F-doped TiO2 Research Articles

Sunlight-activated composite TiO2-F-V-Mo materials for photodegradation of the organic pollutant methylene blue

F-doped TiO2 photocatalyst materials were prepared using solid-state and sol-gel synthesis with varying weight percentages of LiF or NH4F. Subsequently, molybdate and vanadium oxide were added to the prepared powders to create composite photocatalysts with reduced bandgap energy, enhancing light absorption in the visible region of the spectrum, which is essential for effective photocatalytic activity using sunlight. The synthesized powders were characterized by thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and specific surface area using the BET method. The crystallization and anatase-to-rutile phase transformation of the powders were verified by X-ray diffraction (XRD), and the composite nanoparticles were further investigated by transmission electron microscopy (TEM). The photocatalytic activity of the F-doped commercial TiO2, sol-gel synthesized TiO2, and prepared composite powders was evaluated through the photocatalytic degradation of methylene blue (MB) in water under ultraviolet (UV), UV–visible, and sunlight irradiation. The results indicated that the incorporation of Molybdenum and Vanadium significantly influenced the photocatalytic efficiency by substantially reducing the bandgap of this composite photocatalyst. The LiF-doped TiO2 powders synthesized by sol-gel using TTIP, and doped with vanadium and molybdenum, activated by sunlight, exhibited high performance in MB degradation compared to commercial TiO2 and undoped synthesized TiO2 powders, achieving an optimal degradation rate of 7.26 × 10⁻⁹ mol per gram of photocatalyst.

Role of fluorine doping on the electron transport layer of F-doped TiO2 (Titanium dioxide) for photovoltaic systems and its environmental impact

Role of fluorine doping on the electron transport layer of F-doped TiO2 (Titanium dioxide) for photovoltaic systems and its environmental impact

Fluorine Doping Mediated Epitaxial Growth of NaREF4 on TiO2 for Boosting NIR Light Utilization in Bioimaging and Photodynamic Therapy.

By integrating TiO2 with rare earth upconversion nanocrystals (NaREF4), efficient energy transfer can be achieved between the two subunits under near-infrared (NIR) excitation, which hold tremendous potential in the fields of photocatalysis, photodynamic therapy (PDT), etc. However, in the previous studies, the combination of TiO2 with NaREF4 is a non-epitaxial random blending mode, resulting in a diminished energy transfer efficiency between the NaREF4 and TiO2. Herein, we present a fluorine doping-mediated epitaxial growth strategy for the synthesis of TiO2-NaREF4 heteronanocrystals (HNCs). Due to the epitaxial growth connection, NaREF4 can transfer energy through phonon-assisted pathway to TiO2, which is more efficient than the traditional indirect secondary photon excitation. Additionally, F doping brings oxygen vacancies in the TiO2 subunit, which further introduces new impurity energy levels in the intrinsic band gap of TiO2 subunit, and facilitates the energy transfer through phonon-assisted method from NaREF4 to TiO2. As a proof of concept, TiO2-NaGdF4 : Yb,Tm@NaYF4@NaGdF4 : Nd@NaYF4 HNCs were rationally constructed. Taking advantage of the dual-model up- and downconversion luminescence of the delicately designed multi-shell structured NaREF4 subunit, highly efficient photo-response capability of the F-doped TiO2 subunit and the efficient phonon-assisted energy transfer between them, the prepared HNCs provide a distinctive nanoplatform for bioimaging-guided NIR-triggered PDT.

Effect of Annealing Temperature on F-doped TiO2 Spin Coated Thin Films

Effect of Annealing Temperature on F-doped TiO2 Spin Coated Thin Films

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.

Hydrophobic fluorine-doped carbon-wrapped TiO2 particles as efficient and stable photocatalysts for gaseous toluene degradation

Moisture-resistant TiO2-based catalysts with high activity and stability are urgently needed to satisfy requirements for the treatment of volatile organic compounds (VOCs). In this work, a novel hydrophobic F-doped carbon-wrapped TiO2 catalyst (TiO2 @HFC) was synthesized by a facile method and used for the photocatalytic degradation of toluene. TiO2 @HFC displays significantly higher activity under UV/Vis irradiation than commercial P25 TiO2, and remains stable after six cycles. The removal efficiency of toluene was 81.7% after 210 min of reaction, corresponding to a mineralization efficiency of 74.5%. Benefiting from the hydrophobic F-doped carbon layer modification, the incorporation of F into TiO2 crystals, and increased Ti3+ content, TiO2 @HFC is characterized by efficient separation and utilization of photoexcited charge carriers, enhanced adsorption of toluene, and robust resistance towards water vapor. This work demonstrates the potential application of the TiO2-based photocatalyst to efficiently remove VOCs in a humid environment.

Crystalline F-doped titanium dioxide nanoparticles decorated with graphene quantum dots for improving the photodegradation of water pollutants

Carbon dots are emerging photoactive materials with high chemical stability, aqueous solubility, abundant surface functional groups and low-cost production. Their great advantages, incorporated into the high photocatalytic activity of the TiO2, result in hybrid systems that overcome some of the photocatalytic drawbacks associated with TiO2. In this work, a facile synthesis of hybrids of F-doped TiO2 and N-doped graphene quantum dots (F-TiO2@N-GQDs) is reported. These systems have demonstrated efficient photocatalytic properties in light-driven pollutant reduction from water. Therefore, using a simple and low-cost synthesis method, the N-GQDs act as electron reservoirs improving the pairs e--h+ lifetime in TiO2 by decreasing charge recombination, increasing their photocatalytic capacity. The photocatalysts showed very effective degradations of different contaminants such as methylene blue (90% degradation) ciprofloxacin (62% degradation) and naproxen (60% degradation) in short periods of up to 15 min and 4-chlorophenol (59% degradation) in 30 min using UV light (300 W).

Models of Polaron Transport in Inorganic and Hybrid Organic-Inorganic Titanium Oxides.

Polarons are a type of localized excess charge in materials and often form in transition metal oxides. The large effective mass and confined nature of polarons make them of fundamental interest for photochemical and electrochemical reactions. The most studied polaronic system is rutile TiO2 where electron addition results in small polaron formation through the reduction of Ti(IV) d0 to Ti(III) d1 centers. Using this model system, we perform a systematic analysis of the potential energy surface based on semiclassical Marcus theory parametrized from the first-principles potential energy landscape. We show that F-doped TiO2 only binds polaron weakly with effective dielectric screening after the second nearest neighbor. To tailor the polaron transport, we compare TiO2 to two metal-organic frameworks (MOFs): MIL-125 and ACM-1. The choice of MOF ligands and connectivity of the TiO6 octahedra largely vary the shape of the diabatic potential energy surface and the polaron mobility. Our models are applicable to other polaronic materials.

F-doped TiO2(B)/reduced graphene for enhanced capacitive lithium-ion storage

A composite of F-doped TiO2(B) and reduced graphene oxide (F-TiO2(B)/rGO) was successfully synthesized via a one-step hydrothermal route. It was found that the introduction of F ions in the synthetic process has led to the uniform dispersion of TiO2(B) on rGO nanosheets. The F ions have also been doped into the lattice of TiO2(B), which greatly improved the conductivity of the materials. Consequently, this composite delivered a large capacity of 249.4 mA h g−1 at 0.2 A/g. It also demonstrated a capacity of 203.1 mA h g−1 and an excellent capacity retention of 96% after 500 cycles even at a high current density of 2 A/g.

Mechanism of photocatalytic reduction of CO2 to CH4 on F-doped defective anatase TiO2(101) surface: A density functional theory study

Photocatalytic reduction of CO2 into CH4 has attracted comprehensive concerns as an effective solution to meet the energy crisis and global warming. F-doped defective anatase TiO2 was reported to effectively improve the photocatalytic efficiency and the selectivity of CH4 generation. However, the mechanism behind it remains unclear. Herein, we systematically studied the photocatalytic pathway of CO2 reduction to CH4 on F-doped defective anatase TiO2(101) by density functional calculations. First, we found that F doping leads to the enhanced reduction potential of photoexcited electrons. Furthermore, we identified a thermodynamically feasible reaction path: CO2→CO/HCOO→CHO→CH2O→CH3O→CH3OH→CH3→CH4. The whole reaction is exothermic, elucidating an extremely strong reduction activity of the TiO2(101) surface. Our work provides some new insights into the CO2 reduction mechanisms of F-doped TiO2, which will help to design TiO2-related photocatalysts with high catalytic performance.

Improved electronic interaction and dispersing effect derived from the F-doped TiO2support on RuOxto boost the electrocatalytic oxygen evolution performance

F–TiO2is prepared and innovatively adopted to support RuOxnanoparticles for enhancing the OER stability, activity and noble-metal utilization.

Non-toxic fluorine-doped TiO2 nanocrystals from TiOF2 for facet-dependent naproxen degradation

In the present study, the photocatalytic degradation of naproxen (NPX), which is a nonsteroidal anti-inflammatory drug (NSAID), frequently detected in drinking water, was investigated. The F-doped TiO2 with defined morphology was successfully obtained from TiOF2 and applied for photocatalytic degradation under UV–vis and visible light. All samples were characterised by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, zeta potential, diffuse reflectance spectroscopy, and Brunauer–Emmett–Teller surface area analyses. The effect of morphology on the photocatalytic activity of the F-TiO2 nanostructures with exposed {1 0 1}, {0 0 1} and {1 0 0} facets was studied. Octahedral F-TiO2 particles with exposed {1 0 1} facets revealed the highest photocatalytic activity, and degraded 100% of the initial NPX concentration after 40 min of the photodegradation process under simulated solar light (UV–vis). Moreover, this sample exhibited the highest TOC removal and NPX degradation under visible light (>420 nm). Based on HPLC-MS analysis, it was assumed that {0 0 1} facets present in fluorinated decahedral nanostructures promote the formation of a dimer, which further hinders the mineralisation rate. Therefore, decahedral nanostructures exposing {1 0 1} and {0 0 1} facets revealed lower photocatalytic activity than octahedral F-TiO2 particles with exposed {1 0 1} facets, which is also consistent with DFT studies. Finally, toxicity assessment of post-process suspensions using Microtox bioassay confirmed that fluorine-doped octahedral anatase particles are non-toxic, although fluorine ions were the reactants of the synthesis from TiOF2. Overall results showed the possibility of application of highly efficient and environmentally safe fluorine-doped anatase photocatalysts in improved degradation of naproxen.

Biogenic synthesis of nano-photocatalysts doped TiO2 nanoparticles and their application in photocatalytic degradation

The significant effect of TiO2 predominantly used as photocatalytic degradation catalyst and could also be used against viruses in future. The modified TiO2 nano-photocatalyst with F and I-doping was prepared using expired egg-white as template through sol-gel method at different concentrations. In this study, aqueous solution of methylene-blue used as target degradation product in presence of prepared TiO2-nanoparticles under simulated-sunlight and LED visible-light. Therefore, particle size of F and I-doped nanoparticles was observed at 12 and 11.8nm (low-concentration) and, 13.2 and 16.2nm (high-concentration) respectively, where removal efficiency exhibited 6.2 and 43.0% at higher and lower-concentration simultaneously of F-doped TiO2 nanoparticles.

Characteristics of Doped TiO2 Nanoparticle Photocatalysts Prepared by the Rotten Egg White.

In this study, expired egg white was used as a template, and a sol–gel method was employed to prepare pure-phase TiO2 nano-powder and mixed-phase powders doped with NaF and NaI. The influences of different calcination temperatures, doping elements, and doping amounts during the preparation process on the photocatalytic performance and activity of the prepared TiO2 powders were studied. The results of the experiments showed that the F-doped TiO2 had the highest photocatalytic activity when the doping amount was 1.2%, as examined by EDS, where the sintering temperature was 500 °C. F-doped TiO2 nanoparticles were also synthesized by the sol–gel method using tetrabutyl titanate and NaF mixed with expired egg white protein as the precursor. The F-TiO2 photocatalyst was characterized using FE-SEM, HR-TEM, EDS, XPS, and UV-Vis, and the photocatalytic activity was evaluated by photodegradation of methylene blue under visible light. The results showed that doping with F reduced the energy band gap (3.04 eV) of TiO2, thereby increasing the photocatalytic activity in the visible-light region. The visible-light wavelength range and photocatalytic activity of the catalyst were also affected by the doping amount.

Resistive switching properties for fluorine doped titania fabricated using atomic layer deposition

This study demonstrates a new resistive switching material, F-doped TiO2 (F:TiO2), fabricated by atomic layer deposition (ALD) with an in-house fluorine source for resistive random access memory (RRAM) devices. Controlling oxygen vacancies is required since RRAM uses resistive switching (RS) characteristics by redistributing oxygen ions in oxide, and poor oxygen defect control has been shown to significantly reduce RRAM reliability. Therefore, this study designed an F based RRAM device using fluorine anions rather than oxygen defect for the main agent of RS behavior. We developed the F:TiO2 RRAM material using a novel in situ doping method in ALD and investigated its RS behaviors. The Pt/F:TiO2/Pt device exhibited forming-less bipolar RS and self-rectifying behavior by fluorine anion migration, effectively reducing the sneak current in crossbar array architecture RRAM. The doped fluorine passivated and reduced oxygen related defects in TiO2, confirmed by x-ray photoelectron spectroscopy analysis. Adopting the F-based RS material by ALD provides a viable candidate for high reliability RRAM.

Modulation of the photocatalytic activity and crystallinity of F-TiO2 nanoparticles by using green natural carboxylic acids

Ultrareactive F-doped mesoporous TiO2 nanoparticles with potential environmental applications have been synthesized using green natural carboxylic acids.

Mechanism of Photocatalytic Reduction of Co2 to Ch4 on F-Doped Defective Anatase Tio2: A Density Functional Theory Study

Mechanism of Photocatalytic Reduction of Co2 to Ch4 on F-Doped Defective Anatase Tio2: A Density Functional Theory Study

Precipitation method to prepare conductive F-doped SnO2-coated rutile TiO2 whisker and its application in coating

Precipitation method to prepare conductive F-doped SnO2-coated rutile TiO2 whisker and its application in coating

Site-dependent photoinduced charge carrier dynamics in nitrogen/fluorine doped TiO2 nanoparticles

Electron and hole trapping/recombination dynamics in N-doped and F-doped TiO2 nanoparticles.

Preparation of supporting photocatalysts for water treatment using natural sunlight as an alternative driving energy

The present study focus on synthesis of visible-light active pure, Fluoride (F) - and Silica (Si)-doped titanium dioxide (TiO2) photocatalyst. Designing the nanoparticles under sol–gel process of synthesis method is adopted. Characterizations such as SEM, XRD, FTIR, and DLS revealed about the crystallinity, physico-catalytic properties of the photocatalysts. The nanomaterials were tested for their photocatalytic properties against crystal violet, methyl orange, oil and grease and chemical oxygen demand (COD) remediation. To check the degradation efficiency samples were kept in different light sources namely natural sunlight, dark + sunlight and LED light and were tested using UV–Vis spectroscopy. It is noteworthy that the as-synthesized materials best acted on target parameters under natural sunlight (visible range) which a renewable sources of energy taken as an alternative driving energy. Specifically, Si-doped TiO2 was found to be superior over F-doped and pure (undoped) TiO2 in terms of degradation efficiencies.