大孔钙钛矿型氧化物催化剂制备及其对碳烟燃烧的催化性能

采用有机络合和溶液燃烧相结合的方法制备了La_1-xK_xFe_1-yCo_yO₃ (x=0, 0.1；y=0, 0.5)催化剂，通过X射线衍射（XRD）、傅立叶红外吸收光谱（FT-IR）和扫描电镜等分析手段对La_1-xK_xFe_1-yCo_yO₃ 催化剂进行了表征。结果表明，制备的催化剂为钙钛矿型复合氧化物，具有蜂窝状大孔结构，平均孔径大于50 nm。采用超声辅助的方法让碳烟颗粒扩散到催化剂孔道内，利用程序升温反应技术评价了La_1-xK_xFe_1-yCo_yO₃ 催化剂对柴油车尾气中碳烟颗粒物的催化燃烧活性，结果表明，大孔钙钛矿催化剂具有较高的碳烟催化燃烧活性，与纯碳烟的燃烧峰值温度(Tm）相比，下降了（165~239） ℃。通过A位和B位离子的部分取代，可以使钙钛矿型氧化物催化剂的催化氧化性能进一步提高，m降低超过70 ℃。

Preparation of macroporous perovskite-type oxide catalysts and their catalytic properties for soot combustion

La_1-xK_xFe_1-yCo_yO₃ (x=0, 0.1;y=0, 0.5) catalysts were prepared by combined method of organic ligation and solution combustion. The samples were characterized by means of XRD, FT-IR and SEM. The results indicated that the catalysts obtained were mixed oxides with perovskite type structure and a lot of honeycomb like macropores, with average diameters of the macropores of over 50 nm. With the help of ultrasonic, soot could be embedded into the inner pores of the macroporous catalysts. Catalytic activity of the catalysts for catalytic combustion of soot from diesel engines were treated by temperature programmed reaction. Compared with pure soot, the peak temperatures(Tm) for soot combustion over macroporous perovskite catalysts decreased by (165-239) ℃. The partial replacement of the ions at A site or B site by other cations further enhanced the catalytic activity of perovskite type oxides catalysts. For example, Tm was lowered by more than 70 ℃.