含氧气氛下预硫化钙钛矿LaCoO_3上的CO还原SO_2反应

Reduction of Sulfur Dioxide with Carbon Monoxide over Sulfurized LaCoO_3 in the Presence of Oxygen

对钙钛矿LaCoO3 在含氧气氛下的预硫化过程进行了研究 .结果表明 ,在一定含氧气氛下硫化后的LaCoO3 催化剂 ,用于含氧气氛下CO还原SO2 反应具有很高的活性 .XRD物相分析结果表明 ,硫化后的LaCoO3 仍保持钙钛矿物相结构 ,但同时出现新的硫化物La2 O2 S和氧化物Co3 O4物相 .通过对硫化前后的催化剂进行O2 TPD和SO2 TPD分析 ,认为CO还原SO2反应机理可能是在一定的温度下 ,在钙钛矿LaCoO3 上发生CO氧化燃烧反应 ,在硫化物La2 O2 S上发生CO还原SO2 反应 。

The catalytic reduction of SO 2 with CO to elemental sulfur was considered to be the best way to get rid of SO 2 from flue gas. However, the catalyst can be poisoned by oxygen in the flue gas. In this study, with pre poisoned by SO 2, activated by O 2 CO and then sulfurized by SO 2 O 2 CO, the perovskite LaCoO 3 had excellent performance in the catalytic reduction of SO 2 with CO to elemental sulfur in the presence of 2%O 2( X (SO 2) =97%, Y (S) =95% at 500 ℃). The XRD result revealed that the perovskite structure of LaCoO 3 was unchanged after activation sulfurization, but new phases La 2O 2S and Co 3O 4 appeared. For the perovskite LaCoO 3 samples before and after activation sulfurization, the experiments of SO 2 TPD, O 2 TPD, and CO combustion in the presence of SO 2 showed that the activation sulfurization of LaCoO 3 can inhibit the formation of sulfate. At certain temperature, CO on the perovskite phase can combust with O 2 quickly, at the same time SO 2 on La 2O 2S phase can be reduced by CO, and the two reactions can be stimulated each other.