Zirconia Nanofibers Research Articles

SnS2 nanosheets/Ag2S quantum dots heterojunction supported by YSZ nanofibers enable real-time room-temperature NO2 gas sensor

Air pollution has emerged as a critical global issue, necessitating the development of effective real-time gas monitoring technologies. However, conventional gas sensors face limitations such as high energy consumption and sluggish response/recovery kinetics. In this study, we report a novel SnS2/Ag2S heterojunction supported by yttria-stabilized zirconia nanofibers (YSZ@SnS2/Ag2S) through a facile electrospinning, hydrothermal and subsequent cation-exchange method. This hierarchical composite nanofiber consists of well-distributed Ag2S quantum dots (QDs) attached to vertical anchored SnS2 nanosheets, forming an interconnected network supported by YSZ nanofibers. The integrated sensor exhibited high response of 3.27 and swift response/recovery times of 12/27 s to 1 ppm NO2 at room temperature, respectively. Benefited from highly permeable three-dimensional continuous conductive nanofibers, along with the hierarchical nanosheets/QDs structure, the gas transmission/diffusion and number of reactive sites were ensured. Additionally, the interfacial built-in electric field of SnS2/Ag2S heterojunction further enhanced the electron transfer, carrier migration and gas-sensitive reaction kinetics. This study provides insights into the development of functional composite nanofibers and paves the way for the exploitation of real-time room-temperature gas sensing applications.

Solution blow spun flexible zirconia nanofibers toward high-performance 2D and 3D nanostructures

Polymer templates are critical in the preparation of ceramic fibers from precursor solutions, but the available options are limited. Here, ZrO2 nanofiber films and aerogels are developed by solution blow spinning method using hydroxypropyl methylcellulose (HPMC) and polyvinylpyrrolidone (PVP) as templates. The effects of HPMC ratio, polymer concentration, and calcination temperature on the morphology and structure of the ZrO2 nanofibers are investigated. The nanofiber films with an areal density of 20 mg cm−2 exhibit excellent filtration property, achieving a filtration efficiency of 94.94% and a pressure drop of 136 Pa at an airflow velocity of 32 L min−1. The nanofiber aerogels display low density of 50 mg cm−3, low thermal conductivity of 0.039 W m−1 K−1, as well as superior compressibility, demonstrating significant potential for thermal protection applications. This work expands the formation template option of ceramic fibers, offering significant guidance in the development of flexible, high-temperature-resistant ceramic fiber materials.

Electrospinning synthesis and characterization of zirconia nanofibers annealed at different temperatures

The main goal of this study was to produce, in a two-step process, ceramic nanofibers, which were obtained by electrospinning of composite fibrous mats and high-temperature thermal treatment at temperatures of 500 and 600 °C. The next step was to determine the effect of the nanofibers calcination temperature on the morphology and surface, structural and optical properties and photocatalytic activity of zirconia nanostructures. For this purpose, ZrO2 500 and ZrO2 600 were analyzed using scanning electron microscopy with an energy dispersive X-ray spectroscopy, high-resolution transmission electron microscopy and nitrogen adsorption isotherms specific surface tests. The structure of zirconium oxide nanofibers was investigated using X-ray diffraction, which confirmed highly crystalline nature of the materials and the presence of two crystalline phases - monoclinic and tetragonal. Analysis of optical properties, carried out on the basis of graphs of absorbance as a function of wavelength, revealed width of the optical band gap equal to 4.9 and 5.6 eV for nanostructures calcined at 500 and 600 °C, respectively. The nanofibers with a lower energy gap and a higher specific surface area degraded 38.47 % of methylene blue in an aqueous solution under ultraviolet radiation within 210 min.

Electrospinning of ZrO2 fibers without sol-gel methods: Effect of inorganic Zr-source on electrospinning properties and phase composition

The aim of this study was the electrospinning of zirconia nanofibers without sol-gel precursors. Low-cost Zr-oxide and Zr-carbonate inorganic materials, with high molecular Zr-content compared to sol-gel methods, were used for precursor formulation. Using a polyvinylpyrrolidone (PVP) polymeric binder, zirconia nanofibers could successfully be synthesised with both Zr-sources. The effects of different electrospinning parameters were investigated to stabilize the processing and reduce the deviation of nanofiber diameters. Fibres calcined at 1000 °C produced from the two different precursors displayed differing crystal phases of zirconia. The one based on nanoparticles revealed a significantly higher amount of tetragonal phase. Zirconia nanofibers with poly-granular microstructure across the diameter were successfully produced.

Water-stable metal–organic framework (UiO-66) supported on zirconia nanofibers membrane for the dynamic removal of tetracycline and arsenic from water

Water-soluble pollutants including pharmaceuticals and personal care products (PPCPs) and inorganic arsenic have posed challenges to water and the environment. In this work, the water-stable metal–organic framework UiO-66 was loaded on electrospinning zirconia nanofibers membrane via the in-situ solvothermal method. This novel composite membrane had increased surface area, good adsorption performance, and could dynamically remove contaminants from polluted water. Adsorption performance of the composite membrane for tetracycline (TC) and As(III) were investigated using batch experiments. The maximum adsorption capacities were 59.27 mg/g for TC and 143.95 mg/g for As(III). The membrane’s dynamic removal efficiency for TC and As(III) could reach over 90% and 80%, respectively, at a relatively high flux of 60 L/(m2·h), and could be generated and reused. pH values had strong impacts on the electrostatic interaction force, thus influenced the absorption efficiency. The adsorption mechanisms were studied by experimental characterizations and DFT calculations, and the results showed that direct interaction, hydrogen bond and ligand exchange were the main driving forces, and ZrO bond played a significant role in this process. Based on the self-supporting structure and good adsorption performance, we believe this novel composite membrane could find notable applications in wastewater decontamination.

Electrospun zirconia nanofibers and the acid vapor resistance

Excellent chemical stability against corrosive waste gases is a considerable property for ceramic fibers products applied in high temperature filtration and other harsh environment. As one of the promising ceramic fibers candidates for high temperature filtration, zirconia nanofibers (NFs) were prepared by a simple and cost-effective electrospinning technique in the present work. The thermal decomposition process, crystallization and microstructure evolution of zirconia NFs were fully analysed with Fourier-transform infrared spectroscopy (FT-IR), Thermogravimetry and differential scanning calorimetry (TG/DSC), X-ray diffraction (XRD) and Scanning electron microscope (SEM). The microstructure and grain size evolution of zirconia NFs were fully discussed. The results indicated that zirconia NFs with a diameter of about 450 nm were stable up to 1200 °C and apparent grain growth developed at above 900 °C. Furthermore, the HCl acid vapor at 150 °C was used to explore the acid resistance of zirconia NFs. It was found that zirconia NFs possessed good tetragonal phase stability while surface hydration and exfoliation on the surface happened in an acid vapor environment. The water vapor and acid vapor corrosion mechanisms were presented.

Dual-active-sites oriented mesoporous zirconia nanofibers for enhanced removal of phosphate in the presence of humic acid

Excessive phosphate in water will inevitably cause eutrophication and further trigger major environmental issues. Efficient removal of phosphate is of great significance to inhibit water eutrophication, however, humic acid (HA) in water aggravates the uncertainty of phosphate removal. In this work, mesoporous zirconia nanofiber (MZN) was synthesized and applied as an adsorbent for phosphate removal in the presence of HA. The performance and mechanism of the enhanced removal of phosphate by MZN in the presence of HA was systematically studied. The results show that MZN has higher adsorption capacity, stronger affinity, and faster adsorption rate for phosphate in solution with HA than that without HA. In the presence of HA, HA is adsorbed on MZN through complexation, which introduces carboxyl and hydroxyl groups to MZN surface, increasing phosphate adsorption through hydrogen bonding. The boosted removal mechanism of phosphate can be ascribed to the dual-active-sites effect between the complexation of MZN to phosphate and the hydrogen bonding of the adsorbed HA to phosphate. The adsorption of phosphate by MZN in the presence of HA follows the outer-sphere complexation. Column adsorption experiment showed that MZN is feasible and effective for the treatment of phosphate in water containing HA based on the discharge standard of phosphate, and can be reused repeatedly through regeneration. The results indicate that MZN holds a great promise in efficient removal of phosphate in the presence of HA.

Dual-Active-Sites Oriented Mesoporous Zirconia Nanofibers for Enhanced Removal of Phosphate in the Presence of Humic Acid

Dual-Active-Sites Oriented Mesoporous Zirconia Nanofibers for Enhanced Removal of Phosphate in the Presence of Humic Acid

Production and qualification of an electrospun ceramic nanofiber material as a candidate future high power target

In an effort to develop and design next generation high power target materials for particle physics research, the possibility of fabricating nonwoven metallic or ceramic nanofibers by electrospinning process is explored. A low-cost electrospinning unit is set up for in-house production of various ceramic nanofibers. Yttria-stabilized zirconia nanofibers are successfully fabricated by electrospinning a mixture of zirconium carbonate with high-molecular weight polyvinylpyrrolidone polymer solution. Some of the inherent weaknesses of electrospinning process like thickness of nanofiber mat and slow production rate are overcome by modifying certain parts of electrospinning system and their arrangements to get thicker nanofiber mats of millimeter order at a faster rate. Continuous long nanofibers of about hundred nanometers in diameter are produced and subsequently heat treated to get rid of polymer and allow crystallize zirconia. Specimens were prepared to meet certain minimum physical properties such as thickness, structural integrity, thermal stability, and flexibility. An easy innovative technique based on atomic force microscopy was employed for evaluating mechanical properties of single nanofiber, which were found to be comparable to bulk zirconia. Nanofibers were tested for their high-temperature resistance using an electron beam. It showed resistance to radiation damage when irradiated with 1 MeV ${\mathrm{Kr}}^{2++}$ ion. Some zirconia nanofibers were also tested under high-intensity pulsed proton beam and maintained their structural integrity. This study shows for the first time that a ceramic nanofiber has been tested under different beams and irradiation condition to qualify their physical properties for practical use as accelerator targets. Advantages and challenges of such nanofibers as potential future targets over bulk material targets are discussed.

Effect of Zirconia Nanofibers Structure Evolution on the Hardness and Young's Modulus of Their Mats.

Zirconia nanofiber mats containing filaments with the average diameter of less than 100 nm were fabricated. It is found that the hardness and Young’s modulus of the mats are sensitive to the microstructure, phase composition and average diameter of the zirconia nanofibers. The hardness and Young’s modulus of the prepared zirconia nanofiber mats vary from 0.86 to 1.67 MPa and from 133 to 362 MPa, respectively, wherein an increase in hardness is accompanied by the rise in Young’s modulus.

Electrospun mesoporous zirconia nanofibers as effective biomimetic haloperoxidase for pollution conversion and separation

Biocatalytic material is of growing interest as a sustainable approach for environmental remediation. In the present work, mesoporous ZrO2 ceramic nanofibers (MZFs) as biomimetic haloperoxidase were synthesized for integrated pollution conversion and separation by brominated reaction with Br− as bromide source and H2O2 as green oxidant. MZFs were fully characterized by XRD, IR, N2 adsorption and desorption, XPS and SEM. The brominated mechanism was proposed in view of the specific interaction between ZrO2 and H2O2 for the first time. From the results of radical scavengers on brominated reactivity and ESR, it was confirmed that superoxide radical was the main active oxidizing agent in the brominated process. Furthermore, MZFs possessed highly efficient pollution conversion and separation property. 300 mg/L RhB could be fully brominated and separated in 60 min in a green chemistry way. The findings are not only helpful for the understanding of brominated mechanism with H2O2 as green oxidant in a new focus, but also pave a sustainable way to environmental purification and pollution recovery.

Structure, morphology and mechanical properties of arrays of zirconia nanofibers at different heat treatment modes

Mats of yttria-stabilized tetragonal zirconia nanofibers were prepared in the present research. The effect of the mats calcination temperatures (600, 900, and 1200 °C) on their structure and morphology was investigated. It was found that phase composition of the fibers did not change in all range of the calcination temperatures, while the average grain size in fiber increased from 8 to 39 nm. Multi-cyclic and single loading-unloading nanoindentation testing of the ceramic mats showed that the hysteresis loop energy in samples decreases with higher calcination temperature. Hardness and the elastic modulus measured by spherical (with 10 and 250 μm radii) and sharp Berkovich indenters were the highest in the mats calcined at 900 °C. This calcination temperature can be considered an optimal one for preparation of nanofibers mats which mechanical properties are of importance for their application.

Electrospun zirconia nanofibers for enhancing the electrochemical synthesis of ammonia by artificial nitrogen fixation

ZrO2 nanofibers are fabricated using the electrospinning technique and they are used as an electrocatalyst to convert nitrogen to ammonia based on the reaction of N2 + 3H2O = 2NH3 + 1.5O2.

Morphology and Mechanical Properties of 3Y-TZP Nanofiber Mats.

The mats of yttria-stabilized tetragonal zirconia nanofibers were prepared using electrospinning. The effect of calcination temperature in the range of 600–1200 °C on their microstructure, phase composition and mechanical properties was investigated. Phase composition of the nanofibers did not change in all ranges of the calcination temperatures, while the average grain size increased from 8 to 39 nm. Nanoindentation testing of the mats showed a decrease in the hysteresis loop energy in samples with higher calcination temperature. Hardness and the elastic modulus measured with the indentation technique were the highest for the mats calcined at 900 °C.

Shape-Memory Actuation in Aligned Zirconia Nanofibers for Artificial Muscle Applications at Elevated Temperatures

Artificial muscle is one of the key technologies to accelerate the development of robotics, automation, and artificial-intelligence-embedded systems. This work aims to develop shape-memory ceramic ...

Successful electrospinning fabrication of ZrO2 nanofibers: A detailed physical – chemical characterization study

Electrospinning fabrication of Zirconia nanofibers was successfully achieved, followed by different thermal treatment. A careful physical characterization study was performed based on the calcination temperature effect, which was confirmed by a wide range of analysis such as SEM, TG-DT analysis, XRD, FT-IR, DRS, VSM, and PL spectra. The morphological characterization of both polymer and ceramic nanofibers was achieved by SEM images through an image analyzing software. The average diameter of the produced nanofibers was estimated below 100 nm after rising thermal treatment temperature. The thermal behavior of the as-spun ZrO2 nanofibers was studied using thermogravimetric analyses (TGA). The whole powder pattern modeling (WPPM) approach using the PM2K package and the Rietveld refinement approach were applied on the X-ray diffraction pattern to get insight into the effect of calcination temperature on the microstructure parameters of nanostructured zirconia fibers. A comprehensive study was done on the chemical properties of the fabricated samples based on the absorption bands using FT-IR spectroscopy. Chemical study shows a good correlation between the XRD and FT-IR findings. The optical properties were investigated using diffuse reflectance spectroscopy and room-temperature photoluminescence spectra. An enhancement of PL intensity of the ZrO2 calcined at 800 °C could be due to its high crystal quality. The magnetic properties of zirconia nanofibers were investigated by a vibrating sample magnetometer (VSM). Room temperature magnetization results showed a hysteresis loop formation, indicating the ferromagnetic behavior of samples.

Electrospinning of Y2O3- and MgO-stabilized zirconia nanofibers and characterization of the evolving phase composition and morphology during thermal treatment

The current paper focuses on the fabrication of yttria and magnesia stabilized zirconia nanofibers via electrospinning from zirconyl chloride octahydrate and polyvinylpyrrolidone precursors with minor additions of yttrium nitrate hexahydrate (3 mol.%) or magnesium nitrate hexahydrate (10 mol.%). The precursor materials were dissolved in an ethanol-water mixture in a ratio of 75:25. After successful fiber preparation, the thermal decomposition behavior of the starting materials and the subsequent phase evolution at elevated temperatures were studied. Pure tetragonal zirconia nanofibers were obtained for the composition stabilized with 3 mol.% yttria when the thermal treatment was conducted with a heating rate of 10 K/min up to 1100 °C. In future research work, these tetragonal zirconia nanofibers will be used as reinforcing material in metal matrix composites based on metastable austenitic steel. The combination of the TRIP/TWIP-effect in the steel matrix with the stress-assisted tetragonal to monoclinic phase transformation in the tetragonal stabilized zirconia will lead to a composite material with outstanding mechanical properties.

Microstructure and Phase Composition of Yttria-Stabilized Zirconia Nanofibers Prepared by High-Temperature Calcination of Electrospun Zirconium Acetylacetonate/Yttrium Nitrate/Polyacrylonitrile Fibers

For the first time, dense nanofibers of yttria-stabilized tetragonal zirconia with diameter of ca. 140 nm were prepared by calcination of electrospun zirconium acetylacetonate/yttrium nitrate/polyacrylonitrile fibers at 1100–1300 °C. Ceramic filaments were characterized by scanning electron microscopy, X-ray diffractometry, and nitrogen adsorption. With a rise in the calcination temperature from 1100 to 1300 °C, the fine-grain structure of the nanofibers transformed to coarse-grain ones with the grain size equal to the fiber diameter. It was revealed that fully tetragonal nanofibrous zirconia may be obtained at Y2O3 concentrations in the range of 2–3 mol% at all used calcination temperatures. The addition of 2–3 mol% yttria to zirconia inhibited ZrO2 grain growth, preventing nanofibers’ destruction at high calcination temperatures. Synthesized well-sintered, non-porous, yttria-stabilized tetragonal zirconia nanofibers can be considered as a promising material for composites’ reinforcement, including composites with ceramic matrix.

Preparation of Zirconia Nanofibers by Electrospinning and Calcination with Zirconium Acetylacetonate as Precursor.

For the first time, zirconia nanofibers with an average diameter of about 75 nm have been fabricated by calcination of electrospun zirconium acetylacetonate/polyacrylonitrile fibers in the range of 500–1100 °C. Composite and ceramic filaments have been characterized by scanning electron microscopy, thermogravimetric analysis, nitrogen adsorption analysis, energy-dispersive X-ray spectroscopy, and X-ray diffractometry. The stages of the transition of zirconium acetylacetonate to zirconia have been revealed. It has been found out that a rise in calcination temperature from 500 to 1100 °C induces transformation of mesoporous tetragonal zirconia nanofibers with a high specific surface area (102.3 m2/g) to non-porous monoclinic zirconia nanofibers of almost the same diameter with a low value of specific surface area (8.3 m2/g). The tetragonal zirconia nanofibers with high specific surface area prepared at 500 °C can be considered, for instance, as promising supports for heterogeneous catalysts, enhancing their activity.

Structure and mechanical properties of nanofibrous ZrO2 derived from alternating field electrospun precursors

Abstract Nanofibrous zirconia (ZrO2) meshes were prepared from precursor fibers which were synthesized using the method of free-surface, high-yield alternating field electrospinning (AFES). The weight ratio of zirconyl chloride salt to polyvinylpyrrolidone (PVP) polymer in liquid precursors was investigated for its effect on the spinnability and formation of precursor fibers as well as on the resulting fibrous ZrO2. The precursor fiber generation measured at a rate up to 5.6 g/h was achieved with a single flat 25-mm diameter alternating current (AC) electrode, which corresponded to production of up to 1.5 g/h of fibrous ZrO2. The calcination process involved annealing the fibers at temperatures which ranged from 600 °C to 1000 °C and produced 0.1–0.2 mm thick fibrous ZrO2 meshes. Individual nanofibers were found to have diameters between 50 and 350 nm and either a tetragonal (t-ZrO2) or monoclinic (t-ZrO2) structure depending on the calcination temperature. The annealed meshes with total porosity between 98.0 ± 0.2% and 94.6 ± 0.2% showed little deformation or cracking. Tensile strength and modulus of fibrous t-ZrO2 meshes strongly depended on porosity and varied from 0.07 ± 0.03 MPa to 1.05 ± 0.3 MPa and from 90 ± 40 MPa to 388 ± 20 MPa, respectively. The m-ZrO2 meshes resulted similar moduli, but much lower strengths due to their brittleness. A power-law relationship between the elastic modulus and porosity of AFES-derived nanofibrous t-ZrO2 meshes, in comparison with other porous zirconia materials, was also investigated. The results of this study have demonstrated the feasibility of free-surface AFES in sizeable production of zirconia nanofibers and highly porous nanofibrous ceramic structures.