Study on Deactivation of Cu/Al-Ce-PILC in the Selective Catalytic Reduction of NO by Propylene

New pillared clay catalysts were studied for NO removal by hydrocarbon in the presence of oxygen. The purpose of this work is to study the deactivation of Cu/Al-Ce-PILC in the SCR of NO. Montmorillonite was pillared by multi oligomeric hydroxyl cation to synthesize Al-Ce-PILC and treated by (NH_4)_2SO_4, then it was used as catalyst support. Cu/Al-Ce-PILC catalyst was prepared by impregnation and applied to the SCR of NO by C_3H_6.The NO conversion to N_2 reached its maximum of 56% at 350℃ and decreased to 22% at 700℃. To study the deactivation of Cu/Al-Ce-PILC in the SCR of NO at high temperature, the fresh and post-reaction catalysts were characterized by XPS, TPR, TGA, Py-IR and DSC. The results showed that only Cu~+ species existed on the fresh catalyst pretreated in hydrogen, while another species CuO was detected on the post-reaction catalyst. The loss of structural hydroxyl and SO~ 2- _4 on Al-Ce-PILC weakened the surface acidity of the catalyst at high reaction temperature. Furthermore, the coke deposition on the catalyst covered part of the active sites and blocked the pores of the catalyst. The deactivation of Cu/Al-Ce-PILC may be due to the combined effects of CuO formation, the decrease on acidity and the coke deposition, which facilitated propylene combustion and inhibited NO reduction.