Zr doped anatase supported reticulated ceramic foams for photocatalytic water purification

Titanium dioxide films were deposited on macroporous reticulated Al2O3 and alumina–mullite foams with pore sizes of 15 ppi (pores per inch). Coatings were prepared from suspensions of precursor powders of Aeroxide® P25 nanopowder and precipitated TiO2 by using a dip coating process. The TiO2 forms films with a thickness of ∼2–20 μm. The photocatalytic activity was characterized as the mineralization rate of an aqueous phenol solution under UVA irradiation by the TOC technique. Precipitated TiO2 films have nearly the same photocatalytic activity as a titania suspension, in which powder aggregates have a size comparable with the thickness of the films. Samples made of Aeroxide® P25 nanopowder, in which the size of aggregates is ∼0.1 μm show higher efficiency of photodecomposition in suspensions with films. The doping of precipitated anatase with Zr(IV) in the atomic ratio Zr/Ti = 0.008 significantly improves the photocatalytic activity of the foam supported titania. Zr doped anatase films show better performance as the films prepared only from Aeroxide® P25 nanopowder.

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► Thick photocatalytic anatase films on macroporous reticulated ceramic foams.
► Alumina and alumina–mullite macroporous reticulated foams as photocatalyst support.
► Zr doping significantly improves the TiO2 film activity in phenol photomineralization.
► Comparison of photocatalytic activity of thick films and powder suspensions.