Fluorine-doped Titanium Dioxide Research Articles

Photo-Sono activated fluorine-doped titanium-based bone implants for rapid osteosarcoma eradication and bacterial infection elimination

Inadequate elimination of tumor cells, bacterial infection, and insufficient bone fusion are the primary factors contributing to the recurrence of osteosarcoma and implant failure. To overcome these challenges, a multifunctional bioactive titanium-based implant consisting of fluorine-doped titanium dioxide (TiO2) nanoparticles was designed for synergistic therapy activated by near-infrared II (NIR-II) light and ultrasound. The F-doped TiO2 nanoparticles exhibit excellent photothermal and acoustic properties upon excitation by 1060 nm NIR-II laser and ultrasound, respectively. The synergistic effect of hyperthermia and reactive oxygen species (ROS) under photoacoustic action endows the TiO2 nanoparticles with remarkable anti-tumor and anti-bacterial activities, enabling them to eradicate Saos-2 cells within 10 min and S. aureus within 15 min. Meanwhile, the nanostructured surface and appropriate doping of F endow nanoparticles with excellent bone promoting ability.

Morphology and Optical Properties of Spatially-Ordered Copper- and Fluorine-Doped Titanium-Dioxide Films

Morphology and Optical Properties of Spatially-Ordered Copper- and Fluorine-Doped Titanium-Dioxide Films

Colorful carbon nitride based composite films

Carbon nitride based photoelectrodes for solar water splitting devices have attracted tremendous attention. However, for practical applications, it is desirable to develop a kind of carbon nitride based photoelectrode with a wide range of colors for meeting the demand of aesthetic properties when the light harvesting devices are loaded on buildings. This work first presents an innovative strategy for constructing colorful carbon nitride films by adopting multiple-steps thermal vapor condensation (MSTVC) method. Different monomers and amounts are studied to tailor carbon nitride based photoelectrodes with different colors, including dark brown, iridescence, green, bluish violet, reddish brown, red, crimson, orange, dark yellow and black due to the change of the composition and the evolution of impressive surface hierarchical structure caused by the reaction between the sulfur-rich monomers and fluorine-doped titanium dioxide (FTO) layer. The colorful carbon nitride based photoelectrodes also generate satisfied photocatalytic activity, the photocurrent densities are from 13.2 to 96.2 μA cm−2 at 1.23 V vs. RHE. We expect this work can be of interest not just for the development of carbon nitride photoelectrochemical cells, but also for the fundamental exploration and applications in electronics, photonics, sensors and displays.

First-principles calculations of Fluorine-doped Titanium dioxide: A prospective material for solar cells application

This study focuses on the anatase TiO2 doped Fluorine to investigate their structural and electronics properties using Density Functional Theory (DFT) within generalized gradient approximation (GGA) as implemented in Quantum ESPRESSO (QE). For the anatase TiO2 phase the calculated electronic band structures of pure TiO2 and TiO2 doped Fluorine nanocrystals are displayed along a high symmetry directions and the energy range of band structure is plotted from 0.0 eV to 3.9 eV , the energy separation between the bottom of the conduction band and the top of valence band occurred at the Γ and points, indicating that anatase TiO2 is an indirect band gap material with an approximate value of 2.30 eV energy gap, this value is consistent with previous DFT result. When F is added the band structure did not change much because fluorine element doping is conducive to the generation of Oxygen holes and enhances the mobility of effective electrons which can enhance the conductivity of the adsorbent substrate and improve the solar cell performance of the fluorine-doped TiO2. The band gap value obtained for F doped TiO2 was found to be 2.11 eV. The dopant formation energy of Fluorine is calculated to be -55.6 Ry which is equivalent to -756.5 eV.

Functionalized carbon nanotubes decorated with fluorine-doped titanium dioxide nanoparticles on silicon substrate as template for titanium dioxide film photo-anode grown by chemical vapour deposition

Carbon nanotubes decorated with fluorine-doped titanium dioxide (TiO2) nanoparticles on Silicon substrate serves as a template for improved TiO2 growth by chemical vapour deposition (CVD). The study analyses and characterizes several growth conditions for the template finding an optimum for enhanced photochemical activity. Even for non-optimized growth conditions for the CVD grown TiO2 enhancement in photochemical activity is observed when grown on proposed template. With the growth on cheap Si substrates the carbon nanotube-based photo-electrochemical (PEC) electrode has great potential to enhance the PEC activity of TiO2 grown by CVD at relative low temperature.

A novel synthesis route of titanium dioxide with (NH4)0.3TiO1.1F2.1 as by-product

Abstract This work explores a new route for the synthesis of titanium dioxide using scraps and titanium chips, which are typically discarded as waste, as the precursor materials. The band-gap energy of the synthesised materials was determined using diffuse reflectance spectroscopy. The morphology, elemental analysis, crystallinity, and chemical structure of the synthesised materials were determined by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffractometry, and infrared and Raman spectroscopies, respectively. The X-ray and Raman analyses confirmed the formation of titanium dioxide in its tetragonal (anatase) crystalline form after heat treatment (400 °C, 2 h). Moreover, a mixture of (NH 4 ) 0,3 TiO 1,1 F 2,1 and anatase TiO 2 was obtained as a by-product. After heat treatment, this by-product was converted into fluorine-doped titanium dioxide, also in anatase crystalline form. The apparent crystallite size ( L c ) of anhydrous titanium dioxide was found to be smaller than that of the calcined by-product. The diffuse reflectance spectroscopy analysis revealed that the calcined by-product has a significantly higher absorption capacity at higher wavelengths, as well as a lower band-gap energy value. The scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) analyses showed large particulates on which smaller particles are deposited and good dispersion of the elemental components. The anhydrous titanium dioxide sample presents a smaller particle size than the calcined by-product.

Mechanism of performance enhancement via fluorine doped titanium dioxide nanoparticles in dye sensitized solar cells

Abstract Fluorine doped anatase TiO2 nanoparticles are synthesized by hydrothermal method and applied in dye-sensitized solar cells (DSCs) as excellent photoelectrode material. The result shows that fluorine-doping can positively shift the conduction band of TiO2, thus enlarge the driving force for efficient electron injection, reduce the interfacial losses from the charge recombination and consequently facilitate the charge transfer. The conversion efficiency of DSCs with fluorine-doped TiO2 electrodes is improved by 16.2% and results in a 23.1% photocurrent gain. This paper provides a comprehensive understanding on the behaviors of fluorine-doping TiO2 in DSCs from the conduction band shift and the mechanism of electron injection, transfer and recombination and a promising strategy to explore high efficiency DSCs.

Revealing the degradation intermediates and pathways of visible light-induced NF-TiO2 photocatalysis of microcystin-LR

The effect of using only visible light to induce nitrogen- and fluorine-doped titanium dioxide (NF-TiO2) photocatalysis of degradation products of microcystin-LR (MC-LR), the most common problematic cyanotoxin, was explored by looking at the intermediate degradation products. Although the degradation mechanisms and products of conventional UV-based TiO2 photocatalysis of MC-LR have been well elucidated, the same is not true for visible light-based TiO2 photocatalysis. The results of LC/MS2 (and in one case LC/MS3) indicated that the intermediates are not drastically altered in comparison to traditional TiO2 photocatalysis using UV light. The data hint that the degradation is driven by hydroxyl radicals, as is UV-based TiO2 photocatalysis, although the mechanism for producing hydroxyl radicals is unclear since studies indicate drastically slower kinetics for visible light-based photocatalysis of MC-LR. Notably, the data indicate that visible light-induced NF-TiO2 photocatalysis degraded the portion of MC-LR that is responsible for biological toxicity. As a result of this, it was concluded that doping TiO2 with nitrogen and fluorine is an effective method for increasing utilization of visible light while degrading MC-LR in water, although it should still be noted that degradation kinetics are still slower than UV-based TiO2 photocatalysis.

Role of pH on photolytic and photocatalytic degradation of antibiotic oxytetracycline in aqueous solution under visible/solar light: Kinetics and mechanism studies

In this study, the photochemical degradation of the antibiotic oxytetracycline (OTC) at different pH values was investigated in aqueous solution under visible and solar light irradiation. Particular emphasis was given to the kinetics and mechanism during the photolytic and photocatalytic degradation of OTC. A comparative study of the photolysis of OTC under solar light, with different initial concentrations and in the presence of scavengers of reactive oxygen species (ROS), revealed a self-photosensitization pathway with evidence of singlet oxygen generation at pH 8.5 and 11.0 during OTC photolysis. The three-dimensional fluorescence spectra of OTC at different pH values demonstrate that OTC only exhibits significant emission spectra at pH 8.5 and 11.0. The change of the internal electrostatic force between the electron withdrawing group and the dehydrogenation moiety of OTC as a function of solution pH values was proposed as a critical factor influencing the energy states and observed reaction pathways of OTC under light irradiation. Moreover, the mechanism of photochemical degradation of OTC was investigated with nitrogen and fluorine doped titanium dioxide (NF-TiO2) film at different pH values under visible and solar light in the presence of tert-butyl alcohol (TBA), sodium azide (NaN3), potassium iodine (KI) and catalase as scavengers. Five pathways, including direct photolytic degradation, UV/vis light-induced photocatalytic oxidation and reduction, and visible light-induced self-photosensitized oxidation and reduction, were proposed and verified during the photocatalytic degradation of OTC with NF-TiO2 film.

Effects of F doping on TiO 2 acidic sites and their application in QCM based gas sensors

Titanium dioxide (TiO 2) and fluorine doped titanium dioxide (F-TiO 2) particles were prepared by a one-pot hydrothermal synthesis, and applied on quartz crystal microbalance (QCM) resonators to detect trace levels of nerve agent stimulant, dimethyl methylphosphonate (DMMP). DMMP sensing measurements exhibited that TiO 2 functionalized QCM resonators had fast response and recovery as well as satisfactory sensitivity. F-TiO 2 functionalized QCM resonators showed even faster response and higher sensitivity but rather slow recovery. The sensing mechanism and the effect of fluorine doping were examined by diffuse reflectance infrared Fourier transform spectroscopy, revealing that the adsorption took place at Brønsted acid sites at the initial stage and at Lewis acid sites later. Fluorine doping on TiO 2 greatly enhanced the acidity of Lewis acid sites, resulting in faster response but slower recovery than pure TiO 2. X-ray diffraction analyses demonstrated that the fluorine doping could enhance the crystalinity of anatase.

Photocatalytic activity of fluorine-doped titanium dioxide

Fluorine-doped anatase has a higher photocatalytic activity compared to undoped anatase obtained under identical conditions and retains this activity after thermal treatment in a temperature range of 400–700°C. The photocatalytic activity of the evaluated fluorine-doped titanium oxohydroxide with an allowance for its titanium content is insignificantly lower than the photocatalytic activity of fluorine-doped anatase.

The Nature of Defects in Fluorine-Doped TiO2

Fluorine-doped titanium dioxide was prepared via sol−gel synthesis and subsequent calcination in air. The presence of fluorine in the lattice induces the formation of reduced Ti3+ centers that localize the extra electron needed for charge compensation and are observed by electron paramagnetic resonance. Density functional theory calculations using hybrid functionals are in full agreement with such description. The extra electron is highly localized in a 3d orbital of titanium and lies a few tenths of an electron volt below the bottom of the conduction band. The preparation via sol−gel synthesis using aqueous solutions of fluorides also causes the formation of surface F− ions that substitute surface hydroxyl groups (OH−) without generating reduced centers.