| 摘要 |
PROBLEM TO BE SOLVED: To restrain a high cleaning ratio of NOx which is practically allowable even after endurance at a high temperature in purifying exhaust gas containing sulfur oxide in an oxygen surplus atmosphere. SOLUTION: The above exhaust gas is brought into contact with a catalyst for cleaning exhaust gas with at least one kind of metal selected from rare earth metals, and at least one kind of metal selected from transition metals such as Fe, Ni, Co and Mn carried together with noble metals. The two or more carried metals take SO2 contained in the exhaust gas into the catalyst as multiple sulfate. The multiple sulfate produced in this way is easy to be decomposed at a low temperature in a stoichiometrically enriched atmosphere compared with the case of sulfate produced by a single metal, so that the effect of occluding NOx in rare earth metals can be given once more. |
