Photocatalytic ceramic tiles: key-factors in industrial scale-up (and the open question of performance).

Photocatalytic and highly hydrophilic ceramic surfaces were realized by deposition of nanostructured TiO2 coatings on porcelain stoneware large slabs, produced by Lamina technology. Different techniques (silicon roller and ink-jet printing) were used to apply nanotitania coatings on industrially-sintered products in a set of experimental conditions (titania load, surface coverage) and surface finishing (glazed/unglazed) by additional annealing steps. A complete physical and functional characterization of coated surfaces allowed feasibility to be assessed through the industrial scale-up from a pilot line (tile size 40x40 cm) to the production plant (slab size 300x100 cm) by the adoption of suitable, fast and environmentally friendly technological solutions. Key factors affecting the photocatalytic activity are discussed by addressing the open question of actual performance attainable on ceramic tiles.