Exploring the Mechanistic Landscape of Nitric Oxide Oxidation and Ammonia Selective Catalytic Reduction of Nitric Oxide on Cu-Zeolites via Kinetic and Spectroscopic Characterization

Increasingly stringent regulations to reduce emissions of nitrogen oxides (NOx) from exhausts of heavy-duty diesel engines has set the stage to delve into a detailed investigation of engine after-treatment catalysts in order to understand the chemistry during their operation and design the next generation of catalytic formulations to meet future requirements. Small-pore Cu- and Fe-exchanged SSZ-13 catalysts with chabazite (CHA) topology are able to sustain high catalytic rates for selective catalytic reduction (SCR) even after exposure to harsh hydrothermal conditions present in diesel exhaust. Probing the redox behavior and the active site requirements for standard SCR on Cu-SSZ-13 catalysts using a combination of infrared (FTIR) and x-ray absorption (XAS) spectroscopies, kinetic measurements and density functional theory (DFT) calculations forms the basis for this dissertation