(521f) Impact of Lanthanum Siting on Zeolite Y Reactivity

Zeolite Y is a widely used catalyst for petrochemical industries, especially for catalytic cracking and reforming reactions. Lanthanum (La) incorporation enhances its hydrothermal stability and reactivity as well, but traditional LaY synthesis introduces framework defects which complicates the true impact of La in catalysis. This study uses a method to minimize the amount of defects, even defect-free LaY to explore the impact of La siting. We will present in-situ ¹H MAS NMR from H/D exchange with probe molecules, tracking real-time kinetics and changes of the intensity of Bronsted acid sites at controlled, low temperature conditions. Moreover, ²⁷Al MAS NMR will probe the framework integrity, while ²⁹Si MAS NMR and XRD confirm crystallinity across different La loading. To compare the effect of probe molecules size for the H/D exchange reaction, two different molecules having both larger and smaller diameter than the smallest pore opening will be used. The temperature dependence of the H/D exchange reaction rate will be measured by running the experiment at different temperature conditions. Comparing LaY to parent Zeolite Y, we will show La in sodalite sites boosts reactivity, even for hindered molecules, offering mechanistic insights for zeolite design.