Preparation And Catalytic Performance Research Of LaCoO₃ Rare-earth Perovskite Catalysts

With the using of fossil fuel, the emission of nitrogen oxides, carbon monoxide and hydrocarbon is increasing. The pollution not only affects the human life,but also can directly endanger the physical health. Therefore, much attention is paid to the problem that how to effectively purify automobile exhaust both at home and abroad. At present, Noble metal has been used in three-way catalysts as active components, although catalytic performance is good, the precious metal is rare and expensive.The research on the new type catalyst with high efficiency non-noble metal has become the top topic in recent years.The new nanometer perovskite composite oxides catalysts with well catalytic activity have been studied in this thesis. First of all, The LaCoO3 was prepared by the sol-gel method, then doped other metal ions in A bit to obtain La0.8Sr0.2CoO3 and La0.8Ce0.2CoO3; Secondly, The La0.8Sr0.2Co0.8Fe0.2O3 and La0.8Ce0.2Co0.8Cu0.2O3 were obtained by doped with other metal ions in B bit. The catalysts were characterized by means of the X-ray diffraction (XRD) and scanning electron microscopy (SEM).The investigation of the Lao.8Sro.2Coo.8Feo.2O3 catalyst indicated that the catalyst exhibited high catalytic activity, The light-off temperature for C3H6,CO and NO were 250°C,150°C and 243°C; Sr and Fe doped in perovskite structure, causing the structure distortion, increase the specific surface of the catalyst so as to improve the three-way catalytic performance.The investigation of La0.8Ceo.2Co0.8Cu0.2O3 catalyst indicated that the catalyst exhibited high catalytic activity.The light-off temperature for C3H6,CO and NO were 230℃.200℃and 225℃, the three gas can be fully converted before 450℃. Results show that La0.8Ce0.2Co0.8Cu0.2O3 has perovskite structure, Ce and Cu can make the particle of catalyst diminish,and increase oxygen space dispersion degree and specific surface, thereby improve the catalyst three-way catalytic performance.