Sharif Digital Repository

Titanium type lithium ion-sieve nanotubes synthesized by the hydrothermal method were extensively explored over recent years due to its promising properties. However, on account of nanotubes′ tangled structure impeding the lithium adsorption in the interior nanotube walls, unalterable dimensions of the synthesized nanotubes, and a long period of annealing, the anodizing technique was proposed. It is shown that lithium uptake and adsorption capacity is improved because of easier mass transfer during the ion exchange process. This work focuses on a novel anodizing method for nanotube ion-sieve synthesis. The optimum anodizing condition was discovered by altering anodizing voltage, time, and... 

Gelatin-based functional films were prepared by the addition of grapefruit seed extract (GSE, 5 wt% based on gelatin) and various amounts of TiO2 (0.5, 1.0, 3.0, and 5.0 wt% based on gelatin). TiO2 was evenly dispersed in the gelatin film, but the film surface roughness was increased as the concentration of TiO2 increased. The mechanical strength and water contact angle (WCA) of the composite film were the highest, while the water vapor permeability (WVP) was the lowest when 0.5 wt% TiO2 was used. The addition of GSE slightly reduced the UV light transmittance, but the addition of TiO2 almost completely prevented the UV light transmission. The addition of GSE and TiO2 did not significantly... 

The necessity of research in food and nutrition and the emergence of diabetes mellitus call for fast and efficient glucose detection. Here, series of highly sensitive non-enzymatic photoelectrochemical glucose sensor based on engineered titanium dioxide nanotube arrays has been synthesized using a simple electrochemical approach to tune nanotubes morphology in a way that the highest sensitivity factor (525.5 µAmM−1cm−2) and saturation concentrations (0.18 mM) achieved in the photoelectrochemical sensor. The formation of oxygen-rich titanium oxide was confirmed by several techniques. Dependent on the growth condition, nanotube length changed from 1.9 to 8.4 µm while their inner diameter... 

Biocompatibility materials such as Ti6Al4V alloy have many medical applications, but their corrosion resistance and antibacterial properties are low, which limits their medical application. Therefore, to improve these challenges in this study, HAp + 15 wt% TiO2 + 5 wt% Ag nanocomposite coating was applied on Ti6Al4V/TiO2 substrate by sol-gel dip method and sintered at 550 °C. The TiO2 layer was pre-formed on the Ti6Al4V substrate using the gel-sol process. The results showed that the nanocomposite was synthesized correctly, and the particle size was in range of 40–90 nm. The evaluation of the coatings developed showed that TiO2/HAp + 15 wt% TiO2 + 5 wt% Ag coating had higher adhesion... 

Biocompatibility materials such as Ti6Al4V alloy have many medical applications, but their corrosion resistance and antibacterial properties are low, which limits their medical application. Therefore, to improve these challenges in this study, HAp + 15 wt% TiO2 + 5 wt% Ag nanocomposite coating was applied on Ti6Al4V/TiO2 substrate by sol-gel dip method and sintered at 550 °C. The TiO2 layer was pre-formed on the Ti6Al4V substrate using the gel-sol process. The results showed that the nanocomposite was synthesized correctly, and the particle size was in range of 40–90 nm. The evaluation of the coatings developed showed that TiO2/HAp + 15 wt% TiO2 + 5 wt% Ag coating had higher adhesion... 

The necessity of research in food and nutrition and the emergence of diabetes mellitus call for fast and efficient glucose detection. Here, series of highly sensitive non-enzymatic photoelectrochemical glucose sensor based on engineered titanium dioxide nanotube arrays has been synthesized using a simple electrochemical approach to tune nanotubes morphology in a way that the highest sensitivity factor (525.5 µAmM−1cm−2) and saturation concentrations (0.18 mM) achieved in the photoelectrochemical sensor. The formation of oxygen-rich titanium oxide was confirmed by several techniques. Dependent on the growth condition, nanotube length changed from 1.9 to 8.4 µm while their inner diameter... 

Friction stir processing (FSP) is a solid state route with a capacity of preparing fine grained nanocomposites from metal sheets. In this work, we employed this process to finely distribute TiO2 nanoparticles throughout an Al–Mg alloy, aiming to enhance mechanical properties. Titanium dioxide particles (30 nm) were preplaced into grooves machined in the middle of the aluminium alloy sheet and multipass FSP was afforded. This process refined the grain structure of the aluminium alloy, distributed the hard nanoparticles in the matrix and promoted solid state chemical reactions at the interfaces of the metal/ceramic particles. Detailed optical and electron microscopic studies showed that the... 

TiO2 and transition metal (Cr, Mn, Fe, Co, Ni, Cu, and Zn) doped TiO2 nanoparticles were synthesized by the sol–gel method using 2-hydroxylethylammonium formate as an ionic liquid. All the prepared samples were calcined at 500 °C and characterized by X-ray diffraction (XRD), BET surface area determination, energy dispersive X-ray (EDX) analysis, diffuse reflectance spectroscopy (DRS), and Fourier transformed infrared (FT-IR) techniques. The studies revealed that transition metal (TM) doped nanoparticles have smaller crystalline size and higher surface area than pure TiO2. Dopant ions in the TiO2 structure caused significant absorption shift into the visible region. The results of... 

TiO2–graphene (TiO2–GR) nanocomposites were synthesized using photocatalytic reduction method. TiO2–GR nanocomposites were thereafter doped with noble metals (Pt and Pd) by chemical reduction of the corresponding cations. The samples were characterized by different techniques. The addition of GR to TiO2 decreases the crystalline size of TiO2 due to the homogeneous dispersion of the TiO2 nanoparticles on GR sheets and prevention of coagulation of TiO2 nanoparticles during synthesis process. In addition, the surface area of TiO2 was increased by addition of GR and deposition of noble metals which helps to prevent agglomeration of graphene sheets and TiO2 nanoparticles. Red shifts to the higher... 

While the photocatalytic degradation of various organic compounds under UV light irradiation has been widely investigated, visible-light-induced photocatalytic degradation of low levels of pollutants such as dibenzothiophene (DBT) is occasionally reported. In the present work, lanthanide/polyethylene glycol-modified TiO2 (La/PEG/TiO2) has been successfully synthesized by a sol-gel method. The photocatalyst was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV-Vis diffusive reflectance spectroscopy, and energy dispersive X-ray analysis. Moreover, the photocatalytic degradation of DBT under visible light irradiation is investigated for the... 

Nanostructured TiO2-SnO2 thin films and powders were prepared by a facile aqueous particulate sol-gel route. The prepared sols showed a narrow particle size distribution with hydrodynamic diameter in the range 17.2-19.3 nm. Moreover, the sols were stable over 5 months, since the constant zeta potential was measured during this period. The effect of Sn:Ti molar ratio was studied on the crystallisation behaviour of the products. X-ray diffraction analysis revealed that the powders were crystallised at the low temperature of 400 °C containing anatase-TiO2, rutile-TiO2 and cassiterite-SnO2 phases, depending on annealing temperature and Sn:Ti molar ratio. Furthermore, it was found that SnO2... 

Synthesis of 14-aryl or alkyl-14H-dibenzo[a,j]xanthenes using nano-TiO 2 as eco-friendly and efficient catalyst is reported. Short reaction times, high yields, a clean process, simple methodology, easy work-up and green conditions are advantages of this protocol  

TiO2 thin films with mesoporous structure were deposited on quartz substrate by sol-gel dip coating. The structural, morphological and optical properties of the films were characterized by X-ray diffraction (XRD), simultaneous thermal analysis (STA), Fourier transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET), atomic force microscopy (AFM), transmission electron microscopy (TEM) and UV/Vis transmittance spectroscopy. Crystallization of the anatase phase was initiated at 300°C. Its transformation to the rutile phase occurred at 700°C. Anatase and rutile crystallites initially sized 3.2 and 15.3nm, respectively. The anatase phase was under tension; but the rutile phase was... 

The influence of particle size and surface modification on sonocatalytic activity of TiO2 nanoparticles was investigated by measuring the degradation efficiency of methyl orange (MO) as a model pollutant. Crystalline TiO2 nanoparticles with different particles and aggregate size were prepared through solution-phase method with varying synthesis temperatures. Coating with polyvinyl alcohol was performed to enhance colloidal stability of the particles over a wide range of pH values (1.5–7.5). Characterization was carried out using X-ray diffraction, high-resolution transmission electron microscopy, dynamic light scattering, and Fourier-transformed infrared techniques. It was found that... 

Electrospun hybrid membranes were synthesized using electrospinning of Poly (vinylidenefluoride) - titanium tetraisopropoxide (PVDF-TTIP) sol. Asymmetric post-treatment of membrane conducted for deprotonation of titanate and making hydrophilic/hydrophobic dual characteristics. The membranes were characterized by various methods such as wettability, scanning electron microscopy, infrared spectroscopy, X-ray diffraction and liquid entry pressure tests. For evaluating the separation performance, these membranes were applied in the VMD process to treat water heavy metal contaminants. The effects of operating parameters such as flow rate, temperature and membrane properties as porosity, on... 

We synthesize TiO2@SnO2 core-shell nanoparticles (NPs) by a facile two-step aqueous sol-gel method and their photocatalytic activity is compared with the pure TiO2 and SnO2 NPs for degradation of methylene blue under UV irradiation. The chemical property, crystal structure and morphology of the synthesized samples are studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Field emission scanning electron microscopy (FE-SEM) and transmission electron microscope (TEM) techniques. The mechanisms of electron–hole recombination and separation of charge carriers are studied by photoluminescence (PL) and diffuse reflectance spectroscopy (DRS). Furthermore, the kinetics... 

Electrochemical activity of TiO2 nanotube arrays (NTAs) is restricted by a wide band gap of TiO2. To overcome this restriction, we considered systematic research on two effective methods of doping of TiO2 NTAs such as the N-doping and electrochemical reductive doping and predicting the proper application of them. Band gap narrowing was occurred from 3.16 eV for undoped TiO2 NTAs to 2.9 and 2.7 eV at N-doped and self-doped TiO2 ones respectively. The electrochemical responses of the TiO2 NTAs before and after doping were examined by cyclic Voltammetry (CV) curve. To understand the electrochemical behavior of the undoped and doped TiO2 NTAs, electrochemical impedance spectroscopy (EIS) was... 

Recently, membrane fouling has been one of the most important issues in the field of membrane technology. In this regard, TiO2 nanoparticles blended with polymeric membranes have shown to improve fouling performance. In this study, a new PVDF/PAN/TiO2 ultrafiltration blend membrane was prepared via phase inversion by dispersing TiO2 nanoparticles in the PVDF/PAN casting solutions. The effect of different concentrations of TiO2 on the characteristics of membranes (i.e., morphology, hydrophilicity, permeation performance, and antifouling properties) was investigated. Results of scanning electron microscopy analysis showed the finger-like pores and macrovoids decrease due to the presence of... 

The durability of novel metallic artifacts and buildings is an open issue, and the role of smart protecting coatings in extending these artifacts’ lifetimes is crucial. In this paper, the role of γ-Fe2 O3 nanoparticles and reduced graphene oxide (rGO) nanosheets on enhancing the self-cleaning properties of composite TiO2 films and reducing metal alterations due to contact with acid rain and pollutants is investigated. The photocatalytic assessment of the TiO2 based films indicates that there are optimum contents for γ-Fe2 O3 and rGO, which confer the film lower bandgap and tune the TiO2 anatase/rutile ratio. By adding a proper content of γ-Fe2 O3, wettability is reduced both in dark and... 

TiO2 nanotubes (TNTs) were synthesized hydrothermally and modified by Cu2O using a sol-gel method to provide photocatalytic activity in visible light. Cellulose nanofiber (CNF)-based films were prepared by adding TiO2, TNTs, and Cu2O-modified TNT (TNT-Cu2O). The TiO2-based nanoparticles (TiO2, TNTs, and TNT-Cu2O) were uniformly distributed in the base polymer to make compatible and flexible films. The incorporation of nanoparticles significantly enhanced the UV-shielding properties of the film while slightly decreasing the transparency. Incorporating nanofillers improved the film's mechanical and water resistance properties depending on the nanoparticle type. The TNT-Cu2O-added CNF film...