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Yttria-stabilized zirconia (YSZ) fiber composites are highly efficient thermal insulating materials; however, the poor thermal shock resistance limits their versatile applications. In the present study, YSZ fiber was mixed directly with Al2TiO5 fiber, which had an extremely low thermal expansion coefficient, to prepare YSZ−Al2TiO5 (ZAT) fiber composites by compression molding and heat treatment. The minimum thermal expansion coefficient of the prepared ZAT fiber composites was measured to be 7.74×10−6 K−1, which was 26% lower than that of the YSZ fiber composites (10.42×10−6 K−1). It was shown that the prepared ZAT fiber composites maintain the integrity after undergoing 51 thermal shock cycles between 1100 °C and room temperature. Whereas, YSZ fiber composites burst immediately after only one thermal shock cycle under the same condition. In addition, the ZAT fiber composites also exhibit considerable mechanical and thermal insulating performance.

Bi1−xSmxFe0.98Mn0.02O3 (x = 0, 0.02, 0.04, 0.06; named BSFMx) (BSFM) films were prepared by the sol-gel method on indium tin oxide (ITO)/glass substrate. The effects of different Sm content on the crystal structure, phase composition, oxygen vacancy content, ferroelectric property, dielectric property, leakage property, leakage mechanism, and aging property of the BSFM films were systematically analyzed. X-ray diffraction (XRD) and Raman spectral analyses revealed that the sample had both R3c and Pnma phases. Through additional XRD fitting of the films, the content of the two phases of the sample was analyzed in detail, and it was found that the Pnma phase in the BSFMx = 0 film had the lowest abundance. X-ray photoelectron spectroscopy (XPS) analysis showed that the BSFMx = 0.04 film had the lowest oxygen vacancy content, which was conducive to a decrease in leakage current density and an improvement in dielectric properties. The diffraction peak of (110) exhibited the maximum intensity when the doping amount was 4 mol%, and the minimum leakage current density and a large remanent polarization intensity were also observed at room temperature (2Pr = 91.859 μC/cm2). By doping Sm at an appropriate amount, the leakage property of the BSFM films was reduced, the dielectric property was improved, and the aging process was delayed. The performance changes in the BSFM films were further explained from different perspectives, such as phase composition and oxygen vacancy content.

Ba0.7Sr0.29La0.01TiO3 (BSLT) fibers with good crystallinity were prepared by the electrospinning method, and the flexible BSLT/PVDF composite membranes were prepared by a simple papermaking process. The fiber exhibited good fiber morphology after being heat-treated to 900 °C. The composite membrane showed strong tensile strength and excellent dielectric properties. The tensile strength of the 20% PVDF composite membrane was 2.66 times that of pure BSLT membrane. Fiber membrane after compounding with PVDF maintained high dielectric constant er with a small dielectric loss tanδ. It has good frequency stability in the range of 100 Hz to 100 kHz. The dielectric constant of 20% PVDF composite fiber membrane could still reach 49.5 (f = 1000 Hz). The dielectric constant and dielectric loss maintained good stability in the range of 40 to 160 °C. The dielectric constant and dielectric loss of the prepared fiber membrane possessed more stable temperature stability and frequency stability than those of barium titanate-based/organic polymer membranes prepared by other methods.

We have developed a tungsten disulfide (WS2)/multiwall carbon nanotubes (MWCNTs) nanocomposite based QCM gas sensor for (trimethylamine) TMA gas sensing of low concentrations. WS2/MWCNTs nanocomposite was synthesized via the hydrothermal method and was characterized for surface morphology, nanostructure, thermal stability, and elementary composition. The TMA-sensing properties of WS2/MWCNTs nanocomposite based QCM sensor were investigated. The composite based QCM sensor showed faster response time, strong response amplitude, good gas capacity, and good selectivity and stability compared with as prepared WS2 and MWCNTs-1 based QCM sensor. The response time of WS2/MWCNTs based QCM sensor was 294.1 and 142.9 s shorter than WS2 and MWCNTs-1 for 500 ppb TMA gas. And the response of the WS2/MWCNTs based QCM sensor was almost stable over 40 days, and the limit of detection (LOD) was 76 ppb calculated by the ICH method. This was ascribed to the fact that MWCNTs provided a skeleton for the growth of WS2 nanosheets and avoided agglomeration. The special structure could not only improve the structure ability but also expose more active adsorption sites. In order to further investigate the adsorption mechanism of the TMA molecule on (pure/functionalized) WS2 materials, density functional theory (DFT) calculations based on first-principle were conducted in the Vienna Ab-initio Simulation Package under ideal conditions.

We obtained Lu2O3 fibrous membrane, with robust flexibility and high tensile strength, by electrospinning a novel high lutetium content precursor. We observed the microstructure of the membrane and studied the mechanism of the heat-treated atmosphere and temperature on the mechanical properties of the membranes. The results showed that the Lu2O3 content in the precursor was 63%, and the decomposition temperature range of organic matter was wide. Heat treatment in nitrogen retained a small amount of residual carbon in the membrane. A small amount of carbon hindered the mass transfer process, increased the grain boundary density, inhibited the growth of crystal grains, and improved the tensile strength and flexibility of the fibrous membrane. The tensile strength of the Lu2O3 fibrous membrane was as high as 6.81 MPa after heat treatment at 1000 °C for 2 h, which was significantly higher than the reported ceramic fibrous membrane.

A yttria-stabilized zirconia mixed silica nanofibrous membrane (YSZ/SiO2 NFM) was fabricated by the electrospinning method. The well-aligned 3D membrane structure and the composite nanocrystalline-amorphous structure with fine zirconia grain and amorphous silica network, which greatly improved the mechanical properties of YSZ/SiO2 NFMs. The strength of the ceramic fibrous membrane after heat treatment at 1300℃ was reported for the first time, the tensile strength can reach 4.0 ± 0.7 MPa and the strain can reach 5.3 ± 1.1 %. The use temperature of YSZ NFMs was increased by nearly 300℃. The maximum strength was up to 5.9 ± 0.8 MPa, which is currently reported that the highest strength of oxide ceramic nanofibers at the same temperature. The YSZ/SiO2 NFMs after high temperature treatment not only had a good thermal insulation performance, but also had a hydrophobic performance. These attractive properties may provide new opportunities for flexible materials such as high-temperature insulation, fire insulation, and flexible electronics.

Dry reforming of CH4 with CO2 is an effective way to convert these two greenhouse gases into useful industrial feedstock. Here, we designed and developed Ni@Y2O3 nanofibers catalyst by pyrolyzing sheet-like Ni2(CO3) (OH)2 grown in situ on the surface of Y2O3 nanofibers. Y2O3 nanofibers support can not only promote the contact of the reaction gas with the catalyst due to its self-supporting effect, but also improve the ability to capture CO2 because of its basic oxide properties. Meanwhile, the oxygen exchange between the catalyst and CO2 could promote the oxidation of carbon deposits, and further improve activity and stability of the catalyst. Besides, the catalyst obtained by low-temperature pyrolysis could maintain the sheet-structure of nickel on the surface of support, which is conducive to improve its catalytic activity, stability, and resistance to carbon deposition. This work has a positive effect on improving the design of catalysts as well as producing industrial chemicals and reducing the environmental pollution.

In this paper, SnO2 fibers with three-dimensional (3D) interconnected structure were successfully obtained by a simple electrospinning technique with both high quality and reproducibility. The microstructure, physicochemical properties were characterized (FT-IR, XRD, SEM, HR-TEM, TG-DSC, N2-BET, XPS, H2-TPR, O2-TPD) extensively. The catalytic activity was tested in temperature-programmed oxidation (TPO) of model soot. The influence of the heat-treated temperature on the catalysts physicochemical properties and reactivity was evaluated. The fibers were fluffy and self-supporting after heat-treated which could provide a beneficial environment favored by soot catalytic combustion. SnO2 fibers exhibited good thermal stability in phase structures and morphologies at least 900 °C. The SnF-500 exhibited the highest catalytic activity with T10, T50 and T90 at 410 °C, 450 °C and 474 °C. With the increase in the sintering temperature, the crystallinity of SnO2 fiber increases and the Sn–O-Sn bond strengthens, resulting in a decrease in the catalytic activity of the catalyst as the BET surface area and surface oxygen decrease. Our studies provide insights into SnO2 fibers for soot catalytic.

The non-woven mat has a three-dimensionally distributed fiber structure, but because the randomly dispersed structure caused the pore diameter of the separator to enlarge, this may lead to a short circuit of the battery. In this work, organic polyethylene terephthalate (PET) was combined with inorganic zirconia (ZrO2) ceramic fiber using a low-cost papermaking method. The addition of PET blocked part of the macropores of the fiber separator, enabling the separator a suitable pore size. The PET connected the nodes of the zirconia fibers to provide mechanical support. At the same time, the ZrO2-PET composite separator inherited the excellent high temperature resistance of zirconia ceramic fiber and a maintained dimensional stability after heating at 300 °C for 1 h, providing a strong guarantee for the safe performance of the battery. We found that when the concentration of PET was 5%, the highest electrolyte uptake (301.83%) occurred as well as electrochemical performance. In addition, the ZrO2-PET composite separator achieved an excellent cycle performance at 60 °C compared with the polypropylene (PP) separator.

Tea is one of the most popular beverage with distinct flavor consumed worldwide. It is of significance to establish evaluation method for tea quality controlling. In this work, electronic nose (E-nose) was applied to assess tea quality grades by detecting the volatile components of tea leaves and tea infusion samples. The “35th s value”, “70th s value” and “average differential value” were extracted as features from E-nose responding signals. Three data reduction methods including principle component analysis (PCA), multi-dimensional scaling (MDS) and linear discriminant analysis (LDA) were introduced to improve the efficiency of E-nose analysis. Logistic regression (LR) and support vector machine (SVM) were applied to set up qualitative classification models. The results indicated that LDA outperformed original data, PCA and MDS in both LR and SVM models. SVM had an advantage over LR in developing classification models. The classification accuracy of SVM based on the data processed by LDA for tea infusion samples was 100%. Quantitative analysis was conducted to predict the contents of volatile compounds in tea samples based on E-nose signals. The prediction results of SVM based on the data processed by LDA for linalool (training set: R(2) = 0.9523; testing set: R(2) = 0.9343), nonanal (training set: R(2) = 0.9617; testing set: R(2) = 0.8980) and geraniol (training set: R(2) = 0.9576; testing set: R(2) = 0.9315) were satisfactory. The research manifested the feasibility of E-nose for qualitatively and quantitatively analyzing tea quality grades.

ZrO2 nanocrystals with spheres and elongated platelets were systemically prepared through a simple hydrothermal method by the use of ZrOCl2·8H2O and CH3COOK as raw materials. The anisotropic morphology and formation mechanism of the monoclinic and/or tetragonal ZrO2 were investigated by X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscope, and high-resolution transmission electron microscope techniques. The uniform elongated platelets and star-like structures were composed of short nanorods with a diameter of approximately 5 nm and a length of approximately 10 nm. The different morphologies were formed due to the different contents of CH3COO− and Cl− and their synergy. The fluorescence band position and the band shape remained about the same for excitation wavelengths below 290 nm and the different morphologies of the nanocrystals.

This work reports a novel citric-acid-assisted sol-gel method that does not contain any template or hazardous chemicals for the electrospinning of mesoporous silicon-magnesium oxide (MgO–SiO2) ceramic fibers. Citric acid was fully utilized in the preparation of a precursor solution to catalyze tetraethyl orthosilicate (TEOS) hydrolysis, chelate with magnesium ions and cause pore formation during calcination. Moreover, H2O2 addition resulted in fiber decoloration, hydrophilicity, surface area reduction and surface basicity enhancement. The studied mesoporous MgO–SiO2 ceramic fibers (Si:Mg = 1.5:1 atomic ratio) exhibited good morphologies with diameters of 1.23 ± 0.34 μm and a BET surface area of 142.61 m2‧g−1 after heat-treatment at 600 °C. The adsorption characteristics of the ceramic fiber toward Pb(II), Cu(II), methylene blue (MB) and fulvic acid (FA) were studied. The ceramic fibers showed high adsorption capacities of 753.1/481.0 mg‧g−1 for Pb(II)/Cu(II), which obeyed the pseudo-second-order kinetics and the Langmuir isotherm model. The Freundlich model provided a better fit for the MB and FA adsorption isotherms, and the pseudo-first-order model could describe the kinetics data of FA adsorption. The abnormal kinetics of MB adsorption were observed to follow a pseudo-second-order model at the early phase but then followed a pseudo-first-order model. The innovative strategy of synthesizing MSCFs could contribute to the development of composite oxide ceramic fibers that are relevant to a variety of applications.

Phosphate removal is an essential measure in controlling the eutrophication of water. In this work, the electrospinning mesoporous zirconia fibers with high surface area were prepared and used as adsorbents to remove phosphate in aqueous solutions for the first time. The electrospinning mesoporous zirconia fibers which had large surface area and uniform pore size were prepared by the use of ammonium lauryl sulfate (ALS) and triblock co-polymer Pluronic (P-123) as dual surfactants. The morphology and composite were represented by XRD, TGA/DTA, FT-IR, SEM, and TEM. The specific surface area and pore properties of fibers were investigated by nitrogen adsorption-desorption method. These mesoporous zirconia fibers performed an outstanding phosphate adsorption ability whose maximum adsorption capacity could reach 222.79 mg/g, meanwhile, a nice cycle performance was also observed as the removal rate could remain 92.5% after 5 cycles on the initial concentration of 30 mg/L. The Freundlich model and the pseudo-second-order kinetic model were both fitted with the adsorption data properly. Besides, the fibers also performed a nice ability in anti-interference against the changes of solution pH value and co-existing ions. Thus, the prepared mesoporous zirconia fibers would be a potential adsorbent of phosphate removal process under the conditions of actual wastewater treatment, with the advantages of the excellent adsorption efficiency, low in production cost, high repeatable utilization and environment friendly.

Gd2Zr2O7/ZrO2 (GZC) composite fibers were prepared by electro-spinning method. The XRD, XPS and Raman results showed that there were three crystalline phases, tetragonal phase ZrO2, cubic phase ZrO2 and defect fluorite phase Gd2Zr2O7 in GZC composite fibers. GZC fibers remained an intact fiber texture up to 1400 °C according to SEM photographs. The thermal conductivity of GZC fibers was between 0.173 W/(m·K) at 400 °C and 0.309 W/(m·K) at 800 °C, which was lower than that of 7YSZ under the same experimental conditions. The fiber sheet with density about 3.5 g/cm3 has thermal shrinkage less than 3% at 1400 °C. Hence, GZC fibers could be used as refractories for heat protection.

Improving the infrared reflectivity of ZrO2 polycrystalline fibers is of great benefit to its thermal applications. In the present research, we cast a highly uniform TiO2 coating with a thickness ranging from dozens to hundreds of nanometers on ZrO2 fibers by utilizing hydrothermal growth. The coating bonds tightly to the ZrO2 fibers via Zr–O–Ti chemical linkages, and the thickness of the coating can be tailored by varying the hydrothermal growth time. The TiO2 coating, acting as a sheath towards electromagnetic radiation, not only reflected light with wavelengths ranging from the visible region to the infrared region and up to 8 μm but also shielded the Raman signals of the ZrO2 fibers. The present research provides an efficient way to cast controllable and uniform coatings on flexible fiber materials. The obtained ZrO2 fibers coated with TiO2 may have applications such as reinforcement for bulk ceramics, thermal barrier coatings, aerogels, etc., thus performing the dual functions of mechanical strengthening and thermal insulation.

BiFe1−xZrxO3 (x = 0, 3, 6, 9, 12 mol%) (BFZrO) films were prepared via the sol–gel method by applying ITO/glass as substrates. The influence of different Zr doping amounts on the crystal structure, oxygen vacancy content, leakage mechanism and optical, ferromagnetic, ferroelectric and aging properties of the BFZrO films was investigated. XRD and Raman results showed that all the BFZrO (0–12 mol%) films are composed of rhombohedral (R3c space group) and orthorhombic (Pnma space group) phases, and with increasing Zr content, the R3c phase content of the BFZrO films gradually decreases while the Pnma phase content gradually increases. SEM and XPS results showed that Zr doping resulted in smaller and more uniform grains of the BFZrO films, and the oxygen vacancy and Fe2+ contents decreased. Zr doping reduced the leakage current density, increased the band gap, improved the ferromagnetic property and degraded the ferroelectric property of the BFZrO thin films. The changes in the above properties are explained from the perspectives of the changes in the two-phase contents, oxygen vacancy concentration, grain size and so on. Due to the aging being related to the oxygen vacancy concentration and the rearrangement of the defect dipoles, the aging degree of BFO films was significantly reduced by Zr doping.

Yttrium-aluminum-garnet (YAG) ceramic fibers not only have good flexibility, a large aspect ratio, good continuity, light weight, and high strength but also a high melting point, stable physical and chemical properties, high-temperature creep resistance, and excellent optical properties of YAG itself. These properties allow YAG fibers to be used as structural reinforcement and as basic optical materials. In this study, a YAG precursor was selected by comprehensive analysis of the spinning properties of solutions synthesized from aluminum powder, AlCl3·6H2O, and Y(CH3COO)3·4H2O. YAG precursor continuous fibers and nanofibers were spun by extrusion-forming and electrospinning, respectively. The decomposition, crystallization, and microstructure of the fibers were analyzed by thermogravimetry-differential thermal analysis (TG-TDA), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The mechanical properties and diffuse reflectance of the YAG ceramic fibers were also determined. The results showed that the YAG precursor synthesized with an AlCl3·6H2O/Al powder molar ratio of 1:4 and Al/Y ratio of 3:5 had the best spinnability. The bundle of continuous fibers was 50 × 40 μm, and the length of the individual fibers was greater than 50 cm. The diameter of as-obtained YAG continuous fibers was approximately 23 μm. Both YAG continuous fibers and nanofibers showed good flexibility, uniform diameters, and high crystallinity. During the heat treatment process, loss of free water and crystalline water, decomposition and carbonization of organic matter, and crystallization and densification of the fibers occurred. YAG was directly crystallized from an amorphous material at 750 °C with a ceramic yield of 32.5%. The tensile stress and Young's modulus of the as-obtained YAG continuous ceramic fibers reached 851 MPa and 150 GPa, respectively. The average diffuse reflectance of the YAG nanofibers in the wavelength range of 700–2500 nm reached 92.7%.

As a polycrystalline fiber, continuous zirconia (ZrO2) fiber used at high temperatures will cause grain coarsening and strength degradation due to grain growth. In order to suppress the grain coarsening, zirconium carbide (ZrC) and carbon were introduced into ZrO2 continuous fibers by pack carburizing, and ZrC/ZrO2 composite fibers with a radial gradient were subsequently prepared. Due to the pinning effect of ZrC or carbon on the grain boundary, the movement of the grain boundary is limited. The composite fibers obtained in an argon atmosphere at 1400 °C exhibited fine grain, compact micromorphology, and a tensile strength of 784 MPa. The formation process of the composite fiber was accomplished by the interaction of external graphite carbon and internal residual carbon with ZrO2. This work provides a simple and economical method for preparing carbide composite fibers.

We have developed a tungsten disulfide (WS

In the field of thermal insulation, Zirconia (ZrO2) fiber and its products have high thermal expansion coefficients and poor thermal shock resistance, which leads to great challenges in the industry. In this work, aluminum titanate (Al2TiO5) single-phase ceramic fibers were prepared by a sol-gel method, using polyacetylacetone titanium-aluminum (PAAT) as the precursors with electrospinning technology. The single-phase Al2TiO5 fibers exhibited excellent high-temperature resistance, and maintained fibers morphology at a high temperature of 1500 ºC. Next, ZrO2-Al2TiO5 (ZAT) fiberboards were prepared by mixing ZrO2 fibers and Al2TiO5 fibers. The mixture was heat-treated to 1500 ºC to prepare the ZAT fiberboards. Characterization results indicated that the contents of Al2TiO5 fibers have obvious effects on the performance of thermal insulation, strength, thermal expansion, and thermal shock resistance. Particularly, the thermal expansion coefficient of ZAT-8 fiberboards was about 20% lower than that of ZAT-0 fiberboards. These attractive characteristics might give ZAT fiberboards enormous potential in the field of high-temperature insulation.

ZrO2 ceramic fibers have gained widespread study for the high temperature stability, low thermal conductivity and high mechanical properties. While for oxide fibers, grain growth is one of the limiting factors for long-term high temperature applications. In the present study, polycrystalline ZrO2–6 mol % Y2O3 ceramic fibers with the addition of ~0–5 mol % La2O3 to refine the grain size were fabricated by the dry-spinning method. The XRD and Raman spectral results showed that the pyrochlore La2Zr2O7 phase was formed as a second phase in the tetragonal zirconia fiber matrix. The formation of a second phase was an effective way to hinder grain growth for the competition phase effect and solid solution mechanism. With the addition of La2O3, the grain size decreased and concentrated in a smaller range of 50–250 nm compared with the ZrO2–6 mol % Y2O3 matrix at 1400°C. Furthermore, the thermal conductivity of the fibers decreased with the additive of La2O3 less than 3 mol %. The present system is a promising candidate for high temperature applications.

Ceramic coatings have been widely used in industrial fields. K2Ti6O13 fibers could be a potential coating material for low thermal conductivity, high mechanical strength and infrared reflectivity. The precursor fibers, using potassium acetate (CH3COOK) and tetrabutyl titanate (TBOT) as potassium and titanium sources, were prepared by the electrospinning technique with the sol-gel method. To prepare K2Ti6O13 fibers, the mole ratio of K/Ti was adjusted from 1:2 to 1:3. The transformation of other phases of potassium titanates was characterized by XRD patterns and Raman spectra. The effects of mole ratio of K/Ti on morphology of samples have been investigated. Well-crystallized fibers were prepared with single-crystal K2Ti6O13 structure. The corresponding morphology and microstructure evolution were studied by SEM and TEM. The as-obtained K2Ti6O13 fibers possessed the high near-infrared (NIR) reflectivity of 98%.

Surface structure plays a key role on the sensitization process. Mesoporous TiO2 nanofibers with high surface area and improved dye coupling mode were successfully fabricated via a simple, template...

Titanium oxide is a potential high temperature reflective material due to its high melting point, large refractive index, and suitable band gap. The flexible TiO2 ceramic fibers membrane was successfully fabricated by sol–gel method using the polyacetylacetonetitanium (PAT) as the precursor. In order to obtain high-quality TiO2 fibers, the PAT precursor with good stability and good spinnability was optimized by adjusting the molar ratio of acetylacetone to Ti to 1:1. The TiO2 fibers heat-treated at 700 °C had a diameter of 400–500 nm. The crystal phase of TiO2 fibers was anatase, and the surface of fibers was smooth without obvious defects. In addition, the TiO2 ceramic fibers membrane heat-treated at 700 °C had good flexibility and tensile strength, and the average reflectance in the wavelength range of 500–2500 nm was up to 91.3%. The fibers membrane exhibits a significant reflection effect in the practical experiments and maintained good morphology of the fibers after 1200 °C test.

Mesoporous MgO has been used as an adsorbent for the removal of contaminants in water and exhibited outstanding performances. However, the agglomeration phenomena of nanoscale MgO adsorbents suppressed the adsorption capabilities. Herein, compound citrate and propionate ligands were selected as template-free precursors to fabricate the electrospun mesoporous MgO ceramic fibers. The MgO ceramic fibers possessed mesoporous structure with high surface area of 232.34 m2/g and high total pore volume of 0.560 cm3/g. Structure and composition of fibers heat-treated in air and water vapor were investigated systematically. And the MgO ceramic fiber showed high adsorption capacities of 2983.4 mg/g and 1824.0 mg/g for Pb(II) and Cd(II), respectively. The interaction mechanism between MgO fibers and heavy metal ions were thoroughly discussed. The high capacity of mesoporous MgO ceramic fiber was benefited from the hydroxyl-rich surface to release sufficient OH- and the good movability in water. Mesoporous MgO ceramic fibers prepared in the present method with fine quality might become an effective prescription for heavy metal pollution.