3D Printing of Structured Nanotitania Catalysts: A Novel Binder-Free and Low-Temperature Chemical Sintering Method

Pure titania nanoparticles were used successfully to manufacture 3D prints of monoliths using a high-precision paste extruder and a novel binder-free, low-temperature chemical sintering method. Nanoparticles become bonded to each other through formation of oxygen bridges by acid-induced dehydration of surface hydroxyl groups. Two different monolith designs were printed by additive superposition of paste filaments extruded through a 580-mu m-diameter tip. Prints are self-supporting and chemically stable after a thermal post-treatment at 150 degrees C. Such thermal processing does not affect the crystal structure of the phases that constitute the nanoparticles, and the original high anatase content is maintained. The 3D-printed monolith structures show a high photocatalytic activity, as evidenced by the rates of gas-phase acetaldehyde removal.