Abstract

The selective catalytic reduction of NO with ammonia (NH3-SCR) was studied over Cu-ZSM-5 nanocatalysts which were prepared by several methods, including conventional ion-exchange (IE), conventional impregnation (IM), ultrasound-enhanced impregnation (UIM), conventional deposition precipitation (DP) using NaOH and homogeneous deposition precipitation (HDP) using urea. The nanocatalysts were subsequently characterized by FTIR, H2-TPR, NH3-TPD, XPS, XRD, TEM, and BET. The catalytic activity of the Cu-ZSM-5 nanocatalysts for NO removal decreased in the following order: Cu-ZSM-5 (HDP) > Cu-ZSM-5 (UIM) > Cu-ZSM-5 (IM) > Cu-ZSM-5 (IE) > Cu-ZSM-5 (DP). The effect of various preparation methods for Cu-ZSM-5 on the activity of NO conversion were compared and catalytic experiments revealed a strong correlation between the acid sites strength and easily reducible of isolated Cu2+ with NO conversion. Catalyst (HDP) which showed excellent deNO activity mainly contains easily reducibility of isolated Cu2+ions, more strong acid sites and higher specific surface area compared with other catalysts.