations are in good agreement with the experimental data within the investigated range of strain rates and temperatures. [ABSTRACT FROM AUTHOR]

Ferrites (CoFe 2 O 4 , ZnFe 2 O 4 , MnFe 2 O 4 and Mn 0.5 Zn 0.5 Fe 2 O 4 ) nanoparticles can all significantly reduce the desorption temperature of MgH 2 , and CoFe 2 O 4 shows the best catalytic performance among the four ferrites. After dehydrogenation, new by-products including Mg, Co 3 Fe 7 and MgO phases are found for the CoFe 2 O 4 doped samples, and Mg, Fe 3 Zn 10 , Fe and MgO phases are identified for the ZnFe 2 O 4 doped samples. Mg, Fe, Mn and MgO phases are observed for the MnFe 2 O 4 doped samples, while Mg, Fe 3 Zn 10 , Mn, Fe and MgO phases appear for the Mn 0.5 Zn 0.5 Fe 2 O 4 doped samples. New forming phases Co 3 Fe 7 , MgO and Co also have a great catalytic effect on the MgH 2 hydrogen storage properties. The onset desorption temperature of MgH 2 doped with bimetallic catalysts (20 wt.% Co + 20 wt.% MgO and 20 wt.% Co 3 Fe 7 + 20 wt.% MgO) is lower than that of MgH 2 doped with the single catalyst (40 wt.% Co, 40 wt.% MgO and 40 wt.% Co 3 Fe 7 ), indicating that MgO and Co or MgO and Co 3 Fe 7 have the combination catalytic function. [ABSTRACT FROM AUTHOR]

In this work, we demonstrate a novel synthesis of rutile nano-TiO 2 with exposed highly active {1 1 1} facets. This TiO 2 was obtained by a simple one-step hydrothermal route with the assistance of NaF and HCl. In this progress, the Cl − causes the formation of rutile phase while the F − controls the exposure of {1 1 1} facets. With a best mole ratio of Cl − and F − , the percentage of exposed {1 1 1} facets in such rutile nano-TiO 2 can reach 96%. This rutile nano-TiO 2 with exposed {1 1 1} facets has larger specific surface area and as much as 3 times higher photocatalytic activity than rutile TiO 2 nanorods with exposed {1 1 0} facets. This results confirm the {1 1 1} facets have higher photocatalytic activity than {1 1 0} facets. In a deeper analysis, more surface unsaturated O 2c modes on the {1 1 1} facets cause higher adsorption and degradation ability which enhances the photocatalytic activity. The present work shows a further prospect of hydrothermal synthesis for controlling preparation of nano-materials. [ABSTRACT FROM AUTHOR]

In this study, the different crystal forms of titanium dioxide (TiO 2 ) were added into high density polyethylene (HDPE) to fabricate cool material. Crystal structure, crystallization behavior, crystal morphology were investigated by wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC) and polarized optical microscope (POM). Scanning electron microscope (SEM) was applied to observe dispersion of TiO 2 particles in the HDPE matrix and the cross section morphology. The solar reflectance and actual cooling property were evaluated by UV–Vis–NIR spectrometer and a self-designed device. By adding TiO 2 particles into HDPE matrix, the polymer chain could crystallize into more perfect and thermal stable lamella. The presence of TiO 2 particles dramatically increased the number of nucleation site therefore decreased the crystal size. The subsequent solar reflectance was related to the degree of crystallinity, the spherulite size of HDPE, refractive index, and distribution of TiO 2 particles in HDPE matrix. It was found the rutile TiO 2 could largely improve the total solar reflectance from 28.2% to 51.1%. Finally, the temperature test showed that the composites had excellent cooling property, which was in accordance with solar reflectance result. [ABSTRACT FROM AUTHOR]

Copper matrix composites reinforced with graphene nanoplatelets (GNPs) were fabricated using an electroless plating method, and the effects of the GNP content on the thermal conductivity (TC), coefficient of thermal expansion (CTE), and mechanical properties of the composites were studied. The TC, CTE, and strength of the composites were measured in the in-plane and through-plane directions and compared. Increasing the GNP content in the GNP/Cu composite was effective in reducing the CTE and increasing the compressive yield strength of the composite. The compressive yield strength was higher in the through-plane direction, but the maximum compressive strength was higher in the in-plane direction. In the case of compressive deformation in the in-plane direction, a single shear fracture with one fracture direction occurred. The compressive deformation in the through-plane direction of the composite with high GNP content (15% and 20%) exhibited a duplex shear fracture with two fracture directions. The significant findings of the present study are that it is possible to fabricate GNP/Cu composites with uniformly dispersed GNPs and low porosity by electroless plating. In addition, the failure mechanism of GNP/Cu composites was revealed for the first time. [Display omitted] • Electroless plating method can fabricate GNP/Cu composites with uniformly dispersed GNPs and low porosity. • Increasing the GNP content was effective in reducing the CTE and increasing the compressive yield strength of the composite. • Yield strength was higher in the through-plane direction, but maximum strength was higher in the in-plane direction. • Single shear fracture occurred in in-plane direction, while duplex shear fracture occurred in through-plane direction. [ABSTRACT FROM AUTHOR]

Highlights: [•] N doped rutile TiO2 nano-rods were obtained by a hydrothermal route. [•] N doped rutile TiO2 nano-rods show tunable photocatalytic selectivity. [•] Doped nitrogen replaces surface saturated O3c is considered to be the cause. [Copyright &y& Elsevier]

Abstract: Directionally solidified Si–6wt.%TaSi2 eutectic alloy has been studied to characterize the variation of inter-rod spacing at different growth rates (V =6–200μm/s) with a constant temperature gradient (210K/cm). Statistical distributions of inter-rod spacings at each solidification rate are determined. It is confirmed that the relationship between inter-rod spacing and solidification rate obeys the Magnin–Kurz model, and the theoretical value of V =5435.6μm3/s (λa is the average inter-rod spacing) approximately equals to the experimental value of V 1.06 =5343.6μm3.06/s. For the Si–TaSi2 system, the operating parameter ϕ is a function of the solidification rate due to the transition of the TaSi2 phase from facet to nonfacet, and as the solidification rate increases the kinetic undercooling cannot be ignored. [Copyright &y& Elsevier]

Abstract: In this work, room temperature ferromagnetic BiFeO3 ceramics has been prepared through complex-assisted sol–gel method by using tartaric acid as a complex and tested for the efficient adsorption removal of the model compound (Rhodamine B, RhB). The excellent adsorption property of RhB over as-prepared magnetic separable BiFeO3 ceramics has been proved by batch adsorption experiments. Further studies indicate the static-electric adsorption mechanism may play an important role in the adsorption process. This is a first study of its kind where magnetic separable BiFeO3 has been employed for efficient removal of RhB molecules from an aqueous solution. [Copyright &y& Elsevier]

Abstract: Oxide eutectic ceramic in situ composites prepared by directional solidification from the melt in the Al2O3–Ln2O3 systems are promising candidates for the manufacture of turbine blades because of their excellent mechanical properties. With high temperature gradient and rapid cooling rate, directionally solidified (DS) Al2O3/GdAlO3(GAP) eutectic ceramics having smooth surface and full density are successfully prepared by laser zone remelting at the scanning rate of 240–720mm/h. The microstructure development and solidification behaviour under rapid growth rate are investigated. Fine typical DS irregular eutectic structure of “Chinese script” consisting of interpenetrating α-Al2O3 and GAP phases is obtained at the scanning rate below 360mm/h. Further increasing the scanning rate, the as-solidified Al2O3/GAP eutectic presents a combination of “Chinese script” and elongated colony microstructure with complex regular structure. Inside the colonies, the rod-type or lamellar-type eutectic microstructures with ultra-fine GAP surrounded by the Al2O3 matrix are observed. The interphase spacing is strongly dependent on the laser scanning rate, rapidly decreasing to the sub-micron range for the samples grown at the highest rate. Moreover, the formation condition and solidification mechanism of the particular microstructure of the ceramic composite during rapid solidification are discussed. [Copyright &y& Elsevier]

Abstract: The melt superheating treatment is carried out for DZ125 superalloy during directional solidification. Under the same thermal gradient and solidification velocity, the microstructure evolution of directionally solidified DZ125 superalloy is systematically investigated by changing the melt superheating temperature. The results show that the dendrite is refined with the melt superheating temperature increasing from 1500°C to 1650°C. However, it becomes coarse after the melt superheating treatment at 1750°C. The dendrite segregation first reduces with the increase of melt superheating temperature between 1500°C and 1650°C, but becomes more severe when the superheating temperature is higher than 1650°C. The carbide morphology presents script-like when the melt superheating temperature is below 1600°C. Further increasing the melt superheating temperature, it is mainly blocky and nodular. Moreover, the reason of microstructure evolution with melt superheating treatment is discussed. The results are useful for promoting the development of high quality directionally solidified superalloy. [ABSTRACT FROM AUTHOR]

Abstract: The photoluminescence and afterglow characteristics of Zr doped CaTiO3:Pr3+ phosphors were investigated. Zr4+ substitution for Ti4+ leads to the enhancement of red fluorescence and phosphorescence at 613nm originating from 1D2 to 3H4 transition of Pr3+, and the increase of the lifetime for the 1D2 state. The enhancement of emission intensity was attributed to the change of the lattice structure, the increase of the Pr3+ amount, and the decrease of the concentration of the defects quenching red emission. The increase of lifetime was thought to originate from the increase of the density of [PrCa]0 traps. [Copyright &y& Elsevier]

Abstract: A novel process is introduced for controlling diameter of carbon nanofibers by changing electric field in a chemical vapor deposition system. It was found that an increase in electric field produced a smaller diameter and narrower diameter distribution of carbon nanofibers, that is, the carbon nanofiber diameter varied in series of 19.2±8.6, 13.8±4.7, and 8.0±2.4nm corresponding to the electric field of 0, 25,000, and 50,000V/m, respectively. The theoretical calculation reveals that the mechanism for this change is because Ni catalyst particles become liquid at the reaction temperature and the diameter of the Ni catalyst becomes smaller under the electric field. [Copyright &y& Elsevier]

Abstract: The melt superheating treatment during the directional solidification is carried out for DD3 Ni-based monocrystal superalloy. With the unchanged thermal gradient and withdrawn rate for different melt superheating temperatures, the influence of the melt characteristic on the microstructure and the mechanical property is studied. The results show that the dendrite and the γ′ precipitate are all obviously refined while the γ′ precipitate becomes more regular when the superheating temperature is increased from 1500°C to 1640°C and then to 1780°C. The superheating treatment has no obvious influence on the dendrite segregation of Al, Cr and Co but can reduce the dendrite segregation degree of W, Mo and Ti. With the elevated superheating temperature, the γ′ rafts become more stable and the stress rupture property under 1040°C/190MPa is improved. [Copyright &y& Elsevier]

Abstract: Directionally solidified ceramic eutectic in situ composite as a candidate for a high-temperature structural material has attracted considerable attention and various preparation techniques have been developed. In this study, pore-free eutectic ceramics of Al2O3/Y3Al5O12 (YAG) are prepared from melt by laser rapid solidification technique in order to investigate the microstructure characteristic and solidification behavior which are considered to be important factors influencing the properties of eutectic materials. The results show that: (1) The Al2O3/YAG eutectic displays a “Chinese script” structure, and faceting is the most important factor to determine the formation of the irregular eutectic morphology. (2) The scanning rate and power density of the laser beam are the most primary technological parameters affecting the eutectic microstructure. The eutectic spacing is extremely fined due to the high-temperature gradient and solidification rate, and decreases with the increase of the scanning rate and the average is only around 1μm. (3) Elongated colonies with the periodic distribution are observed in the solidified eutectic due to the high destabilization of solid–liquid interfaces caused by the ununiformity of the laser heat-flux distribution when the scanning rate is higher than 2000μm/s. [Copyright &y& Elsevier]

• CuSe/MoSe 2 2D/2D face-to-face heterojunction photocatalysts were prepared. • The photocatalytic and photoelectrochemical activity of the CuSe/MoSe 2 photocatalysts is largely enhanced. • The CuSe/MoSe 2 heterojunction show lower internal resistance and higher carrier separation efficiency. Photocatalysis and photoelectrochemistry are effective approaches to solve the energy and environmental crises. The suitable catalyst is the key for photocatalysis and photoelectrochemistry. Metal selenides have good prospects for their narrow band gap, low internal resistance, and related high photoelectric performance. In this work, a novel CuSe/MoSe 2 2D/2D face-to-face heterojunction photocatalyst was obtained through a simple hydrothermal route. These CuSe/MoSe 2 2D/2D heterojunction photocatalysts show excellent performance in photocatalytic degradation and photoelectrochemistry. With an optimized CuSe loading ratio of 2.5%, the heterojunction photocatalyst displays an improved degradation rate by 4.5 times and increased photocurrent by 7.6 times than the pristine MoSe 2. The large improvement in photocatalysis and photoelectrochemistry can be ascribed to the 2D/2D face-to-face contact between MoSe 2 nanoplates and CuSe nanosheets. Given this mode, the interface between CuSe and MoSe 2 can be maximized, and good binding can be obtained. The electrochemical impedance and the fluorescence emission spectroscopic methods confirm that the internal resistance is reduced, whereas the separation efficiency is improved. This work demonstrates the prospect of metal selenides used in environmental treatment and hydrogen energy utilization. [ABSTRACT FROM AUTHOR]

In this work, we report on the discovery of the high-pressure phase of Ba 2 FeS 3 with quasi one-dimensional (1D) spin chains, which was synthesized under high-pressure and high-temperature conditions. A systematic study was carried out via structural, transport, magnetic and thermodynamic measurements. The high-pressure phase of Ba 2 FeS 3 (denoted by Ba 2 FeS 3 (HP)) crystallizes in a K 2 AgI 3 -typed orthorhombic structure with the space group of Pnma (62) and the lattice parameters of a = 8.6831 (1) Å, b = 4.2973 (1) Å, and c = 17.0254 (2) Å, respectively, which consists of chains of corner-sharing FeS 4 tetrahedra along the b axis. Ba 2 FeS 3 (HP) undergoes a long-range antiferromagnetic transition at T N ∼56 K, above which the magnetic susceptibility curve exhibits a round hump behavior with the maximum temperature T max ∼110 K. In addition, the intrachain coupling J intra is about −18 K obtained by using the Wagner-Friedberg model. The specific heat data suggest that the total magnetic entropy change ΔS caused by the long-range ordering transition is only ∼20% of the expected value for a S = 2 system. For comparison, the properties of K 2 CuCl 3 -typed Ba 2 FeS 3 with similar quasi 1D spin chains were presented as well. Our results indicate that both compounds exhibit a typical feature expected for compounds with 1D spin chains. • The new phase of Ba 2 FeS 3 was synthesized under high pressure conditions. • The structure and physical properties of two polymorphs of Ba 2 FeS 3 were studied in detail. • High-pressure phase of Ba 2 FeS 3 displays an antiferromagnetic ground state with one-dimensional spin chains. [ABSTRACT FROM AUTHOR]

The new ternary pnictides La 3 Ti X 5 (X = P, As) and the solid solutions of La 3 Ti(Sb 1- x As x) 5 (x = 0–1) and La 3 Ti(As 1- y P y) 5 (y = 0–1) were synthesized under high pressure and high temperature conditions. The crystal structure of La 3 Ti X 5 (X = P, As) was determined from the X-ray powder diffraction data. These compounds crystallize in a hexagonal Hf 5 Sn 3 Cu-anti type structure with the space group P 6 3 / mcm and lattice parameters a = 8.7927 Å and c = 5.7643 Å for La 3 TiP 5 , and a = 9.0267 Å and c = 5.9071 Å for La 3 TiAs 5 , in which the face-sharing Ti X 6 octahedral chains running along the c axis are separated by La3+ in the interstice sites with a distance about 9 Å, presenting a strong one-dimensional crystal structure. Physical properties measurements indicate La 3 Ti X 5 (X = P, As) are Pauli paramagnetic metals. The calculations reveal that La3+ ions are not perfectly ionic owing to the non-negligible contributions of La to the density of state (DOS) at the Fermi level and bridge the X atoms between the chains, which make the samples to be 3-dimensional metals. What's more, the change of X in La 3 Ti X 5 from Sb to P increases the ionicity of La3+ and thus decreases the electron hopping between the conducting chains. • The first ternary compounds La 3 Ti X 5 (X = P, As) in the La–Ti- X system were synthesized under high pressure. • La 3 Ti X 5 (X = P, As) exhibit a strong one-dimensional crystal structure character. • The properties were explored as X varies from Sb to P. [ABSTRACT FROM AUTHOR]

Due to a variety of outstanding physical and chemical properties such as wide band gap, low resistance, good catalysis, high surface-to-volume ratio, high sensitivity and strong interaction with gas molecules, one-dimensional (1D) micro- and nanoscale indium oxide (In 2 O 3 ) structures are capable for high-performance optical, electrical and chemical devices, which have attracted much attention in the last decade. In this paper, we first summarize various fabrication methods of 1D micro- and nanoscale In 2 O 3 structures such as chemical vapor deposition, hydrothermal method, thermal evaporation method and electrospinning, then the interesting electrical and optical properties and their potential applications including gas sensors, field-emission transitions, photocatalysts and ultraviolet detectors are reviewed. At last, in order to fulfill the potential applications of 1D micro- and nanoscale In 2 O 3 structures, some challenges have also been discussed. [ABSTRACT FROM AUTHOR]

In this work, by a simple method of hydrothermal synthesis, the CdSSe/Bi 2 WO 6 S-scheme heterojunction catalyst is successfully obtained and the results are verified by XPS, EPR, band structure, etc. The S-scheme heterojunction can maintain the strong redox potential energy position of both catalysts, and adjust the electron transfer path to improve the electron-hole separation efficiency, and thus improve the charge transfer efficiency. CdSSe has a high conduction band (−1.13 eV) and a narrow bandgap width (1.59 eV), exhibiting good light absorption characteristics and reduction ability; the valence band position of Bi 2 WO 6 is much low (2.58 eV), indicating good oxidation activity. This heterojunction has excellent oxidation and reduction capabilities and exhibits multifunctional catalysts. Its photocatalytic degradation ability of tetracycline hydrochloride is 2.2 times that of the original CdSSe, while its photoelectrochemical activity is 11 times that of CdSSe, reaching a photocurrent density of − 2.081 mA/cm2 at 0 V (vs. RHE). The electrocatalytic activity of its hydrogen evolution has also been enhanced. This study developed a design strategy for a novel bifunctional S-scheme heterojunction catalyst. [Display omitted] • CdSSe/Bi 2 WO 6 S-scheme heterojunction catalyst was successfully obtained. • The S-scheme heterojunction can maintain both narrow bandgap width and high redox potential energy. • The catalysts have enhanced performance in photoelectrochemistry, electrocatalysis and photocatalysis. • The photoelectrochemical and photocatalytic activity increases by 11 and 2.2 times respectively. [ABSTRACT FROM AUTHOR]

Abstract The incorporation of TiN and Y 2 O 3 nanoparticles together into Ni-W matrix have been investigated by pulse electrodeposition in present study. The microstructural, surface properties and corrosion resistance of Ni-W/TiN-Y 2 O 3 nanocrystalline coating have been studied. It illustrated that the electrodeposited coatings have dense and nodular structure without defects. Results confirmed that TiN and Y 2 O 3 particles were uniformly embedded in the composites. The embedded particles could improve the hardness and anti-corrosion properties of the obtained coating. The crystallite size calculated based on the preferred orientation (111) plane was of 14–17 nm, illustrating the formation of nanocrystalline structure. The mean R a value was about 84.6 nm. Electrochemical impedance tests revealed that the preferred combination of operating parameters for optimum corrosion resistance was 70%, 1000 Hz, 40 min and 4 A dm−2. However, the best hardness and anti-wear properties were obtained at parameters of 50%, 500 Hz, 6 Adm−2 and 60 min. The extreme values of hardness and corrosion resistance were not realized simultaneously. The operating parameters should be kept in a certain balance to avoid the formation of inferior properties in any aspects of the coating; then the other performance advantages could be brought into full play. The preferred combination of operating parameters was optimized to be duty cycle of 70%, frequency of 1000 Hz, duration time of 40 min and average current density of 4 Adm−2, which enabled the electrodeposited coating optimum corrosion resistance and high mechanical properties. Highlights • Ni-W/TiN-Y 2 O 3 nanocrystalline coating was fabricated by pulse electrodeposition. • The microstructural and surface properties of the coating were investigated. • The effect of operating parameters on hardness were examined and optimized. • The effect of process parameters on corrosion resistance were evaluated and optimized. • The nanocrystalline coating owns high hardness and excellent corrosion resistance. [ABSTRACT FROM AUTHOR]

Abstract The poor rate performance and inferior cycling life of Ni-rich layered oxide cathodes, which are related to low lithium conductivity and structure degradation during cycling, are the obstacles to commercial utilization. Herein, we apply a solid grinding approach based high temperature calcination to synthesize Na-substituted, F-substituted and Na-F-substituted LiNi 0.6 Co 0.2 Mn 0.2 O 2. The synergistic coupling effect of both sodium and fluorine substitution on particle morphology and structure is systematically investigated. The galvanostatic charge/discharge results show that Na and F co-substituted sample displays improved rate performance as well as superior capacity retention. The cooperative substitution of Na and F has synergistic effect on enlarging the interlayer spacing, which is favorable for increasing lithium diffusivity and enhancing the rate capability. Meanwhile, the Na incorporated into the Li layer and the partial substitution of metal-O bond by stronger metal-F bond can help to stabilize the crystal system, thus enhancing the structural stability. This work presents some new thought into synthesis of high-performance cathode materials through strategic cationic-anionic co-substitution. Highlights • Effect of Na and F substitution on morphology and structure is investigated. • Na and F co-substituted sample displays improved electrochemical performance. • The co-substitution enlarges interlayer spacing and enhances structure stability. [ABSTRACT FROM AUTHOR]

Abstract Controlling hierarchical structure assembled by nanoplates with exposed {010} active planes is essential to optimize the electrochemical performance of nickel-rich layered oxide cathode materials. In this work, nickel-rich layered oxide cathodes with various degrees of packing and surface area of exposed {010} facets were synthesized via a simple continuous co-precipitation method and a stepwise calcination process. The effects of structure and morphology on the Li+ transport kinetics of LiNi 0.58 Co 0.25 Mn 0.17 O 2 were systematically evaluated by physical and electrochemical characterizations. The results show that the enhanced growth of {010} active facets, namely, the lateral plane of the primary nanoplates can facilitate the Li+ intercalation/deintercalation and thus improve the rate capability. Meanwhile, the compact micro-sized secondary particle guarantees the structural stability of the Ni-rich cathodes. The LiNi 0.58 Co 0.25 Mn 0.17 O 2 material with optimized structure manifests high discharge capacities (185 mAh g−1 at 0.1 C), outstanding high-rate capability (106 mAh g−1 at 50 C) and excellent long cycle life (capacity retention of 78% after 500 cycles at 5 C). Highlights • Ni rich cathode with preferentially exposed {010} active facets is synthesized. • The enhanced growth of {010} active facets can facilitate Li+ diffusion. • The cathode with preferentially exposed active facets shows excellent performance. [ABSTRACT FROM AUTHOR]

Abstract Dynamic tuning upconversion color is the most convenient approach through modulation of pump power density and NIR wavelength for anti-counterfeiting. However, most of bulk upconversion systems suffer from the insensitive response to excitation power and NIR wavelength (980 nm and 1550 nm). Herein, we demonstrate that the excitation power density sensitivity and NIR wavelength sensitivity of bulk microcrystals could be improved via co-doping Li+/Lu3+ ions. More interestingly, co-doping ions with different valences affect the emission color tendency at 1550 nm excitation, which is contrary to previous reports. The emission color of bulk NaYF 4 :Er/Yb/Li/Lu microcrystals transform from yellow to bright green color through adjusting pump power density and pump wavelength (980 nm and 1550 nm). Moreover, the mechanism of the results has been systematically discussed. The tunable emission colors of bulk NaYF 4 :Er/Yb/Li/Lu microcrystals can be easily distinguished with naked eyes and difficultly counterfeited. Therefore, the upconversion materials have a promising application in transparent anti-fake printing. Highlights • Emission color sensitivity of sample in response to pump power density is enhanced. • Red-to-green ratio decreases largely with pump power density of 980 nm laser. • Tunable emission color of samples is achieved by modulation of pump wavelength. • The emission color at 1550 nm excitation is affected by valances of co-doping ions. [ABSTRACT FROM AUTHOR]

Abstract Electroless nickel/nickel-boron (Ni/Ni-B), Ni/alkaline Ni-P and Ni/acidic Ni-P double-layer coatings were deposited on AZ31 magnesium (Mg) alloy prepared by environmental fluoride-free solution under low temperatures. The morphologies, compositions, and crystal structures of three different double-layer coatings were characterized by field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD), respectively. The corrosion resistance of the different double-layer coatings on Mg alloy surface was studied by electrochemical polarization and electrochemical impedance spectroscopic (EIS) tests, which indicated that the Ni/Ni-B coating presented the more superior corrosion resistance than the Ni/alkaline Ni-P and Ni/acidic Ni-P coatings. Meanwhile, the Ni/Ni-B coating exhibited good repeatability through the electrochemical polarization tests for three Ni/Ni-B samples that prepared under the same processing conditions. In addition, the optimal plating time for the Ni-B coating was further determined by electrochemical polarization tests of samples with different plating times. Highlights • The double-layer Ni/Ni-B coating on AZ31 Mg alloy is prepared by electroless method under relatively lower temperatures. • The pretreatment, activation and plating solutions completely remove fluoride. • The Ni/Ni-B coating exhibits good repeatability. • The optimal plating time of the outer Ni-B coating is obtained. [ABSTRACT FROM AUTHOR]

Abstract Desiring a high-performance infrared (IR) material with a wide band gap and large second harmonic generation (SHG) response motivates the studies about the chemistry and electronic structure of microscopic structures. In this research, the covalence, electronic structure and mechanism of SHG effect for a typical IR system, d10 metal chalcogenides with AB 2 S 4 (A = Cd, Hg; B = Al, Ga) family, were systemically investigated. It reveals that the dp hybridization, size effect and the cation electronegativity induce the changes of band gaps. Besides the decrease of charge-transfer energy enlarging the SHG effect, we found that the strong covalent interaction between atoms is also beneficial to the SHG enhancement. More importantly, the nonlinear optical (NLO) functional units for superior IR performances were investigated, and the results show that IIIA-S functional units have strong covalent interaction and more priority on NLO properties. Furthermore, the electronic structures of sulfur in the compounds are susceptible to the type of cations, and consequently affect the NLO properties. Highlights • The influence of d10-metal and IIIA cations on band gap were analyzed. • The difference of electronic structures of S was captured by the bandwidth. • The enhanced NLO effect originates from strong dp hybridization and covalence. [ABSTRACT FROM AUTHOR]

A multi valence state Cu 2−x Se/FeSe 2 (CFS) Z-type heterojunction catalyst was constructed by hydrothermal synthesis of 0D Cu 2−x Se nanoparticles supported on 1D FeSe 2 nanorods. In the catalysts, the Cu 2−x Se shows multi valence as Cu2+ and Cu+ as well as FeSe 2 had two valence states: Fe2+ and Fe3+. This multivalent state is conducive to electron transport, will reduce its resistivity, and change among different valence states in electrochemical reactions, resulting in improve its photoelectrochemical and electrocatalytic performance. Moreover, this Z-type heterojunction catalyst exhibited good oxidation and reduction ability which reveals the appropriate 0D/1D structure improves the carrier transport. That has been confirmed by photoelectrochemical, electrocatalytic and photocatalytic tests. Under the optimal composited ratio, the degradation rate (k) and photocurrent density of the heterojunction photocatalyst were 1.35 and 3.65 times higher than those of Cu 2−x Se, respectively. The detected superoxide radical (O2-•) could prove the formation of Z-type heterojunction. This work provides a new strategy for developing a multifunctional boosted catalyst and reveals their promising applications in photoelectrochemistry, electrocatalysis, and photocatalysis. [Display omitted] • A multi valence state Cu 2−x Se/FeSe 2 (CFS) Z-type heterojunction catalyst was constructed. • This multivalent state is conducive to photoelectrochemical and electrocatalytic performance. • The photoelectrochemical performance of the catalyst has an enhancement of 3.65 times. • The detected superoxide radical (O 2 -•) could prove the formation of Z-type heterojunction. [ABSTRACT FROM AUTHOR]

The influence of substituting Mo for W on solidification characteristics of Re-containing single crystal superalloy was investigated via experimental analysis and thermodynamic calculation. W-rich single crystal superalloy (Alloy W) and Mo-rich single crystal superalloy (Alloy Mo) both had typical dendritic microstructure, while interdendritic precipitations of Alloy W and Alloy Mo were γ′ phase+γ/γ′ eutectic phases and γ′ phase+NiMo phase, respectively. Meanwhile, W significantly segregated to dendritic region in Alloy W, while Mo segregated to interdendritic region in Alloy Mo. Moreover, substituting Mo for W obviously decreased the microsegregation degree of Re and Al elements. The influence of substituting Mo for W on microsegregation behavior of alloying elements (e.g. Re) effectively decreased the tendency of forming freckle during solidification. Furthermore, substituting Mo for W decreased liquidus temperature and solidus temperature of single crystal superalloy. [ABSTRACT FROM AUTHOR]

Respiratory monitoring is an effective method to assess human health and provides valuable information for early warning and diagnosis of respiratory diseases. However, respiratory monitoring equipment relies on traditional power supply model, which limits real-time monitoring of breathing in fields of outdoor adventure, nomadism and long-distance running. As a solution, a triboelectric nanogenerator (TENG)-driven self-powered humidity sensor for human breath monitoring was prepared. A flexible TENG composed of Ti 3 C 2 T x : PDMS composite film and Ni/Cu polyurethane foam sponge was used as self-powered part of the device, RGO-TiO 2 humidity sensor was used as the respiratory sensing part of the device. Compared with the traditional humidity sensor, TENG-driven self-powered RGO-TiO 2 (TENG-RGTO) shows high response (359.2), fast response/recovery time (1/5.2 s), good reversibility, small humidity hysteresis (0.54%) in the range from 0% RH to 95% RH. Furthermore, TENG-RGTO humidity sensor can realize recognition of breathing states at different frequencies and intensities in real time. Meanwhile, a breathing alarm device driven by humans is designed. This research not only broadens the application range of TENG but also provides a new design idea for self-powered breathing monitoring sensor. • TENG was prepared with Ti 3 C 2 T x : PDMS composite film and Ni/Cu polyurethane foam sponge as friction layer. • RGO-TiO 2 heterojunction humidity sensor with more oxygen vacancy defects and hydrophilic functional groups is synthesized. • TENG and humidity sensor are integrated to form a TENG-driven self-powered RGO-TiO 2 sensor. • Sensor has high response, fast response/recovery time, high reversibility, small hysteresis and excellent stability. • TENG-RGTO sensor has shown application potential in human breathing and self-powered breathing alarm devices. [ABSTRACT FROM AUTHOR]

Two-dimensional MoSSe nanoplates demonstrate low internal resistance and outstanding reduction potential, while Bi 2 WO 6 nanoparticles exhibit zero-dimensional appearance and high oxidation potential. Herein, novel MoSSe/Bi 2 WO 6 step-scheme (S-scheme) heterojunction photocatalysts (MSSB) were prepared to combine the properties of those two materials. These catalysts were confirmed to have lower internal resistance (as low as 0.07 kΩ), and higher carriers' separation efficiency due to the well-contacted two-dimensional/zero-dimensional structure. More importantly, the heterojunction catalysts displayed both good oxidation and reduction performance which have been confirmed by the conducted catalytic tests. With an optimized Bi 2 WO 6 loading ratio, degradation rates (k) and photocurrent density of the MSSB2 sample were 2.09, and 8.31 times more than that of MoSSe, as well as 1.77, and 26.27 times more than that of Bi 2 WO 6. Active species (superoxide radical •O 2 − and hydroxyl radical •OH) were detected by the electron spin resonance tool which could infer that a S-scheme heterojunction has already constructed between the Bi 2 WO 6 and MoSSe. Driven by the MoSSe and band edge bending, the e – on the conduction band of Bi 2 WO 6 readily slid toward MoSSe and recombines with the h + on the valence band of MoSSe, while retaining the powerful e – and h + with high redox potential on the CB of MoSSe and VB of Bi 2 WO 6. This work further provided a novel strategy for developing S-scheme nano-heterojunction catalysts and revealed their prospects in photoelectrochemistry and photocatalysis. [Display omitted] • Novel 2D MoSSe/0D Bi 2 WO 6 S-scheme heterojunction catalysts (MSSB) were obtained. • The photoelectrochemical and photocatalytic activity of the MSSB catalyst were largely enhanced. • The photocurrent of the MSSB catalyst has an enhancement of 26.27 times. • The photocatalytic degradation rate of the MSSB catalyst has an enhancement of 2.09 times. [ABSTRACT FROM AUTHOR]