铑含量对贵金属型三效催化剂性能的影响

Effect of the Rhodium Content on the Performance of Supported Nobel Metal Three-way Catalysts

在固定催化反应装置上 ,用自制的三效催化剂 (APC型催化剂 )净化模拟液化石油气 (LPG )机动车的排气。实验考察了活性组分中铑含量对催化性能的影响。结果表明 ,在空速为 1 1 0 0 0h- 1 的条件下 ,Rh含量适中的 2 # 催化剂 ,其Pt/Pd/Rh =0 0 4 % /0 0 2 % /0 0 4 % ,在富氧区 5 4%～ 1 2 6%时的氧操作窗口比较宽 ,为 6 8% ;NO和CO的催化起燃温度分别低至 1 80℃和 2 2 5℃ ,但是HC的净化效果未受明显影响 ,净化率 >94% ;Rh含量与起燃温度的关系曲线成一“V”形 ,波谷位于Rh含量为 0 0 4 %之处 ;当Rh含量控制在 0 0 30 %～ 0 0 4 3%时 ,三效净化起燃温度不超过 2 5 0℃ ;动力转化能力高。

Simulated emission from liquidized petrol eu m gas (LPG) automobile was treated by three-way catalyst(TWC)on a f ixed bed catalytic reactor.The effect of the rhodium content on the performance of the TWC was also studied.With the space velocity of 11000h -1 ,the result s showed that moderate content of rhodium,corresponding to the sample 2 with Pt/ Pd/Rh=0 04%/0 02%/0 04%,leaded to a wide oxygen operation window(6 8% in the range of 5 4%～12 6%),and a low light-off temperature(T 50 ,for removing N O and CO,180℃ and 225℃,respectively).At the same time,the removal rate of HC r emained as high as over 94%.Simultaneously,the curve of T 50 (the light-off temperature for 50% purification rate) vs content of rhodium appeared as a sh ape of 'V',and the lowest point corresponded to the rhodium content of 0 04%.When rhodium content controlled in the range from 0 030%～0 043%,T 50 was low er than 250℃;the catalyst showed a good ability of dynamic conversion.