Large-scale synthesis of hollow titania spheres via flame combustion

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• 作者：Jie  ; Liu ; Yanjie  ; Hu ;   ; ^{huyanjie@ecust.edu.cn} ; Feng  ; Gu ; Chunzhong  ; Li  ; ;   ; ^{czli@ecust.edu.cn}
• 关键词：Flame combustion ; Hollow spheres ; Titania ; Formation mechanism ; Large-scale
• 刊名：Particuology
• 出版年：2011
• 出版时间：December 2011
• 年：2011
• 卷：9
• 期：6
• 页码：632-636
• 全文大小：884 K

文摘

A one-step method for continuous large-scale synthesis of well-defined hollow titania spheres was established by feeding titanium tetrachloride mixed with ethanol vapor to a facile diffusion flame. A mixture of TiCl₄ and C₂H₅OH vapor was transported at 100 m/s into a flame reactor and condensed into mesoscale droplets due to Joule¨CThomson cooling and the entrainment of cool gases into the expanding high-speed jet. Hollow crystalline TiO₂ spheres with good thermal stability were formed after the hydrolysis of TiCl₄ in the H₂/air flame at about 1500 ¡ãC. Structural characterization indicates that the hollow spheres, with uniform diameter of 300 nm and shell thickness of 35 nm, consist of 20?0 nm TiO₂ nanocrystallites. A formation mechanism of the hollow spheres was proposed, involving the competition between chemical reaction and diffusion during the flame process. The present study provides a new pathway for continuous and large-scale engineering of hollow nanomaterials.