Synthesis Of TiO2 Nanoparticles Research Articles

Selective Photocatalytic Oxidation of 5-HMF in Water over Electrochemically Synthesized TiO2 Nanoparticles

TiO2 nanoparticles were prepared via an electrochemical method using pulse alternating current and applied in the photocatalytic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF). Its physicochemical properties were characterized by SEM, HRTEM, XRD, and BET methods. The effect of scavenger and UVA light intensity was studied. The results revealed that electrochemically synthesized TiO2 nanoparticles exhibit higher DFF selectivity in the presence of methanol (up to 33%) compared with commercial samples.

Comparative study on antimicrobial activities of green synthesized TiO2 nanoparticles of Tephrosia purpurea leaves with its crude extracts

The present study deals with the enhancement of antimicrobial potential of Tephrosia purpurea crude extracts by making their composite with TiO2 nanoparticles against ubiquitous pathogens which may cause skin and wound infections. The synthesis was accomplished by the sol-gel method using precursor Titanium isopropoxide. The nanoparticles characterized by XRD, FESEM and FTIR techniques. XRD results showed that particles were in anatase phase with average crystallite size 12- 24 nm. FESEM reveals the spherical surface morphology of the nanoparticles. FTIR spectra gave the idea about associated functional groups with the synthesized particles. The antimicrobial potential of chemically synthesized TiO2 nanoparticles, green synthesized TiO2 nanoparticles and the crude extracts tested against Escherichia coli MTCC 40, Pseudomonas aeruginosa MTCC 2474 and Streptococcus pyogenes MTCC 442 which are actively involved in skin and wound infections. Results showed that green synthesized TiO2 nanoparticles gave better results in comparison with chemically synthesized TiO2 nanoparticles and crude extracts.

In situ synthesized TiO2-polyurethane nanocomposite for bypass graft application: In vitro endothelialization and degradation.

The in vitro endothelial response of human umbilical vein endothelial cells was investigated on a poly (caprolactone)-based polyurethane surface vs an in situ TiO2-polyurethane nanocomposite surface, which has been produced as scaffolds for artificial vascular graft. The in situ synthesis of TiO2 nanoparticles in polyurethane provided surface properties that facilitated cellular adhesion, cell sensing, cell probing and especially cell migration. Cells on the nanocomposite surface have elongated morphology and were able to produce more extracellular matrix. All of these advantages led to an increase in the rate of endothelialization of the nanocomposite scaffold surface vs pure polyurethane. The presence of TiO2 nanoparticles with very good distribution in polyurethane increased the degradability of the scaffolds by increasing the phase separation and hydrophilicity in the nanocomposite film. The results showed that the degradation mechanism of nanocomposite films prompted the interconnectivity of spaces inside structures that probably could give extra chances to improve migration and proliferation of cells, as well as, the delivery of nutrients and metabolites inside the pores of the scaffold. The outcomes revealed that the rate of endothelialization of the nanocomposite scaffold after 7days of in vitro cell culture was 1.5 times and the rate of degradation of the nanocomposite film was 2 times after 8weeks of immersion scaffolds in PBS compared to the polyurethane scaffolds. In addition, the nanocomposite scaffold possessed good mechanical properties. Despite its high modulus, it was flexible with a 500% elongation at break.

Effects of pure and mixed stabilizers on opto-electrical properties and morphology of TiO2 nanoparticles synthesized by sol-gel method

Titanium dioxide (TiO2) is acknowledged as the most advanced nanomaterial. It has been used in certain application, such as semiconductor, photocatalyst, dye solar cells, paints, dyes, cosmetics, antifogging coatings, self-cleaning windows, etc. Although TiO2 nanoparticles occur naturally in mineral form, but the particles are also being synthesized through different well-known techniques. The past literature reveals that sol-gel methodology is considered as the most attractive and suitable technique for the preparation of such kind of nanoparticles. This article reports the effects of three different stabilizers (HCl, HNO3 and mixture of HCl+HNO3) on the morphological and opto-electrical properties of TiO2 nanoparticles. The nanoparticles of TiO2 were synthesized through sol-gel process by using titanium tetra isopropoxide (TTIP) as precursor in a solution of deionized water and isopropanol at 80 °C under constant stirring. The synthesized TiO2 nanoparticles were characterized through X-ray Diffractometry (XRD), Scanning electron microscopy (SEM) and UV-Visible spectrophotometry. The grain size with perfect crystallinity obtained through XRD were in good agreement with SEM results. The grain size of the prepared TiO2 nanoparticles using HCl, HNO3 and (HCl+HNO3) were 3 nm, 2.8 nm and 3.3 nm, respectively. The optical characterization of TiO2 revealed band gap energy values of 4.10 eV, 6.16 eV and 6.14 eV corresponding to absorption edges at 302 nm, 201.2 nm and 201.73 nm, respectively. The smaller grain sizes were having larger band gaps.

Microwave plasma assisted sol-gel technique for synthesis of TiO2 nanoparticles

Titanium dioxide (TiO2) nanoparticles have attracted the attention of research community due to their novel functionalities as compared to the bulk material. TiO2 is an excellent photocatalyst due to its high photosensitivity, nontoxicity, high refractive index, strong oxidizing ability, high stability, wide band gap and high resistance to photochemical. The main objective of this study was to investigate the influence of microwave (MW) plasma treatment on TiO2 nanoparticles synthesized using sol-gel method. TiO2 nanoparticles were obtained through sol-gel method at ambient temperature. The suspension was heated at 300 °C for 2 hours to evaporate the organic content. The obtained nanoparticles were placed in partially vacuumized chamber for MW plasma treatment. The plasma treatment is a promising technique for oxidation of nanomaterials. Both plasma treated and untreated samples were evaluated with X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-Visible spectroscopy for crystallite size, crystal phases, band gap energy and surface morphology. The obtained results confirmed the existence of anatase and rutile phases of TiO2 with smaller particle size within the range of 0.2 to 14 nm. The particles were of aggregated and trigonal shapes. The MW Plasma treatment improved the photocatalytic activity of TiO2 nanoparticles by raising their band gap energy and reducing the grain size.

Surface modified TiO2/reduced graphite oxide nanocomposite anodes for lithium ion batteries

Anatase TiO2 nanoparticles with an average crystallite size of ~ 20 nm are synthesized through a sol-gel method. A composite anode for Li-ion batteries is prepared with the synthesized TiO2 nanoparticles and reduced graphite oxide (RGO) as the conductive carbon source. After the preparation of TiO2/RGO nanocomposite, a novel surface modification is carried out by the employment of H2O2 to enhance the overall electrochemical performance of nanocomposite anode (TiO2/RGO-P composite). The physical and chemical characterizations of the surface modified TiO2/RGO-P composites are performed with X-ray powder diffraction (XRPD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and atomic force microscopy (AFM) analyses. The electrochemical performance of TiO2/RGO-P composite electrodes is investigated via galvanostatic charge-discharge cycling tests in a potential window of 1.0–3.0 V. Compared to the plain TiO2/RGO composite anode, the TiO2/RGO-P composite anode has higher reversible capacities and better cycling performance due to the enhanced and stable formation of 3D channels of TiO2 nanoparticles with RGO stemming from the surface modification with H2O2. The TiO2/RGO-P composite anode delivers reversible discharge capacities around 291 mA h g−1 at a rate of 100 mA g−1, whereas the value stays at 214 and 143 mA h g−1 for the plain TiO2/RGO composite and TiO2 nanoparticle without any RGO, respectively.

Effects of synthesized nanoparticles and Henna-Tragacanth solutions on oil/water interfacial tension: Nanofluids stability considerations

Rising global energy demand has encouraged engineers to create and design new methods to improve oil recovery from reservoirs. In this study, feasibility of using Henna extract as a natural surfactant and synthesized nanoparticles (Titanium dioxide (TiO2), Silicon dioxide (SiO2), Graphene and composite of TiO2-Graphene) for reduction of oil-water interfacial tension has been experimentally investigated. Nanoparticles were synthesized via sol-gel method and XRD, FESEM, EDAX and FTIR tests were conducted to confirm the authenticity of this synthesizing materials. Nano-surfactants were stabled with a natural water-based suspending surfactant called Tragacanth extract, which could be introduced as a practical substitute for industrial nanoparticles' stabilizers in oil industry. After CMC determination of Henna extract surfactant, the optimal concentration of Tragacanth extract surfactant, with the purpose of nano-surfactants’ stabilization, was determined through particle size and zeta potential tests. Results of interfacial tension (IFT) measurements showed that the increase of Henna extract concentration from 0 wt% to 10 wt% reduced IFT between kerosene and water from 37.23 to 15.24 mN/m. Furthermore, adding 1 wt% of synthesized TiO2 nanoparticle to the Henna extract surfactant at its CMC value reduced IFT from 18.43 to 14.57 mN/m. As an impact of this significant reduction in IFT value, oil recovery factor could be improved drastically during EOR operations. Results proved that TiO2 nano-surfactant was as effective as industrial surfactants, which put human's and environment's health at risk and impose heavy economic strain on governments.

Electrospun Ag-TiO2 Nanofibers for Photocatalytic Glucose Conversion to High-Value Chemicals.

TiO2 nanofibers were fabricated by combination of sol–gel and electrospinning techniques. Ag-doped TiO2 nanofibers with different Ag contents were prepared by two different methods (in situ electrospinning or wetness impregnation of Ag on TiO2 nanofibers) and heat treated at 500 °C for 2 h under an air or N2 atmosphere. The obtained catalysts were characterized by field emission scanning electron microscopy, X-ray diffraction, photoluminescence, and N2 adsorption analyzed by the Brunauer–Emmett–Teller (BET) method. Photocatalytic glucose conversions with electrospun TiO2 and Ag-doped TiO2 nanofibers for production of high-value products were carried out. From different doping methods, the results indicated that 1 wt % Ag-TiO2 nanofibers prepared by an in situ method with calcination under N2 achieved the highest glucose conversion (85.49%). From several Ag loading contents (i.e., 0, 1, 2, and 4 wt %) in Ag-doped TiO2 nanofibers, the nanofibers exhibited different glucose conversions [in order of 2 wt % (99.65%) > 1 wt % (85.49%) > 4 wt % (77.72%) > 0 wt % (29.64%)]. Arabinose, xylitol, gluconic acid, and formic acid were found as the high-value chemicals with the photocatalytic reaction of TiO2 and Ag-doped TiO2 nanofibers under UVA irradiation. Product yields of each converted chemicals from different photocatalysts from different Ag loading contents showed relatively same trends with the glucose conversion. From all results, it can be concluded that the good characteristics of 2 wt % Ag-TiO2 nanofibers such as the smallest anatase crystallite size (8.25 nm) and the highest specific surface area (SBET = 53.69 m2/g) promoted the highest photocatalytic activity. Additionally, TiO2 and Ag-doped TiO2 nanofibers exhibited higher photocatalytic performance for glucose conversion than commercial TiO2 (P25) and synthesized TiO2 nanoparticles. Finally, Ag-doped TiO2 nanofibers showed recycling ability with high photocatalytic glucose conversion after four-time use.

DC-Plasma over Aqueous Solution for the Synthesis of Titanium Dioxide Nanoparticles under Pressurized Argon.

Nanomaterials that comprise titanium dioxide (TiO2) nanoparticles have received much attention owing to their wide applications; presently, the green synthesis of TiO2 nanoparticles is a developing research area. In this study, the TiO2 nanoparticles were synthesized through a DC-pulsed discharge plasma over an aqueous solution surface under a high-pressure argon environment. The titanium-rod electrode was utilized as the material source for the TiO2 nanoparticle generation. Experiments were performed at room temperature with pressurized argon at 1–4 MPa. To generate a pulse electrical discharge plasma, a DC power supply of 18.6 kV was applied. The Raman spectroscopy showed that the TiO2 nanoparticle with a brookite structure was formed dominantly. The scanning transmission electron microscopy equipped with energy dispersion spectroscopy (STEM coupled with EDS) indicated that TiO2 coated with carbon and that without carbon coating were successfully produced at the nanoscale. The process presented here is an innovative process and can update the existing information regarding the synthesis of metal-based nanoparticles using pulsed discharge plasma under an argon environment.

A Novel Approach to Synthesize TiO2 Nanoparticles: Biosynthesis by Using Streptomyces sp. HC1

A simple, yet effective and rapid approach for the synthesis of titanium dioxide nanoparticles (TiO2 NPs) using Streptomyces sp. HC1 was developed. The in vitro activity of TiO2 NPs was demonstrated against human pathogenic bacteria and fungi. The synthesized nanoparticles were characterized using various methods and instruments, such as Zetasizer, X-ray diffraction, Fourier transmission infrared spectroscopy, atomic force microscopy, and scanning electron microscopy. TiO2 NPs were observed to be spherical in shape with size in the range of 30 to 70 nm. Antimicrobial activities of TiO2 NPs against Staphylococcus aureus ATCC 29213, Escherichia coli ATCC 35218, Candida albicans, ATCC 10231, and Aspergillus niger ATCC 6275 were evaluated. It was observed that TiO2 NPs showed higher antimicrobial activity against bacteria (12 mm) than against fungi. Moreover, TiO2 NPs also showed potent antibiofilm activity against Pseudomonas aeruginosa ATCC 27853. Hence, the present study highlights the biological synthesis and characterization of TiO2 NPs, and their applications in the field of biomedical sciences.

Controllable synthesis of TiO2 nanoparticles and their photocatalytic activity in dye degradation

Titanium dioxide nanoparticles were synthesized by hydrolyzing titanium tetrachloride (TiCl4) in a controlled manner using a homemade glass apparatus. The structural properties and chemical composition were studied using X-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy, Brunauer-Emmett-Teller surface area analysis, selected area electron diffraction, energy dispersive spectroscopy, and X-ray photoelectron spectroscopy. The X-ray diffraction pattern and the high-resolution transmission electron microscope analyses confirmed that the TiO2 nanoparticles are composed of photo-active anatase and brookite phases. The photocatalytic activity of the TiO2 nanoparticles was demonstrated by photo-degradation of methylene blue and congo red under UV–Vis light illumination. Studying how pH affects the degradation of methylene blue revealed that its photocatalytic degradation on TiO2 nanoparticles is more efficient under alkaline conditions, whereas the congo red degradation is more efficient under acidic conditions.

Nanocomposite film with green synthesized TiO2 nanoparticles and hydrophobic polydimethylsiloxane polymer: synthesis, characterization, and antibacterial test

Abstract The green synthesis of nanoparticles is of considerable interest because it is eco-friendly, cost-effective, biocompatible, and non-toxic. Split pulse extract was used as a reducing/capping agent for the synthesis of titanium dioxide (TiO2) nanoparticles. Green synthesized nanoparticles were embedded in the polydimethylsiloxane (PDMS) membrane by using a solution casting technique to develop a nanocomposite. This thin film was characterized using Fourier transform infrared spectroscopy, scanning probe microscopy, high-resolution scanning electron microscopy, ultraviolet-visible spectroscopy, and contact angle analysis. The antibacterial property of the TiO2/PDMS nanocomposite was examined, and the results showed excellent antibacterial activity of TiO2/PDMS compared to PDMS without nanoparticles. The nanocomposite film exhibited antibacterial activity against Gram-positive and Gram-negative bacteria in the presence of TiO2 nanoparticles in the polymer. Here, different weight percentages of TiO2 nanoparticles, i.e. 0%, 7%, 10%, and 13%, were loaded on the PDMS surface to enhance its antibacterial activity. The green synthesis of TiO2 nanoparticles embedded in PDMS and their suitability for antibacterial activity are reported for the first time.

Green synthesis of TiO2 nanoparticles from Syzygium cumini extract for photo-catalytic removal of lead (Pb) in explosive industrial wastewater

AbstractGreen synthesis is a simple, non-toxic, economical and eco-friendly approach for the synthesis of nanoparticles. In the present work, nanoparticles of titanium dioxide (TiO2 NPs) were synthesized using an aqueous solution of Syzygium cumini leaf extract as a capping agent. These green synthesized TiO2 NPs were further evaluated for photo catalytic removal of lead from industrial wastewater. Obtained nanoparticles were characterized using: high-resolution scanning electron microscopy (HRSEM), high-resolution transmission electron microscopy (HRTEM), X-ray energy dispersive spectroscopy (EDS), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), dynamic light scattering (DLS) and Brunauer-Emmett-Teller (BET). Obtained results revealed that synthesized TiO2 NPs possess spherical morphology with anatase phase with a large BET surface area of 105 m2/g. Photo catalytic studies of TiO2 NPs for lead removal from explosive wastewater were performed in a self-designed reactor. Inductive coupled plasma spectroscopy (ICP) was used to determine the lead concentration. Obtained results witnessed 75.5% removal in chemical oxygen demand (COD) and 82.53% removal in lead (Pb2+). This application of green TiO2 NPs is being explored for the first time.

Enhanced Photocatalytic Activity of Au/TiO2 Nanoparticles against Ciprofloxacin

In the last decades, photocatalysis has arisen as a solution to degrade emerging pollutants such as antibiotics. However, the reduced photoactivation of TiO2 under visible radiation constitutes a major drawback because 95% of sunlight radiation is not being used in this process. Thus, it is critical to modify TiO2 nanoparticles to improve the ability to absorb visible radiation from sunlight. This work reports on the synthesis of TiO2 nanoparticles decorated with gold (Au) nanoparticles by deposition-precipitation method for enhanced photocatalytic activity. The produced nanocomposites absorb 40% to 55% more radiation in the visible range than pristine TiO2, the best results being obtained for the synthesis performed at 25 °C and with Au loading of 0.05 to 0.1 wt. %. Experimental tests yielded a higher photocatalytic degradation of 91% and 49% of ciprofloxacin (5 mg/L) under UV and visible radiation, correspondingly. Computational modeling supports the experimental results, showing the ability of Au to bind TiO2 anatase surfaces, the relevant role of Au transferring electrons, and the high affinity of ciprofloxacin to both Au and TiO2 surfaces. Hence, the present work represents a reliable approach to produce efficient photocatalytic materials and an overall contribution in the development of high-performance Au/TiO2 photocatalytic nanostructures through the optimization of the synthesis parameters, photocatalytic conditions, and computational modeling.

Shape-controlling effects of hydrohalic and carboxylic acids in TiO2 nanoparticle synthesis.

The ability to synthesize nanoparticles (NPs), here TiO2, of different shapes in a controlled and reproducible way is of high significance for a wide range of fields including catalysis and materials design. Different NP shapes exhibit variations of emerging facets, and processes such as adsorption, diffusion, and catalytic activity are, in general, facet sensitive. Therefore, NP properties, e.g., the reactivity of NPs or the stability of assembled NPs, depend on their shape. We combine computational modeling based on density functional theory with experimental techniques such as transmission electron microscopy, energy-dispersive x-ray spectroscopy, and x-ray powder diffraction to investigate the ability of various adsorbates, including hydrohalic and carboxylic acids, to influence NP shape. This approach allows us to identify mechanisms stabilizing specific surface facets and thus to predict NP shapes using computational model systems and to experimentally characterize the synthesized NPs in detail. Shape-controlled anatase TiO2 NPs are synthesized here in agreement with the calculations in platelet and bi-pyramidal shapes by employing different precursors. The importance of the physical conditions and chemical environment during synthesis, e.g., via competitive adsorption or changes in the chemical potentials, is studied via ab initio thermodynamics, which allows us to set previous and new results in a broader context and to highlight potentials for additional synthesis routes and NP shapes.

Green synthesis of TiO2 nanoparticles using lemon peel extract: their optical and photocatalytic properties

ABSTRACT Lemon is an essential therapeutic plant of the Rutaceae family having a variety of vital phytochemicals. The TiO2 nanoparticles (NPs) have been synthesised by the green synthesis method from lemon peel extract for the first time. Hydrolysed extract of lemon peel contains hesperidin flavanol that releases aglycone to act as a capping and reducing agent. The Synthesised samples are characterised through X-rays diffraction spectroscopy (XRD), energy dispersive X-rays spectroscopy (EDX), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and ultraviolet and visible (UV–Vis) spectroscopy techniques. The SEM results depict that the prepared specimen is purely comprised of the agglomerated structures. A close study from TEM exhibits the spherical shape of the particles with the particle size ranges from 80 to 140 nm and anatase form according to the XRD. The Tauc plot prepared from the UV–Vis spectrum shows a bandgap of 3.08 eV. Photocatalytic response of the prepared TiO2 for the degradation of rhodamine B (RhB) is also studied. The results showed that synthesised particles possess more than 70% photocatalytic activity which is more efficient as compared to commercial TiO2 particles.

Effect of Calcination Temperature on Photocatalytic Activity of Synthesized TiO2 Nanoparticles via Wet Ball Milling Sol-Gel Method

In this work, TiO2 nanoparticles were successfully synthesized with narrow size distribution via a wet ball milling sol-gel method. The effect of calcination temperature on photocatalytic activity was observed from particle size, crystallite size, and phase transition of TiO2 nanoparticles. Increasing calcination temperature increased particle size, crystallite size, and the crystallinity of synthesized TiO2. Phase transition depended on variation in calcination temperatures. A two-phase mixture of anatase and brookite was obtained with lower calcination temperature whereas a three-phase mixture appeared when calcination temperature was 500–600 °C. With higher temperature, the rutile phase kept increasing until it was the only phase observed at 800 °C. Anatase strongly affected the photocatalytic activity from 300 °C to 600 °C while the particle size of TiO2 was found to have a dominant effect on the photocatalytic activity between 600 °C and 700 °C. A mixture of three phases of TiO2-600 exhibited the highest methylene blue degradation with the rate constant of 9.46 × 10−2 h−1 under ultraviolet (UV) irradiation.

Influence of 2,4-Diamino-6-Phenyl-1-3-5-triazine on bio synthesized TiO2 dye-sensitized solar cell fabricated using poly (ethylene glycol) polymer electrolyte

An ecofriendly TiO2 from a plant extract of Averrhoa bilimbi with cost effective and non-toxic with cis dithiocynato-N, N-bis(2,2- bipyridyl-4,4-dicarboxylic acid)ruthenium(II) (N3 dye) in dye-sensitized solar cells (DSSC) reports better efficiency of 5.2%. The green synthesized TiO2 nanoparticles along with 2,4-Diamino-6-Phenyl-1-3-5-Triazine (DPT) doped Poly(ethylene glycol) (PEG)/KI/I2/Pt shows better efficiency in dye-sensitized solar cells. The green TiO2 was characterized with XRD, UV, FTIR, SEM, TEM and EDX techniques confirm the band gap of 3.2 eV and 15 nm size for TiO2. The mechanical and electrical properties of DPT doped PEG/KI/I2 polymer electrolyte were characterized with XRD, FTIR, EIS, DSC and TGA and it was confirmed that the DPT well miscible with PEG polymer electrolyte and improves the electrical conductivity and enhances the efficiency of DSSC.

Biomimetic TiO2-chitosan/sodium alginate blended nanocomposite scaffolds for tissue engineering applications.

The study is aimed to synthesize potent metal oxide based biomimetic nanocomposites to overcome the risk associated with artificial bone tissue engineering. High purity TiO2 nanoparticles are synthesized via hydrothermal route. A biomimetic nanocomposite scaffolds containing chitosan-sodium alginate (4: 4) blended with three different (0.5, 1, and 1.5wt%) concentrations of hydrothermally synthesized TiO2 nanoparticles are obtained by solvent casting technique. The physico-chemical and thermal degradation properties of as-synthesized TiO2 nanoparticles and their nanocomposite scaffolds are analyzed. In-vitro cytotoxicity and biocompatibility of the prepared TiO2 nanoparticles and nanocomposites are tested against human bladder tumor (UC6) and osteosarcoma (MG-63) cell lines. Antibacterial property is tested against Escherichia coli and Staphylococcus aureus. These studies reveal that TiO2 nanoparticles and polymeric nanocomposites contain good physico-chemical and mechanical properties for enhanced in-vitro biocompatibility suitable for biomedical applications. Biomimetically prepared chitosan-sodium alginate scaffold containing TiO2 nanoparticles (1wt%) is found to exhibit superior biocompatibility for bone tissue engineering applications.

Transparent and Flexible Cellulose Triacetate–TiO2 Nanoparticles with Conductive and UV-Shielding Properties

Cellulose triacetate (CTA) and sol–gel synthesized TiO2 nanoparticles were used to develop and characterize novel nanocomposites modified also with poly(ethylene oxide-b-propylene oxide-b-ethylene ...