Effect of the preparation method on the catalytic properties of copper-containing zeolite Y applied for NH3-SCR-DeNOx†
Two series of zeolite Y were prepared with varying particle sizes (estimated to be 100 or 400 nm) by applying different synthesis gel composition ratios as well as different ageing and hydrothermal steps. Copper-containing zeolite Y samples were obtained through ion-exchange, thoroughly characterized and tested for the selective catalytic reduction with NH3 (NH3-SCR-DeNOx). The catalytic activity of the prepared materials varied significantly due to the different nature of copper species. Results show that catalysts CuY-0h-A and CuY-24h-A (approx. particle sizes 2676 and 475 nm, respectively) facilitate a higher NO conversion both in the presence and absence of water vapor, exhibiting however stronger N2O formation above 250 °C. On the other hand, nearly X-ray amorphous Y-0h-B and Y-24h-B after ion-exchange led to decreased activity of CuY-0h-B and CuY-24h-B (approx. particles sizes 345 and 128 nm, respectively). Additional insight into the activity of the catalysts was obtained through in situ DR UV-vis spectroscopy.