Effect of the Titanium Isopropoxide:Acetylacetone Molar Ratio on the Photocatalytic Activity of TiO2 Thin Films (original) (raw)
Related papers
Catalysts
TiO2 thin films, modified by acetylacetone (AcacH) in solution, were deposited on glass substrate by ultrasonic spray pyrolysis and tested for photocatalytic activity in a multi-section continuous flow reactor by degradation of acetone and acetaldehyde under ultraviolet and visible light. The increase in molar ratio of AcacH in respect of titanium (IV) isopropoxide (TTIP) from 1:5 to 1:8 modified the electronic structure of the films, favoring enhanced photocatalytic activity. The photocatalytic activity was enhanced approximately twofold on the film with molar ratio 1:8 under both irradiations; the film completely oxidized 10 ppm of acetone and acetaldehyde. The photocatalytic efficacy of TiO2 films in oxidation of air pollutants was three times higher compared to the industrial glass Pilkington ActivTM. Moreover, all the synthesized films indicate antibacterial efficiency against E. coli of over 99% under ultraviolet. TiO2 film, with TTIP:AcacH molar ratio 1:8 having great possibi...
Journal of Physics: Conference Series, 2012
Thin nano-sized TiO 2 films were deposited on aluminum foil substrates by the spray pyrolysis method, using Ti(i-OPr) 4 (TIP) and TiCl 4 (TC) as precursors. The films were characterized by means of X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS). According to the XRD patterns the as-deposited films appear to be amorphous. The thermal treatment at 400 o C leads to the formation of anatase nano-crystallites. The XPS analyses showed that the Ti2p broad photoelectron peak of as-deposited TC films indicated a mixture of Ti 3+ and Ti 4+ oxidation states. After treatment at 400 o C the Ti2p peak displays only Ti 4+ oxidation state for both TIP and TC films. The number of hydroxyl groups on the surface is decreased after the thermal treatment. The photocatalytic activity of the films was studied towards degradation of azo dye Reactive Black 5 (RB5) as model wastewater pollutant under visible light illumination. It was found out that the films obtained from TC were more active than those obtained from TIP films. The thermally treated samples are better photocatalysts than those non-treated, because they posses anatase crystalline phase and stoichiometric TiO 2 . The TOC measurements showed minimal concentration of total organic carbon in the dye solution after 180 min of visible light irradiation.
Titanium dioxide thin films: the effect of the preparation method in their photocatalytic properties
Journal of Molecular Catalysis A-chemical, 2005
Titanium dioxide thin films were deposited by DC reactive magnetron sputtering and spray pyrolysis methods on glass and glass coated with fluorine tin oxide (FTO). The films were characterized by X-ray diffraction, scanning and transmission electron microscopy, atomic force microscopy and UV–vis spectroscopy. The influence of a reactive atmosphere: a 50/50 Ar–O2 mixture on TiO2 thin films deposited by sputtering has been studied following the evolution of surface and structural properties and has been correlated, when possible, with photocatalytic properties under UV illumination. Also transparent TiO2 thin films have been prepared by spray pyrolysis using a low concentration of titanium precursor and different substrates temperatures. At higher substrate temperatures the films were polycrystalline in anatase phase; at lower substrate temperatures the films presented amorphous configuration. The best photocatalytic activity was found for films deposited by spray pyrolysis at Ts = 450 °C and for those deposited by magnetron sputtering those deposited at 16 mTorr gave the higher photodegradation rates.The behavior of photodegradation of methylene blue on TiO2 thin films when illuminated with UV radiation can be observed in the graphic. For films deposited by magnetron sputtering the variation is followed for pressure increasing in the sputtering chamber. For films deposited by spray pyrolysis the influence of substrate temperature on the photocatalytic activity of TiO2 thin films can be followed from the graphic. The best results are obtained in films deposited at 16 mTorr and with Ts = 400 °C, respectively.
Preparation and characterization of photocatalytic TiO2 films
2005
In the present research, Titanium dioxide (TiO 2) has been synthesized by sol-gel spin coating technique on Corning glass substrates. The sol-gel process can be easily controlled and reproduced. Titanium tetraisopropoxide, isopropanol and deionized water were used as starting materials. This precursor solution was deposited onto Corning glass substrates by spin coating and annealed at 400 and 500 C. Their photocatalytic activity was investigated by examining the degradation (oxidation) of Diuron ® , under UV and solar radiation. In order to compare the photocatalytic activity of TiO 2 and to establish possible correlations between the physicochemical properties of the prepared coatings, these were characterized by UV-Vis spectroscopy and X-ray diffraction (XRD) techniques. X-ray diffraction patterns confirmed TiO 2 anatase phase formation.
Thin Solid Films, 2008
Thin TiO 2 films were prepared with the dip-coating technique by using sols deriving from titanium tetraisopropoxide. TiO 2 films were formed on glass substrates previously covered by a SiO 2 layer obtained from a tetraethylortosilicate sol. The films, after a thermal treatment at 673 K, mainly consisted of TiO 2 anatase. The samples were characterised by X-ray diffraction, UV-Vis spectroscopy, scanning electron microscopy and atomic force microscopy. The photoactivity of the various films was tested by using as probe reaction the photo-oxidation of 2-propanol in gassolid regime. The photoreactivity results indicated that the TiO 2 films were efficient for degrading 2-propanol under UV illumination, propanone being the only compound detected as intermediate product. Films prepared by using Degussa P25 appeared to be more photoactive, but the coating was easily detached by wiping.
Thin Solid Films, 2006
Titanium dioxide (TiO 2 ) thin films were prepared using Titanium [bis(dipiraloymethanate) diisopropoxide] (Ti(dpm) 2 (OPr i ) 2 ) and Titanium isopropoxide (Ti(OPr i ) 4 ) complex compound precursors by Chemical Vapour Deposition (CVD) and photo-assisted CVD. Structural information on TiO 2 thin films was obtained in synchrotron radiation experiments: high-resolution Grazing Incidence X-ray Diffraction (GIXRD) and h -2h XRD experiments were performed on the high-resolution powder diffractometer at the Hamburg Synchrotron Laboratory. Chemical composition of thin films was studied by high-resolution Laser Ionization Mass Spectrometry technique, surface composition by X-ray Photoelectron Spectroscopy, and surface morphology by Atomic Force Microscopy. Photocatalytic activity of TiO 2 thin films was studied using a photocatalytic reactor. The fungicide Fenarimol was chosen as chemical indicator and its degradation kinetics was followed by High Performance Liquid Chromatography. D
A short review is presented on the authors, investigations on the influence of the crystal structure and the morphology on the sorption ability and photocatalytic activity under UV-irradiation of thin TiO2 films produced by spray-deposition process. Commercially available TiO2 (Degussa P25 and Tronox), titania modified by mechanoactivation as well as TiO2 doped with gold and, mainly, with lanthanides (produced by sol–gel process or from mixed-metal citric complexes) are used as starting materials. Organic dyes, phenol, oxalic acid and pesticides were used as model pollutant. Conclusions are drawn for the effect on the photocatalytic activity of films morphology, anatase content, substrate chemical nature, deposition conditions (temperatures of deposition and post-deposition annealing, suspension medium nature, additives presented and its ultrasonic treatment), type of titania used and its modifi- cation by mechanochemical treatment and by doping with gold or lanthanides (lanthanum, gadolinium and neodymium).
Materials Research Bulletin, 2004
TiO 2 thin-film photocatalysts coated onto glass were prepared either by plasma enhanced chemical vapour deposition (PECVD) deposition or by a dip-coating process using sol-gel solutions. The influence of the addition of a polymer and of a highly viscous solvent on physical properties (thickness, crystallite size and porosity) of TiO 2 thin films and on their photocatalytic efficiency was evaluated.
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...
Photocatalytic activity of sprayed TiO2 films deposited on different substrates
Thin photocatalytically active TiO2 fi lms are successfully deposited on glass and alumina foil substrates by spray pyrolysis method. The films are characterized by means of X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), X-ray Photoelectron Spectroscopy (XPS), Thermal Analyses (TG-DTA). The XRD spectra of TiO2 thin fi lms, treated at 400◦C showed formation of nanosize anatase phase. The fi lms were studied with respect to the photo-initiated bleaching of azo dye Reactive Black 5 (RB5) under UV illumination. The influence of the substrate, treatment conditions and pH of the dye solution on the decoloration were investigated. It was found that the films, deposited on alumina foil revealed a better photocatalytic activity than those on glass substrates, due to the furrowed surface of the alumina substrate. The highest rate of decoloration was obtained at low pH value of the dye solution for fi lms treated at 400◦C.