Microstructure and photocatalytic activity of titanium dioxide nanoparticles (original) (raw)
Spectroscopic analyses of the photocatalytic behavior of nano titanium dioxide
Nano titanium dioxide TiO2was synthesized using hydrolysis method then subjected to several characterizations. XRD revealed that the as-prepared sample is pure anatase phase and after calcinations at 500C for 3 h the crystallinity has increased. The crystallite size calculated by Debye–Scherrer’s formula is 8 nm. The HRTEM image shows an average size of about 9 nm, which is close to the XRD calculation from Scherrer’s formula. PM3 semiempirical quantum mechanical calculations were conducted to present the electronic as well as thermal properties for TiO2. FTIR spectra between 800 and 400 cm 1 are the verification for the lattice vibrations of anatase TiO2. The photo catalytic degradation of methylene blue (MB) was tested by the prepared nano TiO2. Results indicate that, the maximum degradation efficiency reached 94.4% after 120 min of UV irradiation. This increase in the degradation efficiency of TiO2 could be attributed to the reduction in particle size that enhanced the crystallinity as a result of heat treatment
A study of the photocatalytic activity of titanium dioxide nanopowders
Russian Journal of Applied Chemistry, 2008
Photodestruction and adsorption of dyes in aqueous suspensions of nanopowders of titanium dioxide of anatase modification was studied. The photocatalytic activity of titanium dioxide nanopowders was examined in relation to the dispersity of particles and pH of the medium.
Characterization and photocatalytic activities of nanosized titanium dioxide thin films
2011
Thin films of titanium dioxide with high surface area are prepared by sol-gel dip-coating technique. In this regards, Titania nano sols with high photocatalytic activity were prepared by dissolving titanium alkoxide in alcohol and water under acidic conditions. Photocatalytic activities of titanium dioxide thin films were measured in the presence of methylene blue. Microstructure and photocatalytic activity of the films, nanopowders and titanium dioxide sols were investigated using X-ray diffraction, scanning electron microscopy, specific surface area, zeta sizer and ultraviolet-visible spectrometry techniques. Particle size analysis of sols showed that the mean particle sizes were 15 to 128 nm. X-ray diffraction analyses revealed that anatase crystal structure was produced with crystallite size below 11 nm. Increasing mass percent of anatase phase and specific surface area, enhance the photocatalytic activity. Scanning electron microscopy images showed that the addition of methylce...
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) .
Synthesis of Nano Titanium Dioxide and Its Application in Photocatalysis
This paper presents a simple way to synthesize titaniumdioxide nanotubes by using a microwaveassisted reaction of TiO2 particles and NaOH solution. The main advantage of the introduction of microwave into the reaction system is the extremely rapid kinetics for synthesis. This method is simple and easy to reproduce. Structural and microstructural characterizations of titania nanotubes were accomplished using X-ray diraction (XRD), scanning-electron microscopy (SEM) and transmission-electron microscopy (TEM) techniques. The specic surface area was calculated using the Brunauer-Emmett-Teller model and was found to be 52 m 2 /g. A high photocatalysis of our TiO2 nanotubes was obtained.
Titanium dioxide nanostructures as efficient photocatalyst: Progress, challenges and perspective
International Journal of Energy Research, 2020
In the growing energy consumption, the photocatalysis seems to be very helpful due to promising environmental applications. Several semiconducting nanostructures are reported as photocatalysts but still, the researchers are finding a way towards higher efficiency. The TiO 2 nanostructures with different sizes, morphologies, synthesis methods and dopants have been reviewed to study their effect on photocatalysis. The TiO 2 photocatalysts are presented to be widely used in energy and eco-friendly applications including water purification, hydrogen production, phenol degradation, Cr(VI) and CO 2 reduction. The photostability, accessibility and environmental harmlessness have been presented as a break through towards the global energy crisis due to potential application in photocatalytic hydrogen evolution. Besides variety of useful applications, the efficiency is limited due to wide bandgap, fast charge recombination, and many other factors. The progress of TiO 2 photocatalyst along with the limitations underway and their possible solutions have been presented from reported literature. It is predicted that an approach towards highly efficient photocatalyst could be achieved in the form of nanostructured TiO 2 .
The influence of surface properties on the photocatalytic activity of nanostructured TiO2
Journal of Catalysis, 2003
Nanostructured TiO 2 with 11-(P11) and 5-nm (P5) crystal sizes were prepared by a modified sol-gel method. Controlled crystallization and a pretreatment process were employed to obtain TiO 2 with different surface roughness and degree of hydroxylation, while maintaining an identical crystal (i.e., 11 or 5 nm) and aggregate (i.e., 100 nm) sizes, phase structure (i.e., anatase), and crystallinity (i.e., X-ray diffraction peak intensity). Using the photooxidation of airborne trichloroethylene as a probe reaction, we were able to identify that the hydroxyl groups on low-coordinated titanium atoms are responsible for the generation of dichloroethylene and dichloroacetaldehyde by-products. Their presence usually means lower TCE conversion and in some cases leads to catalyst deactivation.
Reviews in Biological and Biomedical Sciences, 2018
Over the past decades, nanotechnology has increasingly developed and reached to monopolize almost all of the human activity areas. Materials with nanoscaled dimensions are not only developed for technological or medical purposes, but also, they can be found in daily commercial products. So, nanoparticles' applications found a welldefined place in our modern life. Almost 70% of global pigment production is based on titanium dioxide (TiO 2 ), which represents also one of the top five nanoparticles used in consumer products. TiO 2 surrounds our lives, being always present whether we want to take care of our health, wash our teeth or protect ourselves from harmful ultraviolet (UV) radiation. Moreover, TiO 2 is commonly used as a white pigment in different inks, paints, varnishes, plastics, papers, cosmetic products, also being the most common food additive (E171). But, the main perspectives of TiO 2 nanoparticles are related to different photo-induced phenomena, leading to the complete mineralization of pathogens and toxic non-biodegradable compounds, with low costs and high efficiency. Here, the authors aimed to present a brief review mainly focused on the ability of TiO 2 to create surfaces with self-cleaning, anti-fogging and antibacterial properties, as well as on the current photocatalytic applications of TiO 2 in new medical sanitizing techniques and biomedical devices development, wastewater management and air purification, energy and hydrogen production, and for obtaining "smart" clothes.
Transactions of Nonferrous Metals Society of China, 2012
Using Ti powder as reagent, TiO 2 nanoneedle/nanoribbon spheres were prepared via hydrothermal method in NaOH solution. The samples were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) with selected area electron diffraction (SAED), X-ray diffraction (XRD), and UV-visible light absorption spectrum. The results indicate that the growth orientations of the crystals are influenced by the hydrothermal temperature and NaOH concentration. The diameter of the nanoneedle spheres and nanoribbon spheres (40í50 ȝm) are almost the same as that of Ti powders. TiO 2 nanoneedle/nanoribbon sphere powders are anatase after heat treatment at 450 °C for 1 h. Furthermore, methyl orange was used as a target molecule to estimate the photocatalytic activity of the specimens. Under the same testing conditions, the photocatalytic activities of the products decrease in the following order: TiO 2 nanoneedle sphere, TiO 2 nanoribbon sphere and P25.