Study On Preparation And Properties Of Catalysts Used For Selective Catalytic Reduction Of NO_x

Some catalysts,cordierite as carrier and Cu, Cu-Ni,Cu-Ag,Cu-La,Cu-Ce, Cu-Ni-Co,Cu-Ni-Ag,Cu-Ni-La or Cu-Ni-Ce as active components, were synthesized by impregnation method.This paper adoptted the method of temperature progress to evaluate the selective catalytic reduction(SCR) activity of all the catalysts conducted in fixed-bed fluxion reactor.The experiment results show that the Cu,Cu-Ni,Cu-Ce or Cu-Ni-Ce catalysts prepared by 1 mol·dm^-3 Cu(NO₃)₂, Ni(NO₃)₂ and 0.1 mol·dm^-3 Ce(NO₃)₃ have higher catalytic activity for SCR NO, in comparison with others. The structure characterization of Cu, Cu-Ni, Cu-Ce,Cu-Ni-Ce were analyzed and discussed by some characterization techniques such as XRD,TPR,BET,pore size distribution and so on.Cu supported on cordierite had a catalytic activity for the selective reduction of NO_x Particularly, Cu-Ni had a higher activity than Cu at lower temperature.At some extent,La and Ce increased the activity of Cu prepared by low concentration Cu(NO₃)₂ and decreased that of Cu prepared by high concentration Cu(NO₃)₂. The catalytic activity orderliness of Ag is the opposition of La,Ce.Co or Ag decreased the catalytic activity of Cu-Ni. La or Ce increased catalytic activity of Cu-Ni prepared by 1 mol·dm^-3 Cu(NO₃)₂ and Ni(NO₃)₂.Cu-Ni-Ce had a higher activity than Cu-Ni-La.Cu-Ni-Ce has higher activity in the range of 150℃ and 350℃,and it makes the efficiency of the NO_x reduction exceed up to 70 percent.The reasearch result indicates that catalytic activity relates with not only species of the active component but also the loaded quantity,but it isn't the more loaded quantity the higher activity. The catalytic activity also bears on the quality of carrier,the decentralization extent of active components,harmony performance among the active components.In the course of catalytic reductive reaction, Cu is in the form of CuO and...