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Nowadays, the fabrication of robust and earth-abundant hydrogen evolution electrocatalysts with noble-metal-like catalytic activities is still facing great challenges. In this report, nanorod (NR)-shaped nickel sulfide (NiS) is successfully decorated on graphene (Gr) by utilizing carbon cloth (CC) as a substrate (NiS-Gr-CC). Benefiting from the NR morphology and strong interfacial synergetic effect between NiS and Gr, the NiS-Gr-CC electrocatalyst shows good catalytic activity for hydrogen evolution reaction (HER). Specifically, the low Tafel slopes of 46 and 56 mV dec-1 along with the small overpotentials of 66 and 71 mV at 10 mA cm-2 are obtained in the acidic and alkaline electrolytes, respectively. Density functional theory results indicate that the combination of NiS and Gr can optimize the adsorption energy of H* during the HER process. The long-term durability measurement result reveals that our NiS-Gr-CC heterostructure has good electrocatalytic cycling stability (∼ 80 h) in both acidic and alkaline electrolytes. These results confirm that the NiS-Gr-CC heterostructure is a promising candidate for hydrogen evolution electrocatalyst with high catalytic activity.

Shape memory polymer composites (SMPC), which are a type of stimuli-responsive material, show better mechanical properties than pure shape memory polymers. However, different engineering applications have different requirements for the fiber content of SMPC. For example, some parts of the structure require more fibers to enhance strength, while other parts require fewer fibers to maintain deformability. In order to solve this problem, a functionally graded shape memory polymer composite (FG-SMPC) is proposed in this work. The contents of the fibers for the FG-SMPC can be changed along the geometric dimension of the material, enabling different performance requirements to be met in different parts of the structure. Based on the constitutive model of the SMP and the mechanics of composite materials, the mechanical behaviors of the FG-SMPC under thermal loading are discussed. The results show that such materials exhibit gradient behaviors for both the intensity and shape memory effect with different gradient distributions.

Tin(II)oxybromide, Sn14O11Br6 (TOB), was synthesized successfully via the high-temperature solution method in a closed system for the first time. Its structure displays two-dimensional [Sn14O11Br6] layers constructed from highly distorted [SnO3]4− and [SnO2Br]3− polyhedra. Besides, TOB possesses good thermal stability and a birefringence larger than 0.248 at 546.1 nm. First-principles calculations reveal that TOB shows giant optical anisotropy of Δn = 0.265 at 546 nm owing to the superior arrangement of highly distorted Sn–O/Br polyhedra.

Purpose This paper aims to study the effect of load on the tribological behaviour of Cu-based composites, so as to obtain a suitable applied load on these composites. Design/methodology/approach Cu-based composites were prepared by powder sintering with direct current electric current heating and tested by Universal Mechanical Test-3 with a ball-on-disk at room temperature. Findings The results showed that Cu-based composites are might suitable for working under low load. There is only mild damage on the surface under a load of 2 N. While it has microcracks and shows signs of cavitation at a certain depth at 20 N and 50 N. In addition, it is evident that there are three zones in the cross-section of the matrix, namely, a mechanical mixing layer, ceramic layer and substrate, respectively. Originality/value There are two wear mechanisms at different loads, and the evolution of worn surfaces with sliding time is also involved. Thus, the developed material can be used for light load sliding electrical contact material applications.

Purpose The purpose of this paper is to propose a method with capability of short-time implementation. Design/methodology/approach This paper was directed using both experimental tests and simulations to propose a comprehensive method for lifetime estimation of the solder joints. Findings A new method with good agreement with experimental tests has been proposed. Originality/value It is confirmed that paper is original.

Titanium alloy drill pipe material used in the oil and gas industry has excellent characteristics such as high-specific strength, high-temperature resistance, and corrosion resistance. In this study, a systematic examination of the aging process of Ti-5Al-3V-1.5Mo-2Zr drill pipe material, and the microstructure evolution and properties was carried out. The results show that the optimum solution system is 930 °C/1 h/WQ (water quenching). After the aging treatment, the granular changes for α and β phases lead to an increase in the size of the initial lamellar α phase, the volume fraction of the secondary α phase, and the overall strength while the elongation decreases. As the aging temperature increases, the tensile strength and yield strength initially increase by 27 and 29.5%, respectively, and subsequently decrease. The elongation decreases to 9.5%, leading to an excellent performance. With the gradual decrease in the tensile strength and yield strength, the elongation increases gradually. When the heat treatment process is 930 °C/1 h/WQ + 600 °C/6 h/AC, the elongation is 11.5%. TEM observations revealed that a large number of dislocation piles existed at the α/β phase interface after aging treatment, thereby, increasing alloy strength. The more the volume fraction of the secondary α phase precipitated, the smaller the size, leading to a more significant strengthening effect.

Amine-functionalized imidazolium-based poly(ionic liquid) brushes on mesoporous silica were synthesized via “grafting through” technique and were applied as model sorbents to understand physisorption and chemisorption of carbon dioxide molecules. The experimental results reveal that the total adsorption capacity of model sorbents derived from temperature programmed desorption (TPD) approach reaches 1.72 mmol·g−1 that is much higher than the sum of adsorption capacity of bare mesoporous silica and free polymers at 25 °C under carbon dioxide partial pressure of 0.2 bar. The proposed physical adsorption and chemical adsorption of carbon dioxide molecules in TPD response curves were validated by volumetric desorption measurement. It is also observed that physical adsorption is completely reversible and chemical adsorption is irreversible. The results demonstrate that the temperature programmed desorption technique is an effective approach to differentiate chemisorption and physisorption of gaseous species on solid sorbents, which is beneficial for understanding of adsorption mechanism and materials design.

Sufficient stabilization of comminuted mid-shaft clavicle fractures via plate fixation is difficult to achieve. Various augmentations, including interfragmentary screws and cerclage wiring, have been adopted to reinforce fixation stability. The present study aimed to assess the biomechanical stability of augmented plate fixations using the finite element method. First, a clavicle fracture model was created from CT data. Fixation was then induced using a locking compressive plate (LCP) with the following four augmentations: i) Double inner cerclage wirings (DICW), ii) double outer cerclage wirings (DOCW), iii) a single interfragmentary screw (SIS) and iv) double interfragmentary screws (DIS). Compressive and bending forces of 100 N were subsequently applied at the acromial region of the clavicle. The stress distribution, displacement and fracture micro-motions of the model were assessed and compared. The DOCW resulted in the highest stress exerted on the LCP, followed by SIS, DICW and DIS. For the clavicle fracture, DICW, DOCW and SIS resulted in high stress levels. However, DIS fixation alone resulted in levels of stress that were below the yield strength of cortical bone. Displacement analysis revealed that DOCW fixation resulted in the greatest degree of displacement and fracture micro-motions, followed by SIS, DICW and DIS. The results indicated that SIS, DIS and DOCW may be used as augmentations of LCP fixation for comminuted mid-shaft clavicle fractures. However, DIS was the recommended augmentation due to it exerting the lowest stress and the highest stability compared with the other fixations. The DICW may be used to aid fracture reduction and plate placement in surgery but should be avoided for permanent fixation.

The development of non-precious metal-based electrocatalysts for oxygen reduction is essential for the practical applications of oxygen-involved electrochemical energy conversion and storage device...

Introducing Pb2+ cations with lone pair electrons in borates is efficient to form multiple crystalline forms. Here, we report two new compounds, α-Pb4B2O7 and β-Pb4B6O13, which exhibit different crystal forms from the previously reported lead borates, β-Pb4B2O7 and α-Pb4B6O13, respectively. Two sets of polymorphs: α-, β-Pb4B2O7 and α-, β-Pb4B6O13, exhibit completely different crystal structures and diverse optical properties. Thermal gravimetric and differential scanning calorimetry (TG-DSC) and variable-temperature powder X-ray diffraction (XRD) analyses were performed to study their thermodynamic stabilities. Structure-property relationships were discussed through first-principles calculation. Notably, the new phases, α-Pb4B2O7 and β-Pb4B6O13, have larger birefringence than their corresponding polymorphs due to the rearrangement of the functional groups in their structures.

Cemented sand gravel (CSG) is different from ordinary concrete in its mechanical properties such as elastic modulus due to the non-sieving of aggregate. On the basis of previous studies, the serial model, parallel model, Hashin-Shtrikman model and the elastic modulus prediction method based on the mesoscopic random aggregate simulation have been analyzed, and the influences of different mesoscopic component parameters on the elastic modulus calculation of the above four methods have been studied. The results show that the elastic modulus and tensile strength of meso component have great influence on the elastic modulus of random aggregate simulation, the elastic modulus of cement mortar has the largest impact on the series model and the Hashin-Shtrikman lower boundary model, and the elastic modulus of the aggregate has the greatest influence on the parallel model and the Hashin-Shtrikman upper boundary model. This paper proposed to determine the meso-component parameters of the elastic modulus prediction model through mesoscopic inversion, studied the correlation between the meso-component volume fraction and the overall elastic modulus of the material, and by adding a correction factor to the correlation, concluded that when the meso-component volume fraction falls between 35% and 55%, the random aggregate model-based prediction and the equivalent theoretical model can better predict the elastic modulus of the CSG. This study may provide theoretical basis for CSG mix design and multi-scale model research.

A homemade 25/400 thulium-doped silica fiber for high power laser and an all-fiber bi-direction pumped thulium-doped master-oscillator power-amplifier (MOPA) configuration with output power of 406 W are presented. The concentration of Tm 2 O 3 and Al 2 O 3 was set as 2.6 wt.% and 1.01 wt.% respectively. Cladding Absorption at 793 nm was measured to be 3 dB/m. The output power of 406 W was obtained by improving coating stripping of splice for thermal management, corresponding to slope efficiency of 54%. The 3 dB spectral linewidth was narrow as 84 pm. Neither amplified spontaneous emission (ASE) nor non-linear effect was observed and the output power only limited by pump power.

Herein, the manganese cobalt sulfide nanoparticles (MnCo2S4 NPs) were successfully prepared by a hydrothermal strategy. The TEM result demonstrates that the size of the MnCo2S4 NPs is approximately 50 nm. The BET results indicate that such MnCo2S4 NPs have a large specific surface area that offers abundant reaction active sites during the electrochemical reaction procedure. Further, we assessed the electrochemical behavior of the MnCo2S4 NPs in a three-electrode system, demonstrating it possesses an excellent electrochemical capacitance of 1150 F g−1 at 1.0 A g−1. Particularly, after 5000 cycles, 88.2% of the initial electrochemical capacitance was maintained, suggesting its extraordinary cycling stability. These outstanding electrochemical properties demonstrate the MnCo2S4 NPs would be an exceptional electrode material for advanced energy storage devices.

In this work, Bi2S3/MoS2/Bi2MoO6 hetero-structured porous films were fabricated via a facile anion exchange process using the as-prepared Bi2MoO6 nanoflake array film as substrate material. The formation of Bi2S3/MoS2/Bi2MoO6 ternary hetero-structured porous film is both thermodynamically controllable and reaction time dependent. Systematic experiments were done to investigate the products at each reaction stage and disclose the relationships between the composite components and reaction temperature and time. The study showed that the energy barrier need to be overpassed when MoS2 and Bi2S3 were simultaneously produced. The optimized Bi2S3/MoS2/Bi2MoO6 photoelectrode exhibited significantly higher photoelectrocatalytic efficiency than Bi2MoO6, binary Bi2S3/Bi2MoO6 and Bi2S3/MoS2 photoelectrodes. The remarkable degradation efficiency of the Bi2S3/MoS2/Bi2MoO6 photoelectrode comes from the synergy of high quality assembly and heterostructure interfaces between the three components. The optimized film assembly and stepwise band alignment in the ternary heterostructure composite contribute to visible light utilization, transport and separation of charge carriers, mass transport, and accessibility of active sites. The generated active species such as superoxide anions (O2-) and holes were detected to promote the decomposition of organic pollutants. The reasonable photoeletrocatalytic degradation mechanism was also proposed.

Ultraviolet (UV) nonlinear optical (NLO) crystals which can produce short-wavelength lasers via a direct second harmonic generation (SHG) process are of great importance in modern laser technology. Currently, the exploration of UV NLO crystals in borosulfates is nearly stagnant since the non-phase matching (PM) property lies on the small birefringence induced by the intrinsically small optical anisotropy of the tetrahedral groups. Herein, for the first time, the planar [BO3 ] units were introduced into borosulfates leading to a boron-rich borosulfate (NH4 )2 B4 SO10 with unprecedented [B4 SO10 ]∞ layers and evidently enhanced birefringence. To the best of our knowledge, it achieves the shortest SHG PM wavelength of 252 nm in all reported borosulfates with deep UV cutoff edge (184 nm), large SHG response (1.1×KDP at 1064 nm and 0.15×β-BBO at 532 nm) and large birefringence (0.053 at 1064 nm) and is easy to grow single crystals via simple chemical vapor deposition method. These results confirm the feasibility of utilizing planar [BO3 ] units to optimize birefringence of borosulfates, and also open up broad prospects for UV NLO crystals in boron-rich borosulfates.

High energy storage composite films were synthesized by solution blending polyimide (PI) and liquid acrylonitrile-butadiene rubber (LNBR). Experimental results showed that the composite films exhibited outstanding mechanical, thermal, and dielectric properties. When the content of LNBR was 5 wt%, the composite films showed remarkable thermal properties, superior tensile strength (106.02 MPa) and tensile modulus (2.57 GPa), high dielectric constant (4.79, 1 kHz), and low dielectric loss (0.0075, 1 kHz). Noticeably, the breakdown strength still remains at a high level (303.59 kV mm−1). In addition, the dielectric constant of the composite films decreased slightly with the increasing frequency. The dielectric loss were less than 0.025 within the testing frequency range. In particular, the composite films exhibited high energy storage density (up to 1.95 J cm−3). This study indicated that the PI/LNBR composite films will be a promising candidate for high energy storage materials.

Herein, MoS2/CdSe/TiO2 ternary composites have been successfully synthesized by a simple approach. The SEM and TEM results demonstrate that MoS2/CdSe/TiO2 ternary composites have a porous structure, which can provide more active sites and mass charge transport pathways in a catalytic system. The optical measurement demonstrates that the MoS2 and CdSe coexisted in the porous TiO2 structure, which results in a wider visible light absorption than that of pure TiO2. Most importantly, the photoelectrochemical measurement results demonstrate that such ternary composite catalysts exhibit a higher photocurrent performance than that of a binary composite and pure TiO2, owing to the strong synergistic effects among MoS2, CdSe, and TiO2. These superior results show that MoS2/CdSe/TiO2 ternary composites is a promising choice for photoelectrochemical water splitting.

In this study, a novel flexible electrode consisting of homogeneous RuO2 nanoparticles (NPs) wrapped around the carbon fiber cloth (CC) is fabricated by combining the cathodic electro-deposition in the aqueous acidic RuCl3·xH2O solution and annealing in air atmosphere. The as-fabricated RuO2 NPs/CC electrode with electro-deposition duration of 10 min demonstrates a superior electrocatalytic activity with a lower overpotential of ca. 1.05 V vs. SCE and its current density reaches up to 175 mA cm−2 at 1.2 V vs. SCE for chlorine evolution reaction (CER) in 5.0 M NaCl aqueous solution, outperforming many of the reported counterparts. The as-revealed outstanding electrocatalytic activity should be attributed to several beneficial factors such as its typical integrated binder-free 3D architecture, higher usage efficiency of active RuO2 NPs, greatly decreased interfacial resistance, etc. This work paves a way to utilize the carbon fiber cloth decorated with active noble metal oxides for boosting electrochemical Cl2 production.

Copper-based chalcogenides have been paid intensive attention as alternate photothermal catalysts for solar energy conversion. Despite considerable progress of copper sulfides nanostructure fabrication, combining independent copper sulfides polymorphs with various stoichiometries by forming heterojunction is still challenging. Herein, unique hierarchical nanosheet-assembled Cu7S4-Cu9S8 heterostructure hollow cubes with remarkable photothermal aerobic oxidation activity were prepared by a facile onepot chemical transformation route using Cu2O cubes as sacrificial template for the first time. In this reaction system, the introduction of proper sulfur source thioacetamide and moderate alkaline conditions plays a crucial role in phase transformation, and through tunning the reaction time, a series of Cu7S4, Cu7S4-Cu9S8, and Cu9S8 can be selectively prepared. Furthermore, the Cu7S4-Cu9S8 polymorphic heterostructure hollow cubes exhibit significantly enhanced photothermal aerobic oxidation performance of amines to the corresponding imines compared with the individual Cu7S4 and Cu9S8 in both N, N-dimethylformamide and acetonitrile solvent medium. Our results indicated that the strong near-infrared plasmonic absorption of Cu7S4-Cu9S8 facilitated hot carrier transport between Cu7S4 and Cu9S8, which subsequently promoted the catalytic reactions. Especially after uniform load of Au-Pt alloy nanoparticles, the photothermal aerobic oxidation activity was further enhanced due to their boosted synergistic local coupling enhancement effect between distinct components in the N, N-dimethylformamide solvent medium. Such enhanced photothermal reaction could effectively promote sunlight utilization in a wide range of photocatalytic reactions.

We report a successful fabrication of low-cost, high-efficient, structurally-rigid, porous WO3 photoelectrochemical (PEC) catalysts using polystyrene as the template by a sol-gel method and a high-temperature annealing treatment. The scanning electron microscopy and Brunauer-Emmett-Teller surface analysis results indicate that such WO3 monoliths possess a porous structure and a large specific surface area, which can supply lots of photogenerated charge transfer pathways as well as more surface PEC active sites. Compared with a commercially available WO3, our highly porous WO3 PEC catalysts show an excellent PEC water splitting activity. Particularly, the porous WO3 photoanodes calcinated in the presence of oxygen atmosphere at 450 °C for 7 h show the best PEC performance exhibiting the photocurrent density of 0.97 mA/cm2 at 1.23 V versus reversible the hydrogen electrode and the incident photon-to-current conversion efficiency up to 48.9% at 420 nm in 0.5 M Na2SO4 electrolyte under AM 1.5 G irradiation. Such excellent PEC performance is due to the high porosity of the WO3, promoting the fast transfer and the separation rate of photogenerated carriers during the PEC water splitting process.

The Pd ZnO/C catalytic material for ethanol oxidation reaction is prepared by microwave heating-glycol reduction method. Pd ZnO is well polymerized and dispersed on XC72. The results demonstrate that Pd ZnO/C has better electro catalytic activity and stability for ethanol oxidation reaction than Pd/C at room temperature. ZnO/C shows no catalysis for ethanol oxidation. The oxidation peak potential of Pd ZnO/C electrode is shifted negatively to 0.21 V. The current density of Pd ZnO/C electrode is 145 mA cm−2, while that of the Pd/C electrode is 60 mA cm−2. Moreover, single cell discharge test shows that discharge voltage of the Pd ZnO/C electrode reaches to 0.41 V at 30 mA cm−2. In summary, ZnO as a co-catalyst significantly improves the activity of Pd ZnO/C catalyst for ethanol oxidation reaction.

Rational architectural design and catalyst components are beneficial to improve the photoelectrochemical (PEC) performance. Herein, hierarchical SnS2/CuInS2 nanosheet heterostructure porous films were fabricated and decorated with C60 to form photocathodes for PEC water reduction. Large-size CuInS2 nanosheet films were first grown on transparent conducting glass to form substrate films. Then, small-size SnS2 nanosheets were epitaxially grown on both sides of the CuInS2 nanosheets to form uniform hierarchical porous laminar films. The addition of C60 on the surface of the SnS2/CuInS2 porous nanosheets effectively increased visible light absorption of the composite photocathode. Photoluminescence spectroscopy and impedance spectroscopy analyses indicated that the formation of a SnS2/CuInS2 heterojunction and decoration of C60 significantly increased the photocurrent density by promoting the electron-hole separation and decreasing the resistance to the transport of charge carriers. The hierarchical SnS2/CuInS2 nanosheet heterostructure porous films containing multiscale nanosheets and pore configurations can enlarge the surface area and enhance visible light utilization. These beneficial factors make the optimized C60-decorated SnS2/CuInS2 photocathode exhibit much higher photocathodic current (4.51 mA cm-2 at applied potential -0.45 V vs reversible hydrogen electrode ) and stability than the individual CuInS2 (2.58 mA cm-2) and SnS2 (1.92 mA cm-2) nanosheet film photocathodes. This study not only reveals the promise of C60-decorated hierarchical SnS2/CuInS2 nanosheet heterostructure porous film photocathodes for efficient solar energy harvesting and conversion but also provides rational guidelines in designing high-efficiency photoelectrodes from earth-abundant and low-cost materials allowing widely practical applications.

Although homoepitaxial growth of multiple 4H-SiC wafers in one run can be realized in commercial specialized chemical vapor deposition equipment, wafers must be loaded onto a rotatable large susceptor and overspread on it, which leads to the diameter of the susceptor increases as the number or the total area of the epitaxial wafer increases. in this work, we demonstrated a facile method for growth of multiple 4H-SiC wafers assembled in a simple holder via a home-made single-wafer conventional chemical vapor deposition equipment without a large susceptor. The structural properties of the obtained 4H-SiC films on each wafer were investigated by means of optical microscope, AFM, SEM and Raman. Results showed that high quality of homogeneous 4H-SiC film was epitaxially grown on the inner region of each wafer, while on the outer region, influenced by the mechanical parts of the simple holder, the quality was degraded. At last we draw a prospective on homoepitaxial growth of whole wafer through further reducing the adverse outer region via advanced holder and wafer assembly, which could greatly improve production efficiency and reduce energy consumption.

Foreign atom doping is known to not only modify the electronic structure but also improve the intrinsic activity of catalysts. Herein, we fabricate three-dimensional (3D) self-supporting nanoporous cobalt–aluminum intermetallic (np-Co(Al)) through dealloying of Al90Co10 master alloy to in situ introduce Al element into the precursor. The intrinsic Al dopant is determined to be insensitive to S vapor but beneficial to generate numerous Al-doped CoS2 nanowires (Al-CoS2 NWs) when they were subjected to solid–vapor sulfurization treatment. The density functional theory (DFT) calculations evidence that spontaneous Al-doping in CoS2 crystal could enhance the hybridization between Co d-orbital and S p-orbital near the Fermi level. On the one hand, the Co-sites are more active than that of the S-sites, and the intermediate hydrogen (H*) adsorption free energy (ΔGH*) of Al-CoS2 is only −0.16 eV when adsorbed on the bridge site of Co. On the other hand, the embedded Al can not only facilitate the activity improveme...

A new class of aggregation-induced emission (AIE) fluorophores HAPHs with excellent two-photon properties is developed from styrylquinoline. Among them, the probe HAPH-1 exhibits good sensitivity towards pH and viscosity and has been successfully used for simultaneous pH and viscosity detection in living cells through two-photon microscopy.

A new tin borate fluoride Sn2B7O12F has been successfully synthesized by the high-temperature solution method in a closed system. It crystallizes in the monoclinic space group C2/c. The structure features a new fundamental building block (FBB) [B7O16]11−, which further condenses to an infinite 2∞[B14O24]6− layer extended in the ab plane. The adjacent layers are bridged by the unique isolated [Sn4O12F2]18− clusters, which are constructed from two [Sn2O7F]11− polyhedra sharing a common edge. First-principles calculations have shown that the birefringence of Sn2B7O12F is about 0.07@1064 nm, which originated from the the synergistic contributions of the B–O and Sn–O/F interactions.

A new barium fluorooxoborate, BaB5O8F·xH2O (x ≈ 0.17), with two interesting independent three-dimensional B–O/F frameworks has been synthesized by a solid-state reaction in a closed system. Compared with the lead fluorooxoborate PbB5O8F, BaB5O8F·xH2O exhibits a comparable birefringence and a wider UV transparency window.

A new complex alkaline-earth metal borosilicate chloride Ba3Ca4(BO3)3(SiO4)Cl has been successfully synthesized by the high-temperature solution method. It crystallizes in the space group P63mc (no. 186) of the hexagonal system. Its structure features a 3∞[Ca4(BO3)3(SiO4)] framework formed by interconnected 1∞[Ca4(BO3)3(SiO4)O9] chains with large octagonal star-like channels, in which the 1∞[Ba3Cl] chains are located. The second harmonic generation (SHG) measurement shows that Ba3Ca4(BO3)3(SiO4)Cl has an SHG of about 0.6 times that of KH2PO4 and it is phase matchable. In addition, it melts congruently and exhibits a wide transparent range with the UV cut-off edge below 190 nm. All the above indicates that Ba3Ca4(BO3)3(SiO4)Cl could be regarded as a potential ultraviolet nonlinear optical material.

We present process optimization for rapid homoepitaxial growth of thick 4H-SiC films on 4° off-cut substrates via hydrogen chloride chemical vapor deposition (HCVD). The gas used is a mixture of HCl additive, SiH4, C2H4 and H2. After characterization of the 4H-SiC films using Nomarski, AFM, Raman and XRD, we investigate the effect of HCl additive, Cl/Si ratio, on the quality of the epitaxial film and the growth rate. With the optimized chlorine based method HCVD, the 4H-SiC epitaxial growth rate was up to 52 μm/h in a home-made vertical hot-wall HCVD system. At a steady growth rate of 46 μm/h, a 4H-SiC epitaxial film with a thickness of 100 μm was obtained. The epitaxial films were of homogeneous 4H polytype, with a maximum root mean square roughness (RMS) of 1.3 nm.

To study power performance of large displacement UUV with solid oxy-hydrogen energy propulsion, a design solution of solid oxy-hydrogen power system is finished. Firstly, by using GA algorithm, structural optimization study for stream turbine is finished with maximizing inner efficiency in design condition, which matches the propulsion power requirements of the large displacement UUV. Secondly, the method of underwater rapid and controllable hydrogen and oxygen generation is designed, and whose mass flow is obtained according to the principle of minimum Gibbs free energy and Hess law. At last, calculations of cruising ability for large displacement UUV with solid oxyhydrogen energy propulsion is finished. Results show that solid oxy-hydrogen energy has doubly increased cruising ability and long-distance distribution ability for large displacement UUV. The scheme in this paper provides a new solution for the remote propulsion of large displacement UUV.

Ni, Co, Mn doped SnS2-graphene aerogel (M-SnS2-GA) supercapacitor materials were synthesized by solvothermal method using metal chlorides and thioacetamide as precursors. The obtained samples formed complex 3D network structures of 2D nanosheets-graphene aerogels as the scanning electron microscopy images indicated. According to the electrochemical tests, the existence of graphene aerogel and doped metal ions fundamentally improved the electrochemical performance of SnS2. Mn-SnS2-GA exhibited the highest specific capacitance among them (523.51 F g−1 at the scan rate of 5 mV s−1), which is almost three times as high as that of SnS2 (171.56 F g−1). Meanwhile, Mn-SnS2-GA also showed excellent stability in cycling test (98.57% retention after 2000 cycles at 10 A/g). The effects of the structure and doping on the performance of the composites were deeply investigated. In addition, a symmetric supercapacitor device was also assembled and tested to confirm the application prospects.

Here, we demonstrate the synthesis of sheet-shaped Co2P grown on carbon cloth (sheet-shaped Co2P-CC) through a facile route. Electrochemical measurements indicated that sheet-shaped Co2P-CC with a loading of 0.6 mg cm−2 Co2P (denoted Co2P-CC-0.6) exhibits exceptional electrocatalytic activity in the hydrogen evolution reaction (HER), with an overpotential of 94 mV at a current density of 10 mA cm−2 and a small Tafel slope of 80 mV decade−1 in 1 M KOH. Similarly, sheet-shaped Co2P-CC-0.6 was also found to be an excellent electrocatalyst for the HER in 0.5 M H2SO4 and in 0.5 M phosphate buffer solution (PBS), with overpotentials of 95 and 231 mV at a current density of 10 mA cm−2, respectively. Sheet-shaped Co2P has a large surface area, meaning that it can provide a relatively large number of active sites on its surface, and CC is an highly conductive substrate that, when used in conjunction with Co2P, can enhance the conductivity of the electrocatalyst. These outstanding results show that sheet-shaped Co2P-CC could be an excellent candidate for a highly efficient electrocatalyst.

It is well known that both catalytic efficiency and stability are the two important parameters of photocatalysts for visible-light-driven hydrogen production reactions. However, light-driven hydrogen evolution based applications still suffer from sluggish reaction kinetics due to the lack of high-performance photocatalysts. In this paper, we successfully synthesized a ternary porous CdS/WO3/TiO2 photocatalyst with high efficiency and stability via two-stage approach. The as-prepared samples are characterized by XRD, FESEM, EDS, TEM, XPS, and UV–Vis, respectively, which illustrated that the CdS and WO3 moieties are in-situ formed inside the porous TiO2. Particularly, the photocatalytic hydrogen (H2) evolution rate of such ternary 8% CdS/WO3/TiO2 (molar ration of CdS:WO3:TiO2 = 8:8:100) photocatalyst ranges up to 2106 μmol h−1 g−1 under visible-light irradiation, which is higher than that of pure TiO2 and other binary (CdS/TiO2 and WO3/TiO2) porous photocatalysts. The superior H2 evolution efficiency can be attributed to the coexistence of CdS and WO3 in porous TiO2 which can promote the interfacial charge transfer and separation as well as extend the light absorption up to the visible range.

As a most promising anode candidate, silicon has the shortcomings of low electron conductivity and high volume expansion of 300%, hindering its applications in lithium ion batteries (LIBs). In this study, one-dimension porous silicon nanowires (pSi-NWs) were prepared through a simple metal-assisted chemical etching process by using metallurgical silicon as raw material. To consolidate the structural integrity of pSi-NWs, a crossed carbon skeleton (c-Cs) was introduced into pSi-NWs via in-situ polymerization and carbonization process. The resultant pSi-NWs@c-Cs composite delivered the high capacity of 1253 mAh g−1 with good cycling stability as well as the notable rate capability (476 mAh g−1 at 4 A g−1), much superior to those of pSi-NWs and pSi-NWs@reduced graphene oxide composite. The enhanced electrochemical performance of pSi-NWs@c-Cs composite is attributed to the crossed carbon skeleton in constructing the advanced Si/C interface to more effectively improve the electron conductivity of pSi-NWs and acting as the protective shell to keep the structure integrity of pSi-NWs. As the additive of commercial graphite anode, 28% of capacity augment (460 mAh g−1 at 0.2 A g−1) was realized by adding 20 wt% of pSi-NWs@c-Cs composite into graphite, demonstrating its promising applications in LIBs.

A novel proton conductor has been designed by the surface immobilization of protonated polyimidazolium monolayer on titanate nanotubes (TiNTs) through a polymer brush strategy. 2,2′-Azobis(2-methylpropionitrile) (AIBN)-type initiators are first attached to TiNTs followed by a free radical polymerization of protonated 1-vinylimidazole (VyImBF4) on the surface. The chemical structure of the resulting poly(VyImBF4)-modified TiNTs is verified by Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS). TGA curve indicates their good thermal stability. The maximum proton conductivity achieves 6.74 × 10−4 S cm−1 at 200 °C under dry condition and 3.60 × 10−2 S cm−1 at 120 °C under 100% humidity, respectively, when the polymerization is carried out under a polymerization time of 3 h and an immobilized initiator concentration of approximately 42.4 mmol L−1. The proposed preparation of poly(VyImBF4)-modified TiNTs would give a new idea for the design of other ion conductors.

Efficient production of hydrogen through visible-light-driven water splitting mechanism using semiconductor-based composites has been identified as a promising strategy for converting light into clean H2 fuel. However, researchers are facing lots of challenges such as light absorption and electron-hole pair recombination and so on. Here, new sheet-shaped MoS2 and pyramid-shaped CdS in-situ co-grown on porous TiO2 photocatalysts (MoS2 CdS TiO2) are successfully obtained via mild sulfuration of MoO3 and CdO coexisted inside porous TiO2 monolith by a hydrothermal route. The scanning electron microscopy and transmission electron microscopy results exhibit that the MoS2 CdS TiO2 composites have average pore size about 500 nm. The 3%MoS2 10%CdS TiO2 demonstrated excellent photocatalytic activity and high stability for a hydrogen production with a high H2-generation rate of 4146 μmol h−1 g−1 under visible light irradiation even without noble-metal co-catalysts. The super photocatalytic performance of the visible-light-driven hydrogen evolution is predominantly attributed to the synergistic effect. The conduction band of MoS2 facilitates in transporting excited electrons from visible-light on CdS to the porous TiO2 for catalytic hydrogen production, and holes to MoS2 for inhibiting the photocorrosion of CdS, respectively, leading to enhancing the efficient separation of electrons and holes.

Photoelectrochemical (PEC) water splitting using high-performance catalysts shows considerable promise in generating environment-friendly hydrogen energy. Its practical applications, however, suffer from several shortcomings, such as low photocurrent density, large onset-voltage value, and poor durability. In this study, CuS and CdS quantum-dot-cosensitized porous TiO 2 -based PEC catalysts (CuS-CT) have been successfully synthesized via in situ sulfuration of CuO and CdO coexisting inside a porous TiO 2 monolith by a hydrothermal method. Compared to porous TiO 2 , CuS-sensitized porous TiO 2 (CuS-TiO 2 ), and CdS-sensitized porous TiO 2 (CdS-TiO 2 ) in terms of PEC performance, the CuS-CT photoanode exhibited a significantly high anodic photocurrent for water splitting under simulated sunlight radiation. The photocurrent produced by the optimized sample of 7% CuS-5% CdS-TiO 2 (7% CuS-CT) was nearly 2.7 times higher than that of pure porous TiO 2 at 1.0 V versus a reversible hydrogen electrode (RHE). Porous TiO 2 possesses large surface areas that can drive fast electrolyte transport and afford more surface reaction active sites. On the other hand, CuS and CdS quantum dots not only broaden the visible light absorption range, but also improve photoinduced electron-hole separation efficiency. The co-sensitized multi-nanostructures photoanodes lead to a remarkable and promising application in PEC water splitting reactions.

Two new rare-earth borates, MBaYB6O12 (M = Rb, Cs), which are the first reported compounds in M2O-BaO-RE2O3-B2O3 (M = Rb, Cs; RE = rare-earth) quaternary systems, have been discovered through a high-temperature solution method and their structures were determined by single-crystal X-ray diffraction. These two compounds are isostructural with the centrosymmetric space group R (no. 148) and the fundamental building blocks are the B3O6 groups which are nearly parallel to each other. The spectral measurement shows that the cutoff edges of the two compounds are all down to the deep-ultraviolet (deep-UV) region (below 200 nm). And the experimental birefringence of RbBaYB6O12 and RbBaYB6O12 is about 0.12 at 589 nm. Moreover, first-principles theoretical studies were carried out to gain a better understanding of the structure–property relationships. The calculation results demonstrate that both the compounds have a large birefringence of 0.100 at 589 nm, which corresponds to the experimental value. Both experimental and theoretical studies suggest that MBaYB6O12 (M = Rb, Cs) are potential birefringent materials for UV and deep-UV applications.

NixOy (NiO, Ni2O3) nanoparticles modifies titanium dioxide nanosheet (T) via one-step hydrothermal method, and then bis (vinyl)-hexa (trimethoxyethyl)-polysilsesquioxane (BH-POSS) is distributed on NixOy -T (NT) by utilizing hydrolysis condensation reaction procedure. Thus, BH-POSS/NixOy -T (PNT) is successfully obtained which exhibits boosted absorption ability and enhanced visible light photocatalytic efficiency. Above all, the maximum adsorption capacity (qm) of PNT is up to 848.458 mg/g for crystal violet (CV) within 5 min estimated by Langmuir adsorption model which is 18.7-fold larger as compared to T. Under visible light, the optimal PNT achieves the highest degradation rate constant value (Kapp) for rhodamine B (RhB) of 0.0150 min−1, which is 2.4-fold higher than that of NT. In addition, the present work may help us gain deeper insight into the synergistic effect between the BH-POSS that has larger absorption and NT heterojunction that accelerates electrons-holes separation and provide us with a new design route to make PNT considered as a promising material.

The fabrication of flexible and high-output triboelectric nanogenerators (TENGs) based on low-cost inorganic functional materials has been receiving increasing attention. In this study, sub-10 nm ZnS/ZnO nanoflakes (ZnSO NFs) were successfully synthesized using a facile method and subsequently combined with polydimethylsiloxane (PDMS) as a triboelectric layer material for the flexible TENGs (FTENGs). The prepared PDMS/ZnSO NFs-based FTENGs presented a remarkable output power density (~2.95 mW cm−2) and excellent flexibility (the output power density retained ~82% of its initial value after 2000 bending cycles). Moreover, when a 2 × 2 cm2 PDMS/ZnSO NFs-based FTENG was subjected to a force applied by a human fist, it powered 70 LEDs, which confirms that the ultra-thin ZnSO NFs we developed are promising candidates for high-output FTENGs.

Design and fabrication of bifunctional nanomaterials for energy conversion and storage systems have been receiving great attention. In this report, hollow NiTe2 nanotubes were efficiently synthesized utilizing a hydrothermal reaction route, and were subsequently employed as bifunctional materials for hydrogen evolution reaction (HER) and supercapacitors (SCs). The unique hollow structure can't only supply large surface area and abundant ions transport channels, but also shorten the ions transfer pathways between electrode and electrolyte. Furthermore, the rich defects and Te ions also improve the electrochemical performances to some extent. The electrochemical measurement results show the superior electrocatalytic activity of hollow NiTe2 nanotubes for HER (85 mV under 10 mA cm−2) and electrochemical capacitance for SCs (566 F g−1 @ 1.5 A g−1). Additionally, the hollow NiTe2 nanotubes-based electrodes present excellent electrochemical stabilities in HER and SCs, respectively. Our findings demonstrate that the hollow NiTe2 nanotubes should be good candidates as bifunctional materials for HER and SCs.

Internal curing has been widely used in high-strength concrete because it can replenish water for cement hydration and reduce self-shrinkage. The internal curing effects mostly depend on the self-shrinkage changes and mechanical parameters obtained through a destructive test. This research proposes a fast and nondestructive detection method based on image recognition analysis to determine the effects of internal curing material content on the performance of high-strength concrete. The superabsorbent polymer (SAP) was chosen as the internal curing material. Laboratory uniaxial compression tests, scanning electron microscopy (SEM), and energy dispersive spectroscopy were used to analyze the mechanical properties and phase characteristics of the concrete. Based on the SEM images, the gray level co-occurrence matrix was used to extract texture features of the concrete, and effective SEM image samples were screened out to verify the correlation between texture features and mechanical strength. The results showed that: (1) the four characteristic values of GLCM have a significant linear correlation with SAP content; (2) with the increase in SAP content, self-shrinkage decreases and reaches the smallest point when the SAP content is 0.24 % of the cementing material content; and (3) the relative dynamic modulus of elasticity and maximum shrinkage are negatively correlated with the energy and correlation and positively correlated with the contrast and entropy. Such results provide a simple method of determining the influence of internal curing content on concrete performance.

The discovery of new nonlinear optical (NLO) materials for coherent light generation in the deep-ultraviolet (DUV, wavelength below 200 nm) region is essential for the development of laser technologies. Herein, we report a new material CsB4O6F (CBF), which combines the superior structural properties of two well-known NLO materials, beta-BaB2O4 (BBO) and KBe2BO3F2 (KBBF). CBF exhibits excellent DUV optical properties including a short cutoff edge (155 nm), a large SHG response (approximate to 1.9 X KDP), and a suitable birefringence that enables frequency doubling down to 171.6 nm. Remarkably, CBF melts congruently and shows an improved growth habit. In addition, our rational design strategy will contribute to the discovery of DUV NLO materials.

A hybrid cured resin with excellent dielectric and thermal properties was prepared with bismaleimide–triazine (BT) resin modified with 2,2′-diallylbisphenol A (DBA). The thermal and dielectric properties of the resin were investigated, and the effect of DBA concentration on the curing reaction was determined. Results indicated that DBA significantly influenced the curing reaction and the properties of the cured product. The modified BT resins exhibited outstanding thermal stability (initial decomposition temperature was over 400°C), although the stability was slightly lower than that of pure BT resins. The dielectric constant and dielectric loss of the cured resin decreased when DBA was introduced into the BT resins. Moreover, the fabricated resins showed dielectric constant of 2.91–3.07 and dielectric loss lower than 0.0057 under the testing high-frequency range of 1 GHz to 15 GHz. Overall, the BT resins modified by DBA display great potential to be applied in high frequency field.

Deep-ultraviolet nonlinear optical (DUV NLO) crystals are the key materials to extend the output range of solid-state lasers to below 200 nm. The only practical material KBe2BO3F2 suffers high toxicity through beryllium and strong layered growth. Herein, we propose a beryllium-free material design and synthesis strategy for DUV NLO materials. Introducing the (BO3F)(4-),(BO2F2)(3-), and (BOF3)(2-) groups in borates could break through the fixed 3DB-O network that would produce a larger birefringence without layering and simultaneously keep a short cutoff edge down to DUV. The theoretical and experimental studies on a series of fluorooxoborates confirm this strategy. Li2B6O9F2 is identified as aDUV NLO material with a large second harmonic generation efficiency (0.9 x KDP) and a large predicted birefringence (0.07) without layering. This study provides a feasible way to break down the DUV wall for NLO materials.

A new rare-earth borate LiRb2LaB2O6 (LB-1) has been synthesized using a high-temperature solution method. Interestingly, it shares its topological structure with the famous porous material MOF-5, which is formed from Zn4O(BDC)3 (BDC = 1,4-benzenedicarboxylate). The nodes [OZn4] and organic linkers [BDC] of MOF-5 are carefully substituted with La3+ rare-earth cations and the inorganic linkers [BO3] and [LiO4], respectively, in order to construct a pure inorganic open framework. LB-1 exhibits good thermal and water stability. Moreover, it possesses a short cut-off edge (

Two new acentric polyborates, Ba3(OH)(B9O16)[B(OH)3] and Ba2.16Pb0.84(OH)(B9O16)[B(OH)3] have been synthesized hydrothermally and their structures have been determined by single-crystal X-ray diffraction. Both crystals are isostructural and crystallize in the trigonal space group P31c (no. 159). Their structures feature a three-dimensional (3D) B9O19 framework with 6-membered-ring tunnels, in which the Ba or Pb/Ba cations and [B(OH)3] groups reside. Powder second-harmonic-generation (SHG) measurements reveal that Ba3(OH)(B9O16)[B(OH)3] and Ba2.16Pb0.84(OH)(B9O16)[B(OH)3] are type-I phase-matchable, with SHG responses of 1.1× and 1.2× KH2PO4, respectively. UV-Vis-NIR diffuse reflectance analysis indicates that Ba3(OH)(B9O16)[B(OH)3] and Pb0.29Ba2.71(OH)(B9O16)[B(OH)3] have band gaps of 5.11 and 4.65 eV, respectively. In addition, first-principles calculations were employed to elucidate the origin of the NLO properties and the relationship of structure–properties.