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X-ray characterization, structural analysis, antibacterial activity, and self-cleaning property of Cu-doped TiO2-SiO2 nanocomposite prepared by sonochemical process
(2024-12-01)
Mekprasart, Wanichaya
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Songpanit, Maneerat
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Sanyen, Thanyapa
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Samart, Sutichai
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Chutipaijit, Sutee
TiO<inf>2</inf>-SiO<inf>2</inf> nanocomposites with different copper (Cu) precursor loadings were prepared by a one-step sonochemical process. The mole ratio of Cu precursor in TiO<inf>2</inf>-SiO<inf>2</inf> composite was varied at 0.004, 0.008, 0.020, and 0.040, respectively. The specific X-ray characterization techniques on crystalline structure, chemical composition, and chemical states of Cu-doped TiO<inf>2</inf>-SiO<inf>2</inf> composite were carried out by X-ray diffraction technique (XRD), X-ray fluorescence (XRF), and X-ray photoelectron spectroscopy (XPS), respectively. Surface morphology and chemical bonding of Cu-doped TiO<inf>2</inf>-SiO<inf>2</inf> composite were monitored by field emission scanning electron microscope (FE-SEM) and Fourier transform infrared spectrophotometer (FTIR). For antibacterial properties, the inhibition zone of antimicrobial activity was investigated by varying amounts of Cu precursors in the TiO<inf>2</inf>-SiO<inf>2</inf> composite. After that, Cu-doped TiO<inf>2</inf>-SiO<inf>2</inf> composite powder with different Cu precursor ratios was mixed in PMMA solution and deposited on glass slides to study the optical property and hydrophilicity by UV-VIS-NIR spectrophotometer and contact angle method. XRD patterns of Cu-doped TiO<inf>2</inf>-SiO<inf>2</inf> nanocomposites show the formation of the main TiO<inf>2</inf> anatase phase with the ultrafine particles observed by FE-SEM images. FT-IR spectra of the composites are assigned to the prominent peaks of the Ti-O-Ti and Ti-O-Si bond relating to the TiO<inf>2</inf>-SiO<inf>2</inf> host matrix. Meanwhile, TiO<inf>2</inf>-SiO<inf>2</inf> composites with Cu precursor at 0.004 mol ratio can significantly enhance the antibacterial activity with a large inhibition zone. The contact angle value of Cu-doped TiO<inf>2</inf>-SiO<inf>2</inf> nanocomposite film at 0.040 Cu precursor mole ratio in the TiO<inf>2</inf>-SiO<inf>2</inf> matrix resulted in the optimized composite ratio for achieving a hydrophilic surface on the substrate.
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Alcohol sensing properties of SnO2/CNT nanocomposites synthesized by microwave-assisted process
(2016-01-01)
Sawangjit, Nalita
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Techitdheera, Wichan
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Pecharapa, Wisanu
SnO<inf>2</inf>/CNT nanocomposites were synthesized via microwave-assisted process using SnCl<inf>4</inf>·;5H<inf>2</inf>O as a starting precursor and UV-treated multi-wall carbon nanotubes (MWCNTs) as scaffolds. The concentration of SnCl<inf>4</inf> was varied in the range of 0.01-0.05 M. Effect of precursor concentration on their physical properties and micro structural morphology were investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM). XRD results indicate that the assynthesized composites are the mixture of two separated phases including SnO<inf>2</inf> and MWCNT. SEM images indicate that the surfaces of MWCNT are thoroughly covered with SnO<inf>2</inf> nanoparticles. Comparative gas sensing result reveals that the prepared hybrid SnO<inf>2</inf>/MWCNT composites exhibit much higher sensing sensitivity and recovery property in detecting alcohol gas at room temperature than the bare SnO<inf>2</inf>.
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Efficiency enhancement in dye-sensitized solar cell using TiO2 /ilmenite-derived nanofiber composite as working electrode
(2014-01-01)
Simpraditpan, Athapon
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Wirunmongkol, Thanakorn
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Pavasupree, Sorapong
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Pecharapa, Wisanu
TiO<inf>2</inf> nanocomposite films of calcined TiO<inf>2</inf> nanofibers and commercial-grade TiO<inf>2</inf> nanoparticles Degussa (P25) utilized as working electrode of dye-sensitized solar cells (DSSCs) are prepared by a doctor blade method. TiO<inf>2</inf> nanofibers were synthesized from ilmenite mineral by hydrothermal process in combination with calcinations process. The prepared samples are characterized by XRD, XPS and TEM. The photoelectric conversion performance of the DSSC based on nanocomposite film electrode was compared to the device fabricated by pure P25 at the same film thickness. The result shows that as calcination temperature increases, the transformation of nanofibers to nanorods and nanoparticles were observed. The energy conversion efficiency ({eng}) of the device tends to with increasing calcined temperature. The greatest {eng} is 3.90% obtained from DSSC fabricated from nanocomposite film electrode of 5 wt.% nanofibers calcined at 800 °C for 2 h mixed with P25, indicating the significant enhancement in its performance by the incorporation of the nanofibers. This enhancement of DSSCs may correlate to high surface area, higher light scattering and light harvesting, low charge recombination and fast electron-transfer rate by nanofibers. © (2014) Trans Tech Publications, Switzerland.
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Microwave-assisted synthesis and characterization of zinc oxide/carbon nanotube composites
(2011-12-01)
Potirak, Prayut
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Kahattha, Chokchai
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Pecharapa, Wisanu
A composite material of zinc oxide and carbon nanotubes were successfully synthesized via a sol process using zinc acetate dihydrate and treated multi-wall carbon nanotubes under microwave irradiation. The morphology, microstructure and chemical bonding of as-obtained composites were well characterized using X-ray diffraction, scanning electron microscope, transmission electron microscope, and Fourier transform infrared spectroscopy. Zinc oxide nanoparticles were dispersively coated on the surface of carbon nanotube when the precursor was dried under microwave irradiation without post-annealing. X-ray diffraction results obviously showed the mixture of two phases of carbon nanotube and wurzite zinc oxide whose size is approximately 15 nm. The formation of zinc oxide nanoparticles on carbon nanotube surface in the composite prepared by microwave heating is much better than the composite heated by conventional annealing. Fourier transform infrared spectroscopic results suggest that carboxylic groups and uniform heating by microwave heating could play key roles on the nucleation of zinc oxide on carbon nanotube surface. Copyright © 2011 American Scientific Publishers All rights reserved.

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