锰锆镧固溶体的制备及负载铜催化剂的性能研究

采用改进的共沉淀法制备锰锆镧复合氧化物(MnxZr1-xLayO2-σ)载体,然后采用等体积浸渍法负载活性组分Cu,制得铜基锰锆镧复合氧化物(Cuλ/MnxZr1-xLayO2-σ)催化剂.考察该催化剂催化CO、C3H6和NO转化反应的三效催化性能,并且利用XRD、TG和SEM等方法研究催化剂结构与性能的关系.实验结果表明:Mn:Zr:La摩尔比为0.9:0.1:0.06,Cu负载量为5%时,制得的Cu5%/Mn0.9Zr0.1La0.06O2-σ催化剂催化CO、NO和C3H6转化反应的活性良好;Mn、Zr和La能够形成稳定的Mn-Zr-La固溶体,可以有效提高催化剂的低温活性和热稳定性,并且不出现Cu、Mn、Zr或者La物种在载体表面富集的现象;因此,Cu5%/Mn0.9Zr0.1La0.06O2-σ催化剂具有良好的性能,在该催化剂上CO、C3H6和NO的起燃温度(T50)分别为112℃,253℃,210℃,完全转化温度(T90)分别为154℃、319℃和288℃,至500℃时转化率分别高达100%、97.5%和99.3%.

Preparation of Mn-Zr-La Solid Solution and Performance of its Supported Cu Catalysts

The MnxZr1_xLayO2-σ composite oxide supports were prepared by the modified co-precipitation method, and the Cuλ/MnxZr1-xLayO2-σ, catalysts were prepared by equivalent-volume impregnation method to load the active component Cu on the supports. The three-way catalytic performance of the catalysts for the conversion of CO, C3H6 and NO was investigated. The relationship between the catalytic performance and the structure of the catalysts was also explored by means of XRD, TG and SEM characterization techniques. The experimental results showed that the Cu5%/Mn0.9Zr0.1La0.06O2-σ catalyst exhibited favourable catalytic activity for the conversion reaction of CO, C3H6 and NO when the molar ratio of Mn： Zr： La was 0.9： 0.1： 0.06 and the loading amount of Cu was 5%. The Mn, Zr and La could form a stable Mn-Zr-La solid solution and significantly improve the catalytic low-temperature activity and thermal stability. The enrichment of Cu, Mn, Zr or La species on the carrier surface were not detected as well. Therefore, the Cu5%/Mn0.9Zr0.1Lao.06O2-σ possessed favorable catalytic performance. The light-off temperature （T50） for CO, C3H6 and NO were 112℃, 253 ℃and 210℃ respectively, the complete conversion temperature（T90） were 154 ℃, 319℃ and 288 ℃ respectively, and the rate of conversion could reach up to 100%, 97.5% and 99% at 500℃, respectively.