Photocatalytic Properties Of Titanium Dioxide Research Articles

Self-cleaning SiO2–TiO2 ceramic membrane for enhanced oil–water separation

An efficient and practical method is proposed for the separation of oil–water mixtures and emulsions in sustainable water ecosystems, facilitating energy recovery. The construction of flexible ceramic fiber membranes with high throughput and self-cleaning capabilities has proven effective but challenging. This study reports a novel approach combining the sol–gel and electrospinning techniques to synthesize flexible silicon dioxide (SiO2)–titanium dioxide (TiO2) nanofiber membranes (STNFMs). These membranes possess nanoscale rough structures, granting them superhydrophilicity and underwater superoleophobicity (155°). Exploiting the photocatalytic properties of titanium dioxide, STNFMs-4 not only demonstrates excellent separation performance but also exhibits remarkable self-cleaning abilities. After 2 h of ultraviolet light irradiation, the membrane flux returns to its original level. STNFMs provide a promising solution for highly efficient separation of oil–water mixtures and emulsions, with the potential to play a significant role in water treatment and resource recovery.

Plants exposed to titanium dioxide nanoparticles acquired contrasting photosynthetic and morphological strategies depending on the growing light intensity: a case study in radish

Due to the photocatalytic property of titanium dioxide (TiO2), its application may be dependent on the growing light environment. In this study, radish plants were cultivated under four light intensities (75, 150, 300, and 600 μmol m−2 s−1 photosynthetic photon flux density, PPFD), and were weekly sprayed (three times in total) with TiO2 nanoparticles at different concentrations (0, 50, and 100 μmol L−1). Based on the obtained results, plants used two contrasting strategies depending on the growing PPFD. In the first strategy, as a result of exposure to high PPFD, plants limited their leaf area and send the biomass towards the underground parts to limit light-absorbing surface area, which was confirmed by thicker leaves (lower specific leaf area). TiO2 further improved the allocation of biomass to the underground parts when plants were exposed to higher PPFDs. In the second strategy, plants dissipated the absorbed light energy into the heat (NPQ) to protect the photosynthetic apparatus from high energy input due to carbohydrate and carotenoid accumulation as a result of exposure to higher PPFDs or TiO2 concentrations. TiO2 nanoparticle application up-regulated photosynthetic functionality under low, while down-regulated it under high PPFD. The best light use efficiency was noted at 300 m−2 s−1 PPFD, while TiO2 nanoparticle spray stimulated light use efficiency at 75 m−2 s−1 PPFD. In conclusion, TiO2 nanoparticle spray promotes plant growth and productivity, and this response is magnified as cultivation light intensity becomes limited.

Enhancing the eosin-yellowish dye degradation in drinking water by using TiO2 coatings co-doped with Ni and In.

This work reports on the structural, morphological, and photocatalytic properties of titanium dioxide (TiO2) and TiO2:NiIn (T-NiIn) coatings fabricated by spin coating. The SEM images revealed coatings with average thicknesses of 3.59 and 3.37μm for the TiO2 and T-NiIn, respectively. EDS spectra and Raman studies confirmed the presence of TiO2 co-doped with nickel (Ni) and indium (In) in the coatings. XRD analysis showed the anatase and rutile phases for the TiO2 coatings, while the T-NiIn coatings presented the rutile and brookite phases. These samples were evaluated in the photocatalytic degradation of the eosin-yellowish (EY) dye. The T-NiIn coatings showed 9.1% higher effectiveness than the undoped TiO2 coatings after 300min under UV irradiation. Meanwhile, the T-NiIn coatings exposed to solar light removed 40% more dye than the TiO2 coatings. Furthermore, T-NiIn coating was the most stable because its effectiveness was reduced by only 1.4% after 4 cycles of reuse. Additionally, the scavenger tests confirmed that the main oxidizing sites were the •OH- radicals and the superoxides •O2-. Thus, the use of coatings based on TiO2 co-doped with Ni and In is a feasible strategy to increase the degradation of the EY dye in drinking water.

Enhanced Hemocompatibility of Silver Nanoparticles Using the Photocatalytic Properties of Titanium Dioxide.

Silver nanoparticles (AgNPs) are widely used because of their excellent antimicrobial properties. However, the poor hemocompatibility limits the application of AgNPs in blood contact materials. General approaches to improve the hemocompatibility of AgNPs-containing surfaces are to construct barrier layers or co-immobilize anticoagulant biomolecules. But such modification strategies are often cumbersome to prepare and have limited applications. Therefore, this study proposes a simple UV-photo-functionalization strategy to improve the hemocompatibility of AgNPs. We loaded AgNPs onto titanium dioxide (TiO2) nanoparticles to form a composite nanoparticles (Ag@TiO2NPs). Then, UV treatment was performed to the Ag@TiO2NPs, utilizing the diffusible photo-induced anticoagulant properties of TiO2 nanoparticles to enhance the hemocompatibility of AgNPs. After being deposited onto the PU surface, the photo-functionalized Ag@TiO2NPs coating showed excellent antibacterial properties against both Gram-positive/Gram-negative bacteria. Besides, In vitro and ex-vivo experiments demonstrated that the photo-functionalized Ag@TiO2NPs coating had desirable hemocompatibility. This modification strategy can provide a new solution idea to improve the hemocompatibility of metal nanoparticles.

Диоксид титана, модифицированный марганцем: физико-химические и фотокаталитические свойства

The article presents the results of the studies of the physicochemical and photocatalytic properties of titanium dioxide modified with manganese, by the example of decomposition of organic dyes — ferroin and methylene blue. The correlations between the specific surface area and phase composition of the composites with their photocatalytic activity are revealed.

Effects of Hydrothermal Time on Structure and Photocatalytic Property of Titanium Dioxide for Degradation of Rhodamine B and Tetracycline Hydrochloride.

Using butyl titanate and absolute ethanol as raw materials, TiO2 was prepared by a hydrothermal method with different hydrothermal times, and the influences of hydrothermal time on the structure and photocatalytic performance of TiO2 were investigated. The obtained samples were characterized by XRD, SEM, TEM, BET, PL and DRS, separately. The results show that TiO2 forms anatase when the hydrothermal time is 12 h, forms a mixed crystal composed of anatase and rutile when the hydrothermal time is 24 h, and forms rutile when the hydrothermal time is 36 h. With the extension of hydrothermal time, anatase gradually transforms into rutile and the surface area decreases. Although TiO2-24 h and TiO2-36 h show lower photoinduced charge recombination and higher light source utilization, TiO2-12 h exhibits the highest photocatalytic activity owing to its largest surface area (145.3 m2/g). The degradation degree of rhodamine B and tetracycline hydrochloride reach 99.6% and 90.0% after 45 min.

Comparative study of P25/BiOCl mixtures as photocatalysts in Acid Orange 7 degradation

Objectives. Among strategies used to improve the photocatalytic properties of titanium dioxide (TiO2), coupled semiconductor has been widely studied. Bismuth oxychloride (BiOCl) semiconductor has been highlighted, specially, with hierarchical structures (3D), because it has been shown to have higher performance in the photodegradation of organic dyes in wastewater. Therefore, in this work the degradation efficiency of acid orange 7 (AO7) was studied using TiO2 (P25 Degussa), synthesized BiOCl with hierarchical structure, and mixtures of them as photocatalysts. Methodology. BiOCl was synthesized by the solvothermal method. The BiOCl was characterized by different techniques such as X-ray diffraction (XRD) and scanning electron microscopy (SEM). In addition, the pore distribution and the surface area were determined. Photocatalytic experiments were carried out with a photocatalyst dose of 1 g‧L-1, initial dye concentration of 50 mg‧L-1, and UV light illumination. Contribution. The interaction of P25 Degussa with BiOCl microspheres (75/25, respectively) improved the photocatalytic degradation achieving a 50% degradation efficiency.

Preparation and photocatalytic properties of titanium dioxide modified with gold or silver nanoparticles

A nontrivial and simple method for modifying the surface of anatase polymorphic particles with gold or silver nanoparticles has been developed. The method involves the UV-induced formation of Au (Ag) nanoparticles from the corresponding precursors – HAuCl4 or AgNO3 – in a solution of a stabilizing polymer – chitosan, than dispersing TiO2 particles in the resulting colloidal solution, and subsequent enzymatic destruction of chitosan. As a result, Au or Ag nanoparticles, the size of which is 5.0 ± 0.1 nm and 22.0 ± 0.25 nm, respectively, completely settle on the TiO2 surface. It was found that in the reactions of decomposition of methylene blue and para-nitrophenol in an aqueous solution under UV irradiation, modified TiO2 is 2–2.5 times more photocatalytically active than the initial titanium dioxide. It is essential that the photocatalytic properties of TiO2 modified with Au (Ag) nanoparticles also manifest themselves under the action of visible light.

Physicochemical, optical, and photocatalytic properties of titanium dioxide modified with zinc oxide nanoparticles synthesized by a pulsed plasma chemical method

In this study, particles of titanium dioxide (TiO2) were modified with particles of zinc oxide (ZnO) using a pulsed plasma chemical method, with ZnO initially being obtained by an electrospark method. The particle size of the synthesized TiO2 powder modified with ZnO nanoparticles ranged from 30 to 100 nm. The morphology of the nanoparticles was found to be diverse, mainly represented by spheres, ovals, and parallelograms. The phase composition was a mixture of crystalline phases characteristic of TiO2 (rutile and anatase) and ZnO, with the predominant phase being anatase. The presence of Zn–O–Ti bond is typical for all samples of TiO2 powder modified with ZnO nanoparticles prepared using a pulsed plasma chemical synthesis, which indicates the formation of a solid solution. The optical and photocatalytic properties of the modified nanoparticles were also studied, as well as the band gap was determined. For some samples, a narrowing of the band gap was recorded. The samples showed high photocatalytic activity in the decomposition of methylene blue under the influence of ultraviolet and visible light in the wavelength range of 400–630 nm. Methylene blue degradation efficiency was 66% in visible light spectrum.

Enhanced photocatalytic performance of PdO-loaded heterostructured nanobelts to degrade phenol

Heterostructured catalysts play a significant role in the photodegradation of pollutants in wastewater. Combining the large surface of nanobelts with the high photocatalytic property of titanium dioxide (TiO2) nanoparticles is a promising method for preparing photocatalysts, which have an advanced photocatalytic activity and are easy to precipitate. In this work, titanium dioxide nanobelts (NB) and acid corroded titanium dioxide nanobelts (C-NB) were synthesized via a hydrothermal process under alkaline conditions. Their surfaces were then loaded with palladium oxide (PdO) nanoparticles to prepare heterostructured photocatalysts (PdO-NB and PdO-C-NB) by a well-designed chemical precipitation method. The photodegradation efficiencies of the four catalysts for phenol, as well as for methyl orange, were tested and the order of degradation efficiency was found to be PdO-C-NB > PdO-NB > C-NB > NB. A degradation efficiency of 61% for phenol was achieved within 90 min using PdO-C-NB, which was nearly twice as much as using NB. The enhanced photocatalytic property of PdO-C-NB was due to the large specific surface area, abundant photocatalytic active sites and the low recombination rate of electron-hole pairs. Therefore, the degradation of phenol and methyl orange was speeded up considerably. Considering the high catalytic activity of PdO-C-NB, the heterostructure catalyst is of great significance to the degradation of organic wastewater, and has an important impact on our ecological environment and human health.

Construction and photocatalytic performance of fluorinated ZnO-TiO2 heterostructure composites.

Titanium dioxide, as a promising photocatalytic material, has attracted extensive attention in the field of photocatalytic degradation of organic pollutants in sewage. However, the photocatalytic performance needs to be further improved. In this work, fluorinated ZnO–TiO2 composites (F-ZTO) were prepared by a simple coprecipitation method. The photocatalytic performance of the samples was studied in detail with methyl orange as the target degradation product. The results indicated that under the same conditions, the degradation rates of 6% F-ZTO, F-TiO2 and TiO2 for methyl orange reached 93.75%, 76.56% and 62.89% respectively. This showed that the method used in this work could effectively improve the photocatalytic degradation performance of titanium dioxide. 6% F-ZTO showed an excellent photocatalytic activity, which was attributed to the small grain size, the large specific surface area and the effective inhibition of photoelectron–hole recombination due to fluorination and zinc oxide coupling. In three consecutive cycles, the photocatalytic activity was almost maintained, indicating that 6% F-ZTO had a good recycling performance.

The Influence of Sulphur Dopants on Optical, Textural, Structural, and Photocatalytic Properties of Titanium Dioxide

The Influence of Sulphur Dopants on Optical, Textural, Structural, and Photocatalytic Properties of Titanium Dioxide

Facile and Novel Eco-Friendly Poly(Vinyl Alcohol) Nanofilters Using the Photocatalytic Property of Titanium Dioxide.

This study aimed to develop a highly efficient nanofilter for capturing fine particles using electrostatic forces. Poly(vinyl alcohol) (PVA), a water-soluble synthetic polymer, was selected as the main component of the filter because it can be easily fabricated by electrospinning. Titanium dioxide (TiO2) nanopowder with an anatase structure was applied to the nanofilters as it has the highest photocatalytic activity among the existing photocatalysts. PVA nanofilters fabricated by electrospinning could still be dissolved in water by hydrolysis. Therefore, heat treatment was performed to make the nanofilters stable, thereby forming C=O bonds by keto–enol tautomerization. Structural changes in the PVA nanofilter before and after heat treatment were investigated by X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) analysis. As the TiO2 concentration increased, the fiber diameter of the PVA nanofilter decreased and a homogeneous fiber was obtained. The filtration efficiency and pressure drop also improved significantly, compared to those of the PVA-only nanofilter. Moreover, we observed eco-friendly decomposition of the PVA/TiO2 nanofilter into water and carbon dioxide by a photocatalytic reaction under UV irradiation.

FABRICATION OF TiO2 BASED COMPOSITE MATERIALS BY HYDROTHERMAL METHOD

Composite nanoparticles (nano powders) are nano-sized and can be synthesized with a wide range of organic, inorganic materials and production techniques. Titanium dioxide is one of the most commonly used materials in the production of composite materials. The reason why titanium dioxide is more preferred is that it has a minimum of any reactive step, it does not interfere with the human body and is an organic material that does not contain by-products. The photocatalytic properties of titanium dioxide can be improved by various methods. TiO2 is the most widely used photocatalyst in air purification. In this study, titanium dioxide based composite material was fabricated by hydrothermal method. The electrical, optical and structural properties of the material were investigated with the contribution of three different compositions of cadmium oxide (CdO) for produced in the experiments. For this purpose, SEM, U-V (Vis), I-V and FTIR techniques were used for the characterization and obtained results evaluated.

Hydroxypropyl methylcellulose-TiO2 and gelatin-TiO2 nanocomposite films: Physicochemical and structural properties

Photocatalytic properties of titanium dioxide (TiO2) have been widely studied. However, its tendency to aggregation in biopolymer-based nanocomposites limits its application for food packaging and has been few studied. The aim of this work was to study the dispersion of TiO2 (0–2 wt%) incorporated in the hydroxypropyl methylcellulose (HPMC-TiO2) and gelatin (gelatin-TiO2) film forming solutions. Particle size and zeta potential of TiO2 nanoparticles were investigated. Nanocomposite films were characterized as to the thickness, moisture content, solubility, color, absorption to the light, relative opacity, morphology, chemical composition, crystallinity, thermal and mechanical properties and water vapor permeability (WVP). TiO2 nanoparticles showed better dispersion in acid medium than water. Moisture content, water solubility and WVP of the gelatin-TiO2 films were influenced by the incorporation of TiO2, while HPMC-TiO2 films were not. The increase of relative opacity of the films as TiO2 was more attenuated for the gelatin-TiO2 films due to lower TiO2 aggregation in gelatin. Morphology, chemical composition, crystallinity and thermal properties of the films evidenced that TiO2 was better dispersed in both matrices at 1 wt%. It was also concluded that TiO2 aggregation generated more biphasic regions in HPMC than generated in gelatin, which caused a microstructural reorganization in the matrices.

Photothermal Enhanced Photocatalytic Properties of Titanium Dioxide (B)/Glass Fiber Cloth

Photothermal Enhanced Photocatalytic Properties of Titanium Dioxide (B)/Glass Fiber Cloth

Preparation of graphene-TiO2 nanocomposite films and its photocatalytic performances on degradation of Rhodamine B

PurposeThe aim of this paper is to synthesize graphene-modified titanium dioxide (GR-TiO2) nanorod arrays nanocomposite films, so that these can enhance the photocatalytic properties of titanium dioxide and overcome the problem of difficult separation and recovery of photocatalysts.Design/methodology/approachThe GR-TiO2 nanocomposite films were synthesized via hydrothermal method and spin-coating. The obtained samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), ultraviolet–visible (UV-Vis) diffuse reflectance spectrum and Raman spectrum. The photocatalytic performance of the GR-TiO2 nanocomposite films for degrading Rhodamin B under ultraviolet (UV) was studied by a UV-Vis spectrophotometer. The photocatalytic enhancement mechanism of graphene was studied by photoelectrochemical analysis.FindingsThe introduction of graphene expanded the range of the optical response of TiO2 nanorod arrays, improving the separation efficiency of the photogenerated electron-hole pairs, and thus dramatically increasing its photocatalytic performance.Research limitations/implicationsA simple and novel way for synthesizing GR-TiO2 nanocomposite films has enhanced the photocatalytic performance of TiO2.Originality/valueThe photocatalyst synthesized is easy to separate and recycle in the process of photocatalytic reaction, so it is possible to achieve industrialization.

Effects of reagents on the formation of nanoparticulate titanium dioxide synthesized by sol-gel technique

Photocatalytic properties of titanium dioxide are generally enhanced through formation of nanometer-sized anatase Titanium dioxide (TiO2) phase but to achieve the desired chemical composition and particle size, appropriate selection of initial reagents are required. This study was conducted to examine the effects of the initial reagents, specifically titanium (IV) isopropoxide (TTIP), sub-micrometer-sized TiO2 dissolved in sulfuric acid (H2SO4), and TiO2 dissolved in H2SO4 with added polyacrylic acid, on the chemical compositions and particle sizes of the sol-gel synthesized TiO2 powder. Results indicated that synthesis of TiO2nano-particulates with the respective average sizes of 48 and 85 nm was achievable using TTIP or sub-micrometer-sized TiO2 dissolved in H2SO4 with added polyacrylic acid as initial reagents.. In the absence of polyacrylic acid, the formation of an additional secondary phase and the production of larger particles averaging 130 nm in size were observed. Results of the antibacterial test capability of the synthesized TiO2 also pointed out that powder synthesized from sub micrometer-sizedTiO2 dissolved in H2SO4 with polyacrylic acid added also proved that it is capable of reducing Staphylococcus aureus by more than 99.9%, suggesting that it could be a cost effective replacement for the more expensive TTIP reagent in the synthesis of the desired TiO2nano-particles.

Photocatalytic degradation of gaseous toluene by using TiO2 nanoparticles immobilized on fiberglass cloth

Abstract Photocatalytic properties of titanium dioxide have been exploited for various purposes, including the photocatalytic purification of air, where an immobilized catalyst is preferred over a dispersed one as it has much higher application value. In this work, we have investigated the photocatalytic degradation of toluene on titania nanoparticles immobilized on fiberglass cloth. The progress of the reaction was monitored using a self-constructed photoreactor equipped with UVA lamps. Commercially available P25 and PC500 powder catalysts were successfully immobilized on fiberglass cloth by a “sol suspension” procedure. The prepared photocatalysts were characterized by scanning electron microscopy (SEM), UV–vis-NIR diffuse reflectance spectroscopy (DRS) and Fourier transform infrared spectroscopy (FT-IR). The highest photocatalytic degradation performance was obtained for the PC500 catalyst followed by a 1:1 mixture of P25 and PC500 and the lowest performance was observed in case of the P25 immobilized catalyst. The highest degradation rate of PC500 can be ascribed to its smallest particle size and highest surface area in comparison to others.

Modyfication of photocatalytic properties of titanium dioxide by mechanochemical method

Abstract The paper presents a simple way to improve the photocatalytic properties of titanium dioxide using mechanochemical method. The TiO2 (Anatase) powders was subjected to high-energy ball milling in dry environment and in methanol. It has been shown that it is possible to induce the phase transformation from Anatase to Rutile and produce a material with a higher photocatalytic activity in the UV light. Physicochemical characteristics of the products were based on the following methods and techniques: X-ray powder diffraction (XRD), IR and UV-Vis (DR) spectroscopy, measurements of specific surface area (BET). The photocatalytic activity of the powders was measured in the decomposition reaction of methyl orange in water.