锰前驱体对MnO_x/TiO_2催化剂低温选择性催化还原NO_x影响

以醋酸锰和硝酸锰为前趋体通过浸渍法制备了MA和MN两种系列的MnOx/TiO2催化剂,结合BET、XRD、TPR及FT-IR等手段对催化剂进行了表征,并进行了比较,同时对两种系列的催化剂进行了选择催化还原脱硝的活性测试。结果表明,MA和MN均具有良好的低温催化活性,脱销效率随温度的变化趋势基本相同,在80℃时已经达到80%的脱硝效率;随着温度的升高,在200℃时效率上升至接近100%。通过对催化剂性能测试比较表明,锰的含量对于催化剂的活性有一定的影响。总体上看,MN具有更好的活性,脱销效率较高,并且其活动的窗口也是相对更宽,可能是因为以硝酸锰为前躯体制的的催化剂中MnO2的含量相对较多,即两类前驱体在制备过程中与载体之间的相互作用不同,导致最终催化剂表面活性组分MnOX结构和价态的不同,从而影响催化剂的低温活性。

Effect of Former Hasten Body on Catalyst of MnOx/TiO2 for Low-temperature Selective Catalytic Reduction of Nitric Oxide

Two series of MnOx/TiO2 catalyst were made by acid manganese(MA)and nitric acid manganese(MN)for the former hasten body through the impregnation method which were characterized by various characterization techniques of BET surface area,X-ray diffraction(XRD),temperature programmed reduction(TPR),in situ Fourier transform infrared spectroscopy(in situ FT-IR).Meanwhile their catalytic performance for the selective catalytic reduction of NO with NH3(NH3-SCR)was tested.Results showed that the two series of MnOx/TiO2 catalysts were very active in the low temperature and reductivity of NO has reached 80% at 80 ℃.With the rise of temperature,the efficiency has increased to 100% at 200 ℃.The comparison of performance test of catalysts showed the content of Mn has certain effect on the activity of catalyst.MN-MnOx/TiO2 showed higher efficiency.The temperature window of MN-MnOx/TiO2 catalyst was much wider than MA-MnOx/TiO2 catalyst.Content of MnO2 in MN-MnOx/TiO2 catalyst made of nitric acid manganese was relatively more than MA-MnOx/TiO2 catalyst,which also showed the different interactions with carrier of the two different catalysts.