Mixing of TiO2 (usually as P25) with granulate to generate a 3D printable filament was investigated in sporadic studies before. However, these publications either mainly focused on investigations of mechanical material features (and not on applications in photocatalysis). Or when focusing photocatalytic applications of TiO2 polymer blends, PLA was applied as polymer matrix. . Usually photocatalyst material and polymer granulate were directly fed to a commercial filament extruder.