Structure-Activity Relationships of SSZ-13 And Other Small Pore Zeolites for Catalytic NOx Abatement

Environmental regulations on diesel automobiles have promoted the development of exhaust after-treatment technologies that can abate Nitrogen Oxides (NOx) i.e. Ammonia Selective Catalytic Reduction (NH3-SCR). Recently, the Cu-exchanged SSZ-13 (Cu-SSZ-13) zeolite catalyst has been commercialized due to its efficient reduction of NOx and superior hydrothermal stability in light and heavy-duty diesel vehicles. Nevertheless, a fundamental understanding of this catalyst and the NH3-SCR reaction mechanism are still under debate. In this work, kinetic and characterization studies were performed to gain insight of the active sites on Cu-SSZ-13 and contribute to the understanding of NH3-SCR mechanism. Additionally, hydrothermal stability studies were carried out on small pore zeolites i.e. SSZ-13, SSZ-39, and RTH, to evaluate potential catalysts for the reduction of NOx using NH3-SCR