TiO_2晶相对MnO_x/TiO_2催化剂催化NO氧化性能的影响（英文）  

Influence of the TiO_2 crystalline phase of MnO_x/TiO_2 catalysts for NO oxidation

作　　者：安忠义[1] 禚玉群[1] 徐超[1] 陈昌和[1] 

机构地区：[1]清华大学热科学与动力工程教育部重点实验室,北京100084

出　　处：《催化学报》2014年第1期120-126,共7页

摘　　要：以浸渍在不同晶相TiO2(金红石型(R)、锐钛矿型(A)和P25型(P))上的锰基催化剂为对象,研究了TiO2晶相对MnOx/TiO2催化剂催化NO氧化活性的影响.结果表明,MnOx/TiO2(P)催化剂活性最高,NO转化率在300°C及GHSV=20000 h–1条件下可达83%.各催化剂活性顺序为MnOx/TiO2(P)>MnOx/TiO2(A)>MnOx/TiO2(R).采用X射线粉末衍射、场发射扫描电子显微镜、X射线光电子能谱、H2程序升温还原和O2程序升温脱附等手段研究了TiO2晶相影响MnOx/TiO2催化剂催化活性的作用机理.结果表明,相比于A和R型TiO2,P型TiO2能够增加MnOx在其表面的分散度并抑制催化剂颗粒的团聚和粘连,且更有利于Mn2O3的生成,而后者催化NO氧化活性比其它MnOx更高;此外,P型TiO2可以增加MnOx尤其是Mn2O3的还原性,并可促进O2–从M3+–O键的脱附.Mn-based catalysts impregnated on TiO2 with different crystalline phases （rutile （R）,anatase （A）,and P25 （P）） were studied for the oxidation of NO to NO2.10%MnOx/TiO2（P） was the most active catalyst,giving 83% of NO conversion at 300 ℃ and a GHSV of 20000 h-1.The catalyst activities were in the order MnOx/TiO2（P） 〉 MnOx/TiO2（A） 〉 MnOx/TiO2（R）.The catalysts were characterized by X-ray diffraction,field emission scanning electron microscopy,X-ray photoelectron spectroscopy,H2 temperature-programmed reduction,and O2 temperature-programmed desorption.Compared to anatase and rutile,P25 gave better dispersion of MnOx on the support surface,suppressed the agglomeration of catalyst particles,and also produced more Mn2O3,which was more active for the oxidation of NO.In addition,P25 enhanced the reduction of MnOx,especially for Mn2O3,and the formation of easily desorbed O2-generated from the Mn3＋-O bond.

关 键 词：一氧化氮氧化 锰氧化物 二氧化钛 晶型 污染控制 

分 类 号：O643.32[理学—物理化学]