Comparision of NH3-SCR Activity over Cu-Ce-La/MCM-49 and Cu-Ce-La/MCM-22 Zeolites

The addition of La onto Cu-Ce modified MWW type zeolite (MCM-49 and MCM-22) catalysts were synthesized by ion exchange process and the effect of different support (MCM-49 and MCM-22) on the activity was also discussed for ammonia selective catalytic reduction of NOx (NH3-SCR). The addition of La can significantly improve the catalytic performance of Cu-Ce/MCM-49. Furthermore, the addition of La can also facilitate electron transfer by the cycle of oxidation of Cu2++Ce3+-> Cu++Ce4+ for Cu-Ce-La/MCM-49. The electron transfer is beneficial to "FAST SCR" in that it can promote the conversion of NO to NO2, thus improving denitrification performance. Moreover, La can also provide the excellent surface acidity, which is favorable for the generation of oxygen vacancies. Compared with Cu-Ce-La/MCM-22, Cu-Ce-La/MCM-49 catalyst exhibited better SCR activity within 200-450 degrees C on account of the good redox performance and the more Ce3+ content. In addition, Ce3+ can generate oxygen vacancies, thereby enhancing the catalytic performance. More than anything, Cu-Ce-La/MCM-49 has excellent sulfur tolerance.