Mekprasart, Wanichaya

Preferred name

Alternative Name

MEKPRASART, Wanichaya

Mekprasart, W.

Main Affiliation

Integrated Innovative Technology

wanichaya.me@kmitl.ac.th

Now showing 1 - 10 of 53

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Effect of nitrogen doping on optical and photocatalytic properties of TiO2 thin film prepared by spin coating process
(2013-01-01)
Mekprasart, Wanichaya
;
Khumtong, Thanakorn
;
Rattanarak, Jiravat
;
Techitdheera, Wicharn
;
Pecharapa, Wisanu
Nitrogen-doped TiO<inf>2</inf> thin films were prepared by spin coating on glass substrate. Different amount of nitrogen doped in TiO<inf>2</inf> matrix was 0, 3 and 10%. As-obtained films were annealed at 400°C for 2 h. The optical and photocatalytic properties of N-doped TiO<inf>2</inf> thin films were analyzed via UV-Vis spectrophotometry. The chemical properties were investigated by Fourier transform infrared spectrometer and Raman spectroscopy. When doping TiO<inf>2</inf> with nitrogen, its absorption spectrum is shifted to visible region resulting to the enhancement of photocatalyst properties in dye photodegradation. Raman and FTIR patterns show that N-doped TiO<inf>2</inf> pattern is still identical to undoped TiO<inf>2</inf> pattern resulting to unsubstitutation of nitrogen atom in Ti-O bonding. © 2013 The Authors.
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Characterization and x-ray absorption spectroscopy of ilmenite nanoparticles derived from natural ilmenite ore via acidassisted mechanical ball-milling process
(2017-09-01)
Phoohinkong, Weerachon
;
Pavasupree, Sorapong
;
Wannagon, Anucha
;
Sanguanpak, Samunya
;
Boonyarattanakalin, Kanokthip
In this work activated ilmenite nanoparticles were prepared by chemical-assisted in mechanical ball-milling process from ilmenite ore as starting raw material. The effect of milling process on their phase composition, particle size, surface morphology and local structure were investigated. Phase identification and crystalline structure of ilmenite mineral, milled samples and subsequent leached residues were characterized by x-ray diffraction (XRD). Meanwhile, the distorted octahedral structure and the oxidation state of relevant elements in ilmenite ore and activated ilmenite obtained by different process conditions were analyzed by x-ray absorption spectroscopy (XAS). Particle size and morphologies of the samples were monitored by field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM). Three dominant peaks of TiO2 rutile, FeTiO<inf>3</inf>, and Fe<inf>2</inf>TiO<inf>4</inf> are obviously adulterated in XRD patterns after mechanical milling with water and acid solution when comparing to precursor mineral. However, the contaminated phase of FeTiO3 and Fe<inf>2</inf>TiO<inf>4</inf> was readily decreased by acid-assisted mechanical ball-milling. The enhancement in leaching process of ilmenite residue after milling can be obtained with sulfuric acid. This result suggests that iron contaminated phase could be leached from the sample resulting to the decrease in Fe environment around Ti atom.
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Transparent light-guided plates based on TiO2/Rhodamine6G composite thin films
(2016-11-25)
Mekprasart, Wanichaya
;
Pecharapa, Wisanu
Transparent light-guided plates for solar cell application from nano-titanium dioxide (TiO<inf>2</inf>), rhodamine 6G (R6G) and poly methyl methacrylate (PMMA) composite films were prepared by spin coating technique on glass substrates. Effects of the annealing temperatures and times on the formation of the TiO<inf>2</inf> crystalline film that acted as an initial model for the light-scattered layer in solar concentrators were investigated. Physical and morphological properties of the TiO<inf>2</inf> film were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and atomic force microscope (AFM). After the annealing process, TiO<inf>2</inf> films obviously formed in the anatase phase with the enlarged crystallite size and the high rough surface by the increase of the annealing temperature and the treating time. Meanwhile, the optical properties of the TiO<inf>2</inf> thin films were analyzed via a UV–Vis spectrophotometer. The transparency of the film was significantly affected by the annealing temperature and the aging time. Moreover, the light scattering performance of the TiO<inf>2</inf> layer cooperated with Rhodamine6G in the PMMA matrix as the preliminary model of light-guide plate was investigated by fluorescence spectra. Strong light emission from the light-guide plate could be significantly enhanced by the existence of the TiO<inf>2</inf> crystalline layer acting as the scattering film. Optimized performance of the planar light-guide plate incorporated with Rhodamine6G dye and the light-scattered TiO<inf>2</inf> layer was obtained from the film annealed at 500 °C for 5 h.
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Indium Tin Oxide conductive nanoparticles synthesized by sonochemical method
(2016-10-12)
Noonuruk, Russameeruk
;
Kanoksinwuttipong, Jiruntanin
;
Mekprasart, Wanichaya
;
Techitdheera, Wicharn
;
Sritharathikhun, Jaran
This work reports the synthesis of Indium Tin Oxide (ITO) nanoparticles via sonochemical process at various calcination temperature using InCl<inf>3</inf> and SnCl<inf>4</inf>·5H<inf>2</inf>O as starting precursors for In and Sn sources, respectively. The crystal structure properties of the samples were investigated by X-ray diffraction. Meanwhile, the size, shape and microstructure of the particles were observed by field emission scanning electron microscope and chemical composition was investigated by energy dispersive X-ray Spectrophotometer. The corresponding optical band gap was determined by diffuse reflectance spectra. The XRD results showed that the as-prepared powders were initially formed in amorphous phase and the crystalline structure of powders were obtained after calcination beyond specific temperature. The correlated reactions and mechanisms during sonochemical process responsible for ITO formation are suggested. The comparison between ITO powders prepared by sonochemical process and co-precipitation process is additionally carried out and the results show significant differences in their morphology and crystallite sizes of the particles.
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Quasi-solid-state dye-sensitized solar cells based on TiO 2/NiO core-shell nanocomposites
(2011-07-01)
Mekprasart, Wanichaya
;
Noonuruk, Russameeruk
;
Jarernboon, Wirat
;
Pecharapa, Wisanu
The core-shell nanocomposites of titanium dioxide (TiO <inf>2</inf>) and nickel oxide (NiO) used as modified photoelectrode materials in a quasi-solid-state dye-sensitized solar cell (quasi-DSSC) were synthesized using TiO <inf>2</inf> P-25 and a nickel acetate precursor, via ball milling. The as-obtained intermediate products were annealed at 350, 450, and 550 °C. The structural properties of the NiO/TiO <inf>2</inf> nanocomposites were well characterized via X-ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy. The results imply that NiO-shell-coated TiO <inf>2</inf> nanoparticles can be obtained with the assistance of sufficient thermal energy in the system. The crystallite size of the composite increased as the annealing temperature increased. Among all the prepared conditions, the composite with 0.1 wt% NiO exhibited the best performance, with an optimized solar-energy conversion efficiency of 2.29% and with a short-circuit current density of 7.21 mA/cm <sup>2</sup>. The significant enhancement of the device's current density may be associated with the charge recombination suppression by the NiO shell, which acted as a potential barrier in the composite. The decrease in the recombination of the photo-injected electrons, and the increase in the number of electrons tunneling through the NiO layer at the interface, may have resulted from the presence of a NiO layer on the TiO <inf>2</inf> nanoparticles. Copyright © 2011 American Scientific Publishers All rights reserved.
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Physical, electrical and optical properties of F/Sb Codoped SnO2 synthesized via sonochemical process
(2016-01-02)
Noonuruk, R.
;
Mekprasart, W.
;
Vittayakorn, N.
;
Sritharathikhun, J.
;
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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Comparison study of photocatalytic activity of titanium-rich materials derived from natural minerals ores using acidic leaching
(2017-01-01)
Kansaard, Thanaphon
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Phoohinkong, Weerachon
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Mekprasart, Wanichaya
;
Sanguanpak, Samanya
;
Wannakon, Anucha
Over past decades, titanium dioxide-based materials have been recognized as effectively practical photocatalysts for purification of toxicity waste. However, pure TiO<inf>2</inf> photocatalyst is highly active under ultraviolet illumination. In this work, the effort has been focused on the synthesis of titanium-rich materials starting from minerals ores ilmenite ores and leucoxene ores by ball-milling process in combined with hydrochloric acid leaching method with optimized conditions. Crystallinity and morphologies of as-prepared samples were characterized by X-rays diffraction technique and scanning electron microscope. The photocatalytic activities of both derived-materials were studied and compared by degradation of Rhodamine B organic dye as organic toxicity compound under ultraviolet light and visible light. The results illustrate that the leucoxene-derived sample exhibits superior catalytic performance to the sample derived from ilmenite ores due to the greater Ti-content of the starting leucoxene ores.
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Effects of Zn-dopant on structural properties and electrochromic performance of sol-gel derived NiO thin films
(2015-06-01)
Noonuruk, Russameeruk
;
Mekprasart, Wanichaya
;
Pecharapa, Wisanu
Zn-doped NiO thin films were prepared by sol-gel spin-coating method onto transparent conducting substrates using nickel acetate tetrahydrate and zinc acetate dehydrate as starting precursors. Effects of zinc doping content on the structural, optical and electrochromic properties of NiO films were investigated by X-ray diffraction, X-ray photoelectron spectroscopy, field emission-scanning electron microscope, atomic force microscopy, UV-VIS spectrophotometer and cyclic voltammetry. The results reveal that Zn doping has significant influence on crystallinity deterioration, surface topography alternation and electrochromic performance of the films. The expansion of active surface area due to reduced crystallinity of the films resulting to the increase of charge transfer in the electrochemical reaction. It is indicated that electrochromic performance of sol-gel derived NiO films can be ameliorated by the incorporation of Zn additive at specific content.
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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.
;
Mekprasart, W.
;
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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Photocatalytic performance of ball-milled anatase/rutile mixed phase TiO2 composite powders
(2016-01-01)
Phoohinkong, Weerachon
;
Mekprasart, Wanichaya
;
Pecharapa, Wisanu
Mixed-phase anatase/rutile titanium dioxide (TiO<inf>2</inf>) composite powder is an important material due to the unique properties of photocatalytic activity, which the photocatalytic efficiency of mixed-phase is higher than the only single anatase or rutile phase. In this study, the anatase/rutile mixed phase TiO<inf>2</inf> composite powders were prepared by ball milling of TiO<inf>2</inf> commercial grade powders. Effect of the anatase/rutile phase ratio on photocatalytic performance was investigated. The sample phase ratio is evaluated using X-ray diffraction (XRD) meanwhile the composite morphology is characterized using field emission scanning electron microscope (FE-SEM). The overall results revealed that the mixed-phase anatase/rutile provided significant enhancement in photocatalytic performance compared with only anatase or rutile single phase. In addition, this ballmilling technique is considered an effective process, cost-effectively on energy saving, and suitable for preparing anatase/rutile TiO<inf>2</inf> mixed-phase for photocatalytic application.

Mekprasart, Wanichaya

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