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Optical absorption and FTIR study of cellulose/tio2hybrid composites
(2019-05-01)
Plermjai, Kittiya
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Boonyarattanakalin, Kanokthip
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Mekprasart, Wanichaya
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Phoohinkong, Weerachon
;
Pavasupree, Sorapong
Cellulose/TiO<inf>2</inf> composite was prepared by conventional mixing using distilled water as medium. The structure and relevant properties of cellulose/TiO<inf>2</inf> composite were characterized by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and UV- Vis spectroscopy. XRD results exhibit typical cellulose structure type I. The absorbance spectra of TiO<inf>2</inf>and cellulose exist in vicinity of 200 nm and 350 nm in the UV range, corresponding to the UV-C, UV-B and UV-A. In addition, the UV absorption band of the composite can be extended covering wide UV region. Corresponding FTIR results suggest the existence of chemical bonding or surface interaction between TiO<inf>2</inf> and cellulose.
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Anatase/Rutile TiO2 composite thin films prepared via dip coating technique and their hydrophilicity, stability and photocatalytic activity
(2018-01-01)
Ibrahim, Ammar
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Phoohinkong, Weerachon
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Mekprasart, Wanichaya
;
Pecharapa, Wisanu
In this work, titanium dioxide (TiO<inf>2</inf>) mixed-phase powders were prepared by sonochemical process in combination with calcination at different temperature in range of 400C to 1000C. The as-prepared powders were dispersed with tetraethyl orthosilicate (TEOS) as supported matrix of TiO<inf>2</inf> for homogeneous colloid and used as starting precursor for thin film coating. The designated thin films were deposited onto glass substrates by dip coating process. X-ray diffraction technique was employed to evaluate TiO<inf>2</inf> phase ratio meanwhile the film morphologies and hydrophilicity were investigated using scanning electron microscope and water contact angle, respectively. UV-Vis spectrophotometer was used to analyse the photcatalytic properties of the films. Photocatalytic activity of the prepared film was performed by mean of the decolorization of Rhodamine B dye solution under solar irradiation. The photocatalytic performance of assigned films was investigated and correlated mechanisms responsible for the activity are discussed.
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CPC photocatalytic reactor in presence of immobilized tio 2 and photocatalytic activity
(2017-07-01)
Ibrahim, Ammar
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Phoohinkong, Weerachon
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Mekprasart, Wanichaya
;
Pecharapa, Wisanu
In this present work, compound parabolic collector (CPC) combined with tubular reactors was designed to accept both directly incident and reflected light. The light collecting of CPC reflecter was analysed via light reflection modeling. Titanium isopropoxide was used as a precursor to prepare immobilized titanium dioxide on the borosilicate beads which was used as supporter. The coated beads were prepared via dip coating technique. The photocatalytic activity of immobilized TiO <inf>2</inf> was performed to decolorize the Rhodamine B dye solution under solar irradiation. UV-Vis spectrophotometer was used to characterize the degradation of rhodamine B dye solution and to analyse the photocatalytic performance. The analysis of reflecting on CPC reflector indicates that all incidents are reflected to reactor tube according to the defined concentration ratio as equal one. The photodegradation of rhodamine B dye solution under solar irradiation is clearly observed by over 90% in presence of immobilized TiO <inf>2</inf> on glass beads.
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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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Photocatalytic performance of ball-milled anatase/rutile mixed phase TiO2 composite powders
(2016-01-01)
Phoohinkong, Weerachon
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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.
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Modification of working electrode of dye-sensitized solar cell using TiO2 nanopraticles/TiO2 nanofibers/CNT composite
(2013-10-29)
Mekprasart, Wanichaya
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Jarernboon, Wirat
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Techitdheera, Wicharn
The working electrode of dye-sensitized solar cell was modified using composite material of TiO<inf>2</inf> particles/TiO<inf>2</inf> nanofibers/CNT by doctor blade method. Structural properties of pre-cursor materials and as-prepared working electrodes were well characterized by X-ray diffraction and scanning electron microscopy. The efficiency and relevant parameters of solar cells with modified electrodes were measured. The optimized weight ratios of 1 wt.% TiO<inf>2</inf> nanofibers derived from leucoxene and 0.01 wt.% CNT exhibited the highest improvement of DSSC efficiency with solar efficiency of 1.11% and fill factor of 0.32. The increase of current density may be originated from easier electron transfer that occurred in the device with modified TiO<inf>2</inf> particles/TiO<inf>2</inf> nanofibers/CNT composite. © (2013) Trans Tech Publications, Switzerland.

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