(560ge) Recent Progresses in Enhancing the Hydrothermal Stability of Cu-SSZ-13 Catalyst for Selective Catalytic Reduction of NOx with NH3

Cu-SSZ-13 is a highly active catalyst to remove NO_x by selective catalytic reduction with NH₃ in the emission of diesel-powered engine. However, its stability in high-temperature (HT) hydrothermal conditions is a well-known challenge for applications. The recent progresses in our group in enhancing the HT hydrothermal stability of Cu-SSZ-13 are presented. By mechanically mixing another CHA-type catalyst Cu-SAPO-34 and introducing phosphorus into Cu-SSZ-13 via incipient wetness impregnation, the HT hydrothermal stability is significantly enhanced. The activity of the hydrothermally treated (in 10% H₂O/air at 750 ^oC for 16 h) catalysts increases with the increase of the amount of Cu-SAPO-34 up to 50 wt% in the mixed sample. The delivery of extra-framework P species from Cu-SAPO-34 to Cu-SSZ-13, the migration and coordination of phosphate ions with the framework-bonded Al species are critical in impeding the dealumination process and thus enhancing the HT hydrothermal stability.