Andrey Vyatskikh¹, Kai Liu¹, Carlos M. Portela¹, Akira Kudo¹, Stephane Delalande², Michael R. Hoffmann¹, Julia R. Greer¹; ¹California Institute of Technology, ²PSA Group

Photocatalytic materials, such as titanium dioxide (titania, TiO₂), can harvest sunlight to promote generation of reactive oxygen species (ROS) that damage and deactivate waterborne pathogens. Here, we study the effects of 3D architecture of photocatalytic materials on the efficiency of solar water treatment. We have developed a stereolithography-based additive manufacturing (AM) process for TiO₂. We synthesize pre-ceramic photoresists using hybrid organic-inorganic materials, pattern them using a stereolithography apparatus, and pyrolyze them in air at 1300C to remove the organic content. We demonstrate this process by fabricating periodic cubic and octet architectures with beam diameters of 115-170 um and unit cells of 0.65-1.14 mm. The resulting structures are comprised of >99wt% rutile TiO₂, as confirmed by Energy-Dispersive Spectroscopy, Raman spectroscopy, and Transmission Electron Microscopy. This titania AM process offers a promising pathway to creating safe and efficient photocatalytic reactors for household water disinfection.