Browsing by Author "Agartan, Lutfi"

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Citation - WoS: 8
Effect of H₂o Ratio on Photocatalytic Activity of Sol-Gel Tio₂ Powder
(Ice Publishing, 2013) Agartan, Lutfi; Kapusuz, Derya; Park, Jongee; Ozturk, Abdullah; Metallurgical and Materials Engineering; 06. School Of Engineering; 01. Atılım University
Effect of water/tetraethyl orthotitanate molar ratio (R) on the formation and morphology of sol-gel-derived titania powder has been studied. Solutions for R of 3 and 5 have been prepared. Initial viscosity of the solutions and viscosity of the gels prepared by aging the solutions for some time were measured. Results revealed that lower gel viscosities lead to better crystallization of the aerogel. Aerogels were dried at 80 degrees C for 24 h and then calcined at 300 degrees C for 1 h to obtain titania powders. The structural and morphological analyses of the powders were performed using X-ray diffraction and scanning electron microscopic characterization techniques. Titania particles obtained after calcination composed of only anatase phase and were in the size range of 9-50 nm. The photocatalytic activity of the powders was evaluated in terms of the degradation of methylene blue (MB) solution under UV (ultraviolet) illumination. A diffuse reflectance spectroscopy was used for the band gap energy measurements. Results revealed that R had a profound effect on the particle morphology and photocatalytic activity of sol-gel-derived titania powders. The titania powders prepared from the solution for R of 5 degraded 99.47% of MB solution under UV illumination in 90 min.
Citation - WoS: 30
Citation - Scopus: 36
Effect of Initial Water Content and Calcination Temperature on Photocatalytic Properties of Tio₂ Nanopowders Synthesized by the Sol-Gel Process
(Elsevier Sci Ltd, 2015) Agartan, Lutfi; Kapusuz, Derya; Park, Jongee; Ozturk, Abdullah; Metallurgical and Materials Engineering; 06. School Of Engineering; 01. Atılım University
The effects of initial water content and calcination temperature on sol gel synthesized TiO2 powders were studied. Mother solutions had water/Ti-precursor mole ratios (R ratio) of 1, 5, 10, and 50. Dried aerogels were calcined for 3 h at temperatures of 300, 400, and 500 degrees C to obtain crystallized TiO2 nanopowders in the range of 15-30 nm. PE-scanning electron microscopy and X-ray diffraction techniques were employed to investigate the morphological and structural properties of the nanopowders synthesized. Profound effect of gel viscosity was observed on the formation mechanism and extent of crystallinity in the powders. Methylene blue degradation test results suggest, photocatalytic performance is enhanced as initial water content and calcination temperature increased. Band-gap energy of the powders ranged from 3.09 to 3.27 eV. Overall, this study shows that initial water content and calcination regime have a profound effect on the phase assembly, crystallite size, band-gap energy, and photocatalytic performance of sol gel synthesized TiO2 nanopowders. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
Citation - WoS: 3
Synthesis of Tio₂ Nanostructures Via Hydrothermal Method
(John Wiley & Sons inc, 2015) Bilgin, Nursev; Agartan, Lutfi; Park, Jongee; Ozturk, Abdullah; Metallurgical and Materials Engineering; 06. School Of Engineering; 01. Atılım University
Titania (TiO2) nanostructures were produced via hydrothermal method using amorphous TiO2 powders synthesized by the sol-gel precipitation process. The hydrothermal system was isolated from the environment and hydrothermal reactions were allowed to execute at 130 degrees C for 36 h at autogeneous pressure, and at a stirring rate of 250 rpm. Scanning electron microscopy (SEM) analysis revealed that TiO2 nanofibers formed instead of nanotubes upon utilization of amorphous TiO2 precursor. After hydrothermal synthesis, the powders were acid treated by HCl several times. X-ray diffraction (XRD) analysis identified that the synthesized powders were Na-titanate and remained Na-titanate even after subjecting to acidic treatments several times. The photocatalytic performance of the powders was evaluated by degradation of methylene blue (MB) solution in UV illumination. Results were compared with nanotubes which were synthesized previously using P25 commercial titania powder and have shown that TiO2 in tubular structure offers better photocatalytic performance for the degradation of MB solution under UV illumination as compared to fiber-like structure.