3D printing of photocatalytic nanocomposites containing titania nanoparticles

Titanium dioxide is a semiconductor ceramic material presenting notable electronic and physico-chemical properties. Its anatase form is characterized by excellent photocatalytic properties in presence of UV light, which justify its use for pollutants degradation or for the realization of self-cleaning surfaces. The potential of titania can be further valorized by integrating its unique properties in 3D printed parts and the most promising technology to do this, in consideration of its high resolution and flexibility, is vat photopolymerization. In the present work, titania/polymer composites are 3D printed using this technology and the resulting materials, containing nominal titania amounts up to 10% wt., are characterized from the morphological, microstructural and mechanical point of view. In addition, their photocatalytic activity is evaluated by performing Rhodamine B degradation tests under UV light. The composites showed remarkable activity levels, with a rate constant higher than 0.25 h-1 for the composite containing 10% wt. titania. Activity was increased by a local enrichment of TiO2 in correspondence of the surface, resulting from the 3D printing process, and by a partial degradation of the polymer present between the titania particles in proximity of the surface.