On the synergism between La2O2S and CoS2 in the reduction of SO2 to elemental sulfur by CO

In our study of the catalytic reduction of SO2 to elemental sulfur by CO in the presence of La2O2S and CoS2, a synergistic effect between the two sulfides was observed which not only increased the catalytic activity but also suppressed the formation of the side-product COS. It was also found that the crystal phase of CoS2, which can be easily reduced by CO, could be retained when La2O2S coexisted even in small quantities. A mechanism was proposed based on the COS intermediate mechanism and the remote control concept. (C) 1996 Academic Press, Inc