焙烧温度对新型MnO_x-FeO_y催化剂结构和性能的影响  

Effects of Calcination Temperature on Structure and Performances of MnO_x-FeO_y Catalyst

作　　者：张路[1,2] 姜浩锡[1,2] 赵静[1,2] 李永辉[1,2] 

机构地区：[1]天津大学绿色合成与转化教育部重点实验室,天津300072 [2]天津大学石油化工技术开发中心,天津300072

出　　处：《石油化工》2015年第11期1288-1294,共7页Petrochemical Technology

基　　金：国家自然科学基金项目(20976120);天津市自然科学基金项目(09JCYBJC06200)

摘　　要：以Mn（acac）3和Fe（acac）3（质量比1∶1）为原料，采用超临界抗溶剂法制备了Mn-Fe复合氧化物前体，在适宜的温度下焙烧后得到新型MnOx-FeOy纳米球形催化剂。通过TG-DTG、N2吸附-脱附、XRD、XPS、NH3-TPD表征和活性评价，考察了焙烧过程对MnOx-FeOy催化剂的结构、活性组分的组成及其选择性催化还原（SCR）反应性能的影响。实验结果表明，前体的焙烧过程促进了催化剂晶体结构的转变，对Mn-Fe固溶体的形成具有重要作用。当焙烧温度为500℃时，所制备的MnOx-FeOy催化剂表面B酸和L酸中心的数量最多、SCR反应性能最好，在原料气（NO（φ=1×10^-3）、NH3（φ=11×10^-3）、O2（φ=2%）和Ar（平衡气））空速50000 h-1、反应温度180～260℃、常压条件下，NO的转化率保持在92%以上，最高达97%，且N2选择性为100%。MnOx-FeOy composite oxide precursor was prepared from Mn（acac）3 and Fe（acac）3 with a mass ratio of 1∶1 by supercritical anti-solvent method,and then MnOx-FeOy n anosphere catalysts were prepared through the calcination of the precursor at diff erent temperature. The catalysts were characterized by means of TG-DTG,N2 adsorption-desorption,XRD,XPS and NH3-TPD, and used in the selective catalytic reduction of NO. The infl uences of the calcination process on the structure,composition and activity of the catalysts were investigated. The results indicated that the calcination promoted the crystal structure transformation and the solid solution formation. At the calcination temperature 500℃ and mass ratio of Mn（acac）3 to Fe（acac）3 1∶1,there were more Br？nsted and Lewis acid sites on the surface of the prepared catalyst, so its reduction performance was better. Under the conditions of GHSV 50 000 h-1 of feed gas withφ（NO） 11×10^-3,φ（NH3） 11×10^-3,φ（O2） 2% an d Ar（balance gas）,180-260℃ and atmospheric pressure,the conversion of NO and the selectivity to N2 could reach more than 92% and almost 100% respe ctively,with the highest conversion of 97%.

关 键 词：锰-铁复合氧化物 选择性催化还原 焙烧温度 超临界抗溶剂法 一氧化氮 氮气 

分 类 号：TQ426.8[化学工程]