Study of photocatalytic degradation of phenol

This experimental work studies photocatalytic degradation of phenol. The semiconductors used were zinc oxide (ZnO) and three commercial titanium oxides (TiO2) (Dégussa P25, TiO2-A1 and TiO2-A2). The rate of removal was greater for Dégussa P25 and ZnO. To understand the difference between photocatalytic activity of the three titanium oxide powders, a measure of the grain diameter under MEB as well as analyses by X- ray were made. The anatase form was identified with a difference in the diameter of grains and crystallites. The diameter of the grain was practically equal to that of the crystallite for the P25, and it was equivalent to three and five crystallites for TiO2-A1 and TiO2-A2, respectively.

The great difference noted in the follow-up of the degradation of phenol by UV spectroscopy and by HPLC for three types of TiO2 brought us to make this study. C ZnO presented photocatalytic activity comparable to TiO2 Degussa P25. C For the same type of catalyst as the TiO2 in the anatase form, the one with the thinnest diameter is most active. However, a supplementary ray was found for the P25 whereas it does not appear in the specter of the two other catalysts. C The Degussa P25 is formed from only one crystallite. All the grains are active; which is why it is better than the other two TiO2 catalysts.