3D printing of structured nanotitania catalysts: a novel binder-free and low-temperature chemical sintering method

Abstract

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-lm-diameter tip. Prints are self-supporting and chemically stable after a thermal post-treatment at 150ºC. 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.