A study on the synthesis, characterization and photocatalytic activity of TiO 2 derived nanostructures (original) (raw)
Related papers
Materials Letters, 2006
Transparent nanocrystalline pure anatase titania (nano-TiO 2 ) was synthesized by hydrothermal process at 200 -C. Photocatalytic activity of the nano-TiO 2 as in the form of sol was tested for degradation of Methylene Blue (MB) and Reactive Red 120 (RR-120) in aqueous solutions. Structural and physico-chemical properties of the nano-TiO 2 were characterized using powder XRD, SEM, BET, FT-IR and elemental analyses. Complete photodegradation of RR-120 was successfully achieved by aid of the nano-TiO 2 whereas MB was not degraded, maybe because of reversible color change in nano-TiO 2 sol/MB mixture after the UV irradiation was stopped. Potocatalytic activity of the synthesized the nano-TiO 2 for degradation of RR-120 was compared with Degussa P-25 at optimum conditions determined for RR-120. It was found that the nano-TiO 2 can be repeatedly used with higher photocatalytic activity than Degussa P-25. D
Green synthesis of TiO2 and its photocatalytic activity
Journal of Materials Science: Materials in Electronics, 2015
Anatase titanium dioxide nanoparticles were prepared from titanium oxysulphate (TiOSO 4) as a precursor and the base polymer Polyvinyl Pyrrolidone is used as a capping agent. TiO 2 nanoparticles were characterized by XRD, SEM, TEM, EDS, FT-IR, DLS, UV-Vis. Diffuse reflectance spectrophotometer. From XRD analysis it is seen that obtained diffraction peaks are broad which indicating that crystallite size is very small. Scanning Electron Micrograph (SEM) revealed that TiO 2 nanoparticles has diameter of 10 nm calcined at 400°C. Photocatalytic activity was checked by employing the Methyl Orange as a model pollutant under UV-light (365 nm) which shows 94 % photo-degradation in 150 min. The novelty of present approach is the large scale production of polymer capped TiO 2 nanocrystals by using sol-gel process.
Desalination, 2011
In the present study, titanium dioxide nanoparticles were synthesized by sol-gel method, from various precursors in some solvents under different synthesis conditions such as solvent percent, water percent, reflux temperature, reflux time, sol drying method and calcination temperature. Structure, size, band gap and specific surface area of nanoparticles were determined by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-Vis reflectance spectroscopy (DRS) and BET analysis methods. The photocatalytic activity of TiO 2 was evaluated in the photodegradation of C.I. Acid Red 27 as a model contaminant from textile industry under UV-C light irradiation. Results indicate that structure and photocatalytic activities are functions of precursor type, solvent type and other synthesis conditions. TiO 2 nanoparticles synthesized in the presence of methanol as solvent and titanium (IV) isopropoxide as precursor under 3 h reflux at 80°C with sol thermal drying and calcination temperature of 450°C indicate high photocatalytic activity in comparison with TiO 2 -P25 (Degussa Co.).
Materials Today: Proceedings, 2019
The application of heterogeneous photocatalysis is described as an advanced oxidation process (AOP) for the degradation of the diazo reactive dye using immobilized TiO 2 as a photocatalyst. Starting TiO 2 solutions were prepared with and without the addition of polyethylene glycol (PEG) and TiO 2 films were directly deposited on a borosilicate glass substrate using the sol-gel dip-coating method. The surface morphology and the nanoscale roughness of TiO 2 films were studied by means of atomic force microscopy (AFM). Structural properties of TiO 2 were identified by Xray diffraction (XRD). The decomposition behaviour of organic compounds from the gels was investigated using thermal gravimetry (TG) and differential scanning calorimetry (DSC). Photocatalytic activities of TiO 2 films in the process of degradation of the commercial diazo textile dye Congo red (CR), used as a model pollutant, were monitored by means of UV/vis spectrophotometry. The kinetics of the degradation of the CR dye was described with the Langmuir-Hinshelwood (L-H) kinetic model. The addition of PEG to the TiO 2 solution resulted in the changes in the film surface morphology, and affected the ratio of anatase-rutile crystal phases and the photocatalytic activity of TiO 2. The TiO 2 film prepared with PEG is characterized by higher roughness parameters (R a , R max , R q , R z and Z max), a lower amount of the rutile phase of TiO 2 , a higher amount of the anatase phase of TiO 2 and a better photocatalytic activity compared to the TiO 2 film without the addition of PEG.
Recent advances in basic fabrication techniques of TiO 2 -based nanomaterials such as nanoparticles, nanowires, nanoplatelets, and both physical-and solution-based techniques have been adopted by various research groups around the world. Our research focus has been mainly on various deposition parameters used for fabricating nanostructured materials, including TiO 2 -organic/inorganic nanocomposite materials. Technically, TiO 2 shows relatively high reactivity under ultraviolet light, the energy of which exceeds the band gap of TiO 2 . The development of photocatalysts exhibiting high reactivity under visible light allows the main part of the solar spectrum to be used. Visible light-activated TiO 2 could be prepared by doping or sensitizing. As far as doping of TiO 2 is concerned, in obtaining tailored material with improved properties, metal and nonmetal doping has been performed in the context of improved photoactivity. Nonmetal doping seems to be more promising than metal doping. TiO 2 represents an effective photocatalyst for water and air purification and for self-cleaning surfaces. Additionally, it can be used as an antibacterial agent because of its strong oxidation activity and superhydrophilicity. Therefore, applications of TiO 2 in terms of photocatalytic activities are discussed here. The basic mechanisms of the photoactivities of TiO 2 and nanostructures are considered alongside band structure engineering and surface modification in nanostructured TiO 2 in the context of doping. The article reviews the basic structural, optical, and electrical properties of TiO 2 , followed by detailed fabrication techniques of 0-, 1-, and quasi-2-dimensional TiO 2 nanomaterials. Applications and future directions of nanostructured TiO 2 are considered in the context of various photoinduced phenomena such as hydrogen production, electricity generation via dye-sensitized solar cells, photokilling and self-cleaning effect, photo-oxidation of organic pollutant, wastewater management, and organic synthesis.
Synthesis and photocatalytic activity of TiO2 Nanoparticles
Titanium dioxide (TiO2) nanoparticles have been synthesized by sol gel method. The synthesized nanoparticles followed by calcinations at different temperatures in the range 200-800°C for 2 hours. Both the evolution of the crystal size and nature of the phases were studied as a function of annealing temperatures. These materials display a good thermal stability up to 400°C, in term of crystal size، and up to 600°C, regarding the crystalline phase. The phase purity and crystallite size of as grown TiO2 particles were characterized via X-ray diffraction (XRD). The characterized results indicated that the synthesized TiO2 powders had a pure two phases anatase and rutile structures and the average particle sizes were about 5-53 nm. The synthesized TiO2 nanoparticles exhibited 1.0053% time higher photocatalytic activity for Bismarck Brown R than that of commercial Hombikate (UV100) .
TiO2 Nanoparticles with High Photocatalytic Activity Under Visible Light
Catalysis Letters, 2009
TiO 2 nanoparticles (C-TNT) with high visible light activity were obtained by carbonization of titania nanotubes (TNT) in an ethanol atmosphere under elevated pressure at 180 and 220°C. New material was characterised by means of UV-Vis/DR, FTIR/DRS, TEM, and XRD. The photocatalytic activity was tested during monoazo dye decomposition under artificial solar light irradiation. Modified photocatalyst (220°C, 4 h) had higher photocatalytic activity than both the pristine and commercial P25 catalysts.
Effect of physical chemistry parameters in photocatalytic properties of TiO2 nanocrystals
Comptes Rendus Chimie, 2013
We used a new synthesis of TiO 2 anatase 6 nm nanocrystals prepared at room temperature (Hegazy and Prouzet, 2012 [10]) to explore the influence of different physical-chemical parameters on photocatalysis, and bench-tested the material against two commercial powders made of either pure anatase (Sigma TM), or composite anatase-rutile particles (P25 Degussa TM). The initial as-synthesised material demonstrates a low photocatalytic activity, which is greatly improved after thermal activation as a result of improved crystallinity without any drastic change in crystal size. The influence of several other parameters was studied, the resulting tests being compared with commercial products. The cumulative improvement provided by these different parameters led finally to a material that exhibits a higher photocatalysis compared to commercial anatase, and similar to the commercial material usually used for reference (P25). This study, which can apply to other titania materials, illustrates how the post-treatment and process adaptation can help to optimise an initial material.
The Journal of Physical Chemistry C, 2008
A simple and efficient inorganic acid-assisted hydrothermal route has been developed for the synthesis of single-crystalline TiO 2 nanostructures with use of protonic tetratitanate hydrate fibers as a precursor. A variety of TiO 2 nanostructures, including aligned nanorods, nanoporous nanostructures, nanocubes, and diamondshaped nanocrystals, have been prepared with this method. The morphology, crystalline phase, composition, average grain size, band gap, and microstructure of the nanostructures have been determined as a function of the nature and concentration of the inorganic acid (HCl, HNO 3 , or H 2 SO 4) used for the synthesis. The rutile phase is obtained by using HCl for a concentration range of 0.1-0.4 M and also for 6 M concentration, HNO 3 for a concentration range of 0.1-0.2 M and >7 M, and H 2 SO 4 for a narrow concentration range of 0.1-0.9 M. Likewise, the anatase phase is obtained by using both HCl and HNO 3 for concentrations of around 0.9 M, and a broader concentration range of 2-7 M with H 2 SO 4. An increase in the band gap of the TiO 2 nanostructures from 2.97 to 3.35 eV is observed as the crystalline phase changes from rutile, to a mixture of rutile and anatase, and subsequently to pure anatase. Correspondingly, the photocatalytic activity of the synthesized nanostructured materials is found to be dependent on the crystalline phase, composition, and surface area.
This work systematically investigated the relationship between structure, morphology, photoelectrochemical (PEC) and photocatalytic (PC) properties of TiO2 catalysts. A series of TiO2 catalysts with various phase compositions (anatase-, brookite- and finally rutile-rich samples) and morphologies (1D morphology, rhomboid nanoparticles (NPs) and flower-like assemblies of nanorods) were prepared by an acidic hydrothermal treatment of hydrogen titanate nanofibres (H-TNFs). The structures of the samples, such as crystal phase composition and their spatial distribution, were extensively characterised, and the samples were tested for photocatalytic degradation of ethanol. A strong correlation is found between PEC and PC properties. PEC measurements revealed that the brookite-rich samples generated high but unstable photocurrents. The anatase and rutile-rich samples showed good stability, but for the rutile-rich samples low photocurrents were detected due to the poor conductivity of this polymorph. In contrast, the sample containing 93.2% anatase and 6.8% brookite with elongated morphology not only showed the ability to generate high photocurrents but also maintained a stable photoresponse upon an extended period of time, because of its well-balanced bi-crystalline structure and elongated morphology. Therefore, the abilities to generate high photocurrents and to maintain a stable photoresponse are equally important and probably a prerequisite for a good photocatalyst.