Brookite and rutile powders as efficient photocatalysts for air and water depolluting treatment
Résumé
Understand the differences between the various polymorphs of TiO2, anatase, rutile and
brookite, constitutes an extensive work since nearly 40 years. However, it still remains an
important technical lock to solve in order to explain and improve the photocatalytic efficiency.
In this way, our researches were dedicated, in a first step, to the synthesis of very well
defined morphology of the three TiO2 phases with mastered shape and chemical
composition [1].
Then, their photocatalytic activity in aqueous and gaseous phase was characterized using
several models pollutant (formic acid, phenol and toluene). Some efficiency was correlated
to the electronic properties using Time Resolved Microwave Conductivity (TRMC) [2].
These results allow us to compare the photocatalysts in the same controlled conditions.
Thus a classification is realized according to the TiO2 phase and the photocatalytic activity.
We highlight that similar distribution is obtained whatever the pollutant type and the studied
phase (air or water). Moreover, interesting rutile and brookite powders were synthesized
presenting similar or better photocatalytic activity than TiO2-P25 (Evonik), considered as
the actual best commercial photocatalyst [3].