Highly efficient photocatalytic TiO2 coatings deposited by open air atmospheric pressure plasma jet with aerosolized TTIP precursor
Résumé
A simple method to deposit photocatalytic TiO2 coatings, at a high rate (20–40μms−1), and
with a high porosity, is reported in this paper. This method, which allows the treatment of
membranes (with an 800 nm pore size), is based on the introduction of a liquid precursor
sprayed into an open-air atmospheric pressure plasma jet (APPJ). The photocatalytic activity
of the TiO2 thin films prepared by APPJ have been compared with our best N-doped TiO2 thin
films, deposited by reactive radio frequency (RF) magnetron sputtering, previously reported in
the literature. The morphology, chemical composition, photoelectrochemical, and
photocatalytic properties of the coatings have been studied in this paper. Significant control of
the porosity and crystallinity was achieved by varying the deposition parameters and the
annealing temperature. Under optimized conditions, the TiO2 coatings deposited by APPJ are
characterized by a higher photocatalytic activity as compared to the optimized thin films
deposited by RF sputtering. This difference can be explained by the higher specific surface of
the APPJ coatings. Finally, the most interesting characteristic of this APPJ-liquid spray process
is its capacity to treat membranes without blocking the pores, and to produce photocatalytic
membranes which can efficiently combine filtration and photocatalysis for water treatment.