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用共沉淀法制备了一组Mg-Fe复合氧化物催化剂,用于N2O催化分解,考察了催化剂组成、焙烧温度、负载助剂钾等参数对其催化活性的影响。采用N2物理吸附、X射线衍射、H2-程序升温还原等技术对催化剂进行了结构表征。结果表明,500℃焙烧的Mg0.6Fe0.4Fe2O4催化剂对于N2O分解反应有较高活性,而K改性的催化剂活性均有所降低,且K的负载量越高,改性催化剂的活性越低,这是由于负载的K粒子抑制了表面铁物种的还原,降低了催化剂的比表面积。在有氧无水、水氧共存条件下连续反应10h,Mg0.6Fe0.4Fe2O4的催化活性和稳定性均显著高于FeOx催化剂。
A series of Mg-Fe composite oxide catalysts were prepared by coprecipitation method for the catalytic decomposition of N2O. The effects of catalyst composition, calcination temperature and potassium content on the catalytic activity were investigated. The structure of the catalyst was characterized by N2 physical adsorption, X-ray diffraction and H2-temperature programmed reduction. The results show that the calcined Mg0.6Fe0.4Fe2O4 calcined at 500 ℃ has a higher activity for N2O decomposition and a lower activity of the modified K catalyst. The higher the K loading, the lower the activity of the modified catalyst. This is due to the fact that the supported K particles inhibit the reduction of surface iron species and reduce the specific surface area of the catalyst. The catalytic activity and stability of Mg0.6Fe0.4Fe2O4 were significantly higher than that of FeOx catalyst in continuous reaction of oxygen and water with the coexistence of water and oxygen for 10h.