Search

In order to obtain lithium disilicate glass-ceramics for dental restoration with both high strength and high translucency, lithium disilicate glass-ceramics with different MgO contents were prepared by melt-casting and heat treatment method. The effects of MgO content on the crystallization temperature, microstructure and flexural strength of lithium disilicate glass-ceramics were investigated. The results indicate that Mg2+ exists in the form of [MgO 4 ] in the network of lithium disilicate glass-ceramics when the MgO content is 0.56 mol% (M0.56), which is beneficial to increasing the homogeneity and thermal stability of the glass system, and short rod-like lithium disilicate crystals can be formed after heat treatment at 840°C. Thus, the obtained lithium disilicate glass-ceramics exhibit excellent comprehensive performance, with the flexural strength being 312 ± 23 MPa, and the average transmittance of visible light being 37.3% (d = 1.62 mm). Especially, the glass-ceramic sample shows better translucency than the commercially available products. The research results are of great significance for developing high performance lithium disilicate glass ceramics and promoting its broad application in the field of dental restoration. [Display omitted] • Lithium disilicate glass-ceramics with high flexural strength and good translucency were prepared. • The coordination number of Mg2+ with oxygen in the glass-ceramic is closely related to the content of MgO. • [MgO 6 ] is beneficial to crystallization of lithium disilicate and improvement of strength, but is not good for translucency. • [MgO 4 ] is conducive to improving the uniformity of lithium disilicate glass-ceramic, which is good for translucency. [ABSTRACT FROM AUTHOR]

In this paper, Zn-doped VO 2 nanoparticles have been successfully fabricated by a two-step hydrothermal-annealing process, and the thermally induced visible light transmittance enhancement of Zn-doped VO 2 has been studied for the first time. It is found that Zn-doped VO 2 not only exhibits excellent solar modulation ability (Δ T sol = 15.27%) but also can reduce the phase transition temperature and increase the visible light transmittance after the heat-induced phase transition (ΔT lum =+5.78%). Moreover, with the increase of Zn doping concentration, the phase transition temperature (T c) and phase transition hysteresis (Δ T) both decrease. It is shown that the Zn-doped VO 2 -PU films not only have good solar light modulation ability and properties of improving visible light transmission after phase transition, but also have good durability. The research result is of great significance for improving the visible light transmittance after phase transition and realizing the practical application of VO 2 in the field of smart windows. [Display omitted] • Zn-doped VO 2 nanoparticles were prepared by a two-step hydrothermal annealing method. • The visible light transmittance of Zn-VO 2 film doped with 2.50 at% Zn increased by 5.74% after heat-induced phase transition. • Compared with pure VO 2 film, the solar modulation ability of Zn-2-VO 2 film is increased by 110% (ΔTsol = 15.27%). • With the increase of Zn2+ doping concentration, the phase transition temperature (T c) decreases linearly (~-0.49 K/at% Zn). [ABSTRACT FROM AUTHOR]

In order to obtain ideal Cs x WO 3 powders that combine transparent thermal insulation and outstanding photocatalytic degradation of pollutants, Tm3+, Yb3+ co-doped Cs x WO 3 ((Tm, Yb)-Cs x WO 3) urchin-like nanoclusters were synthesized in situ by facile solvothermal reaction and subsequent heat treatment. The effects of Tm, Yb co-doping on the crystal structure, adsorption/photocatalysis, visible transmittance and near-infrared (NIR) absorption of Cs x WO 3 particles were investigated. The results indicate that the as-prepared (Tm, Yb)-Cs x WO 3 samples exhibit significantly improved photocatalytic activity while maintaining excellent visible transmittance and NIR shielding properties. In particular, sample 2T-10YC with 2 mol% Tm/10 mol% Yb co-doped Cs x WO 3 exhibited highest photocatalytic activity with the photocatalytic degradation efficiency of Rhodamine B attaining to 69.86%, and its films prepared from dispersion of powder samples exhibit high transparent heat shielding performance with visible transmittance 71.4% and NIR shielding rate 90.8%, respectively. The enhanced photocatalytic activity of the sample can be ascribed to the lattice distortion and decrease of band gap caused by Tm, Yb co-doping, and the increased light utilization due to the formation of impurity energy level and multiple light reflection caused by hierarchical structure can also enhance the photocatalytic activity. Moreover, the introduction of Tm and Yb elements can also refine the Cs x WO 3 grains, which is conducive to improving the visible transmittance. Thus, the as-prepared bifunctional (Tm, Yb)-Cs x WO 3 particles will have potential application prospects in the field of energy-saving and environmental purification. Urchin-like Tm, Yb-codoped Cs x WO 3 nanoclusters have been successfully synthesized via a facile solvothermal method. The (Tm, Yb)-Cs x WO 3 particles have excellent bifunctional features with exhibiting high photocatalytic degradation of Rhodamine B and transparent heat insulation performance simultaneously. The photocatalysis enhancement mechanism of the (Tm, Yb)-Cs x WO 3 particles was discussed. Image 1 • Urchin-like Tm, Yb-codoped Cs x WO 3 particles were synthesized by solvothermal method. • Tm, Yb-Cs x WO 3 particles have bifunctional features: heat shielding and photocatalysis. • Tm, Yb co-doping can inhibit the recombination of photogenerated electron-hole pairs. • Tm, Yb co-doping could greatly enhance the photocatalytic activity of Cs x WO 3. [ABSTRACT FROM AUTHOR]

The use of environment-friendly biomass for the preparation of functional materials has attracted increasing attention. In this study, bacterial cellulose (BC) was prepared from fruit waste via kombucha fermentation without involving any secondary enzymatic hydrolysis treatments. A three-dimensional network of bacterial cellulose aerogels (BCAs) with ultralow density (5.693 mg/cm3), high porosity (98–99%), and low thermal conductivity (23.4 mW/(m·K)) were obtained using two directional freeze-drying techniques. Here, the proposed freezing method can not only control the concentration of BC but make access to fibres reassembly by extremely low temperature freezing (−196 °C), which can further form a multi-stage pore structure. To increase their compressive resistance and optimise their ability to adsorb organic solvents and oils, the aerogels were subjected to chemical vapour deposition using methyltrimethoxysilane. The modified biomass aerogel exhibits a compression resilience exceeding 90% and achieves a hydrophobic angle of approximately 146.4°. This cost-effective, environmentally friendly, and highly efficient BCAs can be employed to treat oil spills and industrial waste. [Display omitted] • Fruit waste can be turned into a powerful adsorbent material for oil and organic solvents. • The fermentation offers ultra-low cost due to the absence of enzymatic hydrolysis. • The silane-covered aerogel provides excellent compression resilience for circulating sorption. • Adjustment of multistage pore structure by twice directed freezing method facilitates sorption. • Lightweight porous biomass BCA exhibits ultra-low thermal conductivity of 23.4 mW/(m·K). [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Controllable synthesis of Cs x WO 3 were conducted using organic acid as deoxidizer. • Tartaric acid exhibits the best reducibility in the synthesis of Cs x WO 3. • The reduction mechanism of different organic acid for generating W5+ was studied. • Cs x WO 3 formed with oxalic acid after annealing has the best visible transmission. Abstract In order to further improve the transparent thermal insulation of Cs x WO 3 , controllable synthesis of Cs x WO 3 nanoparticles from cheap and environment-friendly Na 2 WO 4 ·2H 2 O and Cs 2 SO 4 by solvothermal method was conducted using different organic acids as reducing agents. The reducibility and reduction mechanisms of citric acid, tartaric acid and oxalic acid were investigated. It has been confirmed that tartaric acid has the strongest reducibility, and could produce the most W5+ and oxygen vacancies in the Cs x WO 3 products before heat-treatment. The Cs x WO 3 nanoparticles synthesized with oxalic acid after heat-treatment exhibited the best crystallinity and the visible light transmission was about 10% higher than that of tartaric acid and citric acid. It is significant for the low-cost production of Cs x WO 3 nanoparticles with higher transparent thermal insulation performance. [ABSTRACT FROM AUTHOR]

In order to further improve the flexural strength of lithium disilicate glass-ceramic, surface strengthening by ion exchange using Rb, Cs nitrates has been studied for the first time. The influences of ion exchange using rubidium and cesium salts on the flexural strength and corrosion resistance have been investigated. It was found that the mechanical properties of the lithium disilicate glass-ceramic could be increased greatly by the ion exchange in rubidium nitrate (RbNO 3 ) salt. After ion exchange for 4 h in RbNO 3 salt, the flexural strength and microhardness increased from 169 MPa and 587 kgf mm −2 (5.75 Gpa) of the original lithium disilicate glass-ceramic to 493 MPa and 654 kgf mm −2 (6.4 Gpa), respectively. Moreover, the corrosion resistance of the lithium disilicate glass-ceramic was further improved by ion exchange in rubidium and cesium nitrate salts. Furthermore, the maximum thickness of the ion exchange layer using RbNO 3 and CsNO 3 was only 4.3 µm and 0.45 µm respectively. Such a thin exchange layer, which will only require very low Rb + , Cs + ions exchange amount, indicates that the molten salts of RbNO 3 and CsNO 3 can be reused for many times. So it is suggested that surface strengthening of lithium disilicate glass-ceramic by ion exchange using Rb, Cs nitrates is cost-efficient and very suitable for the actual production and applications. [ABSTRACT FROM AUTHOR]

Pt-doped K x WO 3 nanorods with excellent near-infrared shielding and heat insulation performance were prepared by solvothermal reduction method using cheap sodium tungstate as raw materials. The effects of K/W ratio and Pt doping on the microstructure, morphology and transparent heat insulation performance of K x WO 3 particles were investigated. It was found that Pt doping contributed to increasing the content of W in reduced state (W 5+ and W 4+ ), promoting the uniform growth of hexagonal K x WO 3 nanorods and decreasing the particle size. Compared with the undoped K x WO 3 particles, Pt-doped K x WO 3 samples exhibited improved near-infrared shielding and heat insulation properties. Particularly, when K/W was 0.4, the incorporation of trace Pt (0.1 mol%) greatly improved the near-infrared shielding and transparent insulation properties of K x WO 3 particles, which is ascribed to its lower powder resistivity and more content of W in reduced state (W 5+ and W 4+ ). Whereas too much Pt-doping amount tended to decrease the visible light transmittance of K x WO 3 . The mechanism of Pt doping promoting the W 5+ /W 4+ formation and improving the heat insulation of K x WO 3 were discussed. It is suggested that the trace Pt-doped K x WO 3 particles with excellent transparency and heat insulation properties are more suitable for the preparation of transparent insulation films and have broad applications in the field of energy-saving window glasses. [ABSTRACT FROM AUTHOR]

Adsorption and photocatalytic degradation are effective ways to remove pollutants from water and achieve purification effect. In order to obtain composite aerogels with high adsorption capacity and visible light photocatalytic performance, a new type of Ag/AgBr/AgI@SiO 2 composite aerogels (ABIS) was prepared by in-situ synthesis and supercritical drying. It has been proved that the pore size, pore volume and specific surface area of the composite aerogels can be effectively improved by using N, N-dimethylacetamide (DMAC) as pore expanding agent. The as-prepared Ag/AgBr/AgI@SiO 2 composite aerogels with large pore volume, large pore size and uniform pore network structure not only showed high adsorption capacity for tetracycline, but also exhibited high separation and migration efficiency of photo-generated carriers, thereby being capable of reducing the recombination rate of photo-generated electron-hole pairs. Especially, the composite aerogel ABIS-2-N2 with loading 0.01 mol% Ag/AgBr/AgI and adding DMAC as pore-expanding agent, showed the highest adsorption/photocatalytic degradation efficiency for antibiotic tetracycline under visible light, and meanwhile exhibited high performance of photocatalytic degradation of tetracycline and recycling stability in the range of pH= 2–10. The superoxide anion (·O 2 -) was proved to be the main active substance to degrade tetracycline by the active substance capturing experiment. This work provides a new effective strategy for preparing composite aerogel materials with large pore volume, large pore size and adsorption/photocatalysis synergistic action, and the as-prepared composite aerogel will have important application value in the field of water purification. [Display omitted] • Ag/AgBr/AgI@SiO 2 composite aerogel with large pore volume and pore size was prepared. • The pore structure of the composite aerogel can be regulated by N,N-dimethylacetamide. • The porous structure of aerogel can push the photocatalytic degradation of antibiotic. • The composite aerogels exhibit efficient adsorption/photocatalytic synergistic effect. [ABSTRACT FROM AUTHOR]

The construction of semiconductor heterojunction photocatalyst is an effective way to improve the photocatalytic performance. In this study, a novel S-type heterojunction Cs x WO 3 /BiOI photocatalyst, with both photothermal effect and good photocatalytic activity, was constructed in graphene aerogel. The as-prepared composite aerogel showed high adsorption/photocatalytic activity and cycling stability for removal of enrofloxacin. Especially, the aerogel sample 1.0CIGA with Cs x WO 3 :BiOI molar ratio 1.0 showed a high removal efficiency of enrofloxacin with attaining to nearly 100% within 60 min. Moreover, the photothermal conversion effect of Cs x WO 3 can further promote the photocatalytic degradation reaction efficiency. The degradation intermediate products and possible degradation pathways of enrofloxacin were analyzed and explored. In addition, the energy band structure and charge transfer mechanism of Cs x WO 3 /BiOI heterojunction were studied by density functional theory (DFT) and other test methods. This work is of great significance for developing efficient photocatalytic materials and the as-prepared Cs x WO 3 /BiOI@graphene composite aerogel with high adsorption/photothermal catalysis will have promising applications in the field of environmental purification. [Display omitted] • A novel s-type Cs x WO 3 /BiOI heterojunction was constructed in graphene aerogel. • The composite aerogels showed excellent removal efficiency for enrofloxacin. • The degradation pathway of enrofloxacin by Cs x WO 3 /BiOI@graphene aerogel was analyzed. [ABSTRACT FROM AUTHOR]

Adsorption and photocatalytic degradation of pollutants are both considered to be effective ways of removing pollutants from environment. Here, a novel highly porous BiOBr/Cs x WO 3 @SiO 2 composite aerogel with adsorption/self-heating photothermal catalysis synergistic effect was constructed using melamine resin as template. Multiple detection results demonstrated that the template melamine resin is conducive to expanding pore volume of the composite aerogels. Moreover, owing to the high pore volume and excellent photothermal conversion as well as the BiOBr/Cs x WO 3 heterojunction catalysis effect, the composite aerogel with BiOBr/Cs x WO 3 molar ratio 2:1 exhibited the most efficient removal of antibiotic tetracycline from water, with the adsorption/self-heating photothermal catalytic degradation rate of tetracycline being close to 100% after 30 min of darkroom adsorption and 60 min of light irradiation, and it also showed high removal efficiency of other pollutants. The efficient adsorption/self-heating photothermal synergistic catalysis mechanism and photocatalytic degradation pathway of tetracycline have been analyzed. This work will provide a new idea for constructing SiO 2 -based composite aerogel photocatalytic materials and the adsorption/self-heating photothermal catalytic synergetic effect will be a promising way for environment purification. [Display omitted] • BiOBr/Cs x WO 3 @SiO 2 composite aerogels with high pore volume were constructed. • The addition of melamine resin can help to obtain highly porous composite aerogel. • The composite aerogel shows adsorption/photothermal catalytic synergistic effect. • The BiOBr/Cs x WO 3 heterojunction can greatly improve the photothermal catalysis. • The mechanism of self-heating photothermal synergistic catalysis has been analyzed. [ABSTRACT FROM AUTHOR]

In order to develop a novel high efficient energy-saving film, Li, Cs co-doped tungsten bronze (Li m Cs n WO 3 , m + n = 0.35) nanoparticles with excellent near-infrared (NIR) shielding properties were prepared by a facile solid state reaction method. It has been clarified that Li+-doping can control the crystal growth of Cs x WO 3 , resulting in formation of hexagonal nanorods with high aspect ratio, which is conducive to enhancing the local surface plasmon resonance (LSPR) and improving the NIR shielding performance. The as-prepared Li m Cs n WO 3 films from dispersion of nanoparticles with Li/Cs = 0.2:0.8 could exhibit excellent transparent heat shielding performance with the maximum visible light transmittance 75.18% and NIR shielding rate 97.65%. Moreover, the temperature difference between the outside surface and air in the box for the film glass during the thermal insulation test is 3 times that of ordinary glass. In addition, the regulation mechanism of Li+-doping on the crystal structure and NIR shielding properties were investigated. It is found that the mixed alkali effect in the Li m Cs n WO 3 nanoparticles is favorable for obtaining hexagonal Cs 0·32 WO 3 crystal grains with improved NIR shielding performance and stable crystal structure. This work has great significance for promoting industrial production and practical applications in the field of energy-saving window films. [Display omitted] • Li m Cs n WO 3 nanorods were synthesized by a facile solid-state reaction method. • Li, Cs co-doping can lead to the growth of Li m Cs n WO 3 nanorods with high aspect ratio. • The mixed alkali effect is helpful for forming stable hexagonal nanorods. • The Li m Cs n WO 3 nanorods exhibit improved near infrared shielding performance. [ABSTRACT FROM AUTHOR]

Highlights: [•] Dispersion and stability of Cs0.33WO3 particles were investigated and optimized. [•] Excellent dispersion of Cs0.33WO3 particles was achieved with titanate coupling agent. [•] The as-prepared Cs0.33WO3 coating exhibited higher near-infrared shielding ability. [Copyright &y& Elsevier]

Highlights: [•] TiO2 and Si-OCP composite coatings were synthesized on zirconia ceramics. [•] Low temperature degradation of ZrO2 substrate could be suppressed by TiO2 layer. [•] Si-doped OCP coating was firstly synthesized by biomimetic method. [ABSTRACT FROM AUTHOR]

Cesium tungsten bronze (Cs x WO 3) has potential applications in the field of energy-saving window glasses due to its visible light transparency and near-infrared (NIR) shielding ability. In order to further improve the NIR shielding performance and realize low-cost large-scale production of tungsten bronze, in this work, K, Cs co-doped t ungsten bronze (K m Cs n WO 3 , m + n = 0.32) were fabricated by facile solid-state reaction method. It has been clarified that K, Cs co-doping could promote the formation of W5+ and thus enhance the localized surface plasmon resonance (LSPR). Moreover, the K, Cs co-doping is conducive to the formation of single or double bond between W5+ and O, and the double bond W5+=O can increase the strength of small polaron effect and greatly improve the NIR shielding at wavelength 730–1100 nm. Particularly, when K:Cs (mol) = 0.2:0.8, the maximum visible light transmittance of 66.89% and near-infrared shielding rate of 98.25% could be achieved respectively. This work is of great significance for developing Cs x WO 3 tungsten bronze with improved NIR shielding performance and realizing its industrial production and practical applications in the field of energy-saving windows. Image 1 • Using the solid-phase method to obtain low-cost, high-performance K m Cs n WO 3 powder. • The bonding mode of W5+ and O in the K m Cs n WO 3 powder is affected by K/Cs molar ratio. • The W5+=O in the particle can promote small polaron effect and infrared shielding. • K, Cs co-doping is beneficial to regulate the small polaron and LSPR intensity. [ABSTRACT FROM AUTHOR]

Abstract: The low temperature coal pyrolysis technology and the atmospheric and vacuum tar distillation were combined to establish a low-rank coal based process system, which can co-produce semicoke, syngas and light oil. And then the simulation models of key units and whole system were also developed. As the calculation results, the lignite with 41.0% moisture can be converted to semicoke, syngas and light oil. Their yields are 42.31%, 8.47% and 4.10%, respectively. The distribution shows that the energy consumption and the exergy loss of drying unit are all the largest with 323.1 kW and 300.1 kW, and those of pyrolysis unit rank the second with 196.2 kW and 131.4 kW. Based on a graphic illustration of energy analysis, the reasons of energy consumption and depreciation were explained. The energy grades of products are increased or decreased at the cost of energy consumption and depreciation. A heat integrated co-production system was proposed to assess the energy saving potential of the original system. The energy consumption and the exergy loss for the whole system have been reduced by 14.9% and 10.9%, and the heat integration effect of drying unit has a relatively larger influence on that of the whole system. [Copyright &y& Elsevier]

Although pure silicon oxycarbide (SiOC) aerogels have unique properties of low density and high temperature resistance, they are still difficult to apply at a large scale due to brittleness. To overcome this drawback, a strong boron nitride/silicon oxycarbide (BN/SiOC) aerogel composite with high-temperature resistance and thermal insulation was prepared by the sol-gel method and pyrolysis of the precursor aerogel. The microstructural, mechanical and thermal insulation properties of the composites were investigated, and the effect of the BN content on the microstructure and properties was also clarified. The results indicate that the obtained mesoporous composites exhibit low thermal conductivity (0.04–0.20 Wm−1 K−1) and high-temperature resistance (∼1300 °C). As the BN content increased from 0 to 15 vol %, the compressive strength of the composites increased from 2.2 to 20.3 MPa. The obtained composites exhibit considerable promise in high-temperature thermal insulation applications. Image 1 • The sol-gel method was developed for preparing BN/SiOC aerogel composites. • The mechanical properties of the composites were considerably improved by adding BN particles. • The BN/SiOC aerogel composites possess nanometre pore structures. • The composites have excellent thermal insulation performance at high temperature. [ABSTRACT FROM AUTHOR]