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Article Citation - WoS: 32Citation - Scopus: 28Photocatalytic activity of hydroxyapatite-precipitated potassium titanate whiskers(Elsevier Science Sa, 2010) Park, JongeePhotocatalytic properties of hydroxyapatite (HAP)-precipitated multifunctional potassium titanate (KT) whiskers were investigated in terms of the decomposition of methylene blue (MB) in aqueous solution under UV irradiation. Hydroxyapatite was formed on the surface of KT whiskers through a biomimetic process in simulated body fluid (SBF). The SBF used in this investigation had concentrations of calcium and phosphate ions 10 times greater than those of human plasma. Results revealed that hydroxyapatite precipitation enhanced the photocatalytic activity of the KT whiskers. In the case of unreacted KT whisker, complete degradation of methylene blue took 5.5 h, on the other hand degradation time decreased to 3.5 h when the whisker was precipitated with hydroxyapatite. (C) 2009 Elsevier B.V. All rights reserved.Article Citation - WoS: 49Citation - Scopus: 55Synthesis of Α-fe2o3< Heterogeneous Composites by the Sol-Gel Process and Their Photocatalytic Activity(Elsevier Science Sa, 2020) Bouziani, Asmae; Park, Jongee; Ozturk, Abdullahalpha-Fe2O3/TiO2 heterogeneous composites were synthesized by the sol-gel process to increase the photocatalytic activity of TiO2. The structural, morphological, and optical characteristics of the composites were determined by X-ray diffraction, scanning electron microscope, and UV-vis diffuse reflectance spectroscopy. Results revealed that the incorporation of alpha-Fe2O3 to TiO2 widened the visible light absorption ability of TiO2. It was realized that the calcination temperature plays a crucial role in morphology development hence photocatalytic activity of the alpha-Fe2O3/TiO2 heterogeneous composites. The photocatalytic activity of the composites calcined at various temperatures was evaluated for the degradation of Methylene Blue (MB) and Phenol (Ph) in aqueous medium under UV and sun-like illuminations. The alpha-Fe2O3-TiO2 composites exhibits superior photocatalytic efficiency to degrade both MB and Ph as compared to both pristine TiO2 and pristine alpha-Fe2O3 under sun-like illumination. The alpha-Fe2O3/TiO2 composite degraded approximately 90 % of MB and 50 % of Ph in 180 min sun-like illumination. Improvement in photocatalytic activity is attributed to the separation of photogenerated electron/hole pairs through the interaction of alpha-Fe(2)O(3 )and TiO2.Article Citation - WoS: 29Citation - Scopus: 29A Newly Constructed Photoactive System, Fe(iii)-c/N-bi2< for Efficient Visible Light Photocatalysis(Elsevier Science Sa, 2018) Sudrajat, Hanggara; Park, Jongee; Hartuti, Sri; Park, Jongee; Park, Jongee; Metallurgical and Materials Engineering; Metallurgical and Materials EngineeringIn this study, two strategies are simultaneously applied for photocatalytic activity enhancement of Bi2O3. The first strategy is to increase the light absorption via simultaneous carbon and nitrogen doping. The second strategy is to increase the charge carrier separation via Fe grafting. Transmission electron microscopy observation reveals the presence of Fe nanoclusters resided on the Bi2O3 surface. Near edge Xray absorption fine structure (NEXAFS) analysis confirms the valence state of the Fe species to be +3, and their coordination to be octahedral. The C K-edge and N K-edge NEXAFS spectra furthermore confirm the incorporation of C and N species in the Bi2O3 structure. This newly constructed photocatalyst, denoted as Fe(III)-C/N-Bi2O3, shows appreciably enhanced photocatalytic performance for the decomposition of 2,4-dichlorophenol under visible light as compared to bare Bi2O3. (C) 2018 Elsevier B.V. All rights reserved.
