Morphology-Sensitive Sulfation Effect on Ceria Catalysts for NH3-SCR

In this work, sulfation effect on NH 3 -SCR performance over CeO 2 with different morphology (nanocubes and nanorods) was carefully studied. A morphology-sensitive sulfation effect on NH 3 -SCR activity was observed on CeO 2 . Interestingly, the NO removal efficiencies of CeO 2 nanocubes and CeO 2 nanorods got greatly enhanced after the sulfation at low-temperature range ( 350 °C). A series of characterizations such as N 2 adsorption–desorption, XRD, HR-TEM, TG–DTA, Raman and in situ DRIFTS of SO 2 + O 2 adsorption were conducted to investigate the interactions between SO 2 and nano-shaped CeO 2 . It was revealed that the morphology of CeO 2 nanorods was damaged severely when sulfated at high temperature (> 350 °C), while the structure of CeO 2 nanocubes was relatively stable under the same condition. Furthermore, more sulfate species were found on CeO 2 nanorods than on CeO 2 nanocubes, in particular of bulk like sulfate species. As a result, the NO removal efficiency of CeO 2 nanorods declined greatly when sulfated at high temperature.