掺钾对镁铝复合氧化物四效催化性能的影响

Four-way catalytic performance of MgAlO doped by K

采用共沉淀法和浸渍法合成掺杂钾的镁铝水滑石氧化物(K-MgAlO)催化剂,利用X射线衍射(XRD)、扫描电镜(SEM)和傅里叶红外光谱(FT-IR)对其进行分析表征,并在固定床反应器上通过程序升温试验对模拟柴油车尾气中污染物转化的催化性能进行研究。结果表明,当K掺杂量为7%时,K以高度分散的颗粒散布于MgAlO表面;在K-MgAlO的作用下NO、CO和C_3H_6的转化率达到80%时其对应的温度分别为343、335和298℃,碳烟的起燃温度从380℃降低到253℃。因此,掺杂钾的MgAlO催化剂的催化性能优于MgAlO催化剂,具有良好的四效催化效果。

A series of K-MgAlO catalysts were synthesized by coprecipitation and impregnation methods. The K-MgAlO catalysts were characterized by X-ray diffraction（XRD）,scanning electron microscope（SEM）,and Fourier transform infrared（FT-IR） spectroscopy. The catalytic activity of K-MgAlO for simulation diesel engine exhaust gas was tested by the temperature programmed. The results showed that K existed on the surface of MgAlO in highly dispersed form when it is doped by7%. The conversion rates of NO,CO,and C3H6 using the K-MgAlO catalyst reached 80% at the temperatures of 343,335,and 298 ℃,respectively. The ignition temperature of soot was reduced from 380 to 253 ℃. All the results indicate that the four-way catalytic effect of MgAlO doped by K is stronger than that of the MgAlO catalyst.