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The loading strategy of cocatalysts affects its activity exerting and atom utilization. Here, a novel strategy for loading precious metal (Pt) cocatalysts by means of ultrathin N-doped carbon layer is reported. The strategy is based on a pyrolysis process of predesigned N-containing polymers and Pt complexes on hard-template surface, during which Pt can be reduced by carbon from pyrolysis at high temperatures. Finally, the hollow TiO2 composite with stable and dispersed Pt on its inner surface was prepared. It shows an ultrahigh photocatalytic H2 production activity as high as 25.7 mmol h−1 g−1 with methanol as sacrificial regent, and displays an apparent quantum yield as 13.2%. The improved photocatalytic activity and stability can be attributed to the highly dispersed and ultrafine Pt nanoparticles, enhanced interaction between Pt-species and carbon support, fast photo-excited electron transport from the high graphitization degree of NC layers, ample oxygen vacancies/defects, as well as the manipulated local charge distribution of Pt/NC-layer configuration. Additionally, the universality of the proposed strategy was demonstrated by replacing metal sources (such as, Ru and Pd). This work presented a promising strategy for the design and development of novel photocatalysts, which shows a broad application prospect.

Multi-functionalization is the future development direction for protective coatings on metal surface, but has not yet been explored a lot. The effective integration of multiple functions into one material remains a huge challenge. Herein, a superhydrophobic multilayer coating integrated with multidimensional organic-inorganic components is designed on magnesium alloy via one-step plasma-induced thermal field assisted crosslinking deposition (PTCD) processing followed by after-thermal modification. Hard porous MgO ceramic layer and polytetrafluoroethylene (PTFE) nano-particles work as the bottom layer skeleton and filler components separately, forming an organic-inorganic multilayer structure, in which organic nano-particles can be crosslinked and cured to form a compact polymer-like outer layer with hierarchical surface textures. Remarkably, the chemical robustness after prolonged exposure to aqua regia, strong base and simulated seawater solution profits from polymer-like nanocomposite layer uniformly and compactly across the film bulk. Moreover, the self-similar multilayer structure coating endows it attractive functions of strong mechanical robustness (>100th cyclic rotary abrasion), stable and ultra-low friction coefficient (about 0.084), high-temperature endurance, and robust self-cleaning. The organic-inorganic multilayer coating also exhibits high insulating property with breakdown voltage of 1351.8 ± 42.4 V, dielectric strength of 21.4 ± 0.7 V/µm and resistivity of 3.2 × 1010 Ω·cm. The excellent multifunction benefits from ceramic bottom skeleton, the assembly and deposition of multidimensional nano-particles, and the synergistic effect of organic inorganic components. This study paves the way for designing next generation protective coating on magnesium alloy with great potential for multifunctional applications.

Semiconductor electrocatalysis with weak conductivity can accumulate extremely high carriers at semiconductor-electrolyte interface by self-gating effect, which strongly promotes electrocatalytic efficiency. The correlation between semiconductor carrier mobility and electrocatalysis performance is still unclear. Herein atomic-thin transition metal dichalcogenides based composites have been developed for hydrogen evolution reaction (HER) performed with on-chip microdevices. Electrical and electrochemical measurement of individual flack verified the key role of high carrier mobility for enhanced HER activity. Carrier mobility regulation further demonstrated its high dependence with HER performance under self-gating. Our study provides new insight into the carrier mobility of the semiconductor in the electrocatalysis, paving the way for designing high-performance semiconductor catalysts.

The complex micromechanical response among grains remains a persistent challenge to understand the deformation mechanism of titanium alloys during cold rolling. Therefore, in this work, a multiscale crystal plasticity finite element method of dual-phase alloy was proposed and secondarily developed based on LS-DYNA software. Afterward, the texture evolution and slip mode of a Ti-5.5Mo-7.2Al-4.5Zr-2.6Sn-2.1Cr alloy, based on the realistic 3D microstructure, during cold rolling (20% thickness reduction) were systematically investigated. The relative activity of the 2 ¯ 0>{0001} slip system in the α phase gradually increased, and then served as the main slip mode at lower Schmid factor ( 2 ¯ 3>{10 1 ¯ 1} slip system to the overall plastic deformation was relatively limited. For the β phase, the relative activity of the {110} slip system showed an upward tendency, indicating the important role of the critical resolved shear stress relationship in the relative activity evolutions. Furthermore, the abnormally high strain of very few β grains was found, which was attributed to their severe rotations compelled by the neighboring pre-deformed α grains. The calculated pole figures, rotation axes, and compelled rotation behavior exhibited good agreement to the experimental results.

The study of Frequency Selective Surface (FSS) by Direct ink writing (DIW) has attracted much attention due to the convenience and effectiveness of 3D printing technology. However, the limited printing precision of DIW has heavily restricted its applications as the electromagnetic performance is highly sensitive to it, especially the precision at the microscale. Herein, the ultra-high printing precision of FSS was achieved through DIW by the uniformly dispersed graphene sheets to deeply modify the rheological behavior and the steric hindrance effect. Thus, the highly precision of the printed filament width as thin as 67 μm with a space of only 42 μm were achieved, which is difficult for conventional DIW, and no structural distortion is found after 3D printing, no matter it was 2D printed on a flat surface or the sharply skewed hook face, or even 3D printed to architectural structures. According to the highly improved precision, the electromagnetic performance matching between the designed model and the printed physical FSS device was perfectly achieved, reducing the center frequency error less than 0.3 GHz, and the transmission coefficient error less than 0.046. Our work promises an effective and easy preparation of high-quality FSS from the aid of graphene.

The grain growth kinetics and densification mechanism of (TiZrHfVNbTa)C high-entropy carbide ceramic are investigated in this work. A single phase carbide with a rock-salt structure is formed until 2300 °C, below which an apparent aggregation of V, Zr and Hf exists. It is associated with the slow diffusion rate of V element as well as the relatively poor solubility of VC in HfC (as well as ZrC). The grain growth mechanism gradually changes from surface diffusion to volume diffusion and then grain boundary diffusion with increasing sintering temperature. This is attributed to the variation of activation energy of grain growth. The densification mechanism is principally dominated by the mass transport through lattice diffusion with the activation energy of 839 ± 53 kJ/mol. Through the design of two-step sintering, it is verified that the solid solution formation can effectively promote the densification process.

Several Ni-W-P-TiO2 nanocomposite coatings were developed by the sol-enhanced electroplating method. The phase and elemental compositions of coatings were determined, and the surface and cross-section morphology were characterized. The mechanical and corrosion performance were systematically tested. The results revealed the addition of 5 ml·L−1 TiO2 sol caused a compact coating surface, while higher concentrations of TiO2 reduced the coating thickness and led to the inferior surface microstructure. The comparison in physiochemical properties of prepared coatings confirmed the superior performance of the Ni-W-P-TiO2 nanocomposite coating at 5 ml·L−1 TiO2 sol addition. Under this condition, the best mechanical properties were achieved when abrasive wear was the dominating wear-resistance mechanism, and the best corrosion resistance was obtained due to its smooth and compact surface microstructure.

Solvothermal synthesis technique is an effective method to create composite materials. In this paper, a series of TiO2@MIL-101(Cr) were prepared by the solvothermal method for photocatalytic denitrification of pyridine in fuel under visible light irradiation. The products were characterized by XRD, FT-IR, SEM, TEM, BET, DRS, and ESR. The result shows that 20%TiO2@MIL-101(Cr) has high catalytic activity, the pyridine removal efficiency reaches values as high as 70% after irradiation for 240 min. Finally, we obtained the possible mechanism of photocatalytic denitrification according to the HPLC-MS spectrometry results analysis.

Textured hexagonal boron nitride (h-BN) matrix composite ceramics were prepared by hot-pressing using different contents of 3Y2O3−5Al2O3 (molar ratio of 3:5) as the sintering additive. During hot-pressing, the liquid Y3Al5O12 (YAG) phase showing good wettability to h-BN grains was in situ formed through the reaction between Y2O3 and Al2O3, and a coherent relationship between h-BN and YAG was observed with $${\left[ {010} \right]_{{\rm{h}} - {\rm{BN}}}}{\rm{//}}{\left[ {111} \right]_{{\rm{YAG}}}}$$ [ 010 ] h − BN // [ 111 ] YAG and (002)h-BN//(321)YAG. In the YAG liquid phase environment formed during hot-pressing, plate-like h-BN grains were rotated under the uniaxial sintering pressure and preferentially oriented with their basal surfaces perpendicular to the sintering pressure direction, forming textured microstructures with the c-axis of h-BN grains oriented parallel to the sintering pressure direction, which give these composite ceramics anisotropy in their mechanical and thermal properties. The highest texture degree was found in the specimen with 30 wt% YAG, which also possesses the highest anisotropy degree in thermal conductivity. The aggregation of YAG phase was observed in the specimen with 40 wt% YAG, which resulted in the buckling of h-BN plates and significantly reduced the texture degree.

A series of (Ti0.5Nb0.5)C-x wt.% SiC (x = 0, 5, 10, 20) composites were prepared by spark plasma sintering. Dense microstructures with well‐dispersed SiC particles were obtained for all composites. With the increment of SiC content, the Vickers hardness, Young's modulus and fracture toughness increase monotonically. An optimized flexural strength of 706 MPa was achieved in (Ti0.5Nb0.5)C-5 wt.%SiC composite. (Ti0.5Nb0.5)C-20 wt%SiC composite exhibits the highest fracture toughness of 6.8 MPa m1/2. The crack deflections and the suppression of grain growth were the main strengthening and toughening mechanisms. Besides, (Ti0.5Nb0.5)C-20 wt%SiC composite exhibit the highest thermal conductivity of 45 W/m·K at 800 °C.

Heteroatom-doped carbon materials have demonstrated great potential in the electrochemical reduction reaction of CO2 (CO2RR) due to their versatile structure and function. However, rational structure control remains one challenge. In this work, we reported a unique carbon precursor of soft template-containing porous poly(ionic liquid) (PIL) that was directly synthesized via free-radical self-polymerization of ionic liquid monomer in a soft template route. Variation of the carbonization temperature in a direct pyrolysis process without any additive yielded a series of carbon materials with facile adjustable textural properties and N species. Significantly, the integration of soft-template in the PIL precursor led to the formation of hierarchical porous carbon material with a higher surface area and larger pore size than that from the template-free precursor. In CO2RR to CO, the champion catalyst gave a Faraday efficiency of 83.0% and a current density of 1.79 mA cm−2 at −0.9 V vs. reversible hydrogen electrode (vs. RHE). The abundant graphite N species and hierarchical pore structure, especially the unique hierarchical small-/ultra-micropores were revealed to enable better CO2RR performance.

We propose and demonstrate a single fiber optical tweezer for particle multi-dimensional arrangement based on a high-order Bessel-like beam produced by concatenating a few-mode fiber and a step-index multimode fiber. We use the mode division multiplexing technology to produce the high-order Bessel-like beam with uneven energy distribution. The LP11 and LP21 mode beams are excited by docking a 980 nm single-mode fiber at the outlet of the light source to a few-mode fiber with a defined offset. The few-mode fiber allows LP01, LP11, and LP21 mode beams to be spread in. The high-order Bessel-like beam is focused by a high refractive index glass microsphere integrated on the fiber end facet. The LP01 mode beam is used to trap particles and array them in a one-dimension space (linear arrangement), the LP01 and LP11 mode beams are used to trap and array particles in a two-dimension space (planar arrangement), and the LP01, LP11, and LP21 mode beams are used to trap and array particles in a three-dimension space (solid arrangement). The proposed fiber optical tweezer is simple in structure and will allow us to examine the interaction between the cells when held in close proximity.

The garnet electrolyte Li7La3Zr2O12 with excellent electrochemical properties is one of the crucial materials in all-solid-state batteries. However, the abnormal grain growth (AGG) phenomena easily occurring during sintering process could damage the mechanical strength of the electrolyte. In this paper, a series of Ga–Ba co-doping LLZO samples, Li7-3x + yGaxLa3-yBayZr2O12 (x = 0.25 and y = 0.01, 0.03, 0.05, 0.15, 0.25, 0.35, 0.45, LGBLZO), were synthesized through sol-gel method to investigate the effects of Ba content on phase, morphology and ionic conduction in ceramics. The results demonstrated the influence mechanism of Ba ions in LGBLZO ceramics as follows. Firstly, the Ba ions as substitution of La sites could regulate the concentration of Li ions in lattice, reducing the bulk resistance. Secondly, the BaZrO3 embedded between grains could prevent abnormal growth of grains effectively. These ceramics acquired optimal relative density after sintering at 1160 °C for 15 h. When the Ba ions feed ratio reaches 0.25 pfu, the LGBLZO (y = 0.25) exhibits excellent performance with a relative density of 94.8%, an ionic conductivity of 8.30 × 10−4S/cm and an activation energy of 0.228eV. Above researches provide ideas for the preparation of compact LLZO ceramics with uniform grain size and outstanding properties.

Understanding the structure and dynamic process of water at the solid–liquid interface is an extremely important topic in surface science, energy science and catalysis1–3. As model catalysts, atomically flat single-crystal electrodes exhibit well-defined surface and electric field properties, and therefore may be used to elucidate the relationship between structure and electrocatalytic activity at the atomic level4,5. Hence, studying interfacial water behaviour on single-crystal surfaces provides a framework for understanding electrocatalysis6,7. However, interfacial water is notoriously difficult to probe owing to interference from bulk water and the complexity of interfacial environments8. Here, we use electrochemical, in situ Raman spectroscopic and computational techniques to investigate the interfacial water on atomically flat Pd single-crystal surfaces. Direct spectral evidence reveals that interfacial water consists of hydrogen-bonded and hydrated Na+ ion water. At hydrogen evolution reaction (HER) potentials, dynamic changes in the structure of interfacial water were observed from a random distribution to an ordered structure due to bias potential and Na+ ion cooperation. Structurally ordered interfacial water facilitated high-efficiency electron transfer across the interface, resulting in higher HER rates. The electrolytes and electrode surface effects on interfacial water were also probed and found to affect water structure. Therefore, through local cation tuning strategies, we anticipate that these results may be generalized to enable ordered interfacial water to improve electrocatalytic reaction rates. Interfacial water consists of hydrogen-bonded water and Na·H2O, its structure changes at hydrogen evolution reaction (HER) potentials, and when structurally ordered it aids interfacial electron transfer, resulting in higher HER rates.

In this paper, inorganic halide perovskite cesium lead bromide (CsPbBr3) films are epitaxially grown on (100)-oriented SrTiO3 substrates by pulsed laser deposition (PLD). This method has the distin...

A series of (TiZrHfVNbTa)C high-entropy ceramics with different vanadium contents have been fabricated by pressureless sintering at 2300 °C–2500 °C for 1 h, utilizing self-synthesized carbide powders obtained by carbothermal reduction. The addition of vanadium is beneficial to promote densification process and refine grain, as well as facilitate the homogeneous distribution of metal elements. The distribution of pores is also modified, almost entirely existing at grain boundary, and the integral mechanical properties achieve optimization. However, excess adding vanadium does not favor forming a single-phase (TiZrHfVNbTa)C high-entropy ceramic. The optimal (TiZrHfVNbTa)C high-entropy ceramic sintered at 2300 °C possesses a high relative density of 97.5 % and homogeneous microstructure with small grain size of 1.2 μm. The flexural strength and Vickers hardness reach 473 MPa and 24.9 GPa, respectively. This work has established a cost-effective and convenient preparation of novel (TiZrHfVNbTa)C high-entropy carbide ceramics.

The long application life and reliable performance of magnesium alloys have been putting forward strict requirements for both better chemical stability and functional characteristics of protective coating. Herein, a highly reliable superhydrophobic double-layer coating on AZ31 Mg with excellent anti-corrosion and electrical protection was achieved by assembling modified SiO2-based organic-inorganic hybrid films on Plasma Electrolytic Oxidation (PEO) ceramic bottom layer. The coating exhibits preferable antiwater surfaces with a barrier layer isolating the underlying substrate from the external environment, rendering a long-term active corrosion protection for the multilayer covered magnesium alloy. Remarkably, the coating achieves high electric insulation with volume resistivity of 1.7 × 1012 Ω cm, breakdown voltage of 1405.2 ± 117.1 V and dielectric strength of 40.2 ± 3.3 V/μm. Simultaneously, its dielectric properties with a low dielectric constant (e ≈ 3.75) and a low dielectric loss (tan δ ≈ 0.0058) outperform those of some current dielectric coatings with similar components. Moreover, the superhydrophobic coating displays strong mechanical robustness undergoing 50th linear abrasion, superior environmental stability (thermal shock, prolonged solution immersion, salt-spray corrosion and UV irradiation), and high adhesion strength. The excellent multifunction benefits from the introduction of ceramic bottom layer, the assembly of compact nanocomposite films, and the synergistic effect of organic-inorganic components. This study provides a new inspiration for designing advanced protective coating with a great potential for the applications of sensitive electronic devices.

Cr doped diamond-like carbon (DLC) coating was deposited on the carburized Ti6Al4V alloy (TA) by magnetron sputtering (MS). The physical and chemical characteristics of Cr doped DLC coating were obtained using scanning electron microscope, energy dispersive spectroscope, Raman spectrometer, X-ray photoelectron spectroscopy and Fourier transform infrared, and the mechanical property and adhesion force were analyzed by nanoindenter and scratch tester. The effects of carburizing treatment on the coefficient of friction (COF) and wear mechanism of Cr doped DLC coatings were investigated on a ball-on-disk tribometer. The results show that the adhesion force and mechanical property of Cr doped DLC coating deposited on the carburized TA are higher than those deposited on the original TA. The average coefficients of friction (COFs) of Cr doped DLC coatings deposited on the original and carburized TAs under the dry-friction condition are 0.157 and 0.143, respectively, showing that the carburizing treatment has the obvious effect of friction reduction for the Cr doped DLC coating. The wear mechanism of Cr doped DLC coating deposited on the carburized TA is combined action of abrasive wear and adhesive wear, which are contributed to the enhancement of mechanical property of Cr doped DLC coating by carburization treatment. Furthermore, the average COFs of Cr doped DLC coatings deposited on the original and carburized TAs under the oil-lubrication condition are 0.152 and 0.131, respectively, which are superior to those under the dry-fiction condition. The carburizing treatment promotes the formation of self-repairing carbonyl of Cr doped DLC coating, and the oil-wet characteristic of Cr doped DLC coating with the aromatic aldehyde of C O as the functional group plays the main role of friction reduction.

The adhesion between the carbon fibre reinforced copper matrix composite material and the coating is of particular importance for the mechanical and functional properties of the resulting system, and also for its handling and for the lifetime of the final product. To have a better understanding of the microstructure at the interface region, three different coating processes, i.e. electroplated Nickel coating, alkyd resin coating and polyolefin coating have been carried out and compared using SEM/EDX techniques. The experimental results indicate that the electroplated Nickel coating gives the best adhesion strength at the interface, suggesting this method the most promising approach and can be further investigated for electrical and electronic engineering applications in power industry.

Accurate real-time molecular-level monitoring of the physicochemical properties of species at the solid–liquid interfaces under ambient conditions with good temporal and spatial resolution is an en...

Continuous carbon-fibre-reinforced Cs-geopolymer composite (Cf/CsGP) were prepared, and its in-situ conversion was investigated during high-temperature treatments. The effect of treatment temperature on the thermal evolution process and mechanical properties of the resulting products were systematically evaluated. The results indicated that the crystallization temperature of Cf/CsGP composite was considerably delayed because the amorphous structure of carbon fibres was not conducive as a nucleation substrate for pollucite derived from the CsGP matrix. Moreover, the integrity of the corresponding resulting products derived from the Cf/CsGP composite were damaged due to thermal shrinkage that occurred during the high-temperature treatment process. When treatment temperature was ≤1200oC, the mechanical properties of the corresponding products exhibited an upward trend, which was ascribed to the improvement of the densification degree of the resulting composite and well interface-bonding state between carbon fibres and pollucite. However, the mechanical properties of the resulting composites decreased with the treatment temperature continued increased from 1200 to 1400oC. This phenomenon was attributed to the impairment of fibre properties caused by interfacial reactions.

Daylighting structures, including solar cells and building windows, utilize sunlight whilst suffering from undesired solar heat and outdoor dust contamination. A radiative cooling system that is transparent to sunlight and has a superhydrophobic surface would cool and clean the daylighting structures in a sustainable manner. However, the majority of the current daytime radiative cooling systems were designed to fully reflect the incident sunlight to maximize the cooling power. In this work, we optimized both the sunlight transmission and infrared thermal irradiation by modeling the size-dependent scattering and absorption of light by SiO2 spheres embedded in a polymer matrix, we found that the use of nanospheres (20 nm) enabled both high sunlight transmittance (> 90%) and infrared emissivity (~0.85). This theoretical prediction was confirmed by experimental measurements of a solution-processed nanocomposite film. When coated on a solar cell, the as-prepared film not only preserved the power conversion efficiency of the cell (14.71%, uncoated cell has an efficiency of 14.79%) but also radiatively cooled the cell by up to 5 °C under direct sunlight. This reduction of the operating temperature of the solar cell further enhanced its electrical power output, evidenced by an increase in the equilibrium temperature of the LED load by about 14 °C. The nanoscale textured surface formed by the nanospheres further led to superhydrophobicity and thus excellent self-cleaning performance (efficient removal of dust by wind and/or water droplets).

Laminated B4C–TiB2 ceramics with h-BN interface layers were successfully prepared by roll forming and tape casting, and samples with different numbers of stacked layers were obtained. Scanning electron microscopy and X-ray diffraction were used to analyze the microstructure and interlayer crystal phases of the composites, and the bending strength, fracture toughness, and work of fracture were measured. As the number of h-BN layers increased, the fracture toughness increased from 7.38 ± 0.5 MPa m1/2 to 9.01 ± 0.61 MPa m1/2, which is 2–3 times higher than that of monolithic B4C ceramics. As the fracture toughness increased, the hardness remained at a high level (31.67 GPa). Bending tests showed that cracks deflected when they encountered the h-BN interfacial layers. The toughening mechanisms included the deflection and branching of cracks and generation of new microcracks, which increased the length of the propagation path and work of fracture.

In order to obtain polyurethane micelles with targeting property and excellent stability, Fe3O4-modified magnetic amphiphilic polyurethane (MAPU) was successfully synthesized by grafting amphiphilic polyurethane to the surface of Fe3O4 nanoparticles. The structure of MAPU was confirmed by Fourier-transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy (1H NMR), gel permeation chromatography and thermogravimetric analyzer. MAPU could form micelles with the particle size of less than 45 nm, and the micelles showed excellent stability of anti-dilution and storage, determined by dynamic light scattering. MAPU micelles had superparamagnetic property, and magnetically targeted property in HeLa cells measured by vibrating sample magnetometer (VSM) and Prussian blue staining method, respectively. Methyltetrazolium (MTT) assay experiment indicated that MAPU micelles were almost non-cytotoxic. In addition, MAPU micelles could encapsulate hydrophobic model drugs such as Indometacin (IMC) and had a release-sustained effect for IMC.

MXenes have good application prospects due to the attractive mechanical and physicochemical properties. Here, for the first time, silicoboron carbonitride (Si–B–C–N) ceramics with the integration of MXene(Ti3C2Tx) nanosheets were developed, and the influences of MXene additives (1.0–3.0 wt%) on mechanical properties and microstructures were investigated. The ceramics containing 3.0 wt% MXene(Ti3C2Tx) show better mechanical properties including fracture toughness of 7.6 MPa‧m1/2, 36% higher than ceramics without any additives. The toughening mechanisms consist of pull-out, delamination, crack bridging, and crack deflection. This work demonstrates that MXenes are good reinforcements for enhancing the fracture toughness of structural ceramics, and also paves the way for the investigation of high-temperature properties of MXene-containing ceramics.

The development of high efficient and cost-effective photocatalysts for organic matters degradation and hydrogen evolution is of great importance. In this study, heterojunction photocatalysts based In2S3 and MIL-68(In) were synthesized by hydrothermal method. These composites exhibit excellent bi-functionality of photocatalytic Rhodamine B degradation and hydrogen evolution. And it was found that the photocatalytic performance of the composites was dependent on the ratio of In to S. The optimum catalyst In2S3/MIL-68(In)-1.5 exhibits much enhanced photocatalytic performance, offering a removal efficiency of 94.7% within 30 min for 20 ppm of Rhodamine B and a hydrogen evolution rate of 1618.8 µmol h−1 g−1 as a result of the synergist effect of heterojunction between the two components, promoting the charge separation. Besides, the mechanisms for photocatalytic degradation of Rhodamine B and photocatalytic hydrogen evolution were also proposed. This protocol could provide guiding information on the development of other functional photocatalysts.

The geometrical shape of the TRISO-coated particle is closely related to its performance and safety. In this paper, models were set up to study the failure fraction of TRISO particle, considering the real asphericity induced by manufacturing uncertainties. TRISO is simplified as a pressure vessel model, and micro X-ray CT was employed to detect the real geometrical shape. Key geometrical parameters, thickness and volume of the real particle, were then obtained with the 3D measurement method and input into PANAMA code (a German code for fuel performance simulation). Release fraction of fission gas and failure fraction of the TRISO-coated particle were revised with the aforementioned parameters with more accuracy and compared with those of the spherical particle. Obvious increment of failure fraction of the particle is found, which may contribute to the release of fission products.

A facile and simple solid phase method has been proposed to prepare SnO2 with SnSe as the precursor. The as-obtained powders were characterized by XRD, indicating that this material was almost pure SnO2. SEM and TEM images reveal that the microscopic morphology of SnO2 material was affected by the heating rates during the formation process of SnSe. The electrochemical performance of SnO2 as anode material for Li-ion batteries was investigated, which demonstrate that the as-prepared SnO2 at heating rate of 10 °C min−1 and packed by copper foil exhibits as high as 899.5 mAh g–1 initial charge capacity at a current density of 0.1 A g−1. Moreover, the SnO2 material shows a good rate performance, suggesting its promising application as anode material for Li-ion batteries.

Porous polycaprolactone (PCL)/calcium sulfate hemihydrate (CSH) composite fibers with different compositions were fabricated via electrospinning by using chloroform/dimethyl sulfoxide (volume ratio = 8:2) as the co-solvent. It was found that the incorporation of fine CSH powders greatly improved the morphology of the PCL fibers and generated continuous, bead-free PCL/CSH composite fibers with the pore diameter varying from 0.2 to 1.1 μm when 20% CSH was added. As compared with the PCL fibers, the PCL/CSH composite fibers also exhibited enhanced thermal stability and hydrophilicity. The tensile strength and elastic modulus of the PCL/CSH fibrous membranes first increased and then decreased with the increase of the CSH content, while their ductility exhibited a sustained decrease. Moreover, after immersion in water, the PCL-20%CSH composite fibers presented a much higher tensile strength than the pristine ones probably due to the self-setting of the CSH powders through the porous structure. In addition, the PCL-20%CSH composite fibers displayed a strong ability to form bone-like apatite after immersion in simulated body fluid for 3 days, which suggests their potential applications in bone tissue regeneration as a novel type of substitute.

Novel TiC-based composites were synthesized by reactive hot-pressing at 1800 °C for 1 h with ZrB2 addition as a sintering aid for the first time. The effects of ZrB2 contents on the phase composition, microstructure evolution, and mechanical properties were reported. Based on the reaction and solid solution coupling effects between ZrB2 and TiC, the product ZrC may be partially or completely dissolved into the TiC matrix, and then phase separation within the miscibility gap is observed to form lamellar nanostructured ZrC-rich (Zr, Ti)C. The TiC-10 mol.% ZrB2 (starting batch composition) exhibits good comprehensive mechanical properties of hardness 27.7 ± 1.3 GPa, flexural strength 659 ± 48 MPa, and fracture toughness of 6.5 ± 0.6 MPa m1/2, respectively, which reach or exceed most TiC-based composites using ceramics as sintering aids in the previous reports.

Recently, sandwich structures have been widely used in different fields because of their good mechanical properties, but these structures are weak in acoustic performance. In this paper, by combining pyramidal truss core sandwich structure with frame, a new structure is proposed with both good mechanical properties and excellent acoustic performance at low frequency. An analytical model of the pyramidal truss core sandwich structure with frame is developed to investigate the sound transmission loss (STL) performance. Finite element method (FEM) is also used to investigate the STL performance at low frequency. The effects of the incident wave angle and the geometrical parameters on the STL of the structure are discussed.

Through the introduction of gas-phase monomers phthalic anhydride (PA) and p-phenylenediamine (PPD), replenishment of lubricants during high-temperature friction process could be realized. In a 10-...

To significantly improve the electrochemical performance of LiMn2O4, we proposed a simple and low-cost co-modification approach based on the synergistic effect of poly(ethylene glycol) (PEG) and carbon nanotubes (CNT). The CNT@PEG@LiMn2O4 (CNT@PEG@LMO) composite was prepared by ultrasound assisted wet-coating method. PEG is a highly conductive ionic conductor, which can improve the transport efficiency of lithium ions, and CNT is a good electronic conductor, which possesses excellent electrical conductivity. Moreover, the combination of PEG and CNT can effectively inhibit the dissolution of manganese and promote the uniform distribution of LiMn2O4 octahedra. The structure and surface morphology of the CNT@PEG@LMO composite were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical test result showed that the initial discharge capacity of the CNT@PEG@LMO composite could reach up to 123.8 mAh g−1 at 1.0 C with capacity retention of 95.2 % after 100 cycles, which is higher than that of the unmodified LiMn2O4 sample. The high-rate capability of the CNT@PEG@LMO composite was significantly improved. When cycled at 55 °C, the CNT@PEG@LMO composite could show good cycling stability and rate performance. Such excellent electrochemical performance is due to close association with the synergistic effect of PEG and CNT.

Molecular rectifier, as a basic function of molecular electronic devices, has attracted extensive attention for the opportunity in constructing sub-nanometer electronic devices. However, tunneling leakage current has a significant contribution as electronic devices shrink in size, which leads to a challenge in fabricating molecular rectifiers at the sub-nanometer scale. Here, we experimentally demonstrate a sub-nanometer molecular rectifier based on the supramolecular junction assembled between water and 1,4-diazabicyclo[2.2.2]octane (DABCO) molecule. The charge transport through DABCO and corresponding supramolecular junctions exhibits destructive σ-interference, ensuring a sharp conductance variation for transmission modulation. The supramolecular interaction between DABCO and water readily introduces the asymmetric electrode-molecule interaction, which combines with the destructive σ-interference to support the sub-nanometer rectification.

Concentrated photovoltaic (CPV) has been identified as an effective method to further enhance the efficiency of photovoltaic cells. Previous studies on CPV mainly focused on III-V multi-junction cells. Nevertheless, III-V CPV technology is mainly used in niche applications due to its high cost. Here, we use metal-halide perovskite solar cell (PSC) to demonstrate a concentrated photovoltaic-thermoelectric tandem device. The thermoelectric generator (TEG) is utilized to reduce the effect of heat generation under concentrated solar irradiance. Our tandem system achieved a peak power conversion efficiency (PCE) of 25.0% at a solar concentration of 3 suns. This efficiency exceeded that of the single PSC by ~4.7%. Our work proves that by controlling the heat flow in concentrated PSC-TEG tandem system, the redundant heat produced by upper PSC can be effectively reused. This tandem structure provides a promising approach to improve the efficiency and stability of PSC under low-concentrated solar irradiation.

β-Si3N4 ceramics were prepared by gas pressure sintering using α-Si3N4 powders, β-Si3N4 whiskers and Re2O3–MgO (Re = Y, La, Gd, Ho, Yb) additives. The phase transformation from α-Si3N4 to β-Si3N4 was completed after sintering. The distribution of oxide particles gets more homogeneous with the increase of the atomic number of the Re element, resulting in an increase of the grain size and the formation of elongated β-Si3N4 grains, which significantly influence the fracture mode and the mechanical properties of β-Si3N4 ceramics. The thermal conductivity of β-Si3N4 ceramics is determined by both the grain size and the distribution homogeneity of oxide particles, thus showing no regular trend between different specimens.

Tris(dichloromethylsilylethyl)borane is a compound containing a B-C bond and Cl and H elements. Herein, we propose a novel method to synthesize polyborosilazanes using tris(dichloromethylsilylethyl)borane and boron trichlorosilane as boron sources and hexamethyldisilazane as a nitrogen source. The microstructure and chemical composition of the as-synthesized polyborosilazanes and as-annealed SiBCN ceramics were investigated using Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, Raman spectroscopy, scanning electron microscope, and transmission electron microscope methods. The organic precursors were converted entirely into inorganic ceramics at 800 degrees C, and the ceramic yield of the polyborosilazanes was 88% at 1000 degrees C. SiBCN ceramics with irregular shapes contained chemical bonds of B-N, Si-N, and Si-C at 1500 degrees C and retained an amorphous structure below 1600 degrees C. After the first cycle, the fabricated SiBCN ceramic anodes exhibited a reversible capacity of 261.3 mA h/g, which was 2.6 times that reported in the literature (101 mA h/g). The discharge capacity decreased to 157.6 mA h/g after 30 cycles. The satisfactory electrochemical performance of the resulting SiBCN ceramic anodes can be attributed to the formation of conductive carbon species favoring the transport properties of lithium ion.

In the MOFs-based composites, the co-catalyst nanoparticles loads tend to agglomerate. In the self-assembly process of MOFs-based composites, the use of acid modulators solved the accumulation of AgI nanoparticles cocatalyst. The active sites of carboxyl groups and mesoporous structure brought by acid modulator provide more loading sites for AgI nanoparticles. The novel AgI/D-MIL-53(Fe) showed good adsorption and photocatalytic performance in the process of removing tetracycline pollutants. Compared to the degradation efficiency of the MIL-53(Fe) with 50.8%, it of AgI/MIL-53(Fe) increased to 85.1% and which further increased to 96.2% by AgI/D-MIL-53(Fe) based on the HCl modulator. On the one hand, it is beneficial for the mesoporous D-MIL-53(Fe) modulated by HCl modulator to disperse the AgI nanoparticles co-catalyst. On the other hand, AgI nanoparticles, as a photosensitive agent, adsorb visible light to generate photogenerated electrons and holes, and electrons rapidly transferred to the heterojunction bridge Ag0 and then captured by the holes from the D-MIL-53(Fe). The construction of AgI/D-MIL-53(Fe) Z-scheme heterojunction provided favorable conditions for the rapid separation and photogenerated electrons and holes. Finally, ·O2−, ·OH and h+ as the main active free radicals were driving forces. This study provided more possibilities and opportunities for the construction of mesoporous MOFs-based composites.

Channeling carbon dioxide The separation of gas molecules with physisorbents can be challenging because there is often a tradeoff between capacity and selectivity. Zhou et al. report a template-free hydrothermal synthesis of the one-dimensional channel zeolite mordenite, in which some silicon was replaced by iron. Rather than forming a powder that requires further shaping, this mechanically stable material self-assembled into monoliths. Iron atoms bound in tetrahedral zeolite sites narrowed the channels and enabled the size-exclusion separation of carbon dioxide (CO 2 ) over nitrogen (N 2 ) and methane. High CO 2 uptake and highly efficient CO 2 –N 2 separation was demonstrated for both dry and humid conditions. Science , aax5776, this issue p. 315

In this study, SiC whiskers (SCWS) reinforced geopolymer composites (SCWS/KGP) and their ceramic products (SCWS/leucite) were prepared, and effects of SiC whiskers contents on the microstructure and flexural strength of the SCWS/KGP and SCWS/leucite composites were investigated. The results show that the whisker addition has little influence on both phase composition and thermal shrinkage of the KGP composites, but a suitable content of whisker will result in the improved flexural strength, and when the SCWS content is 2 wt%, flexural strength of the SCWS/KGP composite is enhanced by 95% compared with the neat geopolymer. The flexural strength of the composites can be further enhanced significantly after the composites being treated at 1100 °C and 1200 °C and flexural strength of the composite with SCWS content of 2 wt% was 107% and 125% higher than the untreated counterpart, respectively. The increase in flexural strength of the composites should be attributed to the strong leucite formation, whisker debonding and pulling out from matrix during the fracturing process based on the good interfacial bonding state between whisker and leucite matrix.

The high-temperature service performance of nearly fully dense 20 wt% BNW/SiO2 ceramic was systematically investigated. The oxidation damage and strength degradation of the whiskers combined with the surface microstructures of the samples predominantly influence the flexural strength from RT to 1000 °C. In previous work, the temperature dependence of the material properties is invariably ignored when evaluating thermal stress crack initiation and propagation behaviour. In this work, modified thermal shock models that include temperature-dependent material properties were established based on thermal-shock fracture (TSF) theory and thermal-shock damage (TSD) theory. Then, the thermal shock resistance (TSR) of the BNW/SiO2 ceramic was evaluated by preforming a water quenching test. The modified models could better explain the TSR behaviour of the ceramic, indicating that considering the temperature-dependent material properties will reveal the thermal shock damage mechanism more precisely.

MAX phases are a family of ternary carbide or nitride ceramics possessing a layered crystal structure and, due to their chemical bonds having a mixed covalent-ionic-metallic nature, have unique properties combining those of metals and ceramics. In this review, the formation mechanisms of MAX phases from elemental and compound powders are reviewed in detail, as the formation mechanisms are closely related to the unique properties of well-synthesized MAX phases. The stability of MAX phases in some harsh external environments is significantly influenced by the defect population, allowing the mechanisms of defect formation and migration to strongly influence their self-healing performance and radiation tolerance. The properties of MAX phases can be tailored by creating solid solutions, which have lattice distortions, and texturing which results in the preferential orientation of plate-like grains.

SiBCN-reduced graphene oxide (SiBCN-rGO) ceramic composites with different rGO content derived from a single-source precursor were successful synthesized by polymer derived ceramics routes to tune their dielectric properties and electromagnetic wave absorption capacity. SiBCN-rGO ceramic composites with 6 wt% GO annealed at 1300 °C possessed the best microwave absorption performance obtaining the minimum reflection coefficient (RCmin) of −62.71 dB at 10.72 GHz, and the thin thickness of 2.17 mm. Adjusting its thickness to 1.58 mm could obtain the maximum effective absorption bandwidth (RC < −10 dB) of 4.32 GHz. The microwave absorption mechanisms of the as-prepared SiBCN-rGO ceramic composites were mainly attributed to the conductive loss and polarization loss induced by the synergistic effects of amorphous SiBCN matrix, rGO and SiC nanocrystals.

Large inventory and non-degradability made waste glass fiber reinforced plastics (GFRP) a heavy burden to environment. They are increasingly reclaimed through mechanical crushing and used as aggregate replacement in concrete. However, reuse of all-component recycled GFRP (rGFRP) was still limited due to the inconsistent influences of powder and fiber on cementitious materials. In this study, mortar and concrete with two different gradations of all-component rGFRP at 10 wt%, 20 wt% and 30 wt% were investigated with mechanical tests, ultrasonic pulse velocity inspection, Depth-of-Field optical microscopy, Scanning Electron Microscopy (SEM) and micro-CT. It revealed that the splitting strength of cement mortar was significantly increased while 10 wt% of rGFRP was added, whereas the compressive and flexural strength were barely affected. For concrete, the initial and final setting time were prolonged by the addition of 30 wt% rGFRP up to 93.8% and 124.3%, respectively. The mechanical strength of concrete increased with rGFRP content firstly, and then decreased, due to the reduced dispersity of rGFRP and compactness of mortar. When 10 wt% of rGFRP was added, the 28-day compressive, flexural and splitting strength of concrete were optimized to 25.8 MPa, 4.25 MPa and 3.02 MPa, respectively. The failure pattern analysis indicated that rGFRP can restrain crack propagation, reduce crack width and improve the integrity of fractured concrete. The results suggested the potential feasibility of rGFRP as fine aggregate replacement, and provided solid experimental references for practically reusing rGFRP in cementitious materials.

The microstructure，texture distribution and tensile property of 7xxx ultra-thick plate was investigated by optical microscopy (OM), scanning electron microscopy (SEM), electron back scattering diffraction (EBSD), transmission electron microscopy (TEM) and tensile tests. The results show that the microstructure, texture and tensile property were inhomogeneous along the thickness direction. A large number of sub-crystals remained on the surface of the thick plate and was accompanied by much recrystallization. Most of the structures were random texture, and the proportion of typical texture was low at the edge. For the center layer, there were also a lot of recrystallized grains and typical deformed texture along the β-fiber (Brass, S, and Copper) was observed. The 1/4 layer of the plate is a transition one, and had the lowest recrystallized fraction. From surface to center, precipitation phases within grains and grain boundaries gradually coarsen, mechanical properties reduced. At the same thickness, the tensile property showed appreciable anisotropy, the L direction was the highest and the S direction was the lowest.

Laser surface modification technology is one of the most advanced technologies, which uses laser to modify the characteristics of the surface to offer superior performance for various industrial applications. In this study, laser surface hardening behavior of GM246 case iron was investigated. Result shows that excellent laser surface hardening of GM246 cast iron need low power density and scanning speed. With power of 2500 W, scanning speed of 300 mm/min and power density of 2500 W/cm2, the laser surface hardening of GM246 cast iron achieved the hardness of 790HV, which was 2-3 times higher than the hardness of base metal. Also, the depth of laser surface hardening case achieved 0.9 mm and the hardening case demonstrated three subzones.