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本文研究了稀土氧化物,特别是混合轻稀土氧化物对排气净化催化剂活性的影响。稀土元素氧化物Sm_2O_3添加于Pd/γ-Al_2O_3催化剂中,使催化剂对一氧化碳的氧化活性明显提高,转化温度T_(50％)和T_(90％)分别下降50℃和80℃,并提高了钯催化剂的热稳定性。当混合轻稀土氧化物添加于钯或贱金属氧化物催化剂中,催化剂活性也有所提高。其结果为:添加于钯催化剂中,对一氧化碳的转化温度T_(50％)和T_(100％)分别下降9℃和11℃;添加于贱金属氧化物中,T_(50％)和T_(100％)下降20℃和14℃;添加于钯-贱金属氧化物复合催化剂中,T_(50％)和T_(100％)分别下降14℃和12℃。在此基础上,研制出一种活性高、耐水汽、热稳定性好的混合轻稀土排气净化催化剂,并已用于固定污染源有机废气与汽车尾气的净化。
In this paper, the effects of rare earth oxides, especially mixed light rare earth oxides, on the catalytic activity of exhaust gas purification catalysts were studied. The addition of rare earth element Sm_2O_3 to Pd / γ-Al_2O_3 catalyst enhanced the oxidation activity of the catalyst to carbon monoxide. The conversion temperatures T_ (50%) and T_ (90%) decreased by 50 ℃ and 80 ℃, respectively. Thermal stability of the catalyst. Catalyst activity is also improved when mixed light rare earth oxides are added to palladium or base metal oxide catalysts. The results showed that the addition of T_ (50%) and T_ (100%) to carbon monoxide decreased by 9 ℃ and 11 ℃, respectively, when added to the palladium catalyst; 100%) decreased by 20 ℃ and 14 ℃, respectively. T_ (50%) and T_ (100%) decreased by 14 ℃ and 12 ℃ respectively when added to palladium-base metal oxide composite catalyst. On this basis, a kind of mixed rare earth exhaust gas purification catalyst with high activity, water vapor resistance and thermal stability was developed and used to purify organic waste gas and automobile tail gas from fixed sources.