Effects of amorphous contents and particle size on the photocatalytic properties of TiO2 nanoparticles

The photoactivities of ultrafine TiO2 nanoparticles in the anatase, rutile or mixed-phases were tested in the photocatalytic degradation of phenol. Fo r TiO2 nanoparticles mainly in the anatase phase and mixed-phases, their ph otocatalytic activities increased significantly with the content of amorpho us part decreased, the result bring new understanding and insight to photoc atalytic activity of TiO2 nanoparticles. The completely crystallized rutile nanoparticles exhibited size effect in this photocatalytic reaction, the p hotocatalytic activity of rutile-type TiO2 nanoparticles in the size 7.2nm was much higher than that in the size 18.5nm or 40.8nm and comparable to th at of anatase TiO2 nanoparticles. (C) 2001 Acta Materialia Inc. Published b y Elsevier Science Ltd. All rights reserved.