Influence of Preparation Methods on Selective Catalytic Reduction Nitric Oxide by Propene over Silver-alumina Catalyst

摘要

Selective catalytic reduction of nitrogen oxides by hydrocarbons in the presence of oxygen has attracted much attention, because it has the potential ability to remove NOx from diesel exhaust and other oxygen rich fuel gases. So far, alumina-supported metal or/and metal oxides catalysts would be promising candidates for practical applications because of their high activity and stability. Miyadera and Yoshida firstly reported that Ag/Al_2O_3 is move active catalyst for selective reduction of NO in lean-burn condition, since then many researchers have focused on the catalysts prepared by Impregnation methods, and their results show that the most active catalyst is obtained with approximately 2wt% Ag loading by Impregnation. In this paper, we investigated in detail the activity of various Ag/Al_2O_3 catalysts prepared by Impregnation, co-precipitation and sol-gel methods for NO reduction by propene in the presence of oxygen respectively, and found that Ag/Al_2O_3 catalyst with 5 wt% Ag loading prepared by sol-gel method is the most active catalyst, and the temperature window is widest. We also tested the effect of Ag loading and calcination temperature on the activity of catalysts for NO reduction.