过渡金属改性Ce-Zr固溶体催化氧化丙烯和CO

丙烯和CO是大气中主要的有害气体,需有效去除。选取Cu,Co,Ni,Fe为活性组分,采用共沉淀法制备过渡金属M(M=Cu,Co,Ni,Fe)与Ce+Zr+M原子比为1∶40的复合氧化物催化剂(M-CZO)催化燃烧两种有害气体,并采用XRD,BET,TPR对催化剂进行了表征。结果表明,过渡金属改性Ce-Zr固溶体对两种气体催化活性相对CZO大大提高。其中催化氧化CO时,活性顺序为Cu>Co>Ni>Fe,Cu-CZO活性最高,T50和T90分别为95℃和185℃。H2-TPR结果表明,表面氧越活泼,催化氧化CO的活性越高。C3H6催化氧化活性顺序为Co>Cu>Fe>Ni,随着温度升高,CO相对生成量增加,Cu-CZO催化氧化CO活性远高于其他三种催化剂,使C3H6→CO→CO2连续反应快速进行,从而使C3H6总转化率提高,导致Co-CZO的T90比Cu-CZO略高。整体看来,Cu-CZO催化燃烧C3H6效果最好,T50和T90分别为345℃和376℃,CO的浓度低于0.05 mg/L,二次污染最小。

Catalytic oxidation of C3 H6 and CO with transition metal doped Ce-Zr solid solutions

C3H6 and CO were the two main air pollutants,which must be controlled efficiently.M-Ce-Zr-O solid solutions(M=Cu,Co,Ni,Fe) were prepared by co-precipitation method and the atom ratio of Ce+Zr+M to M was 40 ∶1 and Cu,Co,Ni,Fe were served as the active components in the catalysts and the catalysts were characterized by XRD,nitrogen adsorption-desorption and temperature programmed reduction(TPR) techniques.The results showed that the catalytic activity of M-CZO was much higher than that of CZO and the CO combustion performance of the catalysts was the following order:Cu-CZO>Co-CZO>Ni-CZO>Fe-CZO.T50 and T90 of Cu-CZO were 95 ℃ and 185 ℃,whose activity was the highest among M-CZO.H2-TPR indicated that the more active the surface oxygen was,the higher the catalytic activity of CO over M-CZO was.The C3H6 combustion performance of the catalysts was the following order:Co-CZO>Cu-CZO>Ni-CZO>Fe-CZO.Concentration was increased as the temperature increased.Consecutive reaction C3H6→CO→CO2 processed faster over Cu-CZO than that of the other M-CZO catalysts,which made the total conversion increase resulting in T90 of Cu-CZO lower than that of Co-CZO.On the whole,Cu-CZO was the best for C3H6 removal,T50 and T90 were 345 ℃ and 376 ℃ respectively,the concentration of CO was lower than 0.05 mg/L,which almost did not cause the secondary pollution to the environment.