CO为还原剂同时还原SO_2和NO的SnO_2-TiO_2固溶体催化剂 Ⅰ.催化剂的催化性能

SnO_2-TiO_2 Solid Solution Catalyst for Simultaneous Reduction of SO_2 and NO by COⅠ. Catalytic Performance of the Catalyst

采用共沉淀法制备了不同SnO2 含量的SnO2 TiO2 固溶体催化剂 .发现该催化剂对以CO为还原剂同时还原SO2 和NO生成S和N2 的反应具有高活性和高稳定性 .SnO2 含量为 5 0 % (摩尔分数 )的样品活性最高 ,在 35 0℃ ,0 0 5 2 5 %SO2 ,0 0 5 2 %NO ,0 2 0 8%CO和空速 30 0 0h 1的条件下 ,NO转化率接近 10 0 % ,SO2 转化率为 88% ,S和N2 的选择性都接近10 0 % ,反应过程中没有剧毒气体COS生成 .对于SO2 +CO反应 ,该样品也显示了极高的活性 ,在 35 0℃ ,0 10 5 %SO2 ,0 2 0 8%CO和空速 30 0 0h-1的条件下 ,SO2 转化率达 98% ,S的选择性近 10 0 % .但该催化剂对NO +CO反应的催化活性不高 ,在 35 0℃ ,0 10 2 5 %NO ,0 2 0 8%CO ,空速 30 0 0h-1的条件下 ,NO的转化率仅为 5 0 % .上述结果表明 ,SO2 对NO +CO反应具有促进作用 .单独的SnO2 或TiO2 对SO2 +CO ,NO +CO或SO2 +NO +CO反应的催化活性都很低 ,但SnO2 和TiO2 形成SnO2 TiO2 固溶体后催化活性显著增大 ,说明SnO2 和TiO2

A novel highly active SnO 2-TiO 2 solid solution catalyst for the simultaneous reduction of SO 2 and NO by CO to produce S and N 2 has been prepared by coprecipitation. Over the SnO 2-TiO 2 catalyst with a SnO 2 content of 50% (mole fraction), under the reaction conditions of 350 ℃, 0.052?5% SO 2, 0.052% NO, 0.208% CO and space velocity of 3?000 h -1, the NO conversion is nearly 100%, the SO 2 conversion is 88% and the selectivity for S and N 2 is both nearly 100%. In the whole reaction process no COS, a high toxic gas, was formed. The catalyst also shows high activity for the reduction of SO 2 alone by CO, at 350 ℃, 0.105% SO 2, 0.208% CO and 3?000 h -1, the conversion of SO 2 is 98% and the selectivity for S is nearly 100%. But for the NO reduction by CO, the catalyst activity is rather low, at 350 ℃, 0.102?5%NO, 0.208%CO and 3?000 h -1, the conversion of NO is 50%. Therefore, SO 2 shows promotion effect on the reduction of NO by CO over SnO 2-TiO 2. For SO 2+CO, NO+CO or SO 2+NO+CO reactions the catalytic activity of pure SnO 2 or TiO 2 is very low, but the activity of SnO 2-TiO 2 is very high. This suggests that there is synergism between SnO 2 and TiO 2.