In Additive Manufacturing (AM), Material Extrusion (ME), also known as, Fused Filament Fabrication (FFF) and Fused Deposition Modeling (FDM), is one of the most popular additive manufacturing techniques for the production of polymeric components. ME allows the production of porous structures of medium to large size with economical, but reliable equipment and materials. One possible application of such parts could be as support structures for monolithic photo-catalysts.
Photo-catalysts are an attractive alternative for air pollution control. Toxic volatile or-ganic compounds like formaldehyde could be oxidized to non-toxic inorganic com-pounds (CO2 and H2O) with the help of monolithic photo-catalysts. Two main limita-tions of current monolithic photo-catalysts are the low efficiency for photon transfer and the limited contact between activated catalysts and reagents (mass transfer limi-tation). These two limitations can be improved by modifying the geometry of the sup-port structure for photo-catalysts and by building these structures via AM.
In the project FlexiFactory3Dp, the optimal geometry of support structures for photocatalytic applications is being investigated. Two porous structures have been designed and built using ME with two commercially available polymers: PMMA and ABS. One type of the structures has curved pores in order to ensure the maximum incidence of light on the surface of the pore and thin walls to avoid the loss of light by reflection. The other type of structure has straight pores of similar size that can be manufactured with conventional methods and it is used as a reference. The nano-particles of titanium oxide have been characterized and their photocatalytic activity has been evaluated.