Effect of synthesis conditions on the preparation of titanium dioxides from peroxotitanate solution and their photocatalytic activity (original) (raw)
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International Journal of Photoenergy, 2012
The nickel-containing titania was synthesized and employed in the photomineralization of . A nickel-modified titania photocatalyst was prepared by photodeposition method with using Degussa-P25 TiO2particle and nickel chloride as raw materials, respectively. The physical analyses were carried out using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), transmittance electron microscope (TEM), and photoluminescence spectroscopy (PL), to observe changes in particles following nickel modification. The results showed that Ni does not enter into the crystal lattice and is dispersed onto the surface uniformly. Ni improved the intensity of PL spectra with an appropriate Ni content on the surface. The modified titanium dioxide with 0.1 mol% of nickel exhibited two times the -removal activity of bare under ultraviolet illumination. The nickel content in this photodeposition process plays an important role in affinity to molecules, recombination rate of electron-hole pair, and co...
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Titania thin films were synthesized by sol–gel dip-coating method with metallic Ni nanoparticles synthesized separately from an organometallic precursor Ni(COD)2 (COD = cycloocta-1,5-diene) in presence of 1,3-diaminopropane as a stabilizer. Titania was obtained from a titanium isopropoxide precursor solution in presence of acetic acid. A Ni/TiO2 sol system was used to coat glass substrate spheres (6, 4 and 3 mm diameter sizes), and further heat treatment at 400 °C was carried out to promote the crystallization of titania. XRD analysis of the TiO2 films revealed the crystallization of the anatase phase. Transmission Electron Microscopy (TEM) and High Resolution TEM studies of Ni nanoparticles before mixing with the TiO2 solution revealed the formation of Ni nanostructures with an average size of 5–10 nm. High-angle annular dark-field images of the Ni/TiO2 system revealed well-dispersed Ni nanoparticles supported on TiO2 and confirmed by AFM analysis. The photocatalytic activity of the Ni/TiO2 films was evaluated in hydrogen evolution from the decomposition of ethanol using a mercury lamp for UV light irradiation. Titania films in presence of Ni nanoparticles show higher efficiency in their photocatalytic properties in comparison with TiO2.
Synthesis of Ni-TiO2 nanocomposites and photocatalytic degradation of oxalic acid in waste water
International Journal of Innovative Research in Science, Engineering and Technology, 2015
Titania is one of the mostly used photocatalyst because of its high oxidative power, stability, and nontoxicity. Prepared nanocomposites of nickel titania by solution impregnation method. The pure TiO 2 and Ni-TiO 2 were analyzed by XRD for phase and particle size determination, SEM for the Morphology determination, BET for the surface area determination, UV-Vis Spectra for the band gap determination and FT-IR for the molecular bonding determination. XRD confirm the rutile and anatase both phases were present in nanocomposites of TiO 2 and Prepared Ni-TiO 2 .The particle size were found 35 and 80 nm in case of Nickel titania and pure titania respectively by applying Scherer's calculation. SEM analysis confirms that TiO 2 and Prepared Ni-TiO 2 were in nanodiamension. BET analysis was performing to determine the surface area, pore volume and pore radius of the titania and Nickel titania. UV-Vis Spectra of the TiO 2 and Prepared Ni-TiO 2 were observed at below 400 nm and also determine the band gap of TiO2 and Prepared Ni-TiO 2. The band gap observed for TiO 2 and Prepared Ni-TiO 2 were 3.2 and 3.0 eV respectively. The FT-IR spectra also give the peak at 1025 cm-1 for the formation of Ni-O bonding in Ni-TiO 2. The Prepared sample of TiO 2 and Prepared Ni-TiO 2 were subjected to photocatalytic degradation of oxalic acid. The photocatalytic degradation of Oxalic acid occurs efficiently and also investigated the effect of pH, amount of photocatalyst, Temperature, and photocatalyst. The prominent degradation was found in case of oxalic acid in the presence of nanocomposites of Ni-TiO 2. Photocatalytic degradation of oxalic acid follows the pseudo-first-order rate law. The rate constant was increased two times when temperature rises to 10 o C for photodegradation of oxalic acid in presence of TiO 2 and Prepared Ni-TiO 2 .
2017
Ni-doped nanorod TiO2 photocatalysts were prepared by mixing a nickel solution with TiO2 powders via a modified impregnation method. In this study 5, 10, 25 mol% of Ni doping were studied. The physical properties of the Ni-doped TiO2 photocatalysts were studied by several techniques such as X-ray powder diffraction (XRD), scanning electron microscopy (SEM), Fourier-transformed infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and UV-Vis diffused reflectance spectroscopy (DRS). XRD patterns showed that pure TiO2 sample and Ni-doped TiO2 samples were anatase phase. No diffraction patterns of Ni peaks were observed. The crystallite size of Ni-doped TiO2 samples were examined using the Scherrer equation. SEM results revealed that the pure TiO2 and Ni-doped TiO2 nanoparticles had rod-like structures. The FT-IR spectra showed the characteristic bands of the titania and hydroxyl groups on the surface of the titania. The XPS results confirmed the existence of Ni, Ti, O,...
Synthesis of Nano Titanium Dioxide and Its Application in Photocatalysis
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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.
Background: Heavy metals in aquatic systems usually interfere with many beneficial uses of water. Divalent nickel is a commonly occurring toxic metal in natural ecosystems due to the effluent of refineries, electroplating, and casting industries. In aquatic environments, nickel appears as Ni (II) and Ni 0. Despite the high reported toxicity for Ni (II), Ni 0 is only slightly toxic. Various methods have been proposed for the treatment of aqueous solutions containing Ni (II). Photocatalytic reduction is an important process; titanium dioxide has been mostly used as a very efficient photocatalyst. Methods: In this study, the removal of divalent nickel ions in aqueous solutions was studied in the presence of remarkably low dosages of nano-titania photocatalyst. Direct imposed irradiation was utilized for treatment of solutions. Accordingly, the influence of four operational parameters, including temperature within the conventional range of 20 to 40 ° C, was investigated. Design of exper...
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Materials Science in Semiconductor Processing, 2012
TiO 2 nanoparticles were prepared using a surfactant (linoletic acid (LA) or polyethylene glycol-400 (PEG-400)) at various hydrolysis ratios (R¼ H 2 O/C 2 H 5 OH) by the hydrothermal method and studied for photocatalytic degradation of rhodamine B (RhB) under visible light irradiation. Special shapes of TiO 2 nanoparticles, such as cubic, hexagon, bipyramid, and bullet, were found from the use of PEG-400 during the preparation. The cause for the formation of these special shapes is also discussed here. Interestingly, the hydrolysis ratios affected the Brunauer-Emmett-Teller (BET) special surface areas of the TiO 2 nanoparticles. Owing to the effects of the surfactant PEG-400 on the microstructures, the resulting materials exhibited relatively higher photocatalytic activity than conventional TiO 2 nanoparticles in the presence of LA. Furthermore, P-TiO 2-8/10 (P is PEG-400 and 8/10 is H 2 O/C 2 H 5 OH molar ratio) nanoparticles had a similar photocatalytic activity to P25 and TiO 2-10/10.
Oriental Journal of Chemistry, 2017
The present study addresses a tailored preparation method of different structures of TiO 2 nanoparticles over narrow ranges of varying parameters. In this work, titanium-n-butoxide was used to prepare TiO 2 nanoparticles via sol gel method. The influence of the experimental preparation conditions: pH, drying and calcination temperatures were studied at ranges 5-9, 70-110°C, and 450-650 o C, respectively. Slight changes through these mentioned ranges lead to drastically change in the phase transformation, degrees of crystallinity and crystal systems of the prepared TiO 2. Pure anatase and rutile forms as well as different ratios of mixed phases were obtained. X-ray diffraction and transmitting electron microscope TEM techniques were used for the characterization of the prepared samples. The photocatalytic performance of TiO 2 samples were evaluated according to their abilities toward the generation of the highly active hydroxyl radicals. Results indicate that the photocatalytic activities of TiO 2 samples are dependent on their preparation experimental conditions. The maximal photocatalytic activities were noticed at high pH and drying temperature values.