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TiO2 Hybridized with Natural Ilmenite Nanocomposites for Enhanced Visible Light Photocatalytic Activity
(2019-09-16)
Chongsri, K.
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Phoohinkong, W.
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Pavasupree, S.
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Mekprasart, W.
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Boonyarattanakalin, K.
The activated ilmenite nanocomposite of TiO<inf>2</inf> hybridized were prepared by natural ilmenite and commercial TiO<inf>2</inf> anatase assembled using sugar as cross-link agents and carbon source. The heterostructure interface of anatase-ilmenite junction, crystallinity and chemical state were characterized by X-ray diffraction (XRD), UV-Vis diffuse reflectance spectroscopy and X-ray photoelectron spectroscopy (XPS). Composite morphologies and structures were investigated by scanning electron microscope (SEM). Synergistic of low energy gap in range of visible light and interfacial charge separate from TiO2 to ilmenite junction was evaluated in photocatalytic degradation of organic dye. The result from visible light catalytic dye degradation suggests that narrow bandgap energy is associated to ilmenite phase and sensitization by carbon with low recombination rate of generated electron-hole pair transfer. This mechanism occurred by multiphase junction could enhance visible light photocatalytic activity.
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Effect of Milling Speed and Time on Ultrafine ZnO Powder by High Energy Ball Milling Technique
(2019-09-16)
Prommalikit, C.
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Mekprasart, W.
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Pecharapa, W.
The particle size of commercial zinc oxide (ZnO) powder has been found in micron scale. For the improvement of ZnO properties, size reduction in nanoscale is required. In this work, the particle size of ultrafine ZnO powder was reduced by high energy ball milling technique. commercial grade ZnO powder with average size 0.8 μm was used as starting material. Milling speed and time of high energy milling process are considered as crucial parameters affecting size reduction of ZnO particles. Crystalline structure, surface morphological and particle size of the milled samples were investigated by X-ray diffractometer (XRD), scanning electron microscopy (SEM) and particle analyzer, respectively. The results suggested that ZnO patterns after milling process with various milling speed and time were identically in hexagonal crystalline phase affirmed by XRD result. SEM images indicate that size of ZnO products distinctly decrease according to the increase of milling time and speed. ZnO particle size after milling process was found in ultrafine power in range of 200-400 nm. These results suggest that particle size of the commercial ZnO powders can be effectively minimized to few hundred nanometer range depending on force attraction and suitable rotation during milling process with specific speed and time. Moreover, the significant milling parameters will be studied to find the optimum condition for the production of ZnO particles in nanoscale.
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Ga-doped ZnO nanoparticles synthesized by sonochemical-assisted process
(2018-01-01)
Santibenchakul, S.
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Sirijaturaporn, P.
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Mekprasart, W.
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Pechrapa, W.
In this work, the experimental work has been conducted on the synthesis of Gallium (Ga)- doped zinc oxide (ZnO) nanoparticles with different doping concentration (0-5% at.) via sonochemical process. The precursors of Ga-doped ZnO nanoparticle were sourced by zinc acetate dehydrate and gallium (III) nitrate hydrate, respectively. Ammonia (NH<inf>3</inf>) was chosen as a precipitating agent in sonochemical process. The sonochemical time was operated for 10 min by a direct-immersion ultrasonic horn using Sonic model VCX 750 (750W, 20 KHz). Structural properties and morphologies were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results indicated that Ga doped ZnO powder after the synthesis were obtained in ultrafine structure that different form with pure ZnO. XRD analysis revealed that the pattern of Ga doped ZnO powder showed good crystallinity with the wurtzite structure due to the preferred orientation direction and crystallization. Ga doping concentration plays a key role in significant change of ZnO structures.
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Ag nanoparticle-doped SiO2/TiO2 hybrid optical sensitive thin film for optical element applications
(2016-11-25)
Junlabhut, P.
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Boonruang, S.
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Mekprasart, W.
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Pecharapa, W.
The optical sensitive thin film by Ag nanoparticles doped SiO<inf>2</inf>/TiO<inf>2</inf> hybrid was successfully deposited via sol-gel spin coating technique. Photo-induced polymerization of photosensitive Ag-doped SiO<inf>2</inf>/TiO<inf>2</inf> hybrid initiated by irgacure 784 photoinitiator was illustrated under visible region by He[sbnd]Cd laser 442 nm. Silane coupling was used as a starting precursor to providing cross-linking in the photochemical reaction process. The structural properties and existing elements of photosensitive films were characterized by XRD, TEM and EDX. Meanwhile, surface morphology of the photosensitive hybrid films was monitored by FE-SEM. Moreover, the optical absorption of the photosensitive hybrid films was analyzed by UV–Vis spectroscopy. These results indicated that the compatibility of photosensitive hybrid material was formed. The SiO<inf>2</inf>/TiO<inf>2</inf> photosensitive hybrid films with uniformly distributed Ag ions and intensive coloration characteristic for surface plasmon resonance phenomena relating to the enhancement of optical absorption in visible region. As-prepared photosensitive hybrid films with enhanced optical properties can be proposed for optical elements.
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Physical, electrical and optical properties of F/Sb Codoped SnO2 synthesized via sonochemical process
(2016-01-02)
Noonuruk, R.
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Mekprasart, W.
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Vittayakorn, N.
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Sritharathikhun, J.
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Pecharapa, W.
F/Sb-codoped SnO<inf>2</inf> nanoparticles were synthesized via sonochemical process using stannic chloride pentahydrate (SnCl<inf>4</inf>·5H<inf>2</inf>O) as host precursor while antimony(III) chloride (SbCl<inf>3</inf>) and ammonium fluoride (NH<inf>4</inf>F) were chosen as Sb and F dopant precursors, respectively. Their physical properties and morphologies were investigated using X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy and transmission electron microscope while their electrical and optical properties were investigated by Hall measurement and diffuse reflectance spectroscopy. As-synthesized powder of polycrystalline phase SnO<inf>2</inf> nanoparticles can be obtained by one-step sonochemical process and its crystallinity can be improved by calcination process. The formation of crystalline phase of SnO<inf>2</inf> is assisted by cavitation effect provided by intense ultrasonic radiation via rapid collision. The characterization results disclose that Sb dopant has strong influence on both physical and electrical properties while F dopant provide considerable effect on electrical property of the samples. It is noticed that the codoping of both elements with certain contents can significantly heighten its electrical conductivity.
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Characterization and phase formation study of ZnO:Sn nanoparticles synthesized by co-precipitation method
(2014-09-02)
Noonuruk, R.
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Mekprasart, W.
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Supparattanasamai, T.
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Kanyapan, T.
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Techitdheera, W.
ZnO:Sn were successfully prepared by co-precipitation method using zinc acetate dihydrate and tin (IV) chloride hexahydrate as host and dopant precursor sources, respectively. The ratio of Sn doping content in ZnO was designated at 0, 5, 10 and 20 wt.% and calcined at different temperatures at 200, 300, 400 and 500°C. Physical properties and composition of Sn-doped ZnO powder were monitored by X-ray diffraction and scanning electron microscope. Chemical bonding of as-synthesized powders were investigated by Fourier transform spectroscopy. The preliminary results indicate that the crystallinity and morphologies of ZnO nanoparticle are significantly affected by Sn dopant. The phase formation of Zn-Sn-O was observed depending on the Sn-doping composition and calcination temperature. Meanwhile, FTIR results indicate the existence of mixture phases of ZnO:Sn in the compounds which were obtained via precipitation process. © 2014 Taylor & Francis Group, LLC.
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Effect of tin loading on physical properties and phase transformation of as-synthesized Zn-Sn-O compound powder synthesized by co-precipitation method
(2014-01-01)
Kahattha, C.
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Chongsri, K.
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Noonuruk, R.
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Mekprasart, W.
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Pecharapa, W.
Zinc-Tin oxide compounds (Zn-Sn-O) were successfully prepared via a facile co-precipitation process using zinc dichloride dihydrate as the zinc source and tin tetrachloride pentahydrate as an additive source. The as-prepared product of Zn-Sn-O powders with various Sn additive contents (0-60 %wt) were obtained without calcinations process. The effect of Sn additive on structural and microstructure properties of the samples were characterized by X-ray diffraction(XRD), scanning electron microscope(SEM). The results indicate that the crystallinity and morphologies of ZnO nanoparticles are significantly influenced by Sn additive. The phase formations of Zn-Sn-O including ZnO, ZnSn(OH)<inf>6</inf> were observed depending on the Sn-additive composition.
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Investigation of milling time on particle size reduction and photoinduced activity performance of commercial TiO2 for optical energy harvesting applications
(2013-09-18)
Rattanarak, J.
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Mekprasart, W.
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Pecharapa, W.
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Techitdheera, W.
In this research, effect of milling time on crucial physical structures of commercial TiO2 powders in form of anatase phase is investigated. The as-received commercial TiO2 powders were ball-milled with ethanol solvent at room temperature at various operating time ranging from 6-24 hrs. Particle sizes and surface areas of milled powders were characterized by particle analyzer and Brunauer Emmet Teller (BET) method.TiO2 surface morphologies of the powders milled at various times were monitored by scanning electron microscope. The photocatalytic activities of the milled powders were conducted by mean of the photo-induced degradation against RhB aqueous solution. The results reveal that particle size of the commercial TiO2 powders can be effectively minimized to few hundred nanometer range depending on milling time. The drastic reduction in their size results to the increasing active surface area of the particles and the enhanced photo-induced activity that was supported by the photodegradation performance. This enhancement can suggest them to the suitability in optical energy harvesting optoelectronic applications including photovoltaic devices, optical based sensors and related environmental-friendly usage. © 2013 SPIE.
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Ball-milled CuPc/TiO 2 hybrid nanocomposite and its photocatalytic degradation of aqueous Rhodamine B
(2012-11-01)
Mekprasart, W.
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Vittayakorn, N.
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Pecharapa, W.
Hybrid composites of titanium dioxide and copper phthalocyanine were synthesized by ball-milling assisted process in combination with mechanically stirring method. Structural properties of as-synthesized composites were characterized by X-ray diffraction (XRD), X-ray absorption fine structure (XANES) and scanning electron microscope (SEM). The optical absorbance of as-prepared composites and their photocatalytic activities were investigated by UV-vis spectroscopy. XRD and XANES results confirm that CuPc/TiO <inf>2</inf> nanocomposite is still in the same structure of TiO <inf>2</inf> and CuPc. SEM result reveals that the decreasing particle size of ball-milled CuPc has good dispersion on the surface of TiO <inf>2</inf>. Absorptivity in UV region of the composites is heightened and shifted to visible light due to strong absorbance in blue-green spectrum of CuPc. The photocatalytic degradation of Rhodamine B dye solution using as-synthesized composites was investigated under ultraviolet irradiation. The optimized condition for RhB photodegradation was obtained for 1 wt.% CuPc/TiO <inf>2</inf> nanocomposite with efficiency of 87.5% and reaction rate of 0.15 min <sup>-1</sup>. The significant improvement in photocatalytic activity of the hybrid composite may be associated to the enhancement of optical absorption and the inhibition of electron-hole recombination caused by the presence of CuPc in TiO <inf>2</inf> matrix. © 2012 Elsevier Ltd. All rights reserved.
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Effect of Tio 2 compact layer on optical absorpt+ion and fluorescence performance of R6G/PMMA composite light-guided films
(2012-10-29)
Mukdachacharoenchai, P.
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Mekprasart, W.
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Sritharathikhun, J.
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Pecharapa, W.
Rhodamine 6G (R6G) and Poly(methyl methacrylate) (PMMA) light-guided films accompanied with titanium dioxide thin layer were prepared by spin-coating process onto on glass substrate. Dichloromethane was used as disperser for blending R6G and PMMA. The TiO <inf>2</inf> layer thickness was varied by controlling spinning speed. The effects of TiO <inf>2</inf> layer with different thickness on optical absorption and florescence performance of the films were investigated and the results exhibited strong absorption of TiO <inf>2</inf> in UV region and the enhancement in florescence efficiency with increasing TiO <inf>2</inf> film thickness. © (2012) Trans Tech Publications, Switzerland.

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