Mn/ZIF-67复合催化剂低温协同催化还原NO_(x)的研究

Catalytic reduction of NO_(x) by Mn/ZIF-67 composite catalyst at low temperature

考察了溶剂热、浸渍-溶剂热法合成ZIF-67和Mn/ZIF-67催化剂的NH_(3)-SCR脱硝性能,结果发现,Mn和ZIF-67的相互作用不仅拓宽了Mn/ZIF-67催化剂的低温窗口,而且提高了其低温催化活性,该催化剂在100~200℃的脱硝效率大于98%。同时考察了煅烧时间和煅烧温度对Mn/ZIF-67催化剂脱硝活性的影响,得到最佳煅烧时间为3 h、煅烧温度为350℃。XRD、SEM、BET、NO_(x)-TPD、XPS、NH_(3)-TPD等表征结果表明,Mn/ZIF-67催化剂形成的CoMn2O4.5增大了催化剂的比表面积,产生的双金属协同效应增加了表面氧物种和活性酸位点,加速了NH_(3)、NO、NO_(2)反应气体的吸附,进而提高了催化剂的低温脱硝活性。

The NH_(3)-SCR denitrification performance of ZIF-67 and Mn/ZIF-67 catalysts synthesized via solvothermal and impregnation-solvothermal methods is investigated.It is found that the interaction between Mn and ZIF-67 widens the low temperature window of Mn/ZIF-67 catalyst,and also increases its catalytic activity at low temperature.The denitrification efficiency of the catalyst exceeds 98%at 100-200℃.The impact of calcination time and temperature on the denitrification activity of Mn/ZIF-67 catalyst is also investigated.The optimum calcination time and temperature are 3 h and 350℃,respectively.XRD,SEM,BET,NO_(x)-TPD,XPS,NH_(3)-TPD and other characterization results show that CoMn2O4.5 formed by Mn/ZIF-67 catalyst increases the specific surface area of the catalyst,more importantly,the bimetallic synergistic effect increases the surface oxygen species and active acid sites.The adsorption of NH_(3),NO and NO_(2) reaction gases is accelerated,and the denitrification activity of the catalyst at low temperature is improved.