Abstract:

In order to improve the HC-SCR activity, selectivity and stability of Pd based catalyst, and reduce the cost of the catalyst, the non-noble metal Nb is used to modify the texture, structure and redox properties of Pd based catalyst. The high porous Al2O3 support was prepared by adding pore-forming agent EDTA and low-cost commercial Al2O3 powder. Then the Nb modified Pd/Al2O3 catalysts was sucessfully made by impregnation. The catalysts were characterized by XRD,BET,NH3-TPD,H2-TPR,XPS to study the effect of Nb addition on the performance of catalysts in HC-SCR reaction. The results show that the addition of Nb effectively improves the activity of catalysts. The Pd-Nb/Al2O3 catalyst with 5% Nb has the best catalytic activity and stability, the NO conversion is 90% at only 269 ℃.

Key words: HC-SCR, Pd/Al2O3, niobium oxide, de-NOx