Activity of Monolith Cu-ZSM-5 Catalyst for Selective Catalytic Reduction of NO with NH_3

A series of Cu-ZSM-5 catalyst samples with different Cu contents were prepared by an incipient wetness impregnation method and were used for selective catalytic reduction(SCR) of NO with NH3.The results showed that the Cu-ZSM-5 with 8% Cu loading had the highest catalytic activity.The conversion of NO was above 80% at 198–440℃,and the highest conversion was 97% at a space velocity of 30000 h–1.The space velocity had less influence on the catalytic activity,and the catalytic activity temperature window was still wide at a space velocity of 60000 h–1.After hydrothermal aging,the catalytic activity of the Cu-ZSM-5 was significantly higher than that of the commercial V-based catalyst.The addition of H2O and SO2 lead to the reduced activity;however,the catalytic activity was still good.X-ray diffraction and NH3 temperature-programmed desorption results indicated that more Cu immigrated into the cation sites of ZSM-5 and the active sites of the catalyst increased when the Cu content reached 8%.Moreover,the Cu-ZSM-5 had more surface acidity centers and surface acidity,which were beneficial to SCR reaction.