ISSN 0004-881X

Hydrothermal Synthesis of Anatase-Type Solid Solution/Silica Composite Nanoparticles

by Masanori Hirano and Masayuki Kozawa

Department of Applied Chemistry, Faculty of Engineering, Aichi Institute of Technology,
Toyota 470-0392, Japan

Abstract

Composite nanoparticles composed of anatase-type solid solution (Ti_0.7Nb_0.15Sc_0.15O₂) and silica were directly formed from precursor solutions of TiOSO₄, NbCl₅, Sc(NO₃)₃, and TEOS (Si(OC₂H₅)₄) under mild hydrothermal conditions at 180 degC for 5 h using the hydrolysis of urea. The anatase phase of Ti_0.7Nb_0.15Sc_0.15O₂ solid solutions had good crystallinity in comparison with the anatse of pure TiO₂ obtained under the same hydrothermal condition. The crystallite size of anatase-type solid solutions in the composite samples decreased with increased silica content. Their photocatalytic activity and adsorptivity were evaluated separately by the measurement of the concentration of methylene blue (MB) remained in the solution in the dark and under ultraviolet-light irradiation. The photocatalytic activity of anatase was fairly increased by the formation of composite nanoparticles with silica. Anatase-type Ti_0.7Nb_0.15Sc_0.15O₂ solid solution/silica composite nanoparticles containing 10~20 mol% SiO₂ showed good photocatalytic activity under ultraviolet-light irradiation.

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