Amorphous, activity compared with anatase

The photoactivities of ultrafme Ti02 nanoparticles in anatase, rutile, or mixed phases were tested in the photocatalytic degradation of phenol [322]. For Ti02 nanoparticles, mainly in the anatase phase and mixed-phases, the photocatalytic activities increased significantly with the content of the amorphous part decreasing. The completely crystallized rutile nanoparticles exhibited size effects in this photocatalytic reaction and the photocatalytic activity of rutile-type Ti02 nanoparticles with a size of 7.2 nm was much higher than that with 18.5 nm or 40.8 nm and was comparable to that of anatase nanoparticles. 

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