The reduction of sulphur dioxide by carbon monoxide on a La0.5Sr0.5CoO3 catalyst

The semiconducting perovskite oxide, La0.5Sr0.5CoO3, is a catalyst for the reduction of sulphur dioxide by carbon monoxide. Unlike aluminia‐supported metal catalysts, La0.5Sr0.5CoO3 tolerates high levels of oxygen in the gas stream if sufficient carbon monoxide is present to react with all the oxygen. Water vapour (2%) does not adversely affect the reaction; unwanted byproducts H2S and COS are reduced for contact times less than 0.25 s. A computer model is used to predict equilibrium gas compositions for systems containing oxygen and water vapour. During the reaction the catalyst itself reacts with sulphur producing metal sulphides, possibly of simple cubic structure. The perovskite sulphides LaCoS3 and La0.5Sr0.5CoS3 are theoretically unstable.