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  1. 1. Weerachai Sangchay / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 Vol. 2, Issue 6, November- December 2012, pp.1593-1597 Effect Of Ag Doped On Phase Transformation, Morphology And Photocatalytic Activity Of TiO2 Powders Weerachai Sangchay Faculty of Industrials Technology, Songkhla Rajabhat University, Songkhla, Thailand, 90000.ABSTRACT The purpose of this research was to dispersion (the sol). Further reaction causes bonds tostudy the effect of doped Ag on phase form among the sol particles, resulting in an infinitetransformation, morphology and photocatalytic network of particles (the gel). Then the gel isactivity of TiO2 powders. The composites typically heated to yield the desired material. Thispowders were prepared by sol-gel method via method for synthesis of inorganic materials has acalcinations at a temperature 400 °C for 2 h with number of advantages over more conventionala heating rate of 10 °C/min. The microstructure synthetic procedures. For example, high-purityand crystallite size of TiO2 and TiO2-Ag powders materials can be synthesized at low temperatureswere characterized by XRD, EDX and SEM. [10-11]. In addition, homogeneous multi componentFinally, photocatalytic activity was evaluated by systems can be obtained by mixing precursorUV-vis spectrophotometer. The results show all solutions, which allows for easy chemical doping ofsamples have only anatase phase and the the materials prepared.agglomeration. It was apparent that Ag added in In the present experiments, we report on the effectTiO2 has significantly effect on photocatalytic of Ag doped TiO2 powders were prepared by using areaction under UV irradiation. It can be noted sol-gel method. The samples have beenthat TiO2-5Ag powders was found to give the characterized using XRD EDX, SEM and UV-vishighest photocatalytic, 53% under UV. spectrophotometer. Phase transformation, crystallite size, morphology and photocatalytic activity ofKeywords - Ag doping, TiO2, Phase transformation, powders were investigated.Morphology, Photo catalytic activity. II. MATERIALS AND METHODI. INTRODUCTION A. Raw materials Titanium dioxide (TiO2) is almost the only Titanium (IV) isoproxide (TTIP, 99.9%,suitable for industrial use at present and also Fluka Sigma-Aldrich), and Silver nitrate (AgNO3,probable in the future. This is because TiO2 has the 99.9%, Fluka Sigma-Aldrich),) were used as rawmost photocatalytic activity, chemical stability, non- materials. Ethanol (C2H5OH, 99.9%, Mercktoxic nature, large band gap and low cost [1-3]. TiO2 Germany) was used as a solvent.has three crystalline phases: anatase, brookite andrutile, being anatase the material that shows the B. Preparations of TiO2 and TiO2-Ag powdershighest photocatalytic activity, which is attributable TiO2 and TiO2-Ag powders were preparedto the low recombination rate of its photo-generated via a conventional sol-gel method (Fig. 1). Firstly,electrons and holes. However, for practical AgNO3 to maintain the mole ratio of Ag to TiO2 atapplications, the photocatalytic activity of TiO2 0, 1, 2, 3, 4 and 5 mol% of TiO2 and TTIP with fixedneeds further improvement. For this reason, much at 10 ml were mixed into 150 ml C2H5OH and theattention has been paid to doping the material with mixture was vigorously stirred at room temperaturetransition and noble metals, such as Pd, Pt, Rh, Au for 15 min. The pH of mixed solution was adjustedand Ag. Ag is the most promising one for the to about 3 by 3 ml of 2 M nitric acid (HNO 3).improvement of the photocatalytic activity of TiO2. Finally, the solution was stirred for 30 min, dried atAg increases the electron hole separation and can 100 °C for 24 h and calcinations at a temperaturealso facilitate the electron excitation by creating a 400 °C for 2 h with a heating rate of 10 °C/min.local electric field [4]. Many approaches have been used to obtainTiO2 powders, including inert gas condensation [5],hydrothermal processing [6], solution combustion[7], and sol–gel method [8-9]. The sol–gel method asrecently developed as a general and powerfulapproach for preparing inorganic materials such asceramics and glasses. In this method, a solubleprecursor molecule is hydrolyzed to form a colloidal 1593 | P a g e
  2. 2. Weerachai Sangchay / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 Vol. 2, Issue 6, November- December 2012, pp.1593-1597 are 20.7, 20.7, 23.6, 23.6, 23.6 and 23.6 nm for 0, 1, 2, 3, 4 and 5 mol% of Ag doping, respectively. It was found that the crystallite size increases with Ag doping due to the contribution of Ag effect. The presence of Ag and Ti in TiO2 and TiO2-Ag powders was determined by EDX spectra shown in Fig. 3. The result indicates the presence of Ti and Ag in the powders. The surface morphology was observed with SEM. Fig. 4 shows surface morphologies of TiO2 and TiO2-Ag powders. It was seen that for both TiO2 and TiO2-Ag powders, the agglomeration was observed and the particle size decreases with increases Ag doping.Fig. 1. The preparation produces of TiO2 and TiO2- (f) Ag powders by sol-gel method (e) C. Characterizations of TiO2 and TiO2-Ag powders (d The phase composition was characterized )using an x-ray diffractometer (XRD) (Phillips X’pert (c)MPD, Cu-K). The crystallite size was calculated bythe Scherer equation, Eq.1, [12]. The morphology of (bthe synthesized powders was characterized by )Scanning Electron Microscope (SEM) (Quanta 400). (a) D = 0.9 λ/β cosθB (1) Where D is the average crystallite size, λ is Fig. 2. XRD patterns of (a) TiO2, (b) TiO2-1Ag, (c)the wavelength of the Cu Kα line (0.15406), θ is the TiO2-2Ag, (d) TiO2-3Ag, (e) TiO2-4Ag and (f) TiO2-Bragg angle and β is the full-width at half-maximum 5Ag powders(FWHM) in radians. (a) D. Photocatalytic activity test The photocatalytic activity was evaluatedby the degradation of MB under UV and visible lightirradiations using eleven 50W of black andfluorescent light lamps, respectively. A 10 ml of MBwith a concentration of 1 × 10-5 M was mixed with0.0375 g of TiO2 and TiO2-Ag powders and kept in achamber under UV and visible light irradiation for 0,1, 2, 3, 4, 5 and 6 h. After photo-treatment for acertain time, the concentration of treated solutionwas measured by UV-vis. The ratio of remained (bconcentration to initial concentration of MB )calculated by C/C0 was plotted against irradiationtime in order to observe the photocatalyticdegradation kinetics.III. RESULT AND DISCUSSION A. Characterizations The result of XRD patterns of TiO2 andTiO2-Ag powders are shows in Fig. 2. It was foundthat TiO2 and TiO2-Ag powders reveal that only theanatase phase. Ag-compound phase can’t be verifiedin these XRD peaks due to a very small amount ofAg doping. The crystallite sizes of anatase phases 1594 | P a g e
  3. 3. Weerachai Sangchay / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 Vol. 2, Issue 6, November- December 2012, pp.1593-1597 (c) (b) (d) (c) (e) (f) (d) Fig. 3. EDX spectra of (a) TiO2, (b) TiO2-1Ag, (c)TiO2-2Ag, (d) TiO2-3Ag, (e) TiO2-4Ag and (f) TiO2- 5Ag powders (a) 1595 | P a g e
  4. 4. Weerachai Sangchay / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 Vol. 2, Issue 6, November- December 2012, pp.1593-1597 (e) Fig. 5. Photocatalytic activity of TiO2 and TiO2-Ag powders (f) (a) (b) Fig. 6. Photo of MB concentration (a) before UV Fig. 4. SEM surface morphologies images of (a) irradiation and (b) after UV irradiation for 6 h of TiO2, (b) TiO2-1Ag, (c) TiO2-2Ag, (d) TiO2-3Ag, TiO2-5Ag powders (e) TiO2-4Ag and (f) TiO2-5Ag powders B. Photocatalytic activity IV. CONCLUSION 1. TiO2 and TiO2-Ag powders reveal that The photocatalytic degradation of MB by only the anatase phase. All samples of TiO2 andusing TiO2 and TiO2-Ag powders under UV TiO2-Ag powders have the agglomeration wasirradiation is show in Fig. 5. It was apparent that observed and the particle size decreases withAg added in TiO2 has significantly effect on increases Ag doping.photocatalytic reaction under UV irradiation, with 2. The photocatalytic activity of TiO2-Agthe photocatalytic activity increases with increases powders were increased when Ag doping comparedAg doping. The MB degradation percentage of with TiO2 un-doped Ag.TiO2 and TiO2-Ag powders under UV irradiation 3. It can be note that TiO2 doped with 5% Agfor 6 h are 44, 47, 48, 49, 50 and 53% for 0, 1, 2, 3, powders exhibited higher photocatalytic under UV4 and 5 mol% of Ag doping, respectively. It was irradiation is 53%.found that TiO2-5Ag powders show the bestphotocatalytic activity. The photos of MBconcentration of before UV irradiation and after ACKNOWLEDGMENTUV irradiation for 6 h of TiO2-5%Ag powders are The authors would like to acknowledgeillustrated in Fig. 6. Institute of Research & development, Songkhla Rajabhat University, Thailand, Faculty of Industrials Technology, Songkhla Rajabhat University, Thailand and Department of Mining and Materials Engineering, Faculty of Engineering, Prince of Songkla University, Thailand for financial support of this research. 1596 | P a g e
  5. 5. Weerachai Sangchay / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 Vol. 2, Issue 6, November- December 2012, pp.1593-1597 doped TiO2 Nanoparticles Synthesized atREFERENCES Low Temperature,” J Advanced Materials[1] A. Fujishima, T.N. Rao, and D.A. Tryk, Research, vol 214, pp. 197-201, 2011. “Titanium dioxide photocatalysis,” J Photochem and Photobiol, vol. C1, pp. 1-21, 2000.[2] G. Michael, “Dye-sensitized solar cells,” Journal of Photochemistry and Photobiology C: Photochemistry Reviews, vol. 4, pp. 145- 153, 2003.[3] G. Morgan, A. Emmanuelle, C. Nicolas, M. Isabelle, G. Thierry, and P.B. jean, “Sol-gel nanoparticulate mesoporous films with enhanced self-cleaning properties,” Journal of Photochemistry and Photobiology A: Chemistry, vol. 216, pp. 142-148, 2010.[4] E.Z. Carolina, V.M. Paula, F. Marisa, and C.F. Pablo, “Effect of silver adding on the structure and methylene blue photodagradation capacity of titania synthesized via a surfactant template route,” The Journal of the Argentine Chemical Society, vol. 97, pp. 88-1-5, 2009.[5] Z. Marcial, L. Tessy, G. Ricardo, A. Maximilinno, and M. Ruth, “Acetone gas phase condensation on akaline metals dope TiO2 sol-gel catalysts,” J Applied Surface Sci, vol. 252, pp. 828-832, 2005.[6] S. Fanda, A. Meltem, S. Sadiye, E. Sema, E. Murat, and S. Hikmet, “Hydrothermal Syhthesis, Characterization and Photocatalytic Activity of nanozied TiO2 Based Catalysts for Rhodamine B Degradation,” J Chem, vol. 31, pp. 211-221, 2007.[7] T. Mimani, and K.C. Patil, “Solution combustion synthesis of nanoscale oxides and their composites,” Mater Phys Mech, vol. 4, pp. 134-137, 2001.[8] H. Schmidt, G. Jonschker, S. Goedicke, and M. Mening, “The Sol-Gel Process as a Basic Technology for Nanoparticle-Dispersed Inorganic-Organic Composites,” J Sol-Gel Sci Tech, vol. 19, pp. 39-51, 2000.[9] Y. Xianfeng, C. Feng, and Z. Jinlong, “Effect of Calcination on the physical and photocatalytic Properties of TiO2 Powders Prepared by Sol-Gel Template Method,” J Sol-Gel Sci Tech, vol. 34, pp. 181-187, 2005.[10] Z. Jerzy, “Past and Present of Sol-Gel Science Technology,” J Sol-Gel Sci Tech, vol. 8, pp. 17-22, 1997.[11] W. Tianfa, G. Jianping, S. Juyun, and Z. Zhongshen, “Preparation and characterization of TiO2 thin films by the sol-gel process,” J Materials Sci, vol. 36, pp. 5923-5926, 2001.[12] S. Boonyod, W. Sutthisripok, and L. Sikong, “Antibacterial Activity of TiO2 and Fe3+ 1597 | P a g e