Pecharapa, Wisanu

Preferred name

Pecharapa, Wisanu

Alternative Name

PECHARAPA, Wisanu

Pecharapa, W.

Main Affiliation

Integrated Innovative Technology

wisanu.pe@kmitl.ac.th

Now showing 1 - 10 of 221

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Synthesis and characterization of ZnO nanorods by hydrothermal method
(2018-01-01)
Worasawat, Suchada
;
Masuzawa, Tomoaki
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Hatanaka, Yoshinori
;
Neo, Yoichiro
;
Mimura, Hidenori
Hydrogen generation through solar-driven photoelectrolysis of water is a promising technology for clean power supply. Zinc oxide (ZnO) is often applied to a photoelectrochemical (PEC) cells for water splitting, because ZnO has a favorable band edge that straddles the redox potential of photoelectrolysis in water. In addition, formation of ZnO nanostructure is attracting much attention, since the efficiency of PEC cell largely depends on a surface area of contacts. Here we report a modified hydrothermal method to prepare ZnOnanorods, whose structures can be controlled by changing preparation parameters. Our method includes seeding process by simple dip-coating technique, followed by post annealing process and hydrothermal growth process of ZnO nanostructures. The morphology of the grown ZnO depended on the concentration of the solvent used to form the seed layer formation, post-annealing temperature, and growth temperature. At the seed layer solvent concentration of 0.2 M, the ZnOnanorods were needle-like. At 0.9 M, hexagonal ZnOnanorods were obtained. We have successfully prepared hexagonalZnOnanorods by varying seed layer concentration at 0.9M, annealed at 150 ºC for 2 h and grown at 120 ºC for 1 h.
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X-ray absorption spectroscopy analysis and magnetic properties of M-doped TiO2 nanoparticles (M=Co, Mn, Ni and Zn) prepared by co-precipitation method
(2017-08-01)
Wattanawikkam, Chakkaphan
;
Pecharapa, Wisanu
;
Ishihara, Keiichi N.
M-doped TiO<inf>2</inf> nanoparticles (M=Co, Mn, Ni and Zn) were synthesized by co-precipitation method combined with annealing at 500 °C for 2 h. X-ray diffraction (XRD) was used to identify their structural phases. X-ray absorption near edge structure (XANES) was conducted to probe the chemical state and crystal atomic structure of prepared samples. Magnetic properties of all samples were characterized by vibrating sample magnetrometer (VSM). The XRD analyses reveal that all samples crystallize in anatase tetragonal structure with no additional peaks. The XANES spectra exhibit triple pre-edge fingerprint of Ti4+ of oxidation state with six-fold octahedral coordinate structure. Co-, Ni- and Zn- K-edge results indicate that the Co, Ni and Zn ions in M-doped TiO<inf>2</inf> are in 2+ formal oxidation state. Meanwhile, Mn-doped TiO<inf>2</inf> sample contains the different oxidation states of 3+ and 4+. The amount of each oxidation state is confirmed by using linear combination fitting method. The magnetic measurement illustrates the paramagnetic behavior for Co-, Mn- and Ni- doped samples that strongly depend on the doping content and no hysteresis loop is observed in undoped and Zn-doped samples.
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Characterization of Sol-gel derived Ti-doped tungsten oxide electrochromic thin films
(2011-01-01)
Paipitak, K.
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Kahattha, C.
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Techitdheera, W.
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Porntheeraphat, S.
;
Pecharapa, W.
Ti-doped WO<inf>3</inf> electrochromic thin films were deposited onto F-doped tin oxide (FTO) substrates using spin coating technique. The as-deposited films prepared with various concentration of titanium were annealed in air at 500°C. The effect of Ti-doping concentration on structural, surface morphology and optical properties of the films were characterized by X-ray diffractometer, scanning electron microscope and UV-VIS spectrophotometer. The results show that the crystalline of WO<inf>3</inf> can be identified at 2θ values of 24.14° corresponding to 200 orientation. In addition, It was found that the electrochromic performance of WO<inf>3</inf> can be enhanced by small doping concentration of titanium due to structural modification of the films. © 2011 Published by Elsevier Ltd.
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Effect of Ultrasonic Irradiation Time on Physical Properties and Photocatalytic Performance of BiVO4 Nanoparticles Prepared via Sonochemical Process
(2021-01-01)
Kansaard, Thanaphon
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Bangbai, Chatpong
;
Jayasankar, C. K.
;
Pecharapa, Wisanu
Currently, photocatalyst materials have gained considerable attraction because of very rich economic performance of decomposition of highly toxic organic compound to lower toxic composition. The effort of this work was paid to study the effect of sonochemical ultrasonic irradiation time on the relevant properties of visible-light-driven bismuth vanadate (BiVO<inf>4</inf>) photocatalyst without any further thermal treatment process. The chemical bonding of BiVO<inf>4</inf> nanopowder was investigated by Fourier transform infrared (FTIR) and Raman spectrometer technique. Meanwhile their structure was characterized by X-ray diffraction technique (XRD). Field emission scanning electron microscope (FE-SEM) was used to observe particle morphology and chemical compositions was investigated by Energy-dispersive X-ray spectroscopy (EDX). Photocatalytic performance of BiVO<inf>4</inf> nanopowder was studied by decomposition of organic dye as organic pollutant model using visible light to excite photocatalyst materials. It was found that sonochemical irradiation time supplied during chemical process can effectively expedite the formation of BiVO<inf>4</inf> nanoparticle. The optimized condition to obtain the product with enhanced photocatalytic performance of 60% decomposition is achieved as the sample was prepared at 40 min ultrasonic irradiation.
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Sonochemical synthesis and characterization of copper oxide nanoparticles
(2011-01-01)
Wongpisutpaisan, Narongdet
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Charoonsuk, Piyanut
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Vittayakorn, Naratip
;
Pecharapa, Wisanu
Copper oxide (CuO) nanoparticles were synthesized by a sonochemical process using copper nitrate and sodium hydroxide in the presence of polyvinyl alcohol (PVA) as a starting precursor. The precipitated product was calcined at various temperature ranging from 400-700°C. The physical microstructure and morphology of as-calcined nanoparticles were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). From XRD observation, it is evident that the high purity CuO nanoparticles were obtained by this synthesis process. It was additionally revealed that its crystallization and particle size was strongly dependent on the reaction time and calcination temperature. © 2011 Published by Elsevier Ltd.
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Physical properties of Ti-doped ITO nanoparticles synthesized by co-precipitation method
(2016-04-26)
Chongsri, K.
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Kanoksinwuttipong, J.
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Techitdheera, W.
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Pecharapa, W.
Ti-doped indium tin oxide (ITO) nanoparticles (TITO) with different molar ratios of Ti:ITO were synthesized by co-precipitation method using Ti(OCH2CH2CH2CH3)4, InCl3 and SnCl4·5H2O as starting precursors. Deionized (DI) water was selected as the solvent in this process. The as-precipitated powders were calcined at different temperature in range of 700 °C for 2 h. For all samples, their crystal structures, Optical property and morphologies were investigated by X-ray diffraction (XRD), UV-Vis absorption spectroscopy and Scanning electron microscope (SEM), respectively. XRD results reveal that the purity of as-synthesized sample is increased by the increase of calcination temperatures. Moreover, it is noticed that the incorporation of Ti into ITO matrix significantly affects to their relevant physical properties especially optical properties. In addition, SEM micrographs show that the sample agglomeration is noticeably influenced by Ti doping content.
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Glass-Ceramic Na3+x[(Zr/Cr)x(Sc/Ti)2-x(PO4)3 Electrolyte Materials for Na-Ion Full-Cell Application
(2023-01-01)
Gandi, Shyam Sundar
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Katta, Vamsi Krishna
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Jayasankar, C. K.
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Pecharapa, Wisanu
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Ravuri, Balaji Rao
Na<inf>3+x</inf>[(Zr/Cr)<inf>x</inf>(Sc/Ti)<inf>2-x</inf>(PO<inf>4</inf>)<inf>3</inf>] glass-ceramic material compositions containing NASICON-type crystalline phases might be a good candidate as an efficient electrolyte exclusively for Na-ion batteries. All-solid-state Na-ion full cells are designed with the three-layered pellets (NaCo<inf>0.7</inf>(VO)<inf>0.3</inf>PO<inf>4</inf>/Na<inf>3.5</inf>Zr<inf>0.5</inf>Sc<inf>1.5</inf>(PO<inf>4</inf>)<inf>3</inf> (NZSP) and Na<inf>3.5</inf>Cr<inf>0.5</inf>Ti<inf>1.5</inf>(PO<inf>4</inf>)<inf>3</inf>) (NCTP)/Na-metal foil). The electrical conductivity of the NZSPglass-ceramic powder sample achieves to be highest (9.47 × 10−04 S/cm) due to its lower grain boundary resistance (R <inf>gb</inf>) as observed in SEM images and also exhibits best electrochemical stability against conductivity when the samples kept in ambient air for 60 d. The charge/discharge capacities for the initial cycle are 75/69 and 60/53 mAhg−1 to both NZSP and NCTP of two full cells, respectively. However, discharge capacities are boosted up for both these cells without much loss in coulombic efficiency even after 10 cycles.
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Sonochemical Synthesis, Characterization, and Photocatalytic Activity of Perovskite ZnTiO3 Nanopowders
(2016-10-01)
Wattanawikkam, Chakkaphan
;
Pecharapa, Wisanu
Perovskite zinc titanate (ZnTiO<inf>3</inf>) nanopowders were synthesized using the sonochemical method combined with calcinations at 500 °C and 900 °C for 2 h to improve their crystallinity. The effect of calcination temperature on their structural, optical, and photocatalytic properties has been studied. The cubic phase and the mixing phase of cubic and hexagonal were observed in sample calcined at 600 °C and 700 °C, respectively, while the spinel ZnTiO<inf>3</inf> and rutile TiO<inf>2</inf> phase arises in sample calcined over 700 °C. The valence state was investigated by the X-ray absorption near-edge spectroscopy technique, and the corresponding results indicate the existence of Zn2+ and Ti4+ in the powders. The chemical states of the samples were scrutinized by X-ray photoelectron spectroscopy. The average particle size is approximately 20-240 nm. The excellent photocatalytic performance of ZnTiO<inf>3</inf> nanoparticle calcined at 700 °C gave complete degradation Rhodamine B (RhB) in 75 min under ultraviolet light exposure with the k rate of 0.033 min-1 and 55% of decolorization RhB in 210 min under visible irradiation. The sample calcined at 700 °C ensures a good dielectric permittivity with a value 20 and the loss tangent of about 10-2.
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Preparing transparent cobalt-doped ZnO thin films by DC magnetron sputtering
(2017-01-01)
Panyajirawut, Pongladda
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Pratumsuwan, Nattha
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Meesombad, Kornkamon
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Thanawattana, Kridsana
;
Chingsungnoen, Artit
Thin films of cobalt-doped ZnO were prepared by DC magnetron sputtering on glasses. The cobalt dopant concentration was at 3%wt. The sputtering power was set at 200 watts and sputtered for 20 mins. All films are transparent. The films were then annealed at 100-500 °C under air atmosphere. Crystal structural and optical properties of the films were characterized by XRD and UV-Vis, respectively. The XRD patterns show peaks corresponding to (002) plane indicate thin films obtain hexagonal wurtzite structure. The effects of annealing temperature on crystal structure and optical properties were discussed.
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A critical review and future prospects of Dy3+-doped glasses for white light emission applications
(2022-09-01)
Chandrappa, V.
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Basavapoornima, Ch
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Venkatramu, V.
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Depuru, Shobha Rani
;
Kaewkhao, J.
Rare-earth (RE)-doped glassy systems gained much interest because of its wide variety of applications in numerous potential fields that include optical fibers, solid state lasers, optical amplifiers, optical thermometry sensors, waveguides, infrared detectors, spectral converters, display devices, and so on. Within RE ions, the trivalent dysprosium (Dy3+) ion is the most unique and characteristic ion to examine emission properties for white light and visible display emitting devices. Because, Dy3+ ion emits two intense emissions in the blue (~480 nm) and yellow (~575 nm) regions that are assigned to the 4F<inf>9/2</inf>→6H<inf>15/2</inf> and 4F<inf>9/2</inf>→6H<inf>13/2</inf> transition energies, respectively. Under the excitation of blue laser, Dy3+ ions exhibit attractive yellowish white fluorescence emission with higher quantum efficiency. In view of the importance of identifying efficient luminescent emitting materials for the development of optical devices, the present work is to investigate white light emission in new glass composition of B<inf>2</inf>O<inf>3</inf> +TeO<inf>2</inf> +SrCO<inf>3</inf> +ZnO+ZnF<inf>2</inf> +Dy<inf>2</inf>O<inf>3</inf> glass and in turn to compare and discuss these results with reported Dy3+:glasses. The tabulated reported data bank for 68 Dy3+:glasses at one place should prove valuable information for future work on rationalization of theoretical and practical point of view to enrich white light emission quantification, simulation and systemization.

Pecharapa, Wisanu

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