Reduction of sulfur dioxide with carbon monoxide over sulfurized LaCoO3 in the presence of oxygen

The catalytic reduction of SO2 with CO to elemental sulfur was considered to be the best way to get rid Of SO2 from flue gas. However, the catalyst can be poisoned by oxygen in the flue gas. In this study, with pre-poisoned by SO2, activated by O-2-CO and then sulfurized by SO2-O-2-CO, the perovskite LaCoO3 had excellent performance in the catalytic reduction Of SO2 With CO to elemental sulfur in the presence of 2% O-2 ( X (SO2) = 97%, Y (s) = 95% at 500 degreesC) . The XRD result revealed that the perovskite structure of LaCoO3 was unchanged after activation-sulfurization, but new phases La2O2S and Co3O4 appeared. For the perovskite LaCoO3 samples before and after activation-sulfurization, the experiments of SO2-TPD, O-2-TPD, and CO combustion in the presence of SO2 showed that the activation-sulfurization of LaCoO3 can inhibit the formation of sulfate. At certain temperature, CO on the perovskite phase can combust with O-2 quickly, at the same time SO2 on La2O2S phase can be reduced by CO, and the two reactions can be stimulated each other.