Abstract
The Cu-exchanged SSZ-13 with the small-pore chabazite framework is considered as a highly efficient catalyst for selective catalytic reduction of NO with NH3 (NH3-SCR). In order to further improve the catalytic property,a series of Mn ion-assisted Cu/SSZ-13 powder catalysts were prepared by co-exchange method and stepwise exchange method. It is found that the NH3-SCR activity,N2 selectivity,hydro-thermal stability and sulfur resistance of Cu/SSZ-13 are promoted by introducing a minority of Mn (0.15％ to 0.23％ (mass)) through co-exchange method. Characterization results reveal that the Cu,Mn co-exchange enables the higher amounts of Cu2+active sites,the abundant medium strong and strong acid,the optimized ratio of Lewis acid to Brønsted acid etc.,which are required for a good NH3-SCR catalytic property over broad temperature range and under harsh working environment. Moreover,a monolithic catalyst was prepared by impregnating a cordierite ceramic support into the coating slurry containing the optimized CuMn/SSZ-13 powder. The diesel engine bench tests show that Cu,Mn co-exchange gives the monolith catalyst a better catalytic property than commercial catalysts. This work provides an important guidance for the rational design of secondary-ion-assisted zeolites applied in NH3-SCR.
基金项目
National Natural Science Foundation of China(22278086)
维普
万方数据