TiO2 Phase Research Articles

Oxidation and Heat Shock Resistance of Plasma-Sprayed TiC-CoNi Composite Coatings at 900 °C

In this work, the TiC-reinforced CoNi alloy coatings were prepared by the plasma spraying method. Their microstructure, high-temperature oxidation, and thermal shock resistance at 900 °C were studied. The results showed that the CoNi alloy coating exhibited a single phase (c-Co-Ni-Cr-Mo). After adding Ti-graphite mixed powders, the sprayed coating exhibited TiC and TiO2 phases, besides the c-Co-Ni-Cr-Mo matrix phase. For CoNi alloy coating, the main oxidation products were Cr2O3 and CoCr2O4 (NiCr2O4). For TiC-CoNi alloy coating, the main oxidation products were the TiO2 phase, coupled with Cr2O3 and CoCr2O4 (NiCr2O4) phases. The content of oxides increased with the oxidation time. The oxidation weight gain of the TiC-CoNi composite coating was slightly higher than that of the CoNi alloy coating. The formation of TiC could improve the thermal shock resistance of the CoNi alloy coating.

Influence of TiO2 phases and functional groups on photocatalytic reduction of nitroaromatics

Photocatalytic organic transformations have emerged as environmentally sustainable alternatives to traditional synthesis routes. This study delves into the intricacies of photocatalytic reduction of nitroaromatics using bare TiO2 materials, shedding light on critical factors that govern this green and sustainable transformation. Our systems reveal very promising conversion and selectivity levels, consistently exceeding 90% across 13 diverse nitroaromatic substrates. The position and nature of functionalities (e.g., electron withdrawing/donating groups) within the nitroaromatic molecule, as well as the crystal phase of TiO2 (anatase/rutile), emerged as crucial determinants of reaction efficiency. Furthermore, the pivotal role of methanol in this system is highlighted, not only facilitating efficient hole scavenging and byproduct prevention but also multiplying reduction efficiency. This work emphasizes the significance of careful solvent selection, crystal phase optimization, and the role of functional groups as the so-called external factors in optimizing photocatalytic reactions for sustainable and environmentally friendly synthesis.

Weakened Interfacial Hydrogen Bond Connectivity Drives Selective Photocatalytic Water Oxidation toward H2O2 at Water/Brookite-TiO2 Interface.

The formation of H2O2 through the two-electron photocatalytic water oxidation reaction (WOR) is significant but encounters the competition with the four-electron O2 evolution reaction. Recent studies showed a crystal-phase dependence in H2O2 selectivity, where high purity brookite TiO2 (b-TiO2) exhibits remarkable H2O2 selectivity in contrast to the common rutile phase TiO2 (r-TiO2). However, the origin of such a structure-induced selectivity preference remains elusive, primarily due to the complexities associated with the solid-liquid interface system and excited-state chemistry. Herein, we conducted a comprehensive investigation into the selectivity mechanism of WOR at the water/b-TiO2(210) and water/r-TiO2(110) interfaces, employing first-principles molecular dynamics simulations and microkinetic analyses. Intriguingly, our results reveal that the intrinsic catalytic ability of the b-TiO2(210) itself does not enhance H2O2 selectivity compared to r-TiO2(110). Instead, it is the weakened interfacial hydrogen bond connectivity, modulated by the herringbone-like local atomic structure of the b-TiO2(210) surface, that determines the selectivity. Specifically, this weakened H-bond connectivity (i.e., local low water density) at the interface, owing to the strong water adsorption and distinct adsorption orientation, can stabilize the OH• radical and inhibit its deprotonation, leading to an improved H2O2 selectivity. By contrast, the relatively strong interface H-bond connectivity established over r-TiO2(110) accelerates the deprotonation of OH•, with the OH• coverage being 3 orders of magnitude lower than at the water/b-TiO2(210) interface. This study quantitatively demonstrates that the local H-bond structure (water density) at the liquid/solid interface significantly influences photocatalytic selectivity, and this insight may offer a rational approach to enhance the H2O2 selectivity.

Photocatalytic performance of Nd/TiO2 and Nb/TiO2 nanomaterials in the degradation of p‐cresol at room temperature

ABSTRACTBACKGROUNDThe degradation of organic pollutants, such as, p‐cresol, is a challenge for natural mechanisms, so the use of semiconductors as photocatalysts are useful to restore water quality. In this work, the effects of Nd and Nb doping on the structural and photocatalytic properties of TiO2 under UV irradiation were investigated.RESULTSXRD results displayed the formation of anatase, TiO2(B) and rutile phases on the Nd/TiO2 and Nb/TiO2 compounds. The Rietveld analysis estimated the composition of phases, as well as the crystal size for each crystalline phase in the samples (< 43 nm). The crystal sizes and morphology of the powders were observed in the TEM and SEM micrographs. EDS and XPS analysis confirmed the presence of Nd and Nb dopants in the TiO2‐based photocatalysts. The nitrogen adsorption/desorption isotherms results revealed pore sizes between 5‐ 11 nm, as well as surface area values up to ~ 81 m2/g. The diverse compounds showed excellent removal efficiency of p‐cresol under UV‐light (between 10 to 30% faster than commercial TiO2‐P25)CONCLUSIONSThe synthesis method favored the incorporation of the Nd and Nb dopants in the TiO2 structure. Nd/TiO2 specimens showed higher photocatalytic response than Nb/TiO2 samples, possibly, to the synergic effects between phases (anatase and TiO2(B)), higher surface area values (up to ~80.47 m2/g), as well as the nature of dopant. The photocatalysts with better photocatalytic performance demonstrated good degradation rate after 20h.This article is protected by copyright. All rights reserved.

Electrochemical deposition of hydrothermally pretreated TiO2 on aluminium substrate through the formation of peroxotitanium complex and their application towards visible light assisted photocurrent generation

Herein, we report a novel method for the electrochemical deposition of TiO2 on Al substrate through the formation of peroxotitanium complex without any post heat treatment process. The alkaline treated titanium precursors were used as an electrolyte and TiO2 was deposited onto aluminium substrate by both cathodic reduction and electrophoretic deposition through the formation of peroxotitanium complex. The electrodeposition process was optimized by varying the pH, concentration of the electrolyte, deposition voltage, time and area of the electrode respectively. The optimized condition to obtain a maximum yield is as follows: voltage (4.5 V), time (2.5 h), pH (5) and area of the electrode 3 × 3 cm2. The deposits were then characterized using various material characterization techniques such as high-resolution transmission electron microscopy (HR-TEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD) and Raman spectroscopy respectively. The morphological analysis showed the deposition of nanocrystalline TiO2 with irregular morphology on Al substrate. The AFM revealed a non-uniform deposition of TiO2 with high surface roughness (average roughness: 44.60 nm). The XRD pattern and Raman spectrum confirmed the presence of anatase phase of TiO2. The obtained TiO2 were then subjected to photoelectrochemical studies by coating over an ITO electrode. The nanocrystalline TiO2 showed excellent photocurrent response which could be due to the short hole retrieval and fast electron transport across the electrode-electrolyte interface. The proposed method can be promising towards the industrial application for the extraction and recovery of TiO2 from the mineral ore residues and spent mining waste.

Unique properties of titanium dioxide quantum dots assisted regulation of growth and biochemical parameters of Hibiscus sabdariffa plants

Owing to the uniqueness of quantum dots (QDs) as a potential nanomaterial for agricultural application, hence in the present study, titanium dioxide quantum dots (TiO2 QDs) were successfully synthesized via sol-gel technique and the physico-chemical properties of the prepared TiO2 QDs were analyzed. Based on the results, the TiO2 QDs showed the presence of anatase phase of TiO2. TEM examination revealed spherical QDs morphology with an average size of 7.69 ± 1.22 nm. The large zeta potential value (-20.9 ± 2.3 mV) indicate greater stability of the prepared TiO2 QDs in aqueous solutions. Moreover, in this work, the application of TiO2 QDs on Hibiscus sabdariffa plants was conducted, where H. sabdariffa plants were foliar sprayed twice a week in the early morning with different concentrations of TiO2 QDs (0, 2, 5, 10, 15 and 30 ppm) to evaluate their influence on these plants in terms of morphological indexes and biochemical parameters. The results exhibited an increasing impact of the different used concentrations of TiO2 QDs on morphological indexes, such as fresh weight, dry weight, shoot length, root length, and leaf number, and physio-biochemical parameters like chlorophyll a, chlorophyll b, carotenoid contents, total pigments and total phenolic contents. Remarkably, the most prominent result was recorded at 15 ppm TiO2 QDs where plant height, total protein and enzymatic antioxidants like catalase and peroxidase were noted to increase by 47.6, 20.5, 29.5 and 38.3%, respectively compared to control. Therefore, foliar spraying with TiO2 QDs positively serves as an effective strategy for inducing optimistic effects in H. sabdariffa plants.

Zinc doped TiO2 thin films for ethanol detection

TiO2 and Zn-doped TiO2 thin films were prepared by sol gel spin coating technique on glass substrates and their structural, optical and ethanol sensing properties were studied. The films were crystallized into the anatase TiO2 phase after annealing at 500 °C for 2 h. The crystallite size of TiO2 and Zn-doped TiO2 films were in the range of 4–18 nm. The band gaps were in the range: 3.55–3.65 eV. The surface electrical resistivity TiO2 decreased drastically by 1.36 × 10−4 Ω−1 cm−1 on doping with 2 at% of Zn. The ethanol response of films was measured at room temperature (30 °C) and it is found that Zn doping produces a large enhancement in ethanol response. The sample 1.5 at% Zn-TiO2 shows peak response of 44.18 for 500 ppm ethanol. The response and recovery time improve significantly with Zn doping in TiO2.

High temperature oxidation and thermal properties of laminated Ti3Al(Si)C2-TiC/Nb based composites obtained by spark plasma sintering

This paper describes high-temperature oxidation behavior and thermal properties of metal-ceramic laminated composites fabricated by spark plasma sintering of Ti3Al(Si)C2-filled preceramic papers (TAC) and Nb foils. The high-temperature oxidation tests were carried out in air at 800–1300 °C. The phase composition and microstructure of the oxide layers were analyzed by X-ray diffraction and scanning electron microscopy, respectively. The thermal properties were measured by the laser flash method in the temperature range of 30–800 °C. The evolution of the microstructure of the reaction layer (RL) formed at TAC/Nb interfaces was studied. The passive oxidation of the surface TAC layers results in the formation of outer TiO2 and inner continuous Al2O3 phase at temperatures up to 1100 °C, while local accelerated oxidation occurs above 1100 °C. As a result of breakaway oxidation, a multilayer oxide structure consisting of TiO2, Al2TiO5, Al2O3 and SiO2 phases were formed. The oxidation of inner Nb layers from the side surface can lead to high volume expansion and generation of stresses in the ceramic and metal layers due to the formation of Nb2O5 oxide phase. The stress relaxation occurred by complex mechanisms, including plastic deformation of the Nb layers, delamination at the interfaces, and formation of cracks in the reaction and TAC layers. The high temperature exposure results in slight increase in columnar grains in the reaction layers at 1200 °C, while the thickness of RL remains unchanged. The TAC/Nb composites exhibit higher thermal conductivity and diffusivity compared to monolithic TAC ceramic composites.

Structural and optical properties of Mg doped TiO2 nanoparticles synthesized by sol-gel method

Pure and doped titanium oxide (TiO2) nanoparticles with various atomic wt% (0 %, 3 %, 5 % and 7 %) of Mg were prepared by sol-gel method followed by the calcination at 100 °C for 12 h to investigate structural, optical and photoluminescence properties of TiO2 nanoparticles. Subsequently prepared samples annealed at 400 °C for 2 h for crystallization. Eventually, as prepared samples have been characterized using X ray diffractometer, scanning electron microscopy (SEM), Fourier transform Infrared Spectroscopy (FTIR), UV–Visible spectroscopy and Photoluminescence spectroscopy. XRD analysis shows that, prepared samples are crystalline in nature with exhibit of mixed phase (Rutile and Anatase) of TiO2. The crystallite size obtained around 12.0 nm of pure TiO2 nanoparticles. As increase in the doping concentration crystallite size was reduced to 6.76 nm. SEM images demonstrate the uniform growth of nanoparticles. Doping offering the tuning the energy band gap of TiO2. Photoluminescence spectra observed near UV to visible region. The intensity of Photoluminescence emission enhanced with increase of Mg doping at various concentration. Band gap and photoluminescence emission properties of doped TiO2, can be useful for optoelectronic applications and as Photo catalyst. The possible mechanism of coordination for different properties for TiO2 nanoparticles with various doping concentration have been well discussed.

Co-sputtered CuO/TiO2 coatings with varying copper content deposited on Ti6Al4V alloy

In this study, mosaic target material of titanium (Ti) and copper (Cu) was used to deposit CuO/TiO2 coatings on Ti6Al4V alloy. The aim was to examine the change in composition, structure and adhesion of the deposited films on titanium alloy when varying the titanium/copper (20:1, 41:1, 179:1, 418:1 and 837:1) ratio of the target material. The coatings were obtained by sputtering in a glow-discharge in a pure O2 atmosphere for a deposition time of 240 min. All coatings showed homogenous Cu distribution and the film thickness decreased with the reduction of Cu content in the composite target. Cu content in the coatings followed a power function of decrease with reduction of Ti-Cu content in the target while the increase of Ti showed logarithmic dependence. In all coatings, anatase and rutile TiO2 phases were detected whereas Cu atoms participated only in the formation of monoclinic CuO. TiO2-rich coatings demonstrated better adhesion to the Ti6Al4V alloy, whereas the critical loads of CuO-rich films were dependent on coating thickness.

Nonenzymatic Sensor Based on Polythiophene/Titanium Dioxide (PTh/TiO2) Composite for the Determination of Malathion in Water

This study presents a novel nonenzymatic pesticide sensor utilizing a polythiophene/TiO2 (PTh/TiO2) film deposited on a glassy carbon (GC) electrode as the working electrode. The thiophene monomer was polymerized onto TiO2 by cyclic voltammetric method in the range of 0.0-2.5 V with 15 cycles at room temperature. The prepared electrode was used for the sensitive and selective detection of malathion thus providing the basis for facile electrochemical quantification. The surface morphology and crystal structure of the (PTh/TiO2) film were studied by SEM and XRD. FTIR was used for the structural analysis of (PTh/TiO2) film. FTIR results indicated that the PTh/TiO2composite structure was formed. The smooth surface morphology of PTh/TiO2 was supported by SEM results. XRD analysis verified that PTh is covered on TiO2 particles. The crystal phase of TiO2 was changed to amorph state after PTh modification. Additionally, the electrochemical characterization of polymer film and its response to malathion was examined by the CV method. Under optimized operational conditions, the response of the pesticide sensor was measured by CV in the range of -1 to 2.3 V versus the Ag/AgCl reference electrode due to the electrooxidation of malathion. The analysis focused on current values at -0.73 V, where the reduction of the PTh/TiO2 system occurred upon the addition of known amounts of malathion. The PTh/TiO2 composite film was sensitive to malathion in a linear range from 9.9 ppm to 436 ppm. The sensitivity was calculated as 57.5 μA/ µM cm2 whereas the detection limit was calculated as 7.45 µM. The maximum reaction rate was estimated as 767 μA. The developed sensor also showed good selectivity and reproducibility. The nonenzymatic pesticide sensor was successfully applied to detect malathion in tap water with at least 90% recovery.

Photocatalytically active Ag-doped TiO2 coatings developed by plasma electrolytic oxidation in the presence of colloidal Ag nanoparticles

The plasma electrolytic oxidation process of Ti foil in the presence of a colloidal solution of Ag nanoparticles was used for the synthesis of exceptionally photocatalytically active Ag-doped TiO2 coatings. UV–Vis absorption spectroscopy was applied to follow the changes in the surface plasmon resonance band of the Ag nanoparticles as a function of the Ag:PO43− ratio in a phosphate-based electrolyte solution. Transmission electron microscopy revealed the size of the Ag nanoparticles in the range of 3–12 nm. The XRD patterns of the Ag-doped TiO2 coatings confirmed the crystalline anatase TiO2 phase regardless of the dopant concentration and without metallic Ag or crystalline Ag oxide forms. The typical porous morphology of the Ag–TiO2 coatings was observed by scanning electron microscopy. A significantly improved photocatalytic activity of the Ag–TiO2 coatings in the degradation process of the insecticide lindane (gamma isomer of benzene hexachloride) and test molecule methyl orange compared to pure TiO2 was determined using the GC technique. The degradation efficiency of Ag-doped TiO2 coatings is higher for lindane than for methyl orange.

Phase Transformation Strategies for the Construction of Heterojunction TiO2 Photocatalysts

AbstractHeterojunction TiO2 has attracted great attention in photocatalytic applications due to its high efficiency in the separation of photogenerated electron‐hole pairs and strong ability of light absorption. This work concisely summarizes the distinct crystal phases of TiO2 and elucidates the prevalent methods employed in the synthesis of TiO2 heterojunctions. Furthermore, the review highlights novel strategies for the realization of TiO2 phase transformation, thereby contributing to a deeper understanding and advancement in the application of mixed‐phase TiO2 photocatalysts.

Monitoring of UV-A radiation by TiO2/CdS nanohybrid along with the high on-off ratio

Exposure to UV-A light can have detrimental effects on human health, leading to skin damage and an increased risk of skin cancer. In this study, we employed a hydrothermal-assisted method to cultivate TiO2-decorated CdS nanorods for use in UV photodetectors. Our research culminated in the fabrication of an exceptionally responsive and rapid photodetector based on the TiO2/CdS nanohybrid. X-ray diffraction analysis revealed the hexagonal phase of CdS nanorods, predominantly oriented along the (002) plane, and the presence of the anatase phase of TiO2. Scanning electron microscopy (SEM) measurements confirmed the nanorod structure of TiO2/CdS. Optical properties of the TiO2/CdS nanohybrid were investigated through UV–visible absorbance analysis. Additionally, X-ray photoelectron spectroscopy (XPS) provided insights into the surface composition of the prepared nanohybrid, with peaks corresponding to Cd 3d3/2 and Cd 3d5/2 at binding energies of 411.47 eV and 404.73 eV, respectively, and confirming the presence of titanium through peaks of Ti 2p3/2 and 2p1/2 at binding energies of 458.31 eV and 463.8 eV, respectively. Raman analysis indicated the presence of the anatase phase of TiO2 in the composite. Our device exhibited an impressive detectivity of 9.9 × 1012 Jones, an EQE (external quantum efficiency) of 971.36%, and a high photoresponsivity of 2.86 A/W. These results suggest that TiO2/CdS nanohybrids, prepared using a cost-effective and straightforward method, hold promise for UV photodetection applications.

Semi-transparent dye-sensitized solar cells (DSSC) for energy-efficient windows with microwave-prepared TiO2 nanoparticles as photoanodes

Here in this work semi-transparent Dye-Sensitized Solar Cells (DSSC) was constructed using TiO2 nanoparticles prepared by Microwave assisted method as photoanode and its performance was studied. The structural studies of the synthesized TiO2 nanoparticles exhibited anatase phase of TiO2. Optical characteristics were studied through UV–Visible and Photoluminescence spectroscopy (PL) analysis respectively. Further the morphological analysis through Field emission scanning electron microscopy (FESEM) and High-resolution transmission electron microscopy (HRTEM) shows the near spherical shaped particles. The chemical states were analysed through X-Ray Photoelectron Spectroscopy (XPS) analysis.

A facile synthetic approach for TiO2@NiO core‐shell nanoparticles using TiO2@Ni(OH)2 precursors and their photocatalytic application

AbstractThe current study presents a simple and an efficient chemical method for the synthesis of TiO2@NiO core‐shell nanoparticles (CSNPs) as photocatalyst for effective degradation of rhodamine B (RhB) in an aqueous solution upon sunlight irradiation. First, TiO2 spheres were synthesized using a wet chemical method. Then, TiO2@Ni(OH)2 precursors were prepared via homogeneous precipitation and TiO2@NiO core‐shell nanoparticles were obtained on calcination of the precursors. The synthesized precursors and the TiO2@NiO CSNPs were analyzed using XRD, FT‐IR, FESEM and DRS. XRD data shows the presence of both TiO2 and NiO phases in the TiO2@NiO samples. FE‐SEM and TEM analyses confirm coating of NiO NPs on TiO2 spheres with varying shell thickness (40 nm to 170 nm). Optical studies reveal that TiO2@NiO CSNPs possess band gap of about 3.7 eV. Photoluminescence (PL) results show lower recombination rate of e− and h+ pairs in the TiO2@NiO CSNPs. XPS studies confirm the presence of different elements in the TiO2@NiO CSNPs. Magnetic investigations reveal ferromagnetic behavior of the core‐shell NPs at 5 K. The TiO2@NiO CSNPs were explored as photocatalyst for the degradation of rhodamine B in water under natural sunlight. The TiO2@NiO CSNPs exhibit better photocatalytic activity compared to TiO2 and NiO nanoparticles.

Tailoring visible-light active TiO2/cellulose nanocomposites with controlled crystalline structure for enhanced photocatalytic performance.

This work involves a green and simple synthesis of TiO2 nanoparticles on cellulose under mild conditions without the need for calcination via hydrolysis of titanium oxysulfate (TiOSO4). The synthesis conditions, such as sulfuric acid concentration (0-10%wt), temperature (70-90℃), and time (4-8h), focused on precisely controlling the structure of TiO2 to enhance its photocatalytic effectiveness under visible light. At a lower 2.5wt% sulfuric acid concentration, pure anatase was formed on the cellulose, while an increase in the range of 5.0-7.5wt% sulfuric acid concentration yielded a rutile phase, resulting in a mixed phase of anatase and rutile on the cellulose. The pure rutile phase was found at a low temperature (70℃), while increased temperature led to the formation of the anatase phase. These results confirmed that the formation of crystalline TiO2 phase on the cellulose depended on sulfuric acid concentration and temperature for hydrolysis. Additionally, the photocatalytic properties of the obtained materials were evaluated by degradationvisible of Rhodamine B (RhB) under UV and visible light. The findings revealed that the mixed phase (anatase/rutile) of TiO2 on the cellulose demonstrated a superior photocatalytic efficiency (99.2%) compared to pure anatase (85.75%) and rutile (75.08%) when exposed to visible light.

Mechanisms for optimizing the dielectric properties of spinel Li10ZnTi13O32 ceramics by Na+ doping

Herein, the dielectric properties of Na + doped Li10ZnTi13O32 ceramics were investigated by first-principles computational prediction and combined with the solid-phase reaction method. Li9.88Na0.12ZnTi13O32 obtained the best dielectric properties by sintering at 1050 °C for 4 h: εr = 30.01, Q × f = 90,879 GHz (@7.8 GHz), τf = 3.93 ppm/°C. In terms of extrinsic factors, the optimization of the densification, the creation of the second phase TiO2, and the increase of the grain size resulted in better dielectric properties. Intrinsic factors indicate that the weakening of the damping behavior and the increase in the electron cloud density lead to a decrease in the dielectric loss. The increase in ion polarisation and the blue shift of the Raman wavenumber lead to a gradual increase in εr. The temperature stability is optimized depending on the TiO2 content. The optimized Li9.88Na0.12ZnTi13O32 ceramics have unlimited applications in microwave communications.

Enhanced sunlight-driven catalysis for hydrogen generation and dye remediation using synergistic p-Co3O4/n-TiO2 nanocomposites.

In this study, p-Co3O4/n-TiO2 nanocomposites were synthesized using different ratios of cobalt and titanium precursors through a hydrothermal method. These nanocomposites demonstrated notable potential in photocatalytic applications for hydrogen production and orange-red dye degradation under sunlight. Various techniques, including XRD, Raman spectroscopy, XPS, FESEM, TEM, and BET analysis, were used to comprehensively characterize their structural, morphological, and optical properties. The nanocomposites exhibited both cubic and tetragonal phases of Co3O4 and TiO2, and their combined effect resulted in a narrowed band gap. Additionally, the presence of Co3O4 induced surface plasmon resonance on the TiO2 surface, effectively impeding electron-hole recombination. The nanocomposites displayed an average particle size of ∼20 to 30 nm with substantial visible light absorption. High crystallinity and well-dispersed nanocomposites were confirmed by XRD and Raman, with BET surface areas ranging between 49 and 106 m2 g-1. Notably, the p-Co3O4/n-TiO2 nanocomposite showed superior photocatalytic activity, achieving a maximum hydrogen generation rate of 1120 μmol h-1 g-1 and an 83% degradation efficiency of the orange-red dye within 6 minutes under sunlight. This study emphasizes the enhanced performance of the p-Co3O4/n-TiO2 nanocomposite, indicating its potential in photocatalytic applications, conforming to a pseudo-first-order kinetics model.

SYNTHESIS AND STUDY OF Ag-TiO2 NANOPARTICLES FOR APPLICATION IN SELF-CLEANING FABRICS

In this work, the Ag-TiO2 nanocomposite was prepared by sol-gel method and characterized using the Field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) and UV-Vis spectroscopy. The Ag+/Ti4+ ratio significantly influences the phase transition of TiO2 from anatase to rutile in the nanocomposite: the anatase content decreases from 94.9% to 52.6% as this ratio increases from 1.0 to 4.0 %. The initial Ag+/Ti4+ ratio of 1.0 % was chosen for further research due the highest content of TiO2 in the anatase phase. The nanoparticles are fairly monodisperse and have a spherical shape with an average size of about 18-24 nm. Self-cleaning fabric polyester (PET) was modified successfully with Ag-TiO2 nanoparticles by an immersed method. The nanocomposite of Ag and anatase TiO2 was coated by binder in 100-200 nm in size which coating onto the surface of fabric demonstrated self-cleaning surface with different mechanisms: hydrophobic surface as “lotus leaf” effect, photocatalytic degradation Rhodamine B under solar irradiation. The PET fabric coated with the Ag-TiO2 composite demonstrates stronger antibacterial activity (inhibition zone of 1.3 cm) compared to the fabric coated with TiO2 alone (inhibition zone of 0.8 cm). The results showed that after 6 h of irradiation, the photocatalytic activity of the Ag-TiO2/PET fabric sample is significantly better than that of the TiO2/PET fabric sample. The ability to change from hydrophobic to hydrophilic is especially promising to the interest in self-cleaning surfaces, the textile industry, and environmental cleanup.