One-Pot Three-Dimensional Printing Robust Self-Supporting MnOx/Cu-SSZ-13 Zeolite Monolithic Catalysts for NH3-SCR

Honeycomb cordierite coated with Cu-SSZ-13 zeolite is widely used for the selective catalytic reduction of NOx with NH3 (NH3-SCR) to reduce pollutants from vehicle emissions. However, conventional honeycomb catalysts fabricated via coating techniques are limited by low zeolite loadings, loss of the deposited zeolites, and complicated preparation processes. Herein, a facile, one-step three-dimensional (3D) printing strategy is developed to construct MnOx/ Cu-SSZ-13 monolithic catalysts with excellent catalytic performance for NH3-SCR. Iron-containing halloysite nanotubes (Fe-HNTs) are introduced as printing ink additives to ensure mechanical stability and modulate the NH3-SCR performance of monolithic catalysts in high temperature conditions. In situ incorporation of Mn into the Cu-SSZ-13 zeolite monoliths during the 3D printing process boosts the mechanical strength of the monolithic structures from 2.54 MPa to 4.33 MPa as well as broadens the temperature window (165-550°C) of the catalysts for NH3-SCR with NOx conversion of above 80%. Such robust multicomponent-integrated 3D-printed selfsupporting catalysts not only possess high zeolite loading and excellent catalytic activity, but also avoid complicated manufacturing processes, which contrasts with conventional honeycomb catalysts fabricated by extrusion coupled with coating.