制备参数对Mn-Ce/TiO2催化剂脱硝性能的影响

摘要

以锐钛矿型TiO2为载体,采用分步共混法制备了Mn-Ce/TiO2催化剂,通过考察不同活性组分前驱体、焙烧温度以及活性组分负载量对催化剂样品脱硝性能的影响,以确定最佳制备参数;结合XRD(X射线衍射)、XPS(X射线光电子能谱分析)、BET比表积等表征手段研究制备参数对催化剂性能的影响.结果表明:无定型态MnO2含量越多,越有利于提高催化剂的脱硝活性;催化剂样品表面原子浓度比Mn/Ti[或(Mn+ Ce)/Ti]越高,催化剂表面有效活性组分越多,催化剂脱硝活性越好.以自制Mn盐(MX)为前驱体,在Mn-Ce活性组分负载量为16％时,经500℃焙烧的催化剂样品脱硝活性最高;反应空速为10 000 h-,反应温度为80℃时,其脱硝效率可达80％,150℃时脱硝效效率可达99％.%Mn-Ce/TiO2 catalysts were prepared by step-by-step blended method with anatase TiO2 as the supportmaterial.The effects of different active component Mn precursors,calcination temperature,calcination time and loading amount ofactive components were investigated to determine the optimal preparation parameters.Subsequently,the denitrification activity was evaluated.From the characterization of the catalysts by X-ray diffraction,BET surface area,X-ray photoelectron spectroscopy and so on,it was found that the more amorphous MnO2 content in the catalyst,the more helpful to improve the catalytic activity;the lower surface atomic concentration ratio of Mn/Ti (or (Mn + Ce)/Ti),the less active components of the catalyst surface,the worse the denitrification activity.Meanwhile,the samples with self-made Mn precursors and active components loading amount of 16％ exhibited the best denitrification results when calcinated at 500 ℃.The value of denitrification efficiency was 80％ at 80 ℃ and 99％ at 150 ℃ under the test condition of reaction velocity 10,000 h-1.