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Graphene oxide (GO) is regarded as a promising candidate to construct solar absorbers for addressing freshwater crisis, but the easy delamination of GO in water poses a critical challenge for practical solar desalination. Herein, we improve the stability of GO membranes by a self-crosslinking poly (ionic liquid) (PIL) in a mild condition, which crosslinks neighbouring GO nanosheets without blemishing the hydrophilic structure of GO. By further adding carbon nanotubes (CNTs), the sandwiched GO/CNT@PIL (GCP) membrane displays a good stability in pH = 1 or 13 solution even for 270 days. The molecular dynamics simulation results indicate that the generation of water nanofluidics in nanochannels of GO nanosheets remarkably reduces the water evaporation enthalpy in GCP membrane, compared to bulk water. Consequently, the GCP membrane exhibits a high evaporation rate (1.87 kg m−2 h−1) and displays stable evaporation rates for 14 h under 1 kW m−2 irradiation. The GCP membrane additionally works very well when using different water sources (e.g., dye-polluted water) or even strong acidic solution (pH = 1) or basic solution (pH = 13). More importantly, through bundling pluralities of GCP membrane, an efficient solar desalination device is developed to produce drinkable water from seawater. The average daily drinkable water amount in sunny day is 10.1 kg m−2, which meets with the daily drinkable water needs of five adults. The high evaporation rate, long-time durability and good scalability make the GCP membrane an outstanding candidate for practical solar seawater desalination.

Sustainable conversion of waste plastics into valuable carbon materials for diverse applications provides a promising strategy to dispose the municipal and industrial waste plastics. However, it remains a challenge to precisely control the crosslinking reaction for transforming waste polyesters into N-doped porous carbon (NPC) with well-defined microstructures. Herein, we put forwards a strategy of stepwise crosslinking using melamine and ZnCl2/NaCl eutectic salts to convert poly (ethylene terephthalate) (PET) into NPC at 550 °C. We prove that firstly melamine reacts with PET degradation products to form a crosslinking structure, and subsequently ZnCl2/NaCl promote the dehydration and decarboxylation of the crosslinking structure to generate a more thermally stable crosslinking structure. The coordination of two tandem crosslinking reactions is critical to control the microstructure of NPC. Without activations, NPC shows large specific surface area of 1173 m2 g−1, abundant N dopants, and rich oxygen-containing groups. These combined features endure NPC with excellent performance in CO2 capture and solar steam generation, e.g., high CO2 adsorption capacity of 6.47 mmol g−1 and evaporation rate of 1.62 kg m−2 h−1. More importantly, NPC is compared to or prevails over previous carbon-based CO2 adsorbents or photothermal materials. This work will advance the research on “green” reutilization of low-cost polyester wastes to prepare sustainable carbon for solar energy conversion, environmental protection, etc.

In order to enhance tribological performance of both water-based and oil-based lubricant, the SiO2 nanoscale ionic liquid (NIL), an amphiphilic lubricant additive, was prepared by using a sulfuric acid terminated organo-silane as corona and polyether amine as canopy. Various analytical techniques were used to characterize the SiO2 NIL and stability of the nanolubricants. A ball-on-disk tribometer was adopted to investigate the lubrication enhancement of the SiO2 NIL in both water-based and oil-based lubricants. The results show that the SiO2 NIL can reduce the coefficient of friction (COF) and wear in these two lubricant groups, especially in the water-based lubricant. The lubrication mechanisms are ascribed to the polishing, ball bearing and mending effects of the SiO2 NIL.

The growing demand of wearable device and the irreplaceable roles in stealth technique have boosted the exploration of high-performance flexible microwave absorbers. Herein, a novel flexible honeycomb structural absorber (FHSA) of carbon fiber (CF)/polyamide (PA)/carbonyl iron (CIP) composite was successfully fabricated via selective laser sintering (SLS) 3D-printing. The CFs arrangement and unit-structure were rationally controlled during the SLS 3D printing process for acquiring enhanced microwave absorption (MA) property, especially for the high bending angles. Therefore, under the high bending angle of 150°, the minimum reflection loss of the designed FHSA can reach −47 dB at 16.2 GHz with a broadband absorption of 13.2 GHz, covering the whole C2, X, and Ku bands, which breaks the traditional restraints that the flexible absorbers can only have the high MA property in tiling or minor bending status. In addition, the FHSA also showed the advantages of highly flexible deformation, self-recovery and no-crease damage in repeated bending, which could largely improve the environment applicability. This work provides a controllable strategy for the design of flexible microwave absorber, showing potential applications in wearable functional devices and military stealth protection.

Purpose The low-temperature sintering of silica glass combined with additive manufacturing (AM) technology has brought a revolutionary change in glass manufacturing. This study aims to carry out in an attempt to achieve precious manufacturing of silicate glassy matrix through the method of slurry extrusion. Design/methodology/approach A low-cost slurry extrusion modelling technology is used to extrude silicate glassy matrix inks, composed of silicate glass powder with different amounts of additives. Extrudability of the inks, their printability window and the featuring curves of silicate glassy matrix are investigated. In addition, the properties of the low-temperature sintering green part as a functional part are explored and evaluated from morphology, hardness and colour. Findings The results showed that the particle size was mainly distributed from 1.4 µm to 5.3 µm, showing better slurry stability and print continuity. The parameters were set to 8 mm/s, 80% and 0.4 mm, respectively, to achieve better forming of three-dimensional (3D) samples. Besides, the organic binder removal step was concentrated on 200°C–300°C and 590°C–650°C was the fusion bonding temperature of the powder. The hardness values of 10 test samples ranged from 588 HL to 613 HL, which met the requirements of hard stones with super-strong mechanical strength. In addition, the mutual penetration of elements caused by temperature changes may lead to a colourful appearance. Originality/value The custom continuous AM technology enables the fabrication of a glass matrix with 3D structural features. The precise positioning technology of the glass matrix is expected to be applied more widely in functional parts.

This paper presents a non-aqueous Li-air battery model that considers the side reactions of lithium carbonate (Li2CO3) formation from both electrolyte decomposition and carbon dioxide (CO2) in the ambient air. The deposition and decomposition behaviors of discharge products, the voltage, and capacity evolutions during the cycling operation of the Li-air batteries are investigated. The deposition behavior analysis implies that the Li2CO3 generated by electrolyte decomposition is mainly distributed near the separator side, while it is dominantly generated by Li-O2/CO2 reaction near the air side. The formation of Li2CO3 by side reactions makes the Li-air batteries exhibit a peak discharge deposition inside the cathode. Moreover, Li2CO3 is difficult to decompose and gradually accumulates with cycles, especially near the air side. The severe accumulation of Li2CO3 near the air side significantly reduces the O2 diffusion into the electrode, which induces severe cycling performance decay of the Li-air batteries. According to the distribution and evolution of the deposition, three simple hierarchical cathode structures with high porosities near the air side are finally studied. The simulation results indicate that the increase of the local porosity near the air side substantially improves the cycling performance of the Li-air batteries.

Hyperthermia has become an important area of research for cancer treatment throughout the world. Choosing appropriate magnetic nanoparticles for specific performance at the cancerous site of the body is a major problem. In this research work, iron oxide nanoparticles were synthesized using laser ablation and Ag@α‑Fe2O3 and γ-Fe2O3 nanoparticles using chemical methods. The size and shape of synthesized nanoparticles were characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). These nanoparticles were then exposed to the alternating magnetic field in a fluid medium in a calorimeter. The heat generated by nanoparticles in the response to the applied magnetic field due through Neel relaxation and through Brown relaxation effects was measured using an array of the k-type thermometer. Their thermal responses in AC magnetic field to time regarding their types were studied. γ-Fe2O3 produced more heat, sufficient enough to kill the cancer cells selectively.

Solar evaporation has emerged as an attractive technology to produce freshwater by utilizing renewable solar energy. However, it remains a huge challenge to develop efficient solar steam generators with good flexibility, low cost and remarkable salt resistance. Herein, we prepare flexible, robust solar membranes by filtration of porous carbon and commercial paper pulp fiber. The porous carbon with well-defined structures is prepared through controlled carbonization of biomass/waste plastics by eutectic salts. We prove the synergistic effect of porous carbon and paper pulp fiber in boosting solar evaporation performance. Firstly, the porous carbon displays a high light absorption, while the paper pulp fiber with good hydrophilicity effectively promotes the transport of water. Secondly, the combination between porous carbon and paper pulp fiber reduces the water vaporization enthalpy by 20%, which is important to significantly improve the evaporation performance. As a proof of concept, the porous carbon/paper pulp fiber membrane possesses a high evaporation rate of 1.8 kg m−2 h−1 under 1 kW m−2 irradiation. Thirdly, the good flexibility and mechanical property of paper pulp fiber enable the solar membrane to work well under extreme conditions (e.g., after 20 cycles of folding/stretching/recovery). Lastly, due to the super-hydrophilicity and superwetting, the hybrid membrane exhibits the exceptional salt resistance and long-term stability in continuous seawater desalination, e.g., for 50 h. Importantly, a large-scale solar desalination device for outdoor experiments is developed to produce freshwater. Consequently, this work provides a new insight into developing advanced flexible solar evaporators with superb performance in seawater desalination.

Purpose Traditional simulation research of geological and similar engineering models, such as landslides or other natural disaster scenarios, usually focuses on the change of stress and the state of the model before and after destruction. However, the transition of the inner change is usually invisible. To optimize and make models more intelligent, this paper aims to propose a perceptible design to detect the internal temperature change transformed by other energy versions like stress or torsion. Design/methodology/approach In this paper, micron diamond particles were embedded in 3D printed geopolymers as a potential thermal sensor material to detect the inner heat change. The authors use synthetic micron diamond powder to reinforced the anti-corrosion properties and thermal conductivity of geopolymer and apply this novel geopolymer slurry in the direct ink writing (DIW) technique. Findings As a result, the addition of micron diamond powder can greatly influence the rheology of geopolymer slurry and make the geopolymer slurry extrudable and suitable for DIW by reducing the slope of the viscosity of this inorganic colloid. The heat transfer coefficient of the micron diamond (15 Wt.%)/geopolymer was 50% higher than the pure geopolymer, which could be detected by the infrared thermal imager. Besides, the addition of diamond particles also increased the porous rates of geopolymer. Originality/value In conclusion, DIW slurry deposition of micron diamond-embedded geopolymer (MDG) composites could be used to manufacture the multi-functional geological model for thermal imaging and defect detection, which need the characteristic of lightweight, isolation, heat transfer and wave absorption.

Traditional anodic oxidation followed by annealing was performed to prepare a nanoflower-like WO3 film. The XRD results show that triclinic–monoclinic mixed-phased WO3 formed. The TEM images confirmed the heterojunction formation of triclinic–monoclinic WO3. A further reduction treatment of the as-annealed specimens in a mixed solution of EG and NH4F was carried out at a low temperature of 333 K for 24–72 h. The XPS and EPR analysis revealed that the surface and bulk defects formed, and the defect concentration increased with the increase in reduction time. The defects’ introduction decreased the bandgap values and shifted the bandgap structure towards a more positive position. Although the defect introduction did not significantly improve photogenerated electrons and holes’ separation efficiency, it lowered the charge transfer resistance and enhanced the interfacial transfer efficiency. The visible-light-driven photocatalytic activity of the as-reduced WO3 film increased to varying degrees. The as-reduced sample for 48 h exhibited the highest photocatalytic activity, which was 1.7 times that of the as-annealed specimen. A volcanic-like curve relationship between the photocatalytic activity, defect concentration, and reduction time established. A moderate defect concentration is beneficial to improve the photocatalytic performance of the WO3 film. Anodic oxidation followed by a solution reduction is an efficient and economical way to prepare metallic oxide films with a large specific surface area.

A flexible TiO2 nanograss array film on Ti wire mesh was prepared by a mild chemical reaction. To overcome its shortcoming of almost no absorption of visible light, successive ionic layer adsorption and reaction (SILAR) was executed to decorate the prepared TiO2 film with BiOI. The results of XRD and SEM measurements showed that BiOI nanoflakes formed on the surface of TiO2 film, and the loading amounts of BiOI nanoflakes increased with the increase in SILAR cycles. The XPS results confirmed the heterojunction formation of BiOI-TiO2. The photocurrent measurement suggests that a moderate loading amount of BiOI nanoflakes is beneficial to improve the charge separation efficiency, which is ascribed to the heterojunction formation of BiOI-TiO2. The BiOI-decorated TiO2 film with SILAR cycles of seven showed the most excellent visible-light photocatalytic activity among all the samples. Compared with the bareTiO2 nanograss array film, its visible-light photocatalytic activity increased by 11.7 times. The flexible BiOI-decorated TiO2 nanograss array film with high photocatalytic activity shows great applications in air pollution and the pollution caused by offshore oil spills.

Solar evaporation is considered as a promising approach for harvesting freshwater from non-potable water utilizing sustainable solar energy. Integrating the photocatalytic effect into solar vapor generation is beneficial for the substantial augmentation of solar energy utilization for freshwater production and dealing with polluted water when it is used as source water. In this work, a synergistic photothermal–photochemical hybrid membrane is prepared by facilely dip-coating three-dimensional porous carbon nitride (CN) and a two-dimensional MXene on non-woven cotton cloth. The obtained hybrid membrane possesses high light absorption in the whole solar spectrum, a decreased band gap, excellent photothermal conversion accompanied by a reduced non-radiative reflection loss, and enlarged photocurrent by forming a Schottky junction between the MXene and CN under simulated solar light. With the combined merits above, the hybrid membrane shows excellent photocatalytic performance and solar steam generation. Typically, the hybrid membrane degrades 95% Rhodamine B, 92% crystal violet and 72% methyl orange at 3 mg L−1 under 1 kW m−2 irradiation within 60 min. The water evaporation rate is up to 2.30 kg m−2 h−1 with a solar-to-vapor conversion efficiency of 98.9% under one-sun irradiation. Significantly, a large-scale solar conversion device is constructed for outdoor experiments to simultaneously harvest freshwater from contaminated water and degrade organic dyes in source water. The daily freshwater production rate is 5.7 kg m−2, meeting the requirement of two adults. This work demonstrates the promising potential of the hybrid membrane for potable water production and contaminated water treatment within one device and opens an avenue for application in energy conversion and storage.

Rutile TiO2 forms on TiC coatings (TiO2/TiC coatings) during carbon-embedding heat treatment (cHT) for TiC coatings. The photocatalytic activity of TiO2/TiC coatings has been significantly enhanced, especially under visible light. The influence of cHT temperature for TiC and Ti coatings on surface morphology, formed compounds, and photocatalytic activity has also been investigated. In general, rutile TiO2 forms on TiC coatings, whereas TiCxOy forms on Ti coatings. By raising the cHT temperature for TiC coatings, the surface morphology of TiO2/TiC coatings with a pore-like structure significantly changes from nano-size to micro-size, inevitably resulting in the reduction of the accessible surface area. However, the influence of cHT temperature on the Ti coatings is insignificant, demonstrating a smooth surface morphology. Notably, owing to the increased accessible surface area and formed heterojunction of TiO2/TiC, the photocatalytic activity of TiO2/TiC coatings has been significantly enhanced approximately 6 times especially under visible light, compared with that of TiCxOy/Ti coatings. Furthermore, when the cHT temperature has been raised, the photocatalytic activity of TiO2/TiC coatings initially increases and then decreases, achieving their most satisfaction at 1073 K, which is attributed to the narrowed band gap of TiO2 owing to the shifted O 1s spectra.

Considering the severe impacts on the economic losses caused by oil spills, it is of great significance to develop an oil-absorbent material for removing the oil slick from the water surface effectively. As a new oil-absorbent material, magnetorheological fluid (MRF) has unsinkability, hydrophobicity, and lipophilicity, which could effectively remove the oil slick on the water surface while repelling water. Particularly, the prepared MRF shows a good response to external magnetic field. MRFs show high oil removal capacity in fresh water, deionized water, and salt water with efficiencies up to 94.39, 93.65, and 92.71%, respectively. Besides, Fe3O4/OA magnetic nanoparticles (MPs) could be reprepared into MRF by simple treatments. After the fifth cycle, the MRF prepared by the recovered Fe3O4/OA MPs still has high oil removal efficiency, and that means the Fe3O4/OA MPs has excellent reusability and stability. The method for preparing MRFs provided in this work is simple and effective, and the MRFs have a promising potential for cleaning oil slick.

Converting polyesters into carbon materials for energy and environmental applications provides a promising way to recycle urban and industrial waste plastics. However, previous strategies could not precisely control the crosslinking reaction of polyester. Herein, poly(ethylene terephthalate) (PET) is transformed into O,S-doped hierarchically porous carbon (OSHPC) using sodium lignosulfonate (SLS) and ZnO at 550 °C. SLS/ZnO show a synergistic effect on the PET carbonization. Firstly, a crosslinking structure is generated through esterification of carboxylic acid in PET degradation products with hydroxyl group in SLS. Subsequently, ZnO promotes de-carbonylation of crosslinking structure into vinyl-terminated chains and radical species to form carbon framework with rich micropores. Upon ZnO removal, numerous mesopores/macropores are introduced. OSHPC thereby bears micro-/meso-/macropores with rich chemical groups, which favor for water transportation. Meanwhile, the bead-like particles in OSHPC improve sunlight absorption. The combined advantages endue OSHPC with high performance in solar vapor generation to produce freshwater from wastewater/seawater. The evaporation rate under 1 kW/m2 is 1.51 kg/m2/h, and the metallic ion removal efficiency is >99.9%. This work reutilizes waste polyesters to fabricate functional carbon and contributes to environmental remediation and solar energy exploitation.

The polycrystalline FeSe bulks were sintered by solid-state reaction using a two-step sintering process to investigate the effect of graphene addition on the superconductivity and microstructure of the FeSe bulks. With the increase of graphene doping, the thickness of tetragonal β-FeSe sheet decreased obviously due to the existence of graphene between the layers. The grain connectivity of FeSe superconductor is significantly improved, and the critical transition temperature (Tc) is apparently enhanced up to 10.57 K in Fe1.01SeG0.05, which increased by 15.3% compared to the Fe1.01Se bulk without doping graphene. The critical current density (Jc) of Fe1.01SeG0.05 reaches 5 × 103 A/cm2 under zero magnetic field. Moreover, the critical current density (Jc) of Fe1.01SeG0.05 is simultaneously increased under high magnetic field due to the refined grains by graphene doping.

In this study, the wetting states and wetting transition of droplets on the microstructured surfaces are investigated using the multiphase lattice Boltzmann method. The Cassie-Baxter (Cassie) and W...

Titania (TiO2) photocatalyst coatings have been fabricated by the low-cost approach of sulfuric-acid-bath pretreatment (SAP) followed soaked in sulfuric acid (SA) at room temperature then oxidated in air. The influence of the SAP and soaked conditions on the surface morphology and photocatalytic activity of TiO2 on Ti coatings was investigated. With different SAP conditions, the surface morphologies of the TiO2 on Ti coatings clearly show the formed porous-like structure. With higher SA concentration, the porous-like structure becomes obviously. With extending soaked time, the porous-like structure tends to disappear. Raman spectroscopy reveals that the formed TiO2 coatings are with mixed-phase of anatase and rutile. Compared with those of SA concentration and SAP time, the influence of the soaked time on the phase transformation is obvious. Notably, the photocatalytic activity of TiO2 on Ti coatings had been efficiently enhanced by extending the soaked time, compared with those of higher SA concentration and longer SAP time. The enhanced photocatalytic activity of TiO2 on Ti coatings could be related with the changed surface morphology, mixed-phase of anatase and rutile, and formed hydroxyl groups.

Anodic oxidation was utilized to prepare Bi2O3 film on pure bismuth foil in NaOH and oxalic acid electrolytes. In NaOH electrolyte, β-phase Bi2O3 film with a flat surface was prepared. In oxalic acid, β and ω mixed-phase Bi2O3 film consisting of nanorods was formed. Although both the film showed intense visible light absorption, the sample prepared in NaOH showed an overall shift of VBM and CBM towards negative potential compared the sample prepared in oxalic acid. The shift weakened the oxidizing power of photo-generated holes; however, it made it possible to form $${}^{ \cdot }{\rm O}_{2}^{ - }$$ species through one-electron transfer reaction between photo-generated electrons and oxygen. It enabled the conversion of the key oxidizing species from ·OH radicals to $${}^{ \cdot }{\rm O}_{2}^{ - }$$ radicals in the film prepared in NaOH. Although the film prepared in NaOH possessed higher charge separation efficiency, charge carrier transfer resistance, and greater amounts of ·OH and $${}^{ \cdot }{\rm O}_{2}^{ - }$$ species, the film prepared in oxalic acid showed a slightly higher photocatalytic activity in the degradation of MB dye under visible light irradiation. This is explained by the fact that the latter had a greater specific surface area than the former. In addition, mixed-phase effect may also help to the photocatalytic activity improvement.

Solar vapor generation is emerging as a promising technology using solar energy for various applications including desalination and freshwater production. However, from the viewpoints of industrial and academic research, it remains challenging to prepare low-cost and high-efficiency photothermal materials. In this work, we report the controlled carbonization of polypropylene (PP) using NiO and poly(ionic liquid) (PIL) as combined catalysts to prepare a Ni/carbon nanomaterial (Ni/CNM). The morphology and textural property of Ni/CNM are modulated by adding a trace amount of PIL. Ni/CNM consists of cup-stacked carbon nanotubes (CS-CNTs) and pear-shaped metallic Ni nanoparticles. Due to the synergistic effect of Ni and CS-CNTs in solar absorption, Ni/CNM possesses an excellent property of photothermal conversion. Meanwhile, Ni/CNM with a high specific surface area and rich micro-/meso-/macropores constructs a three-dimensional (3D) porous network for efficient water supply and vapor channels. Thanks to high solar absorption, fast water transport, and low thermal conductivity, Ni/CNM exhibits a high water evaporation rate of 1.67 kg m−2 h−1, a solar-to-vapor conversion efficiency of 94.9%, and an excellent stability for 10 cycles. It also works well when converting dye-containing water, seawater, and oil/water emulsion into healthy drinkable water. The metallic ion removal efficiency of seawater is 99.99%, and the dye removal efficiency is >99.9%. More importantly, it prevails over the-state-of-art carbon-based photothermal materials in solar energy-driven vapor generation. This work not only proposes a new sustainable approach to convert waste polymers into advanced metal/carbon hybrids, but also contributes to the fields of solar energy utilization and seawater desalination.

PurposeThe study aims to explore the composition and microstructure of clay functionally graded materials under the process of double-gradient direct ink writing (DIW).Design/methodology/approachThe investigation focused specifically on the pore characteristics of barite-kaolin clay composite after three-dimensional (3D) printing and sintering as well as its bionic application in geophysical model.FindingsThe model with pore and material variations brought about spatial and nonlinear mechanical properties. Moreover, the vertical gradient and connected pores in the upper kaolin part simulated the natural phenomenon of the landslide model (take Chinese Majiagou landslides as an example). Both the thermal debinding behavior and the kaolin powder particles characteristics [large pore volume (0.019 cm3g–1) and pore size (29.20 nm)] were attributed to the interconnection channels.Originality/valueHence, the macroscopic and microscopic pores achieved by dual-gradient DIW process make it possible to control the permeability and details of properties, precisely in the geological model.

Solar vapor generation, which combines the abundant solar energy and unpurified water, is regarded as a promising technique for water production. However, challenges remain in terms of unsatisfactory sunlight absorbability and slow water transportation. Herein, enlightened by scales of West African Gaboon viper, an efficient sunlight absorbability and water evaporation system has been developed by biomimetic snake-scale-like porous carbon (BSPC) from the carbonization of polycarbonate (PC) waste by ZnO. ZnO catalyzes the de-carboxylation of PC to form numerous micropores that act as porogens to introduce plenty of mesopores and macropores. Owing to the 3D interconnected hierarchical nanopores and rich oxygen-containing functional groups, the as-prepared BSPC exhibits high solar absorption (ca. 95%), low thermal conductivity (0.086 W m−1 K−1), superhydrophilicity, and superwettability. The combined merits endow BSPC with high solar-to-thermal conversion efficiency and fast water molecule transportation, and enable BSPC to demonstrate distinguished performance in interfacial solar-driven vapor generation. For instance, BSPC displays an evaporation rate of 1.58 kg m−2 h−1 under 1 kW m−2, conversion efficiency of 91%, and metallic ion/dye removal efficiency of over 99.99%, making it among the best carbon-based solar evaporators reported so far. This work provides a new opportunity for water purification by the fusion of bioinspired solar evaporation systems and sustainable carbon materials with well-defined microstructures.

Debinding is one of the most critical processes in metal paste injection 3D printing technology (MPI). In order to design the optimal debinding parameters, the debinding temperature, debinding time and heating rate were discussed from the perspective of dynamics. The results showed that there was a peak in liquid phase mass transfer during debinding, exhibiting the characteristics of migration with debinding temperatures. For gas phase mass transfer, when the temperature was 300 °C, the thermal debinding diffusion coefficient was the largest (9.7 × 10−5 cm2 s−1) and the corresponding debinding time was 3.5 h. By analyzing the activation energy of the debinding reaction, when the heating rate was 10 °C min−1, the activation energy required for the thermal debinding reaction was the smallest. Combined with the sintering process, the interwoven structural parts of the copper and cupronickel components were finally obtained. The average hardness of the polymetallic parts was 78.8 HV, and the density was 8.1 g cm−3.

In this work, three-dimensional thermal simulations of single 18650 lithium-ion battery cell and 75 V lithium-ion battery pack composed of 21 18650 battery cells are performed based on a multi-scale multi-domain (MSMD) battery modeling approach. Different cooling approaches’ effects on 18650 lithium-ion battery and battery pack thermal management under fast discharging and external shorting conditions are investigated and compared. It is found that for the natural convection, forced air cooling, and/or mini-channel liquid cooling approaches, the temperature of battery cell easily exceeds 40 °C under 3C rate discharging condition. While under external shorting condition, the temperature of cell rises sharply and reaches the 80 °C in a short period of time, which can trigger thermal runaway and may even lead to catastrophic battery fire. On the other hand, when the cooling method is single-phase direct cooling with FC-72 as coolant or two-phase immersed cooling by HFE-7000, the cell temperature is effectively limited to a tolerable level under both high C rate discharging and external shorting conditions. In addition, two-phase immersed cooling scheme is found to lead to better temperature uniformity according to the 75 V battery pack simulations.

We use the electrochemical deposition method to couple anodized MoO3 films with MoS2 and g-C3N4 (graphitic carbon nitride). The XRD, SEM, and XPS results show that MoS2/MoO3 and g-C3N4/MoO3 heterojunctions form. The coupling with MoS2 or g-C3N4 remarkably enhances the UV and visible light absorption and slightly increases the bandgap of the MoO3 film. Meanwhile, the loading amounts of MoS2 and g-C3N4 have little impact on their optical properties. The coupling with MoS2 or g-C3N4 facilitates the separation and transfer of the photogenerated charges in the MoO3 films. The photocatalytic activity of the MoO3 films is increased by 2.74 and 3.11 times by coupling with MoS2 and g-C3N4, respectively. The photocatalytic activity improvement should ascribe to the Z-scheme systems’ formation. In the Z-scheme systems, photogenerated holes in the valence bands of MoS2 and g-C3N4 would combine with photogenerated electrons in the conduction band of MoO3. The separation of photogenerated electrons in the conduction bands of MoS2 and g-C3N4 and photoexcited holes in the valence band of MoO3 is achieved spatially. The slight performance difference of MoS2/MoO3 and g-C3N4/MoO3 composite films should attribute to the oxidizing ability difference of the photogenerated electrons in the conduction bands of MoS2 and g-C3N4.

Hydrogel has been regarded as one of the most promising candidates for next-generation solar evaporation technology to produce freshwater from non-potable water. However, synthesizing hydrogel absorbers that can precisely regulate water state and significantly reduce the water vaporization enthalpy remains a grand challenge. Herein, we report the rational design of a novel hydrogel hybrid solar evaporator constructed by poly(vinyl alcohol) and sodium lignosulfonate (SLS), with addition of carbon nanotube as a light absorption material. The abundant sulfonate and hydroxyl groups of SLS enhance the interplay between hydrogel and water molecule through electrostatic interaction and hydrogen bond. As such, the presence of SLS not only remarkably promotes the hydrophilicity and water transport of hydrogel, but also precisely tunes the state of water molecule and the content of intermediate water for reducing the water vaporization enthalpy. The combined advantageous features endow the as-prepared hydrogel with an evaporation rate up to 2.09 kg m-2 h-1 under 1 Sun illumination, along with good anti-acid/basic abilities, antibacterial property, high salt-tolerance, and self-cleaning capability in purifying different types of wastewater. Finally, an outdoor solar seawater desalination device is designed to generate drinking water from seawater. The daily drinking water production amount per square meter is ca. 13 kg, which satifies the five adults' daily water consumption (12.5 kg). The present study highlights that rationally constructing the molecular architecture of hydrogel and tuning the interplay between water and hydrogel are effective strategies to fabricate advanced hydrogel solar evaporators for addressing the global freshwater shortage.

In present work, the microwave dielectric properties of CaTiO3-added Li2Zn3Ti4O12 ceramics prepared by the conventional solid-state method have been investigated. The phase composition, microstructure and microwave dielectric properties of (1 − x) Li2Zn3Ti4O12–x CaTiO3 (x = 3, 4, 5, 6 and 7 wt%) ceramics were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), EDS and network analyzer. The XRD and EDS results indicated that the ceramics involved Li2Zn3Ti4O12 and CaTiO3 phases. The SEM micrographs shown that as the CaTiO3 contents increased, the average grain size of the composition ceramics decreased. The microwave dielectric properties of the composition ceramics can be effectively controlled by varying the CaTiO3 contents. The values of dielectric constant (er) and τf of the composition ceramics were increased, and the quality factor (Q × f) was decreased with increasing the CaTiO3 contents. Typically, a new temperature stable microwave dielectric material of 0.94 Li2Zn3Ti4O12–0.06 CaTiO3 with excellent microwave dielectric properties of er = 21.7, Q × f = 61,490 GHz, and τf = + 2.68 ppm/°C was attained when sintered at 1175 °C for 4 h.

With MOPA configurations, a fiber coupled 1 kW repetitively acousto-optic Q-switched cw-pumped Nd:YAG rod laser is studied in detail. Low-order aberrations introduced by MOPA systems add difficulties to high efficiency of optical fiber coupling. With 300 μm 0.22 NA fiber coupled, an average power of 1022 W along with 102 ns pulse width at 20 kHz is obtained with 11.6% electro-to-optical efficiency and 93% fiber coupling efficiency, and the corresponding peak power is about 500 kW. The power stability is better than 0.93% at the maximum output power in an hour.

Objective: This study aimed to explore the efficacy of interventional micro-circulation system (IMCS), combining the stromal cell-derived factor 1 (SDF-1)/type I collagen/chitosan composite membrane into TEB in treating with the model of goat tibial LSBD. Methods: The model of goat tibial LSBD was constructed by introducing the IMCS and SDF-1 guiding membrane. Perfusion treatment of CXCR4 + -BMSCs and BMP-2 was performed on the animal model, general conditions of the goats were observed, and changes in the goat's tibia was observed at different time points through imaging techniques. Using RNA extraction and reverse transcription, cDNA was acquired. Alkaline phosphatase (ALP), core binding factor-α1 (Cbfα1) and osteocalcin (OC) content, as well as the mRNA of transformation growth factor-β1 (TGF-β1) in fixed bone tissue samples of the goat, were detected by real-time quantitative PCR (RT-qPCR). Results: The model of goat tibial LSBD repaired by IMCS was successfully constructed. The standing, walking and running functions of the goat recovered well after two months; and imaging revealed that the callus was closely connected and most of the scaffold materials of TEB were absorbed. The detection of the ALP gene in bone tissue samples failed, and the amplified product was non-specific. Furthermore, the levels of Cbfα1, OC and mRNA of TGF-β1 were significantly higher than in normal bones (P < 0.05). Conclusion: The combination treatment of IMCS with slow controlled drug delivery systems and TEB functioned well in repairing goat tibial LSBD. This is a novel method for repairing bone defects.

A facile method for preparing monodisperse NaYF4@SiO2@Au core-shell nanocomposite was developed. Transmission electron microscopy (TEM) as well as EDX (energy dispersive X-ray) was used to characterize the samples. The TEM showed the composite was a core-shell structure, spherical,with the uniform size of about 100 nm. TEM and EDX revealed that the NPs were coated with a layer of SiO2 and Au shell. The core shell structure of NaYF4@SiO2@Au nanocomposite could dispersed in water easily. More importantly, after being coated with SiO2 and Au, it was feasible for function by -SH and-NH2 groups, respectively. The forming process of the Au shell was monitored with TEM. The mechanism of coating Au shell was discussed in detail. It is expected that the core shell nanoparticle will act as multifunctional molecular imaging probes, such as positron emission tomography (PET), magnetic resonance imaging (MRI), optical imaging (OI), or contrast agent for sensing and detection.

Fluoride nanoparticles with multiform crystal structures and morphologies were successfully synthesized by a facile, effective, and environmentally friendly coprecipitation method. Transmission electron microscopy (TEM) was used to characterize the nanoparticles. The nanoparticles were modified by PEI, CTAB, PAA and Ci, respectively. It was feasible for function by -COOH and -NH2 groups, due to the surface modification. Moreover, different surface modifications of the nanoparticles were examined. The possible formation mechanisms for fluoride nanoparticles with surface modification were presented in detail. More importantly, it is expected to be widely applied to biomedicine.

Three dimensional (3D) printing has attracted much more interest from the research community due to its ability to make complex structures with high resolution and simplified fabrication process. Here we constructed composited electrolyte with certain thickness for the application of low temperature of solid oxide fuel cells. The fabrication of a thin and dense Sm-doped ceria composite electrolyte layers with the thickness about 1200 μm utilizing paraffin-based slurry were investigated. To optimize the assembled cells, 1.7 wt. % glassfiber was introduced and an amazing electrochemical performance was observed. The maximum power density can reach 448 mW/cm2, 20% higher than the one without glassfiber and the open-circuit voltage is approximately 1.0 V at 550 °C. It is of great potential for 3D printing technology to develop low temperature solid fuel cells with designed mini-structures.

MgB2 bulks codoped with graphene and nickel with a composition of Mg1−xNixB1.9G0.1 (x = 0.02, 0.04 and 0.06) have been synthesized by an in situ reaction method. The combination effect of graphene and Ni codoping on microstructure, critical current density (Jc) and irreversibility field (Hirr) of MgB2 has been studied. Graphene doping is more efficient than other forms of carbon doping for modifying the MgB2 microstructures due to the two-dimensional structures. The doping of Ni is confirmed to eliminate the porosity present in the graphene-doped sample by the assistance of a Mg–Ni eutectic liquid at low temperature. The results clearly indicate that graphene and Ni codoping are cooperative in improving the Jc of MgB2 bulks in the zero fields due to the superior grain connectivity and high density. The flux pinning by carbon substitution and MgNi2.5B2 nano-inclusions is expected to enhance the Jc value at high magnetic fields. However, the positive action has been extremely offset by the aggregation of impurity structures such as MgNi2.5B2, MgO and over-doped graphene. Consequently, a delicate balance between graphene and Ni, homogeneous dispersion of nano-inclusions in MgB2 grains and more lattice defects are further required to increase the flux pinning centers.

Potassium-doped titania (K-doped TiO2) films had been prepared by molten-salt treatment in KNO3 for Ti-TiC coatings, containing different amount of TiC, in order to achieve enhanced activity of the films. When the amount of TiC is lower than 40%, the partial surface morphology of K-doped TiO2 films clearly shows a nanosheet structure, and the formed nanosheets could increase the accessible surface area. The results show that K-doped TiO2 with composite crystals has formed with different amount of TiC, and the relative Raman peak intensity of Ti-O-K bonding is highest for 40% TiC. Even avoiding high adsorption of K-doped TiO2 films, the films exhibit excellent and stable photocatalytic activity. With increasing the amount of TiC, the photocatalytic activity of K-doped TiO2 films first increases then decreases, reaching the highest for 40% TiC.

The hold-off capacity of high-power repetitively acousto-optic Q-switched Nd:YAG rod laser with different placement methods in the flat-flat cavity is explored in detail. Five types of typical placement are illustrated and it is confirmed that two orthogonally placed longitudinal wave Q-switches which are placed at the larger beam width in the laser cavity have better performance than others in terms of the theory, simulation and experiment. An average power of 408 W along with 79 ns pulse width at 15 kHz is obtained with 12.98% electro-to-optical efficiency and 344 kW peak power.

A biodegradable UV-cured resin has been fabricated via stereolithography apparatus (SLA). The formulation consists of a commercial polyurethane resin as an oligomer, trimethylolpropane trimethacrylate (TEGDMA) as a reactive diluent and phenylbis (2, 4, 6-trimethylbenzoyl)-phosphine oxide (Irgacure 819) as a photoinitiator. The tensile strength of the three-dimensional (3D) printed specimens is 68 MPa, 62% higher than that of the reference specimens (produced by direct casting). The flexural strength and modulus can reach 115 MPa and 5.8 GPa, respectively. A solvent-free method is applied to fabricate graphene-reinforced nanocomposite. Porous bone structures (a jawbone with a square architecture and a sternum with a round architecture) and gyroid scaffold of graphene-reinforced nanocomposite for bone tissue engineering have been 3D printed via SLA. The UV-crosslinkable graphene-reinforced biodegradable nanocomposite using SLA 3D printing technology can potentially remove important cost barriers for personalized biological tissue engineering as compared to the traditional mould-based multistep methods.

We fabricated Sr and Ca-doped CuAlO2 compacts from the mixed powder of CuO, Cu2O, Al2O3, and SrO or CaO by multi-pass hot pressing followed by spark plasma sintering (SPS). The XRD results showed the reaction of CuO, Cu2O and Al2O3 was rather complete and only CuAlO2 single phase was formed when the additive amount of SrO or CaO was appropriate. Multi-pass hot pressing increased the relative density and the usage of plate-like Al2O3 as reaction raw material enhanced the orientation degree. In spite of performance improvement conflicts through elemental doping, density increase and orientation improvement, the measurement on the thermoelectric performance indicated that the electrical resistivity, Seebeck coefficient, power factor, dimensionless figure of merit (ZT) were improved to varying degrees through the synergetic action of elemental doping, density increase, and orientation control. The highest power factor and ZT of the Ca-doped CuAlO2 compacts reached 1.54 × 10−4 W m−1 K−2 and 0.015 at 973 K, respectively. The thermoelectric performance was higher than those of CuAlO2 at the same temperature in published work before.

A novel glass-free MoO3-based dielectric ceramic of Li2Ni2(MoO4)3 was prepared by the conventional solid-state route. The phase compositions, microstructures and microwave dielectric properties were investigated. The XRD data analysis shown that Li2Ni2(MoO4)3 belongs to an orthorhmbic lyonsite-type structure with Pmcn (62) space group during the sintering temperature range from 650 to 725 °C. The Li2Ni2(MoO4)3 ceramic could be well densification at 700 °C for 2 h with 96.8% relative density and exhibited excellent microwave dielectric properties: er = 9.2, Q × f = 41,064 GHz, τf = − 68.86 ppm/°C. Moreover, the Li2Ni2(MoO4)3 ceramic shown excellent compatible with Ag electrode, which makes it a promising candidate for advanced substrate materials in low temperature co-fired ceramic applications.

BiOBr/Bi2O3/BiO0.67F1.66 ternary composites were designed and prepared via a facile chemical precipitation method and their photocatalytic performances were assessed by degradation of rhodamine B (RhB) under visible light illumination. The highest activity was achieved over BiOBr/Bi2O3/BiO0.67F1.66 ternary composite with Br/F molar ratio of 1:1, which approximately degraded 98.61% of RhB after just 15min irradiation. Contrast to pure BiOBr, the enhanced photocatalytic performances of the ternary composites could be attributed to their larger specific surface areas and multiple charge carrier transfer pathways, which efficiently promoted separation of charge carriers. Besides, the formation mechanism of the composites was discussed in detail as well.

We prepared TiO2/SnOx (x = 1, 2) composite coatings through ball milling followed by calcination. The composite coatings were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), spherical aberration corrected scanning transmission microscopy (Cs-corrected STEM), X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR) and other techniques. Bulk oxygen vacancies in the form of vacancy clusters rather than individual sites were directly observed by Cs-corrected STEM. With an increase in the calcination temperature from 873 K to 1073 K or holding time from five hours to ten hours, the concentration of bulk defects also increased. On the other hand, the photocatalytic activity of the as-prepared samples for degrading MB dye increased with the concentration increase of bulk defects. Sample 973 K-10 h showed the best photocatalytic activity whether under the irradiation of UV light or visible light. With a further increase in the concentration of bulk oxygen vacancies, the photocatalytic activity decreased, although surface Ti3+ defects appeared. In other words, a moderate concentration of bulk defects could benefit the enhancement of the photocatalytic activity of the as-prepared samples. Ball milling followed by calcination is an effective method to introduce defects such as oxygen vacancies.

We prepared amorphous and anatase TiO2 nanotube-array (NA) films by anodic oxidation followed by annealing. We characterized the as-prepared samples with X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), photoluminescence spectrum (PL), electron spin resonance (ESR), and so on. The XPS and EPR spectra show that the surface of amorphous TiO2 NA films absorbs chemically dissociated water much easier than that of anatase TiO2 NA films. The amorphous TiO2 NA films show higher photocatalytic activity than anatase TiO2 NA films in RhB degradation under the irradiation of simulated solar light. Furthermore, the photocatalytic activity of amorphous TiO2 NA films ascribes to visible-infrared light rather than UV light. On the contrary, that of anatase TiO2 NA films mainly attributes to UV light. The EPR spectra, photocurrent density and photocatalytic activity evaluation reveal that totally different mechanisms play the key role in photocatalytic degradation of RhB dye for amorphous and anatase TiO2 NA films. For amorphous one, visible light excites electrons from RhB dye molecules and they quickly transfer to the conduction band of amorphous TiO2 NA films, which acted as electron trapping centers. The electron loss of RhB molecules results in their oxidation. In a word, the dye self-sensitization is responsible to the high photocatalytic degradation of RhB dye. On the other hand, the classical theory of photocatalysis could perfectly explain the photocatalytic activity of anatase one. Therefore, this work confirmed on the fact that amorphous TiO2 is inactive. This work completely clarified the origin of high photocatalytic activity of amorphous TiO2.

In this paper, we propose a novel effective optical smoothing scheme to suppress laser plasma instabilities (LPIs) by time-dependent polarization rotation (TPR) on a picosecond timescale. The polarization rotation with time-dependent frequency is generated by the superposition of chirped light pulses with dynamic frequency shift and counter-rotating circular polarization. Compared to light without polarization rotation or pulse chirping, such superposed light with TPR has a broader spectrum and lower temporal coherence. Using the one-dimensional fluid laser-plasma-instability code (FLAME) and PIC simulation, TPR is demonstrated working well in suppressing parametric backscattering, which provides an effective approach to suppress LPIs. In the meantime, a significant improvement of irradiation uniformity of the chirped pulses is achieved by the introduction of proper spatial phase modulation and grating dispersion.