钙钛矿型La_(0.8)Ce_(0.2)Fe_(1-x)Co_xO_3催化剂的制备及其三效催化活性

采用自燃烧法制备了一组钙钛矿型复合氧化物La_(0.8)Ce_(0.2)Fe_(1-x)Co_xO_3(x=0.9,0.7,0.5,0.3,0.1),并考察了其对CO、C_3H_6和NO的三效催化活性。XRD和SEM表征结果显示,La_(0.8)Ce_(0.2)Fe_(1-x)Co_xO_3具有良好的钙钛矿型晶体结构,晶粒大小为纳米级并自组装成片状结构。催化剂的比表面积为14.73~22.43 m~2/g,含有微孔和介孔结构。催化活性评价结果表明:La_(0.8)Ce_(0.2)Fe_(0.1)Co_(0.9)O_3具有很好的三效催化活性,在理论空燃比的条件下,CO、C_3H_6和NO的起燃温度分别为195℃、264℃和290℃,完全转化温度分别为239℃、418℃和415℃,低温三效催化活性良好;Fe和Co的掺杂量同时影响着La_(0.8)Ce_(0.2)Fe_(1-x)Co_xO_3的催化效果。

Preparation of La0.8Ce0.2Fe1-xCoxO3 perovskitee-type catalysts and their three-way catalytic activity

The La_0.8Ce_0.2Fe_1-xCo_xO₃（x=0.9,0.7,0.5,0.3,0.1）perovskite-type composite oxides were prepared by self-combustion process,and their three-way catalytic activities for CO,C₃H₆ and NO was studied. The characterization results by XRD and SEM indicated that the La_0.8Ce_0.2Fe_1-xCo_xO₃ catalysts had good perovskite-type crystal structure,and the grains were nano-scale and had laminated structure by self-assembly. The specific surface areas of the catalysts were 14.73-22.43 m²/g,and microporous and mesoporous structures existed in the catalysts. The evaluation results for catalytic activity showed that：La_0.8Ce_0.2Fe_0.1Co_0.9O₃ had excellent three-way catalytic activity;Under the condition of theoretical air-fuel ratio,the light-off temperatures and the dynamic temperatures of CO,C₃H₆,NO were 195,264,290 ℃ and 239,418,415 ℃,respectively,which exhibiting good low-temperature three-way catalytic performance of the catalysts;The three-way catalytic activity of La_0.8Ce_0.2Fe_1-xCo_xO₃ were affected both by the doped amount of Fe and Co.