共查询到20条相似文献,搜索用时 15 毫秒
1.
Maja Šćepanović Biljana Abramović Aleksandar Golubović Sanja Kler Mirjana Grujić-Brojčin Zorana Dohčević-Mitrović Biljana Babić Branko Matović Zoran V. Popović 《Journal of Sol-Gel Science and Technology》2012,61(2):390-402
Nanocrystalline titanium dioxide (TiO2) powders have been synthesized by sol–gel method using titanium tetrachloride (TiCl4) or tetrabutyl titanate (Ti(OC4H9)4 as precursors, different alcohols and calcination temperatures in the range from 400 to 650 °C. The photocatalytic activity
of as-prepared powders has been tested for the degradation of metoprolol tartrate salt, a selective β-blocker used to treat
a variety of cardiovascular diseases, and compared to photocatalytic activity obtained from Degussa P25. Nanosized TiO2 powders prepared from TiCl4 and amyl-alcohol, calcined at 550 °C, displayed an activity comparable to Degussa P25, whereas the sample from the same series,
calcined at 650 °C, showed higher photocatalytic activity in the whole range of the catalyst loading. Structural, morphological
and surface properties of synthesized TiO2 nanopowders have been investigated by XRD, SEM, EDS and BET measurements, as well as FTIR and Raman spectroscopy, in order
to find out the material properties which enable rapid an efficient decomposition of metoprolol under UV radiation. 相似文献
2.
S. Mahendra Kumar Parag A. Deshpande M. Krishna M. S. Krupashankara Giridhar Madras 《Plasma Chemistry and Plasma Processing》2010,30(4):461-470
Nanocrystalline TiO2 was synthesized using the microwave plasma technique and characterized using X-ray diffraction, transmission electron microscopy, scanning electron microscopy, laser particle size analyzer, UV–vis spectroscopy and BET surface area analyzer. The synthesized TiO2 powder crystallized in anatase phase and the crystallite sizes were in nanometers. The photocatalytic activity of the compound was determined and compared against the activity of the commercial Degussa P-25 TiO2 catalyst. The degradation rates of the dyes were found to be higher over the synthesized TiO2 as compared to that over commercial Degussa P-25 TiO2. 相似文献
3.
《Arabian Journal of Chemistry》2020,13(11):7637-7651
Influence of nitrogen precursors urea, semicarbazide and N,N’-dimethyl urea on the photocatalytic activity of the N-doped TiO2 were studied by a simple decomposition method. The nano N-TiO2 catalysts were synthesized via two different modified approaches by calcination at 500 °C. The synthesized samples were characterized by IR, UV-DRS, Raman, TG-DTA, XRD, EDX, XPS, SEM, TEM and BET analysis. Of the synthesized six samples of N-TiO2 five samples showed better photocatalytic activity towards direct sunlight photo-degradation of methylene blue (MB) and rhodamine B (RhB) than Degussa P25. The catalysts obtained using semicarbazide samples F3 and F4 having large surface area of 76 and 85.8 m2/g displayed maximum photocatalytic activity. The sample F4 was 1.5 times more active than Degussa P25 for the decolourisation of MB and 1.9 times more active for the decolourisation of RhB. The presence of nitrogen, large surface area and coupling of rutile-anatase phases were found to be the main responsible factors for the enhanced photocatalytic activity. The exclusive formation of the anatase phase in the case of urea precursor is attributed to the slow evaporation of urea due to the formation of melamine derived products. The calcination temperature is the deciding factor responsible for the photocatalytic activity of the N-TiO2 samples prepared from precursors which can potentially form the melamine and its oligomerized products on the surface of TiO2. 相似文献
4.
Monica Raciulete 《Journal of solid state chemistry》2010,183(10):2438-2444
An expedite one-step approach using simple precursors has been proposed to obtain metallic oxide compounds and exemplified by preparation of highly dispersed TiO2. The technique consists in heating to 400-500 °C of molten ammonium nitrate stabilized with an organic nitrogen-containing compound (urea, melamine, ammonium oxalate) and containing dissolved metal salt precursor (TiOCl2). The crystallites of the resulting TiO2 demonstrated variable size and shape as a function of stabilizer used. Their activity in photocatalytic oxidation of formic acid also depends on the nature of the stabilizer. The catalysts as-prepared showed high photocatalytic performance, superior to that of the Degussa P25 reference. Nitrogen containing stabilizers play a double role of increasing the process safety and modifying the properties of the solid products. 相似文献
5.
Bifunctional TiO2 Catalysts for Efficient Cr(VI) Photoreduction Under Solar Light Irradiation Without Addition of Acids
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Bifunctional TiO2 photocatalysts co-doped with nitrogen and sulfur were prepared by the controlled thermal decomposition of ammonium titanyl sulfate precursor. They have both photocatalytic activity and Br?nsted acidity, and thus are active in the photoreduction of Cr(VI) under solar light irradiation without the addition of acids. The activity is superior to that of Degussa P25 in the acidified suspension at the same pH adjusted by H2SO4. 相似文献
6.
《Journal of photochemistry and photobiology. A, Chemistry》2006,177(2-3):261-268
TiO2 nanocrystallites were prepared from precursors tetra-n-butyl titanate (Ti(OC4H9)4) and titanium tetrachloride (TiCl4). The precursors were hydrolyzed by gaseous water in autoclave, and then calcined at predetermined testing temperatures. The samples were characterized by X-ray diffraction (XRD), thermogravimetry–differential thermal analysis (TG–DTA), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectra (FT-IR), and UV–vis diffuse reflectance spectra (DRS). The photocatalytic activities of the samples were evaluated by the photobleaching of methylene blue (MB) in aqueous solution and the photocatalytic oxidation of propylene in gas phase at ambient temperature. The results showed that the anatase phase nanocrystalline TiO2 could be obtained at relatively low temperatures (for precursor Ti(OC4H9)4 at 110 °C and for TiCl4 at 140 °C, respectively), and that the as prepared samples exhibited high photocatalytic activities to photobleach MB in aqueous solution. As the calcination temperatures increasing, the decolor ratio of MB increased and reached the maximum value of nearly 100% at 600 °C, and then decreased. The photobleaching of MB by all samples followed the pseudo-first-order kinetics with respect to MB concentration. The photodecomposition amount of propylene by TiO2 nanocrystallites calcined at 600 °C from precursor of Ti(OC4H9)4 is 21.6%, which is approaching to that by Degussa P25 TiO2 (24.9%). 相似文献
7.
Develop a photocatalyst system for solar energy conversion to electric energy or chemical energy is a topic of great interest for fundamental and practical importance. In this study, nitrogen-doped TiO2 with high hydrogen production by photocatalytic water splitting were prepared by microwave-assisted hydrothermal method using titanium sulfate as precursor in the presence of urea. The nitrogen doped TiO2 prepared in this study was pure anatase phase with a high surface area (372?m2?g?1) and showed a very high hydrogen evolution rate of water splitting reaction under UV light irradiation (4,386?μmol?g?1?h?1) and visible light irradiation (185?μmol?g?1?h?1) which was about 15?times higher than commercial TiO2 (Degussa P25). 相似文献
8.
Reza Ojani Jahan-Bakhsh Raoof Ebrahim Zarei 《Journal of Solid State Electrochemistry》2012,16(6):2143-2149
A commercially available TiO2 powder (Degussa P25) has been used to prepare thin films on graphite plates. The photoelectrochemical degradation of rhodamine B was investigated using this photoelectrode. The effects of applied potential, pH, and initial rhodamine B concentration on the photoelectrocatalytic (PEC) degradation of rhodamine B using ultraviolet illuminated TiO2/graphite (TiO2/C) thin film electrode were examined and discussed. Also, direct photolysis, electrochemical oxidation, photocatalytic, and PEC degradation of rhodamine B were compared. Results show that the best responses for PEC are obtained at applied potential of 1.2?V vs. reference electrode, pH?4.0, and initial rhodamine B concentration of 4.2?mg?L?1. 相似文献
9.
Pei Fung Lee Xiwang Zhang Darren D. Sun Jianhong Du James O. Leckie 《Colloids and surfaces. A, Physicochemical and engineering aspects》2008,324(1-3):202-207
In this work bimodal structured titanium dioxide (TiO2) microsphere has been prepared from commercial TiO2 powder and nano-sized titania gel via sol–gel spray-coating technique. Crystallization and transformation behavior of titania gel were investigated. The results revealed that the crystallization and transformation of anatase particles were substantially affected by the concentration of solvent and calcination temperature. Anatase crystallite size of 10 nm was obtained at mole ratio of solvent/precursor 50/1 and calcination temperature of 450 °C. The prepared nano-sized titania gel was embedded within the core (commercial TiO2, P25) during the spraying process. The prepared TiO2 microsphere was characterized using X-ray diffractometer (XRD), scanning electron microscope (SEM), field emission electron microscope (FESEM) and micropore analysis. The photocatalytic activity was monitored by following the degradation of phenol with activity benchmarked against commercial P25 (Degussa). The increase of photocatalytic activity of TiO2 microsphere was attributed to the nano-sized anatase crystallite which has been incorporated into the TiO2 microsphere. 相似文献
10.
Visible‐light‐driven plasmonic photocatalyst Ag‐TiO2 nanocomposite hollow spheres are prepared by a template‐free chemically‐induced self‐transformation strategy under microwave‐hydrothermal conditions, followed by a photochemical reduction process under xenon lamp irradiation. The prepared samples are characterized by using scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, N2 adsorption‐desorption isotherms, X‐ray photoelectron spectroscopy, UV/Vis and Raman spectroscopy. Production of ?OH radicals on the surface of visible‐light illuminated TiO2 was detected by using a photoluminescence method with terephthalic acid as the probe molecule. The photocatalytic activity of as‐prepared samples was evaluated by photocatalytic decolorization of Rhodamine B (RhB) aqueous solution at ambient temperature under visible‐light irradiation. The results show that the surface plasmon absorption band of the silver nanoparticles supported on the TiO2 hollow spheres was red shifted, and a strong surface enhanced Raman scattering effect for the Ag‐TiO2 nanocomposite sample was observed. The prepared nanocomposite hollow spheres exhibits a highly visible‐light photocatalytic activity for photocatalytic degradation of RhB in water, and their photocatalytic activity is higher than that of pure TiO2 and commercial Degussa P25 (P25) powders. Especially, the as‐prepared Ag‐TiO2 nanocomposite hollow spheres at the nominal atomic ratio of silver to titanium ( R ) of 2 showed the highest photocatalytic activity, which exceeds that of P25 by a factor of more than 2. 相似文献
11.
Yanfang Shen Tianying Xiong Hao Du Huazi Jin Jianku Shang Ke Yang 《Journal of Sol-Gel Science and Technology》2009,50(1):98-102
P, N, and Mo ternary co-doped nano TiO2 photocatalysts ((P, N, Mo)-TiO2) were prepared by a single step sol–gel method, which show much enhanced photocatalytic activities over Mo-TiO2, (P, N)-TiO2, un-doped TiO2 and Degussa P25 under visible light irradiation. The degradation rate of 0.72Mo–P-TiO2 is as high as 65.3%, which is about 6.7 times of that of Degussa P25. Possible reasons for the improvement of photocatalytic
activities were analyzed. 相似文献
12.
Nanocrystalline anatase TiO2 powder photocatalysts were synthesized by a vapor-thermal method using tetrabutyl titanate as precursor at a temperature range from 120 to 200 °C. The as-synthesized products were characterized by X-ray diffraction, N2 adsorption-desorption measurement, transmission electron microscopy, high resolution transmission electron microscopy, Fourier transform infrared spectra, Raman spectra, and their photocatalytic activity was evaluated by photocatalytic oxidation decomposition of acetone in air. The results showed that reaction temperature greatly affected the microstructures and photocatalytic activity of the samples. With increasing reaction temperature and time, the average crystalline size of TiO2 particles increased and their crystallization enhanced, while the specific surface area of the products decreased. The TiO2 powders obtained at a temperature range from 150 to 200 °C for 10 h showed good photocatalytic activity and were greatly higher than that of Degussa P-25. 相似文献
13.
E. Ramírez-Meneses A. García-Murillo F. de J. Carrillo-Romo R. García-Alamilla P. Del Angel-Vicente J. Ramírez-Salgado P. Bartolo Pérez 《Journal of Sol-Gel Science and Technology》2009,52(2):267-275
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. 相似文献
14.
Sylwia BzdonJacek Góralski Waldemar ManiukiewiczJan Perkowski Jacek RogowskiMagdalena Szadkowska-Nicze 《Radiation Physics and Chemistry》2012,81(3):322-330
Fe-doped TiO2 catalyst was prepared by wet impregnation, using TiO2 P25 Degussa as a precursor and Fe(NO3)3 as a dopant, followed by irradiation with an electron beam or γ-rays. Surface properties of Fe/TiO2 samples were examined by BET, XRD, ToF-SIMS, and TPR methods. The photocatalytic activity towards destruction of the anionic surfactant, sodium dodecylbenzenesulfonate (SDBS), in aqueous solutions was higher for the irradiated Fe/TiO2 catalysts than for bare TiO2 P25 or that calcined at 500 °C. The results show that irradiated catalysts exhibit a more uniform texture with high dispersion of iron species. An enhancement of the activity of irradiated Fe/TiO2 systems can be attributed to the synergetic effects of small crystallite size and homogenous distribution of iron species including FeTiO3 phase. 相似文献
15.
M. M. Viana C. C. de Paula D. R. Miquita N. D. S. Mohallem 《Journal of Sol-Gel Science and Technology》2011,59(1):19-24
Ag-doped TiO2 wet gels were prepared by sol?Cgel process using a mixture of titanium isopropoxide and silver nitrate as precursor solution, with Ag:Ti molar ratio of 1:6. After drying, the titanium oxide xerogels were used as template in the preparation of nano and microcrystals of metallic silver. The porous network and the structure of the titania matrix influenced the type and distribution of silver crystal produced on the composite surface. Silver nanoparticles segregated to the surface of titania xerogel during the heating step, giving rise to nanocrystals that coalesced forming microcrystals with different shapes and faceting. The microcrystals grew on the composite surface, reaching sizes between 5 and 20 microns and self-organized of different ways. The xerogel heated at 600 °C formed by anatase, rutile and silver nanoparticles exhibited considerable photocatalytic activity to degrade methylene blue. 相似文献
16.
Jun Yang Liwei Zhu Jun Zhang Yuanming Zhang Yu Tang 《Reaction Kinetics and Catalysis Letters》2007,91(1):21-28
Nanosized TiO2/SiO2 catalysts prepared by hydrolysis of titanium n-butoxide in microemulsion showed enhanced photocatalytic activity. In the presence of catalyst ME-2 and after 90 min irradiation
by UV light, methylene blue was completely converted evidenced by the absence of its absorption band in the UV-Vis spectra.
This catalyst demonstrated much better degradation ability than P-25 and naked TiO2. 相似文献
17.
M. P. Fedotova G. A. Voronova E. Yu. Emel’yanova N. I. Radishevskaya O. V. Vodyankina 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2009,83(8):1371-1375
A new method for synthesizing amorphous ultradisperse titanium oxide particles immobilized on the surface of SiO2 aerogel was suggested. TiO2/SiO2 systems containing 3–15 wt % TiO2 were prepared. The chemical composition, structure, and morphology of the surface of the synthesized catalysts were studied
by transmission electron microscopy, X-ray diffraction, and IR spectroscopy. The Brunauer-Emmett-Teller method was used to
estimate the specific surface area of the samples. The photocatalytic activity of the systems was studied in the model reaction
of the decomposition of methylene blue dye. The systems synthesized were found to be more active than TiO2 Degussa P25. 相似文献
18.
A. A. Dar K. Umar N. A. Mir M. M. Haque M. Muneer C. Boxall 《Research on Chemical Intermediates》2011,37(6):567-578
The photocatalytic degradation of a herbicide derivative, Dinoterb (1), has been investigated in aqueous micellar solution in the presence of titanium dioxide (TiO2) and air as a function of irradiation time under a variety of conditions using UV and HPLC analysis techniques. The degradation kinetics was studied under different conditions such as different types of TiO2, catalyst concentration, substrate concentration and reaction pH in the presence of air. The photocatalyst Degussa P25 was found to be more efficient catalyst as compared to other photocatalysts tested. The model compound was found to degrade more efficiently under neutral pH as compared to acidic and alkaline pH. GC/MS analysis of the irradiated samples indicate the formation of 2-isopropyl-4,6-dinitro-phenol as by-product which has been characterized on the basis of molecular ion and mass fragmentation pattern. A probable pathway for its formation has been proposed. 相似文献
19.
Dongfang Zhang 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2012,86(3):498-503
The photocatalytic activity of gold deposited on Degussa P25 titanium dioxide (Au-DP25) in the photodegradation of methyl
orange (MO) was investigated. The as-prepared materials were characterized by X-ray diffraction (XRD), transmission electron
microscopy (TEM) and UV-vis diffuse reflectance spectroscopy (DRS) techniques. The obtained results show that the gold (Au0) deposited TiO2 exhibited visible light plasmon absorption band. The degradation experiment j reveals that the catalytic activity of Au-DP25
in the degradation of MO is higher than that of commercially available Degussa P25 TiO2 (DP25) samples. In addition, the photocatalytic ability of composite Au-DP25 was hardly decreased after a five-cycle for
MO degradation. The kinetics of the MO degradation fitted well the Langmuir-Hinshelwood model. 相似文献
20.
Nanostructured TiO2 crystals were synthesized by gel to crystalline conversion. The crystals obtained were anatase form of titania averaging in 30 nm particles with an intrinsic band gap of 3.1 eV. The photocatalytic behavior was evaluated for the bactericidal effect in water, contaminated with the indicator organism Escherichia coli. The 100% photoinactivation of E. coli was achieved within 60 min with suspended nano-TiO2. The catalytic activity of synthesized nanosample was observed to be 2.6 times more than that of commercial TiO2 sample referred to as Degussa P-25. The photoinactivation of E. coli was tested with irradiation source of different wavelengths to substantiate the influence of particle size and nano crystallinity on electronic band structure. The photoactivity of nano titania enhanced to 1.625 times when the source of irradiation shifted from 360 to 400 nm while Degussa P-25 showed no change. 相似文献