A comparative study of the thermal and hydrothermal aging effect on Cu-SSZ-13 for the selective catalytic reduction of NO with NH3

Abstract

In this work, the characterizations of Cu-SSZ-13 after hydrothermal aging (HTA) and thermal aging (TA) at different temperatures (750, 800, and 850 °C) are compared, and the differences between those two serious aged samples are analyzed. With this data, the effect of steam on catalysts deactivation during hydrothermal aging is analyzed. The TA at 750 and 800 °C causes the dealumination and the agglomeration of Cu 2+ ions to CuO, resulting in the activity loss of Cu-SSZ-13. The presence of steam upon HTA at 750 and 800 °C aggravates the catalyst deactivation by increasing the Al detachment and the Cu 2+ agglomeration. The structure and cupric state are almost the same in the Cu-SSZ-13 after TA and HTA at 850 °C, respectively, indicating that the steam has little influence on the deactivation. The formation of CuAl 2 O 4 spinel is the primary reason for the deactivation after both HTA and TA at 850 °C, probably attributed to the strong interaction between Cu 2+ ions and framework Al sites at high temperatures.