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Article Citation - WoS: 11Citation - Scopus: 10Synthesis and Characterization of Hydrothermally Grown Potassium Titanate Nanowires(Korean Assoc Crystal Growth, inc, 2015) Kapusuz, Derya; Kalay, Y. Eren; Park, Jongee; Ozturk, Abdullah; Metallurgical and Materials EngineeringPotassium titanate (KT) nanowires were synthesized by a one-step hydrothermal reaction between TiO2 and aqueous KOH solution. The effects of KOH concentration and reaction time on hydrothermal formation and KT nanowire growth were investigated. The nanowire growth mechanism was elucidated using a combined study of powder X-ray diffraction, and scanning and transmission electron microscopy. The results revealed that hydrothermal growth was initiated by the formation of amorphous-like Ti-O-K sheets in anatase. Increasing hydrothermal reaction time caused the transformation of anatase to Ti-O-K sheets, from which potassium hexa-titanate (K2Ti6O13) nuclei formed and grew to establish one-dimensional morphology through preferential growth along the b-axis. It was revealed that the hydrothermal reactions followed a quite different mechanism than the well-known calcination route. Potassium tetra-titanate (K2Ti4O9) crystals formed in the amorphous region using the hexa-titanate phase as a nucleation site for heterogeneous crystallization. Increasing the KOH concentration in the solution accelerated the hydrothermal reaction rate.Article Citation - WoS: 8Citation - Scopus: 7Preparation and Photocatalytic Activity of Apatite-Precipitated Tio2(Korean Assoc Crystal Growth, inc, 2011) Soysal, K.; Park, J.; You, S. H.; Shin, D. W.; Bae, W. T.; Ozturk, A.; Metallurgical and Materials Engineering; English Translation and InterpretationApatite was precipitated on the surface of titanium dioxide (TiO2) powder by a biomimetic process. The precipitation was accomplished by immersing TiO2 powder in simulated body fluid (SBF) for 1, 3, 6, 12 and 24 h. Photocatalytic activity of the apatite-precipitated TiO2 (HAp-TiO2) powders was investigated to assess the decomposition of methylene blue (MB) in aqueous solution and the removal of acetaldehyde gas under UV irradiation. Hydroxyapatite precipitation enhanced the photocatalytic activity of the TiO2 powder. The time required for the complete degradation of MB decreased from 3.5 to 2 h with the immersion of TiO2 powders in SBF for 3 h. In terms of acetaldehyde gas decomposition, less than 1 h was sufficient to achieve complete removal for HAp-TiO2 powder but at least 2 h were required for the bare TiO2 powder. HAp-TiO2 powders could therefore be a promising candidate photocatalyst for environmental purification.Conference Object Citation - WoS: 2Citation - Scopus: 4Influence of Boron And/Or Zirconium Doping on Morphology and Optical Properties of Titania(Tanger Ltd, 2011) Kapusuz, Derya; Park, Jongee; Ozturk, Abdullah; Metallurgical and Materials EngineeringSol-gel derived B (boron) and Zr (zirconium) doped TiO2 (Titania) nanoparticles were synthesized. Microstructural, photocatalytic and crystallographic properties of the doped particles were investigated. Highest photocatalytic activity was achieved by 10 wt% Zr doping. 5 wt% doping was the optimum value for effective B doping. B ions were found to form oxygen vacancies behaving as interstitial defects whereas Zr ions substituted Ti4+ ions in the lattice.
