锰铜铈氧化物催化剂氧化NO性能及动力学研究

Oxidating NO ability of MnCuCe-oxide catalysts and research of kinetics

实验以TiO2为载体采用浸渍法制备CuOx/TiO2、CeOx/TiO2、CuCeOx/TiO2和MnCuCeOx/TiO2催化剂,考察这些催化剂氧化NO活性,探究Cu、Ce摩尔比和添加Mn元素对CuCeOx/TiO2催化剂氧化NO活性的影响,使用扫描电镜观察催化剂表面结构。研究发现,Cu、Ce元素配合后的CuCeOx/TiO2催化剂氧化活性明显好于单独含Cu、Ce的催化剂,当Cu、Ce摩尔比为Cu:Ce=1∶2时,CuCeOx/TiO2催化剂氧化活性最好,在NO浓度500×10-6,O210%,空速为24 000 h-1,350℃时,NO氧化度为0.62;添加Mn元素可以提高CuCeOx/TiO2催化剂低温氧化活性,250℃时,MnCuCe/Ti-3和MnCuCe/Ti-5催化剂氧化度为0.53和0.69,300℃时,MnCuCe/Ti-3和MnCuCe/Ti-5催化剂氧化度均为0.76;此外,实验还研究了NO在MnCuCe/Ti-3催化剂上反应的动力学方程。

CuOx/TiO2,CeOx/TiO2,CuCeOx/TiO2 and MnCuCeOx/TiO2 catalysts were prepared by impregnation method,and their activities for NO oxidation,the influences of factors such as mole ratio between Cu and Ce,and addition of Mn onto CuCeOx/TiO2 were investigated. Surface structures observed by SEM were also employed to characterize the catalysts. It was found that the catalysts of Cu combined with Ce showed much better activity than catalysts with only Cu or Ce as active component. Cu∶ Ce = 1∶ 2 was the best mole ratio for CuCeOx/TiO2 catalyst to reach highest activity. When inlet concentration of NO was 500 × 10- 6,O210% and space velocity 24 000 h- 1,oxidation extent of NO over CuCeOx/TiO2 reached 0. 62 at 350℃. Adding Mn onto CuCeOx/TiO2 catalysts increased NO oxidation extent for CuCeOx/TiO2 catalysts at lower temperature. At 250℃,the oxidation extent of NO over MnCuCe /Ti-3 and MnCuCe /Ti-5 were 0. 53 and 0. 69. When temperature reached 300℃,the oxidation extent of NO over MnCuCe /Ti-3 and MnCuCe /Ti-5 were both 0. 76. The kinetics of NO catalytic oxidation reaction over MnCuCe /Ti-3 was researched in this work.