Fabrication and Photocatalytic Properties of Electrospun Fe-Doped TiO2 Nanofibers Using Polyvinyl Pyrrolidone Precursors

Recent Progress in Photocatalytic Applications of Electrospun Nanofibers: A Review

Electrospun fiber-based photocatalysts demonstrate significant potential in addressing global environmental and energy challenges, primarily due to their high specific surface areas and unique properties. This review examines recent advances in the application of these materials in photocatalytic processes, with a particular focus on water splitting and hydrogen production. The principles of the electrospun method are described in detail, along with the operating parameters, material characteristics, and environmental conditions that affect the fiber formation. Additionally, the review discusses the challenges, advantages, and future prospects of photocatalysts incorporating carbon materials, metals, semiconductors, and hybrid structures with improved performance. These materials have the potential to significantly improve the efficiency of hydrogen energy production, water purification, and CO2 recovery, highlighting their importance in engineering sciences.

Photocatalytic behavior for removal of methylene blue from aqueous solutions via nanocomposites based on Gd2O3/CdS and cellulose acetate nanofibers

Efficient cleaning of contaminated water by photocatalysis has become an effective strategy in recent years due to its environmental and ecological designation. Cadmium sulfate (CdS) is an excellent photocatalyst in the visible region but has low quantum efficiency. In order to increase the photocatalytic efficiency, CdS was modified with gadolinium oxide (Gd2O3) and combined with graphene oxide (GO) nanoparticles. The estimated crystallite size (Ds) for Gd2O3, CdS/Gd2O3, and CdS/Gd2O3@GO was 29.6, 11.6, and 11.5 nm, respectively. The degradation of methylene blue (MB) reaches the highest values after 60 min under visible light irradiation with a dye concentration of (0.25 ppm). Whereas in powdered composition the efficiency of dye removal has been enhanced under UV irradiation, it reduced by increasing the MB concentration to 0.50 ppm with visible light irradiation. In addition, the CdS with/without Gd2O3 and GO were integrated into electrospun nanofibrous cellulose acetate (CA) through the electrospinning technique. The compounds of Gd2O3, CdS/Gd2O3, and CdS/Gd2O3/GO were encapsulated into CA nanofibers for the degradation of MB under visible and UV irradiation. The apparent rate constant (k) achieves a value of 0.006, 0.007, and 0.0013 min-1 while the removal efficiency reaches 41.02%, 54.71%, and 71.42% for Gd2O3@CA, CdS/Gd2O3@CA, and CdS/Gd2O3/GO@CA, respectively, after 60 min under UV irradiation.

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.

Photocatalytic and Antimicrobial Properties of Electrospun TiO2-SiO2-Al2O3-ZrO2-CaO-CeO2 Ceramic Membranes

In this study, TiO₂-based ceramic nanofiber membranes in the system of TiO₂-SiO₂-Al₂O₃-ZrO₂-CaO-CeO₂ were synthesized by combining sol-gel and electrospinning processes. In order to investigate the thermal treatment temperature effect, the obtained nanofiber membranes were calcined at different temperatures ranging from 550 to 850 °C. Different characterization methods such as X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), and high-resolution transmission electron microscopy (HR-TEM) were conducted on the obtained membranes to investigate the structural and morphological properties of the nanofibers. The Brunauer-Emmett-Teller surface area of the nanofiber membranes was very high (46.6-149.2 m²/g) and decreased with increasing calcination temperature as expected. Photocatalytic activity investigations were determined using methylene blue (MB) as a model dye under UV and sunlight irradiation. High degradation performances were achieved with the calcination temperatures of 650 and 750 °C because of the high specific surface area and the anatase structure of the nanofiber membranes. Moreover, the ceramic membranes showed antibacterial activity against Escherichia coli as a Gram-negative bacterium and Staphylococcus aureus as a Gram-positive bacterium. The superior properties of the novel TiO₂-based multi-oxide nanofiber membranes proved as a promising candidate for various industries, especially the removal of textile dyes from wastewater.

Electrospun Structural Hybrids of Acyclovir-Polyacrylonitrile at Acyclovir for Modifying Drug Release

In traditional pharmaceutics, drug–crystalline nanoparticles and drug–polymer composites are frequently explored for their ability to modify drug release profiles. In this study, a novel sort of hybrid with a coating of acyclovir crystalline nanoparticles on acyclovir-polyacrylonitrile composites was fabricated using modified, coaxial electrospinning processes. The developed acyclovir-polyacrylonitrile at the acyclovir nanohybrids was loaded with various amounts of acyclovir, which could be realized simply by adjusting the sheath fluid flow rates. Compared with the electrospun composite nanofibers from a single-fluid blending process, the nanohybrids showed advantages of modifying the acyclovir release profiles in the following aspects: (1) the initial release amount was more accurately and intentionally controlled; (2) the later sustained release was nearer to a zero-order kinetic process; and (3) the release amounts at different stages could be easily allocated by the sheath fluid flow rate. X-ray diffraction results verified that the acyclovir nanoparticles were in a crystalline state, and Fourier-transform infrared spectra verified that the drug acyclovir and the polymer polyacrylonitrile had a good compatibility. The protocols reported here could pave the way for developing new types of functional nanostructures.