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用共沉淀法制备了一组具有尖晶石结构的Cu-Fe和Ni-Fe复合氧化物,用于有氧条件下催化分解N2O,考察了催化剂组成对催化活性的影响.用N2物理吸附(BET)、X射线衍射(XRD)、H2程序升温还原(H2-TPR)等技术对催化剂进行了结构表征.结果表明:在不同组成的Cu-Fe、Ni-Fe系列复合氧化物催化剂中,Cu Fe2O4和Ni Fe2O4对于N2O分解反应的初活性较高,这是因为Cu Fe2O4和Ni Fe2O4的比表面积较高、晶粒较小,而且其表面氧物种与金属(Cu2+、Fe3+)的化学作用较弱,氧物种易脱除、脱氧量较高.相比较而言,Ni Fe2O4催化剂上的N2O分解活化能低于Cu Fe2O4,Ni Fe2O4的初活性优于Cu Fe2O4.500℃连续反应100 h,Cu Fe2O4上的N2O转化率降至84.9%,而Ni Fe2O4上的N2O转化率一直保持99%,Ni Fe2O4有较高的催化稳定性.
A series of Cu-Fe and Ni-Fe composite oxides with spinel structure were prepared by coprecipitation method for the catalytic decomposition of N2O under aerobic conditions. The effects of catalyst composition on catalytic activity were investigated. BET, X-ray diffraction (XRD) and H2-temperature programmed reduction (H2-TPR) were used to characterize the catalysts.The results showed that Cu The initial activity of Fe2O4 and NiFe2O4 for N2O decomposition reaction is higher because of the higher specific surface area and smaller grains of CuFe2O4 and NiFe2O4 and the weaker chemical interaction between surface oxygen species and metal (Cu2 +, Fe3 +) , The oxygen species is easy to remove and the amount of deoxidation is higher.Compared with NiFe2O4 catalyst, the activation energy of N2O decomposition is lower than that of CuFe2O4, the initial activity of NiFe2O4 is better than that of CuFe2O4, The conversion of N2O dropped to 84.9%, while the Ni2O conversion of NiFe2O4 kept 99%, NiFe2O4 has high catalytic stability.