Preparation of hollow TiO 2 nanoparticles through TiO 2 deposition on polystyrene latex particles and characterizations
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NANO EXPRESS
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Preparation of hollow TiO2 nanoparticles through TiO2 deposition on polystyrene latex particles and characterizations of their structure and photocatalytic activity Jingang Wang, Jiemei Yu, Xiaoli Zhu and Xiang Zheng Kong*
Abstract In a mixed solvent of water and ethanol, polystyrene/titanium dioxide (PSt/TiO2) composite particles of core-shell structure were prepared by hydrolysis of tetrabutyl titanate in the presence of cationic PSt particles or anionic PSt particles surface-treated using γ-aminopropyl triethoxysilane. Hollow TiO2 particles were obtained through calcination of the PSt/TiO2 core-shell particles to burn off the PSt core or through dissolution of the core by tetrahydrofuran (THF). An alternative process constituted of preheating the PSt/TiO2 particles at 200°C to allow partial crystallization followed by calcination or PSt dissolution by THF. The outcome TiO2 particles thus prepared were examined by TEM, and hollow TiO2 particles were observed. The crystalline phase structure and phase transformation were characterized, which revealed that preheating before the removal of the PSt core was useful to achieve the desired hollow TiO2 particles, and the calcination process was beneficial to the formation of anatase and rutile structures. The tests of TiO2 particles as catalyst in the photodegradation of Rhodamine B demonstrated that a much higher catalytic activity was observed with the TiO2 hollow particles prepared through calcination combined with preheating. Keywords: Nanostructured inorganic materials, Surfaces, Interfaces, Sol-gel processes, PSt/TiO2 core-shell composites, Preheating, Calcination, Photodegradation catalysis
Background With constant increase in the volume and number of organic pollutants, establishment and applications of practical and effective processes for the degradation of these pollutants have been in urgent need. Nanoparticles of titanium dioxide (TiO2) have been extensively studied owing to their high catalytic activity, nontoxicity, cost effectiveness, and high stability. In the preparation of TiO2 particles, it is particularly crucial to achieve the desired structure and crystallinity because they impose a great impact on the particles' catalytic activity. Hollow TiO2 particles, besides their high performance as a catalyst, are also characterized by their high specific surface, high permeability, high strength, and low density [1,2]. The common practice in the preparation of hollow TiO2 * Correspondence: [email protected] College of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, China
particles has been to use a template. The process involves, in a first step, deposition of a TiO2 coat on the surface of inorganic or organic particles [3,4] as the template, leading to the formation of bi-component coreshell composite particles with the shell consisting of TiO2, and followed by removal of the template core material through dissolution by a solvent or through calcination to burn off the core material. Due to the easy hydr
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