TiO2 Fibers Research Articles

Synthesis, characterization, electrochemical impedance spectroscopy performance and photodegradation of methylene blue: Mesoporous PEG/TiO2 by sol-gel electrospinning

Sol-gel and electrospinning methods successfully prepared porous TiO2 fibers. The samples were calcined at temperatures of 450 °C and 550 °C and characterized using different techniques. XRD analysis also revealed crystalline anatase and rutile phases of mp-TiO2 observed at calcining temperatures of 450 °C and 550 °C, whereas as-prepared showed an amorphous-like structure. Relatively higher surface area and photocatalytic efficiency were increased with a decrease in crystallite size. All samples absorb UV region. The Rs value of TiO2 calcined at 550 °C was 16.6 Ω, which is much lower than those of the 450 °C calcined TiO2 powder electrode (52.7 Ω) and as-prepared TiO2 electrode (95.3 Ω). In addition, the Rp resistance of TiO2 calcined at 550 °C electrode (5.85 kΩ) was also lower than those of 450 °C calcined TiO2 powder (39.0 kΩ) and as-prepared TiO2 electrode (68.9 kΩ), revealing better electronic and ionic conduction of TiO2 calcined at 550 °C electrode.

Coaxial electrospinning synthesis free-standing Sn/TiO2 flexible carbon fibers with sheath/core structure for advanced flexible lithium/potassium-ion batteries

Flexible Sn/TiO2 carbon nanofiber (ST-NCF) composites were constructed by doping TiO2 into tin-based carbon nanofibers via coaxial electrospinning. Sn/TiO2 carbon nanofiber was directly used as an anode for Lithium-ion Batteries (LIBs) and Potassium-ion Batteries (PIBs), which show exceptional electrochemical performances. The layered sheath/core structure of the material lead to its good electrochemical properties, where the core Sn carbon nanofiber was encapsulated by the sheath layer of TiO2 nanoparticles. In addition to enhancing its electrical conductivity, the outer TiO2 and N-doped carbon fiber matrix also provide a buffer zone for volumetric strain during charging and discharging. The fiber core Sn and sheath TiO2 form a heterojunction interface on the two-dimensional tube surface, which increases the diffusion rate of ions and electrons. After 100 cycles, TiO2-NCF and ST-NCF-40%TBT (40% TBT indicates the percentage of TiO2 in shell solution to the total composition of shell spinning solution) show capacities of 386.6 mAh g−1 and 1336 mAh g-1, respectively, at 0.5A g-1. After 2000 cycles, ST-NCF-40%TBT in LIBs displayed a high capacity of 299 mAh g-1 at 10 A g-1. After 350 cycles at 1A g-1, the capacity of ST-NCF-40%TBT in PIBs is reserved at 307 mA h g-1. Due to the superior mechanical flexibility of ST-NCF-40%TBT films, it will be a promising anode candidate for flexible LIBs and PIBs.

Electrospinning Nonspinnable Sols to Ceramic Fibers and Springs.

Electrospinning has been applied to produce ceramic fibers using sol gel-based spinning solutions consisting of ceramic precursors, a solvent, and a polymer to control the viscosity of the solution. However, the addition of polymers to the spinning solution makes the process more complex, increases the processing time, and results in porous mechanically weak ceramic fibers. Herein, we develop a coelectrospinning technique, where a nonspinnable sol (<10 mPa s) consisting of only the ceramic precursor(s) and solvent(s) is encapsulated inside a polymeric shell, forming core-shell precursor fibers that are further calcined into ceramic fibers with reduced porosity, decreased surface defects, uniform crystal packing, and controlled diameters. We demonstrate the versatility of this method by applying it to a series of nonspinnable sols and creating high-quality ceramic fibers containing TiO2, ZrO2, SiO2, and Al2O3. The polycrystalline TiO2 fibers possess excellent flexibility and a high Young's modulus reaching 54.3 MPa, solving the extreme brittleness problem of the previously reported TiO2 fibers. The single-component ZrO2 fibers exhibit a Young's modulus and toughness of 130.5 MPa and 11.9 KJ/m3, respectively, significantly superior to the counterparts prepared by conventional sol-gel electrospinning. We also report the creation of ceramic fibers in micro- and nanospring morphologies and examine the formation mechanisms using thermomechanical simulations. The fiber assemblies constructed by the helical fibers exhibit a density-normalized toughness of 3.5-5 times that of the straight fibers due to improved fracture strain. This work expands the selection of the electrospinning solution and enables the development of ceramic fibers with more attractive properties.

Phthalocyanine conjugated manganese ferrite nanoparticles embedded in TiO2 fibers for photo-, sono- and photosono-catalytic degradation of Rhodamine 6G

In this work, zinc (4-carboxylic acid phenoxy)-tris-(3,5-dimethoxyphenoxy) phthalocyanine (Pc) - MnFe2O4 nanoparticles conjugate (Pc-MnFe2O4), embedded on TiO2 fibers (Pc-MnFe2O4-TiO2 fibers) was studied together with individual components for photo-, sono- and photosono-catalytic degradation of Rhodamine 6G. The fabrication of the Pc-MnFe2O4 conjugate and Pc-MnFe2O4-TiO2 fibers resulted in improved photo-, sono-, and photosono-catalytic properties compared to individual analogous. Rhodamine 6G degradation efficiencies for photo-, sono-, and photosono-catalytic processes were 64.5%, 71.5% and 89.8% using Pc-MnFe2O4-TiO2 fibers. Electron paramagnetic resonance (EPR) results revealed that the photo-catalytic process was instigated by 1O2 only, whereas the sono and photosono-catalytic processes were instigated by both 1O2 and ●OH radicals. This study reveals the feasible prospect of Pc-MnFe2O4-TiO2 fibers to be used as photo-, sono-, and photosono catalysts for the degradation of Rhodamine 6G.

New Progress on London Dispersive Energy, Polar Surface Interactions, and Lewis's Acid-Base Properties of Solid Surfaces.

The determination of the polar surface free energy, polar properties, and Lewis's acid base of solid materials is of capital importance in many industrial processes, such as adhesion, coatings, two-dimensional films, and adsorption phenomena. (1) Background: The physicochemical properties of many solid particles were characterized during the last forty years by using the retention time of injected well-known molecules into chromatographic columns containing the solid substrates to be characterized. The obtained net retention time of the solvents adsorbed on the solid, allowing the determination of the net retention volume directly correlated to the specific surface variables, dispersive, polar, and acid-base properties. (2) Methods: Many chromatographic methods were used to quantify the values of the different specific surface variables of the solids. However, one found a large deviation between the different results. In this paper, one proposed a new method based on the London dispersion equation that allowed the quantification of the polar free energy of adsorption, as well as the Lewis's acid-base constants of many solid surfaces. (3) Results: The newly applied method allowed us to obtain the polar enthalpy and entropy of adsorption of polar model organic molecules on several solid substrates, such as silica, alumina, MgO, ZnO, Zn, TiO2, and carbon fibers. (4) Conclusions: our new method based on the separation between the dispersive and polar free surface energy allowed us to better characterize the solid materials.

Facile Synthesis of Fiber‐Reinforced Catalyst for High Performance Ethanol and 2‐Propanol Oxidation

In this study, Pd@TiO2 nanostructure is formed by using TiO2 fibers obtained by the electrospinning method and chemical reduction method, and this nanostructure is used in C2, and C3 alcohol oxidation studies as an application. In addition, TiO2 is compared with the Pd catalyst to investigate the effect of TiO2. In the results obtained, peak current values of 193 and 66.7 mA cm−2 for ethanol oxidation and 127.38 and 36.18 mA cm−2 for 2‐propanol oxidation are observed for Pd@TiO2 and Pd catalysts, respectively. With the addition of TiO2 to the structure, the electrocatalytic activity of C2 and C3 alcohol oxidations increases 3–3.5 times and contributes to the onset potential at an earlier potential. It also shows higher durability and stability in long‐term tests. Moreover, the addition of TiO2 to the structure enhances the electrocatalytic activity and provides high current density and long‐term stability in alcohol oxidation. These results show that fibrous structures in combination with metals improve the effect of catalysts and exhibit high potential for their application in alcohol fuel cells.

Pengaruh Suhu Terhadap Sifat Listrik Polimer Konduktif Polianilin TiO2 Berpenguat Nano Serat Pinang

This research serves to see the effect of temperature on conductive polymers, and the temperature variations used are 27 ℃, 37 ℃, 47 ℃, 55 ℃, 67 ℃, and 77 ℃. The polyaniline used is pure polyaniline and a mixture of polyaniline, TiO2, and nano areca fiber with a mixture percentage of 70%: 27%: 3%. Polyaniline is produced from polymerization of aniline monomer and ammonium peroxydisulfate and nano arecafibers are used from nano arecafibers that have been produced in previous research. Electrical properties testing consisted of electrical conductivity and capacitance tests using an LCR meter. The results showed the lowest conductivity value at 27 ℃ was 0.18 × 10-2 S /cm, and the highest conductivity value at 77 ℃ was 1.22 × 10-2 S/cm for pure polyaniline, while the mixed polyaniline obtained the lowest conductivity value at 27 ℃ was 0,85 × 10-2 S/cm, and the highest value at 77 ℃ was 3.61 × 10-2 S/cm. For the capacitance test, the highest value was obtained at 6.8 μF and 18.9 μF. From the results obtained, the higher the temperature, the higher the conductivity value produced, while the capacitance results show that the higher the temperature used, the lower the capacitance value.

Bioactive TiO2 Fibers Prepared by Solution Blow Spinning: A Promising Approach for Microbial Control

Bioactive TiO2 Fibers Prepared by Solution Blow Spinning: A Promising Approach for Microbial Control

Mnemonic Rutile-Rutile Interfaces Triggering Spontaneous Dissociation of Water.

Water interaction with mineral surfaces is a complex living system decisive for any photocatalytic process. Resolving the atomistic structure of mineral-water interfaces is thus crucial for understanding these processes. Fibrous rutile TiO2 , grown hydrothermally on twinned rutile seeds under acidic conditions, is studied in terms of interface translation, atomic structure, and surface chemistry in the presence of water, by means of advanced microscopy and spectroscopy methods combined with structure modeling and density functional theory calculations. It is shown that fibers while staying in stable separation during their growth, adopt a special crystallographic registry that is controlled by repulsion forces between fully hydroxylated and protonated (110) surfaces. During relaxation, a turbulent proton transfer and cracking of O─H bonds is observed, generating a strong acidic character via proton jump from bridge ─OHb to terminal ─OHt groups, and spontaneous dissociation of interfacial water via a transient protonation of the ─OHt groups. It is shown, that this specific interface structure can be implemented to induce acidic response in an initially neutral medium when re-immersed. This is thought to be the first demonstration of quantum-confinedmineral-water interface, capable of memorizing its past and conveying its structurally encoded properties into a new environment.

Photosono catalytic behaviour of phthalocyanine when supported on electrospun nanofibers: The effect of radical initiators

In this study, two Zn phthalocyanine (ZnPc) complexes containing substituents with varying number of the methoxy groups were investigated when supported on TiO2 fibers in sono-, photo-, and photosono-catalytic degradation of Rhodamine 6 G. The ZnPc on fibers displayed higher activity than when alone. The photosonocatalytic process displayed higher degradation aptitude than sonocatalytic and photocatalytic processes. The electron paramagnetic resonance studies revealed that the photocatalytic process is instigated by singlet oxygen only. However, sonocatalytic and photosonocatalytic processes are instigated by both singlet oxygen and •OH radicals. The utilization of azo-bis-isobutyronitrile and tert-butyl hydrogen peroxide as radical initiators improved the degradation efficiency of photo-, sono- and photosono- catalytic processes. The re-used fibers from sonocatalytic process resulted in significant decrease in catalytic activity, whereas the fibers from photocatalytic process were highly reusable.

Hierarchical porosity design enables highly recyclable and efficient Au/TiO2 composite fibers for photodegradation of organic pollutants

Titanium dioxide (TiO2) nanomaterials are ideal for photocatalytic degradation of organic pollutants but remain infeasible for industrial and municipal wastewater treatment because they cannot simultaneously satisfy two essential criteria for practical application, i.e., high performance and good recyclability. Here, we design and create hierarchically porous TiO2 fibers by dual-polymer templating sol–gel electrospinning combined with precise control over crystallization. The produced fibers own unique interconnected macropores throughout the fiber body that enable significantly enhanced light absorption and unlimited mass transport, making them ideal hosts for anchoring plasmonic nanoparticles (NPs). The Au NP-coupled TiO2 fibers have photocatalytic efficiencies up to 6.6 times higher than plain TiO2 fibers, showing comparable ability as commercial P25 nanopowder in photodegrading methyl blue (MB) and achieving complete decomposition of methyl orange (MO) in 90 min while P25 degrades only 66% MO. Unlike P25 or anatase TiO2 nanopowders that non-reversibly disperse/aggregate in water, our composite fibers can be recollected through natural sedimentation, and their superior performance remains for at least six cycles. This work offers a practical and feasible design for high-performance recyclable photocatalysts for industrial-scale water treatment.

Fibrous TiO2 Alternatives for Semiconductor-Based Catalysts for Photocatalytic Water Remediation Involving Organic Contaminants.

Water decontamination remains a challenge in several developed and developing countries. Affordable and efficient approaches are needed urgently. In this scenario, heterogeneous photocatalysts appear as one of the most promising alternatives. This justifies the extensive attention that semiconductors, such as TiO2, have gained over the last decades. Several studies have evaluated their efficiency for environmental applications; however, most of these tests rely on the use of powder materials that have minimal to no applicability for large-scale applications. In this work, we investigated three fibrous TiO2 photocatalysts, TiO2 nanofibers (TNF), TiO2 on glass wool (TGW), and TiO2 in glass fiber filters (TGF). All materials have macroscopic structures that can be easily separated from solutions or that can work as fixed beds under flow conditions. We evaluated and compared their ability to bleach a surrogate dye molecule, crocin, under batch and flow conditions. Using black light (UVA/visible), our catalysts were able to bleach a minimum of 80% of the dye in batch experiments. Under continuous flow experiments, all catalysts could decrease dye absorption under shorter irradiation times: TGF, TNF, and TGW could, respectively, bleach 15, 18, and 43% of the dye with irradiation times as short as 35 s. Catalyst comparison was based on the selection of physical and chemical criteria relevant for application on water remediation. Their relative performance was ranked and applied in a radar plot. The features evaluated here had two distinct groups, chemical performance, which related to the dye degradation, and mechanical properties, which described their applicability in different systems. This comparative analysis gives insights into the selection of the right flow-compatible photocatalyst for water remediation.

Sunlight Assisted Degradation of Linear Alkylbenzene Sulfonate by Floating Catalyst TiO2-Coconut Fiber

The increasing number of laundry businesses in Pontianak causes increased laundry waste, which is dangerous for health and the environment because anionic surfactants such as Linear Alkylbenzene Sulfonate (LAS) are hard degradable. Photocatalyst is a method that can be used to degrade the LAS structure. TiO2 carried in coconut fiber can optimize sunlight irradiation in degrading LAS content when light reaches the water's surface. This study aims to determine the characteristics and optimum activity time of photocatalyst TiO2-coconut fiber in degrading LAS. Photocatalyst characterization was carried out using XRD, XRF, and DR-UV, while the optimum activity test of photocatalysts in degrading LAS was carried out using a UV-Vis spectrophotometer. XRD diffractogram analysis showed the peaks of coconut fiber at 2θ = 22.2º, 34.8º and TiO2 at 2θ = 25.3º, 37.8º, 48.1º, 55.1º, and 62.1º. The TiO2 attached to the fiber after being synthesized was 21.12%. The band gap of TiO2 and TiO2-coconut fiber is 3.21 and 3.18 eV, with light absorption at 386.5 and 390.3 nm. Photocatalyst was carried out in LAS with a mass ratio of TiO2 and coconut fiber of 20:80; 30:70; 40:60, and 50:50 w/w with a time range of 0, 30, 60, 90, and 120 minutes. The results of photocatalysis of TiO2-coconut fiber in a ratio of 20:80 w/w showed the optimum photocatalytic activity at 120 minutes with the highest degradation rate of 80.43%. This research is expected to be applied as an alternative to handling LAS in laundry industry waste.

150 The Innomat.Life Extended Fibre Human Risk Banding Scheme

Abstract High aspect ratio materials (HARMs) like multi-walled carbon nanotubes (MWCNTs) show material properties that enable innovative applications but also raise concerns about harmful effects to humans due to their asbestos-like pathogenicity. The fibre-pathological paradigm was established for asbestos and other HARM, linking fibre-specific adverse effects to certain material properties such as fibre length, respirability and bio-persistence. A new risk banding scheme for such hazard- and exposure-related properties is introduced. For each relevant property, we defined descriptors and developed/validated methods for their measurement. Based on results from studies conducted in the project or obtained from literature, we defined quantitative band limits. While the fibre-pathological paradigm acted as a starting point, observations of in vitro effect of nanofibers motivated us to incorporate additional properties. Studying macrophage-fibre interactions led us to highlight the importance of the flexural rigidity of fibres for their uptake by macrophages. Also, the bundling of thin constituent fibres was recognized as a mechanism possibly generating less flexible and, therefore, more harmful inhalable particles with high aspect ratio from harmless precursors. Transformation dynamics of fibres in fluids like the phagolysosomal medium were investigated as well to gain a better understanding about fibre bio-durability. Overall, the risk for humans exposed to HARMs is described by the risk banding scheme in which property bands relevant for the hazard potential were juxtaposed to the respective exposure potential. We present results for a selection of HARMs including multiple MWCNTs with varying properties, TiO2 fibres, SiC whiskers, as well as silver and copper nanowires.

Enable thermal insulation improvement of Al2O3 aerogels doped with graded oriented extinction phase-change fiber at large temperature differences

Phase change materials (PCMs) play essential roles in extending transient thermal insulation in the aerospace field; however, the extinction properties variations during the phase change process have seldom been investigated. The present study presents an extinction phase-change fiber (EPCF) design, i.e., composed of extinction material shell as well as the PCM core and dispersed in Al2O3 aerogel. The extinction performance (especially after the phase transition) and the insulation performances at steady and transient states according to specific infrared radiation wavelength modulation are numerically investigated. This study reveals that the extinction characteristic of VO2@SiO2 is superior to that of SiO2 and TiO2 fiber. The extinction performance is improved by ∼8.37% after the phase transition of VO2. Besides, the time constant of VO2@SiO2 increased by ∼2.17 times the pure aerogel at the insulation aspect. Similar conclusions could be self-evidently found in some other EPCFs; furthermore, multi-layer EPCFs design is studied for spectral modulation principle combined with the transient heat transfer characteristic. Our developmental work could inspire some novel ideas on insulation material design in the future and improve the understanding of phase change insulation.

Photocatalytic degradation of oxytetracycline by SiO2–TiO2–Ag electrospun fibers

The contamination and dispersion of antibiotics into the environment through effluents from sewage treatment plants have produced serious consequences like the generation of resistant bacteria, generating a health emergency, so the need arises to develop processes to eliminate antibiotics in effluents. One of the methodologies used is advanced oxidation where a complete degradation of antibiotics can be reached, among the advanced oxidation processes, photocatalysis stands out as an efficient degradation pathway of organic pollutants from a photocatalyst. In the present investigation SiO2–TiO2 fibers were obtained by sol-gel and electrospinning techniques which had a cylindrical morphology and a smooth surface free of defects with a diameter 266 ± 62 nm. In increasing photocatalytic properties, the SiO2–TiO2 fibers were doped with silver by electrodeposition resulting in the deposition of particles with a branched dendritic morphology with a size of approximately 1 μm. The characterization of SiO2–TiO2–Ag fibers by infrared in the fibers eluted bands characteristic of the Si–O–Si and Ti–O–Ti bonds, and by means of the X-ray diffraction were identified crystalline phases corresponding to the anatase and rutile of the Titania, as well as face-centered cubic silver. Oxytetracycline was used as a contaminant to investigate the photocatalytic performance of SiO2–TiO2–Ag material, where from an initial concentration of 30 ppm in the presence of SiO2–TiO2 fibers its degradation percentage was 65%, unlike 90% in 7 h using silver-doped fibers. The increased degradation of oxytetracycline is attributed to the success in decreasing the banned band of SiO2–TiO2 fibers from 3.1eV to 2.5eV to silver doping.

Electrospun Fe doped TiO2 fiber photocatalyst for efficient wastewater treatment

Water pollution caused by industrial wastewater is the most critical environmental problem in the world. Synthetic dyes are commonly used in various industries such as paper, plastic, printing, leather and textile for their ability to impact color. Complex composition, high toxicity and low biodegradability of dyes make them difficult to degrade which causes a substantial negative impact on overall ecosystems. To address this issue we synthesized TiO2 fibers photocatalyst using the combination of sol-gel and electrospinning techniques to be used in the degradation of dyes which causes water pollution. We doped Fe in TiO2 fibers to enhance the absorption in the visible region of the solar spectrum which will also help to increase the degradation efficiency. As synthesized pristine TiO2 fibers and Fe doped TiO2 fibers were analyzed using different characterization techniques such as X-ray diffraction, Scanning electron microscopy, Transmission electron microscopy, UV–Visible spectroscopy, X-ray photoelectron spectroscopy. 5% Fe doped TiO2 fibers show excellent photocatalytic degradation activity for rhodamine B (99% degradation in 120 min). It can be utilized for degradation of other dye pollutants such as methylene blue, Congo red and methyl orange. It shows good photocatalytic activity (97%) even after 5 cycles of reuse. The radical trapping experiments reveals that holes, •O2− and •OH has a significant contribution in the photocatalytic degradation. Due to the robust fibrous nature of 5FeTOF the process of collection of photocatalysts was simple and without loss as compared to powder photocatalysts. This justifies our selection of electrospinning method of synthesis of 5FeTOF which is also useful for large scale production.

Development, characterization and photocatalytic study of biocomposites based on PTFE, TiO2 and LuffaCylindrica fibers

The present study focuses on the use of Luffa Cylindrica fibers as a reinforcing agent in a fluoroplastic (PTFE) polymer matrix and TiO2 nanoparticles as a photocatalytic agent with different mass fractions (%), for the purpose of the preparation and structural characterization of a new biocomposite material. The granulometry and zeta potential were measured using dynamic light scattering and laser Doppler velocimetry respectively. Structural and vibrational properties of the PTFE/TiO2/LC fibers composites were characterized by micro-Raman spectroscopy in oblique backscattering configuration and FTIR spectroscopy. Lastly, thermal properties were investigated using TGA and DSC. Further, the photocatalytic activity of samples was tested for the degradation of Methylene Blue dye (MB) in aqueous medium.

Investigation of the Mechanical and Wear Properties of Epoxy Resin Composite (ERCs) Made With Nano Particle TiO2 and Cotton Fiber Reinforcement

Investigation of the Mechanical and Wear Properties of Epoxy Resin Composite (ERCs) Made With Nano Particle TiO2 and Cotton Fiber Reinforcement

Photodecomposition of water\ethanol mixtures for the production of hydrogen using as catalysts TiO2 fibers

The consumption of hydrogen as an automotive fuel has been growing since the 1980s. It can be used both as a gasoline blend and as a pure fuel. All human activities involve the use of energy. Some examples are: fuels for transport and heating, electricity for various purposes, among others. It is a basic element for the production and commercialization of any goods or services and represents one of the main expenses of families. Thus, projected future trajectories for energy prices are of obvious interest to consumers and producers. The use of hydrogen generation and storage technology is an energy generation option to replace current fossil fuels, as it offers the opportunity to obtain energy with reduced environmental impacts and which does not pollute the environment. In this work, TiO2 fibers were obtained by the electrospinning technique and used as catalysts in the photodecomposition of water-ethanol mixtures for the production of hydrogen. The X-ray diffraction technique (XRD) was used to characterize the synthesized catalysts, the BET method provided measurements of the specific area, and scanning electron microscopy (SEM) analyzed the morphology of the samples. The results indicate that the fibers that contain the anatase phase in greater proportion have a high surface area and were the most effective in the production of hydrogen.